Add files

src/renderer/components/create-torrent-error-page.js

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+const React = require('react')
+
+const { dispatcher } = require('../lib/dispatcher')
+
+module.exports = class CreateTorrentErrorPage extends React.Component {
+  render () {
+    return (
+      <div className='create-torrent'>
+        <h2>Create torrent</h2>
+        <p className='torrent-info'>
+          <p>
+            Sorry, you must select at least one file that is not a hidden file.
+          </p>
+          <p>
+            Hidden files, starting with a . character, are not included.
+          </p>
+        </p>
+        <p className='float-right'>
+          <button className='button-flat light' onClick={dispatcher('cancel')}>
+            Cancel
+          </button>
+        </p>
+      </div>
+    )
+  }
+}

src/renderer/components/delete-all-torrents-modal.js

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+const React = require('react')
+
+const ModalOKCancel = require('./modal-ok-cancel')
+const { dispatch, dispatcher } = require('../lib/dispatcher')
+
+module.exports = class DeleteAllTorrentsModal extends React.Component {
+  render () {
+    const { state: { modal: { deleteData } } } = this.props
+    const message = deleteData
+      ? 'Are you sure you want to remove all the torrents from the list and delete the data files?'
+      : 'Are you sure you want to remove all the torrents from the list?'
+    const buttonText = deleteData ? 'REMOVE DATA' : 'REMOVE'
+
+    return (
+      <div>
+        <p><strong>{message}</strong></p>
+        <ModalOKCancel
+          cancelText='CANCEL'
+          onCancel={dispatcher('exitModal')}
+          okText={buttonText}
+          onOK={handleRemove}
+        />
+      </div>
+    )
+
+    function handleRemove () {
+      dispatch('deleteAllTorrents', deleteData)
+      dispatch('exitModal')
+    }
+  }
+}

src/renderer/components/header.js

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+const React = require('react')
+
+const { dispatcher } = require('../lib/dispatcher')
+
+class Header extends React.Component {
+  render () {
+    const loc = this.props.state.location
+    return (
+      <div
+        className='header'
+        onMouseMove={dispatcher('mediaMouseMoved')}
+        onMouseEnter={dispatcher('mediaControlsMouseEnter')}
+        onMouseLeave={dispatcher('mediaControlsMouseLeave')}
+        role='navigation'
+      >
+        {this.getTitle()}
+        <div className='nav left float-left'>
+          <i
+            className={'icon back ' + (loc.hasBack() ? '' : 'disabled')}
+            title='Back'
+            onClick={dispatcher('back')}
+            role='button'
+            aria-disabled={!loc.hasBack()}
+            aria-label='Back'
+          >
+            chevron_left
+          </i>
+          <i
+            className={'icon forward ' + (loc.hasForward() ? '' : 'disabled')}
+            title='Forward'
+            onClick={dispatcher('forward')}
+            role='button'
+            aria-disabled={!loc.hasForward()}
+            aria-label='Forward'
+          >
+            chevron_right
+          </i>
+        </div>
+        <div className='nav right float-right'>
+          {this.getAddButton()}
+        </div>
+      </div>
+    )
+  }
+
+  getTitle () {
+    if (process.platform !== 'darwin') return null
+    const state = this.props.state
+    return (<div className='title ellipsis'>{state.window.title}</div>)
+  }
+
+  getAddButton () {
+    const state = this.props.state
+    if (state.location.url() !== 'home') return null
+    return (
+      <i
+        className='icon add'
+        title='Add torrent'
+        onClick={dispatcher('openFiles')}
+        role='button'
+      >
+        add
+      </i>
+    )
+  }
+}
+
+module.exports = Header

src/renderer/components/heading.js

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+const React = require('react')
+const PropTypes = require('prop-types')
+
+const colors = require('material-ui/styles/colors')
+
+class Heading extends React.Component {
+  static get propTypes () {
+    return {
+      level: PropTypes.number
+    }
+  }
+
+  static get defaultProps () {
+    return {
+      level: 1
+    }
+  }
+
+  render () {
+    const HeadingTag = 'h' + this.props.level
+    const style = {
+      color: colors.grey100,
+      fontSize: 20,
+      marginBottom: 15,
+      marginTop: 30
+    }
+    return (
+      <HeadingTag style={style}>
+        {this.props.children}
+      </HeadingTag>
+    )
+  }
+}
+
+module.exports = Heading

src/renderer/components/modal-ok-cancel.js

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+const React = require('react')
+const FlatButton = require('material-ui/FlatButton').default
+const RaisedButton = require('material-ui/RaisedButton').default
+
+module.exports = class ModalOKCancel extends React.Component {
+  render () {
+    const cancelStyle = { marginRight: 10, color: 'black' }
+    const { cancelText, onCancel, okText, onOK } = this.props
+    return (
+      <div className='float-right'>
+        <FlatButton
+          className='control cancel'
+          style={cancelStyle}
+          label={cancelText}
+          onClick={onCancel}
+        />
+        <RaisedButton
+          className='control ok'
+          primary
+          label={okText}
+          onClick={onOK}
+          autoFocus
+        />
+      </div>
+    )
+  }
+}

src/renderer/components/open-torrent-address-modal.js

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+const React = require('react')
+const TextField = require('material-ui/TextField').default
+const { clipboard } = require('electron')
+
+const ModalOKCancel = require('./modal-ok-cancel')
+const { dispatch, dispatcher } = require('../lib/dispatcher')
+const { isMagnetLink } = require('../lib/torrent-player')
+
+module.exports = class OpenTorrentAddressModal extends React.Component {
+  render () {
+    return (
+      <div className='open-torrent-address-modal'>
+        <p><label>Enter torrent address or magnet link</label></p>
+        <div>
+          <TextField
+            id='torrent-address-field'
+            className='control'
+            ref={(c) => { this.torrentURL = c }}
+            fullWidth
+            onKeyDown={handleKeyDown.bind(this)}
+          />
+        </div>
+        <ModalOKCancel
+          cancelText='CANCEL'
+          onCancel={dispatcher('exitModal')}
+          okText='OK'
+          onOK={handleOK.bind(this)}
+        />
+      </div>
+    )
+  }
+
+  componentDidMount () {
+    this.torrentURL.input.focus()
+    const clipboardContent = clipboard.readText()
+
+    if (isMagnetLink(clipboardContent)) {
+      this.torrentURL.input.value = clipboardContent
+      this.torrentURL.input.select()
+    }
+  }
+}
+
+function handleKeyDown (e) {
+  if (e.which === 13) handleOK.call(this) /* hit Enter to submit */
+}
+
+function handleOK () {
+  dispatch('exitModal')
+  dispatch('addTorrent', this.torrentURL.input.value)
+}

src/renderer/components/path-selector.js

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+const path = require('path')
+
+const colors = require('material-ui/styles/colors')
+const remote = require('@electron/remote')
+const React = require('react')
+const PropTypes = require('prop-types')
+
+const RaisedButton = require('material-ui/RaisedButton').default
+const TextField = require('material-ui/TextField').default
+
+// Lets you pick a file or directory.
+// Uses the system Open File dialog.
+// You can't edit the text field directly.
+class PathSelector extends React.Component {
+  static propTypes () {
+    return {
+      className: PropTypes.string,
+      dialog: PropTypes.object,
+      id: PropTypes.string,
+      onChange: PropTypes.func,
+      title: PropTypes.string.isRequired,
+      value: PropTypes.string
+    }
+  }
+
+  constructor (props) {
+    super(props)
+    this.handleClick = this.handleClick.bind(this)
+  }
+
+  handleClick () {
+    const opts = Object.assign({
+      defaultPath: path.dirname(this.props.value || ''),
+      properties: ['openFile', 'openDirectory']
+    }, this.props.dialog)
+
+    const filenames = remote.dialog.showOpenDialogSync(remote.getCurrentWindow(), opts)
+    if (!Array.isArray(filenames)) return
+    this.props.onChange && this.props.onChange(filenames[0])
+  }
+
+  render () {
+    const id = this.props.title.replace(' ', '-').toLowerCase()
+    const wrapperStyle = {
+      alignItems: 'center',
+      display: 'flex',
+      width: '100%'
+    }
+    const labelStyle = {
+      flex: '0 auto',
+      marginRight: 10,
+      overflow: 'hidden',
+      textOverflow: 'ellipsis',
+      whiteSpace: 'nowrap'
+    }
+    const textareaStyle = {
+      color: colors.grey50
+    }
+    const textFieldStyle = {
+      flex: '1'
+    }
+    const text = this.props.value || ''
+    const buttonStyle = {
+      marginLeft: 10
+    }
+
+    return (
+      <div className={this.props.className} style={wrapperStyle}>
+        <div className='label' style={labelStyle}>
+          {this.props.title}:
+        </div>
+        <TextField
+          className='control' disabled id={id} value={text}
+          inputStyle={textareaStyle} style={textFieldStyle}
+        />
+        <RaisedButton
+          className='control' label='Change' onClick={this.handleClick}
+          style={buttonStyle}
+        />
+      </div>
+    )
+  }
+}
+
+module.exports = PathSelector

src/renderer/components/remove-torrent-modal.js

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+const React = require('react')
+
+const ModalOKCancel = require('./modal-ok-cancel')
+const { dispatch, dispatcher } = require('../lib/dispatcher')
+
+module.exports = class RemoveTorrentModal extends React.Component {
+  render () {
+    const state = this.props.state
+    const message = state.modal.deleteData
+      ? 'Are you sure you want to remove this torrent from the list and delete the data file?'
+      : 'Are you sure you want to remove this torrent from the list?'
+    const buttonText = state.modal.deleteData ? 'REMOVE DATA' : 'REMOVE'
+
+    return (
+      <div>
+        <p><strong>{message}</strong></p>
+        <ModalOKCancel
+          cancelText='CANCEL'
+          onCancel={dispatcher('exitModal')}
+          okText={buttonText}
+          onOK={handleRemove}
+        />
+      </div>
+    )
+
+    function handleRemove () {
+      dispatch('deleteTorrent', state.modal.infoHash, state.modal.deleteData)
+      dispatch('exitModal')
+    }
+  }
+}

src/renderer/components/show-more.js

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+const React = require('react')
+const PropTypes = require('prop-types')
+
+const RaisedButton = require('material-ui/RaisedButton').default
+
+class ShowMore extends React.Component {
+  static get propTypes () {
+    return {
+      defaultExpanded: PropTypes.bool,
+      hideLabel: PropTypes.string,
+      showLabel: PropTypes.string
+    }
+  }
+
+  static get defaultProps () {
+    return {
+      hideLabel: 'Hide more...',
+      showLabel: 'Show more...'
+    }
+  }
+
+  constructor (props) {
+    super(props)
+
+    this.state = {
+      expanded: !!this.props.defaultExpanded
+    }
+
+    this.handleClick = this.handleClick.bind(this)
+  }
+
+  handleClick () {
+    this.setState({
+      expanded: !this.state.expanded
+    })
+  }
+
+  render () {
+    const label = this.state.expanded
+      ? this.props.hideLabel
+      : this.props.showLabel
+    return (
+      <div className='show-more' style={this.props.style}>
+        {this.state.expanded ? this.props.children : null}
+        <RaisedButton
+          className='control'
+          onClick={this.handleClick}
+          label={label}
+        />
+      </div>
+    )
+  }
+}
+
+module.exports = ShowMore

src/renderer/components/unsupported-media-modal.js

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+const React = require('react')
+const { shell } = require('electron')
+
+const ModalOKCancel = require('./modal-ok-cancel')
+const { dispatcher } = require('../lib/dispatcher')
+
+module.exports = class UnsupportedMediaModal extends React.Component {
+  render () {
+    const state = this.props.state
+    const err = state.modal.error
+    const message = (err && err.getMessage)
+      ? err.getMessage()
+      : err
+    const onAction = state.modal.externalPlayerInstalled
+      ? dispatcher('openExternalPlayer')
+      : () => this.onInstall()
+    const actionText = state.modal.externalPlayerInstalled
+      ? 'PLAY IN ' + state.getExternalPlayerName().toUpperCase()
+      : 'INSTALL VLC'
+    const errorMessage = state.modal.externalPlayerNotFound
+      ? 'Couldn\'t run external player. Please make sure it\'s installed.'
+      : ''
+    return (
+      <div>
+        <p><strong>Sorry, we can't play that file.</strong></p>
+        <p>{message}</p>
+        <ModalOKCancel
+          cancelText='CANCEL'
+          onCancel={dispatcher('backToList')}
+          okText={actionText}
+          onOK={onAction}
+        />
+        <p className='error-text'>{errorMessage}</p>
+      </div>
+    )
+  }
+
+  onInstall () {
+    shell.openExternal('https://www.videolan.org/vlc/')
+
+    // TODO: dcposch send a dispatch rather than modifying state directly
+    const state = this.props.state
+    state.modal.externalPlayerInstalled = true // Assume they'll install it successfully
+  }
+}

src/renderer/components/update-available-modal.js

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+const React = require('react')
+const { shell } = require('electron')
+
+const ModalOKCancel = require('./modal-ok-cancel')
+const { dispatch } = require('../lib/dispatcher')
+
+module.exports = class UpdateAvailableModal extends React.Component {
+  render () {
+    const state = this.props.state
+    return (
+      <div className='update-available-modal'>
+        <p><strong>A new version of WebTorrent is available: v{state.modal.version}</strong></p>
+        <p>
+          We have an auto-updater for Windows and Mac.
+          We don't have one for Linux yet, so you'll have to download the new version manually.
+        </p>
+        <ModalOKCancel
+          cancelText='SKIP THIS RELEASE'
+          onCancel={handleSkip}
+          okText='SHOW DOWNLOAD PAGE'
+          onOK={handleShow}
+        />
+      </div>
+    )
+
+    function handleShow () {
+      // TODO: use the GitHub urls from config.js
+      shell.openExternal('https://github.com/leenkx/leenkxbox/releases')
+      dispatch('exitModal')
+    }
+
+    function handleSkip () {
+      dispatch('skipVersion', state.modal.version)
+      dispatch('exitModal')
+    }
+  }
+}

src/renderer/controllers/audio-tracks-controller.js

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+const { dispatch } = require('../lib/dispatcher')
+
+module.exports = class AudioTracksController {
+  constructor (state) {
+    this.state = state
+  }
+
+  selectAudioTrack (ix) {
+    this.state.playing.audioTracks.selectedIndex = ix
+    dispatch('skip', 0.2) // HACK: hardcoded seek value for smooth audio change
+  }
+
+  toggleAudioTracksMenu () {
+    const audioTracks = this.state.playing.audioTracks
+    audioTracks.showMenu = !audioTracks.showMenu
+  }
+}

src/renderer/controllers/folder-watcher-controller.js

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+const { ipcRenderer } = require('electron')
+
+module.exports = class FolderWatcherController {
+  start () {
+    console.log('-- IPC: start folder watcher')
+    ipcRenderer.send('startFolderWatcher')
+  }
+
+  stop () {
+    console.log('-- IPC: stop folder watcher')
+    ipcRenderer.send('stopFolderWatcher')
+  }
+}

src/renderer/controllers/media-controller.js

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+const { ipcRenderer } = require('electron')
+const telemetry = require('../lib/telemetry')
+const Playlist = require('../lib/playlist')
+
+// Controls local play back: the <video>/<audio> tag and VLC
+// Does not control remote casting (Chromecast etc)
+module.exports = class MediaController {
+  constructor (state) {
+    this.state = state
+  }
+
+  mediaSuccess () {
+    telemetry.logPlayAttempt('success')
+  }
+
+  mediaStalled () {
+    this.state.playing.isStalled = true
+  }
+
+  mediaError (error) {
+    const state = this.state
+    if (state.location.url() === 'player') {
+      telemetry.logPlayAttempt('error')
+      state.playing.location = 'error'
+      ipcRenderer.send('checkForExternalPlayer', state.saved.prefs.externalPlayerPath)
+      ipcRenderer.once('checkForExternalPlayer', (e, isInstalled) => {
+        state.modal = {
+          id: 'unsupported-media-modal',
+          error,
+          externalPlayerInstalled: isInstalled
+        }
+      })
+    }
+  }
+
+  mediaTimeUpdate () {
+    this.state.playing.lastTimeUpdate = new Date().getTime()
+    this.state.playing.isStalled = false
+  }
+
+  mediaMouseMoved () {
+    this.state.playing.mouseStationarySince = new Date().getTime()
+  }
+
+  controlsMouseEnter () {
+    this.state.playing.mouseInControls = true
+    this.state.playing.mouseStationarySince = new Date().getTime()
+  }
+
+  controlsMouseLeave () {
+    this.state.playing.mouseInControls = false
+    this.state.playing.mouseStationarySince = new Date().getTime()
+  }
+
+  openExternalPlayer () {
+    const state = this.state
+    state.playing.location = 'external'
+
+    const onServerRunning = () => {
+      state.playing.isReady = true
+      telemetry.logPlayAttempt('external')
+
+      const mediaURL = Playlist.getCurrentLocalURL(state)
+      ipcRenderer.send('openExternalPlayer',
+        state.saved.prefs.externalPlayerPath,
+        mediaURL,
+        state.window.title)
+    }
+
+    if (state.server != null) onServerRunning()
+    else ipcRenderer.once('wt-server-running', onServerRunning)
+  }
+
+  externalPlayerNotFound () {
+    const modal = this.state.modal
+    if (modal && modal.id === 'unsupported-media-modal') {
+      modal.externalPlayerNotFound = true
+    }
+  }
+}

src/renderer/controllers/playback-controller.js

@@ -0,0 +1,395 @@
+const { ipcRenderer } = require('electron')
+const path = require('path')
+
+const Cast = require('../lib/cast')
+const { dispatch } = require('../lib/dispatcher')
+const telemetry = require('../lib/telemetry')
+const { UnplayableFileError, UnplayableTorrentError } = require('../lib/errors')
+const sound = require('../lib/sound')
+const TorrentPlayer = require('../lib/torrent-player')
+const TorrentSummary = require('../lib/torrent-summary')
+const Playlist = require('../lib/playlist')
+const State = require('../lib/state')
+
+// Controls playback of torrents and files within torrents
+// both local (<video>,<audio>,external player) and remote (cast)
+module.exports = class PlaybackController {
+  constructor (state, config, update) {
+    this.state = state
+    this.config = config
+    this.update = update
+  }
+
+  // Play a file in a torrent.
+  // * Start torrenting, if necessary
+  // * Stream, if not already fully downloaded
+  // * If no file index is provided, restore the most recently viewed file or autoplay the first
+  playFile (infoHash, index /* optional */) {
+    this.pauseActiveTorrents(infoHash)
+
+    const state = this.state
+    if (state.location.url() === 'player') {
+      this.updatePlayer(infoHash, index, false, (err) => {
+        if (err) dispatch('error', err)
+        else this.play()
+      })
+    } else {
+      let initialized = false
+      state.location.go({
+        url: 'player',
+        setup: (cb) => {
+          const torrentSummary = TorrentSummary.getByKey(state, infoHash)
+
+          if (index === undefined || initialized) index = torrentSummary.mostRecentFileIndex
+          if (index === undefined) index = torrentSummary.files.findIndex(TorrentPlayer.isPlayable)
+          if (index === undefined) return cb(new UnplayableTorrentError())
+
+          initialized = true
+
+          this.openPlayer(infoHash, index, (err) => {
+            if (!err) this.play()
+            cb(err)
+          })
+        },
+        destroy: () => this.closePlayer()
+      }, (err) => {
+        if (err) dispatch('error', err)
+      })
+    }
+  }
+
+  // Open a file in OS default app.
+  openPath (infoHash, index) {
+    const torrentSummary = TorrentSummary.getByKey(this.state, infoHash)
+    const filePath = path.join(
+      torrentSummary.path,
+      torrentSummary.files[index].path)
+    ipcRenderer.send('openPath', filePath)
+  }
+
+  // Toggle (play or pause) the currently playing media
+  playPause () {
+    const state = this.state
+    if (state.location.url() !== 'player') return
+
+    // force rerendering if window is hidden,
+    // in order to bypass `raf` and play/pause media immediately
+    const mediaTag = document.querySelector('video,audio')
+    if (!state.window.isVisible && mediaTag) {
+      if (state.playing.isPaused) mediaTag.play()
+      else mediaTag.pause()
+    }
+
+    if (state.playing.isPaused) this.play()
+    else this.pause()
+  }
+
+  pauseActiveTorrents (infoHash) {
+    // Playback Priority: pause all active torrents if needed.
+    if (!this.state.saved.prefs.highestPlaybackPriority) return
+
+    // Do not pause active torrents if playing a fully downloaded torrent.
+    const torrentSummary = TorrentSummary.getByKey(this.state, infoHash)
+    if (torrentSummary.status === 'seeding') return
+
+    dispatch('prioritizeTorrent', infoHash)
+  }
+
+  // Play next file in list (if any)
+  nextTrack () {
+    const state = this.state
+    if (Playlist.hasNext(state) && state.playing.location !== 'external') {
+      this.updatePlayer(
+        state.playing.infoHash, Playlist.getNextIndex(state), false, (err) => {
+          if (err) dispatch('error', err)
+          else this.play()
+        })
+    }
+  }
+
+  // Play previous track in list (if any)
+  previousTrack () {
+    const state = this.state
+    if (Playlist.hasPrevious(state) && state.playing.location !== 'external') {
+      this.updatePlayer(
+        state.playing.infoHash, Playlist.getPreviousIndex(state), false, (err) => {
+          if (err) dispatch('error', err)
+          else this.play()
+        })
+    }
+  }
+
+  // Play (unpause) the current media
+  play () {
+    const state = this.state
+    if (!state.playing.isPaused) return
+    state.playing.isPaused = false
+    if (isCasting(state)) {
+      Cast.play()
+    }
+    ipcRenderer.send('onPlayerPlay')
+  }
+
+  // Pause the currently playing media
+  pause () {
+    const state = this.state
+    if (state.playing.isPaused) return
+    state.playing.isPaused = true
+    if (isCasting(state)) {
+      Cast.pause()
+    }
+    ipcRenderer.send('onPlayerPause')
+  }
+
+  // Skip specified number of seconds (backwards if negative)
+  skip (time) {
+    this.skipTo(this.state.playing.currentTime + time)
+  }
+
+  // Skip (aka seek) to a specific point, in seconds
+  skipTo (time) {
+    if (!Number.isFinite(time)) {
+      console.error('Tried to skip to a non-finite time ' + time)
+      return console.trace()
+    }
+    if (isCasting(this.state)) Cast.seek(time)
+    else this.state.playing.jumpToTime = time
+  }
+
+  // Show video preview
+  preview (x) {
+    if (!Number.isFinite(x)) {
+      console.error('Tried to preview a non-finite position ' + x)
+      return console.trace()
+    }
+    this.state.playing.previewXCoord = x
+  }
+
+  // Hide video preview
+  clearPreview () {
+    this.state.playing.previewXCoord = null
+  }
+
+  // Change playback speed. 1 = faster, -1 = slower
+  // Playback speed ranges from 16 (fast forward) to 1 (normal playback)
+  // to 0.25 (quarter-speed playback), then goes to -0.25, -0.5, -1, -2, etc
+  // until -16 (fast rewind)
+  changePlaybackRate (direction) {
+    const state = this.state
+    let rate = state.playing.playbackRate
+    if (direction > 0 && rate < 2) {
+      rate += 0.25
+    } else if (direction < 0 && rate > 0.25 && rate <= 2) {
+      rate -= 0.25
+    } else if (direction > 0 && rate >= 1 && rate < 16) {
+      rate *= 2
+    } else if (direction < 0 && rate > 1 && rate <= 16) {
+      rate /= 2
+    }
+    state.playing.playbackRate = rate
+    if (isCasting(state) && !Cast.setRate(rate)) {
+      state.playing.playbackRate = 1
+    }
+    // Wait a bit before we hide the controls and header again
+    state.playing.mouseStationarySince = new Date().getTime()
+  }
+
+  // Change the volume, in range [0, 1], by some amount
+  // For example, volume muted (0), changeVolume (0.3) increases to 30% volume
+  changeVolume (delta) {
+    // change volume with delta value
+    this.setVolume(this.state.playing.volume + delta)
+  }
+
+  // Set the volume to some value in [0, 1]
+  setVolume (volume) {
+    // check if its in [0.0 - 1.0] range
+    volume = Math.max(0, Math.min(1, volume))
+
+    const state = this.state
+    if (isCasting(state)) {
+      Cast.setVolume(volume)
+    } else {
+      state.playing.setVolume = volume
+    }
+  }
+
+  // Hide player controls while playing video, if the mouse stays still for a while
+  // Never hide the controls when:
+  // * The mouse is over the controls or we're scrubbing (see CSS)
+  // * The video is paused
+  // * The video is playing remotely on Chromecast or Airplay
+  showOrHidePlayerControls () {
+    const state = this.state
+    const hideControls = state.shouldHidePlayerControls()
+
+    if (hideControls !== state.playing.hideControls) {
+      state.playing.hideControls = hideControls
+      return true
+    }
+    return false
+  }
+
+  // Opens the video player to a specific torrent
+  openPlayer (infoHash, index, cb) {
+    const state = this.state
+    const torrentSummary = TorrentSummary.getByKey(state, infoHash)
+
+    state.playing.infoHash = torrentSummary.infoHash
+    state.playing.isReady = false
+
+    // update UI to show pending playback
+    sound.play('PLAY')
+
+    this.startServer(torrentSummary)
+    ipcRenderer.send('onPlayerOpen')
+    this.updatePlayer(infoHash, index, true, cb)
+  }
+
+  // Starts WebTorrent server for media streaming
+  startServer (torrentSummary) {
+    const state = this.state
+
+    if (torrentSummary.status === 'paused') {
+      dispatch('startTorrentingSummary', torrentSummary.torrentKey)
+      ipcRenderer.once('wt-ready-' + torrentSummary.infoHash,
+        () => onTorrentReady())
+    } else {
+      onTorrentReady()
+    }
+
+    function onTorrentReady () {
+      ipcRenderer.send('wt-start-server', torrentSummary.infoHash)
+      ipcRenderer.once('wt-server-running', () => { state.playing.isReady = true })
+    }
+  }
+
+  // Called each time the current file changes
+  updatePlayer (infoHash, index, resume, cb) {
+    const state = this.state
+
+    const torrentSummary = TorrentSummary.getByKey(state, infoHash)
+    const fileSummary = torrentSummary.files[index]
+
+    if (!TorrentPlayer.isPlayable(fileSummary)) {
+      torrentSummary.mostRecentFileIndex = undefined
+      return cb(new UnplayableFileError())
+    }
+
+    torrentSummary.mostRecentFileIndex = index
+
+    // update state
+    state.playing.infoHash = infoHash
+    state.playing.fileIndex = index
+    state.playing.fileName = fileSummary.name
+    state.playing.type = TorrentPlayer.isVideo(fileSummary)
+      ? 'video'
+      : TorrentPlayer.isAudio(fileSummary)
+        ? 'audio'
+        : 'other'
+
+    // pick up where we left off
+    let jumpToTime = 0
+    if (resume && fileSummary.currentTime) {
+      const fraction = fileSummary.currentTime / fileSummary.duration
+      const secondsLeft = fileSummary.duration - fileSummary.currentTime
+      if (fraction < 0.9 && secondsLeft > 10) {
+        jumpToTime = fileSummary.currentTime
+      }
+    }
+    state.playing.jumpToTime = jumpToTime
+
+    // if it's audio, parse out the metadata (artist, title, etc)
+    if (torrentSummary.status === 'paused') {
+      ipcRenderer.once('wt-ready-' + torrentSummary.infoHash, getAudioMetadata)
+    } else {
+      getAudioMetadata()
+    }
+
+    function getAudioMetadata () {
+      if (state.playing.type === 'audio') {
+        ipcRenderer.send('wt-get-audio-metadata', torrentSummary.infoHash, index)
+      }
+    }
+
+    // if it's video, check for subtitles files that are done downloading
+    dispatch('checkForSubtitles')
+
+    // enable previously selected subtitle track
+    if (fileSummary.selectedSubtitle) {
+      dispatch('addSubtitles', [fileSummary.selectedSubtitle], true)
+    }
+
+    state.window.title = fileSummary.name
+
+    // play in VLC if set as default player (Preferences / Playback / Play in VLC)
+    if (this.state.saved.prefs.openExternalPlayer) {
+      dispatch('openExternalPlayer')
+      this.update()
+      cb()
+      return
+    }
+
+    // otherwise, play the video
+    this.update()
+
+    ipcRenderer.send('onPlayerUpdate', Playlist.hasNext(state), Playlist.hasPrevious(state))
+    cb()
+  }
+
+  closePlayer () {
+    console.log('closePlayer')
+
+    // Quit any external players, like Chromecast/Airplay/etc or VLC
+    const state = this.state
+    if (isCasting(state)) {
+      Cast.stop()
+    }
+    if (state.playing.location === 'external') {
+      ipcRenderer.send('quitExternalPlayer')
+    }
+
+    // Save volume (this session only, not in state.saved)
+    state.previousVolume = state.playing.volume
+
+    if (!state.playing.isReady) telemetry.logPlayAttempt('abandoned') // user gave up waiting
+
+    // Reset the window contents back to the home screen
+    state.playing = State.getDefaultPlayState()
+    state.server = null
+
+    // Reset the window size and location back to where it was
+    if (state.window.isFullScreen) {
+      dispatch('toggleFullScreen', false)
+    }
+    restoreBounds(state)
+
+    // Tell the WebTorrent process to kill the torrent-to-HTTP server
+    ipcRenderer.send('wt-stop-server')
+
+    ipcRenderer.send('onPlayerClose')
+
+    // Playback Priority: resume previously paused downloads.
+    if (this.state.saved.prefs.highestPlaybackPriority) {
+      dispatch('resumePausedTorrents')
+    }
+
+    this.update()
+  }
+}
+
+// Checks whether we are connected and already casting
+// Returns false if we not casting (state.playing.location === 'local')
+// or if we're trying to connect but haven't yet ('chromecast-pending', etc)
+function isCasting (state) {
+  return state.playing.location === 'chromecast' ||
+    state.playing.location === 'airplay' ||
+    state.playing.location === 'dlna'
+}
+
+function restoreBounds (state) {
+  ipcRenderer.send('setAspectRatio', 0)
+  if (state.window.bounds) {
+    ipcRenderer.send('setBounds', state.window.bounds, false)
+  }
+}

src/renderer/controllers/prefs-controller.js

@@ -0,0 +1,38 @@
+const { dispatch } = require('../lib/dispatcher')
+const { ipcRenderer } = require('electron')
+
+// Controls the Preferences screen
+module.exports = class PrefsController {
+  constructor (state, config) {
+    this.state = state
+    this.config = config
+  }
+
+  // Goes to the Preferences screen
+  show () {
+    const state = this.state
+    state.location.go({
+      url: 'preferences',
+      setup (cb) {
+        // initialize preferences
+        state.window.title = 'Preferences'
+        ipcRenderer.send('setAllowNav', false)
+        cb()
+      },
+      destroy: () => {
+        ipcRenderer.send('setAllowNav', true)
+      }
+    })
+  }
+
+  // Updates a single property in the saved prefs
+  // For example: updatePreferences('isFileHandler', true)
+  update (property, value) {
+    if (property === 'isFileHandler') ipcRenderer.send('setDefaultFileHandler', value)
+    else if (property === 'startup') ipcRenderer.send('setStartup', value)
+
+    this.state.saved.prefs[property] = value
+    dispatch('stateSaveImmediate')
+    dispatch('checkDownloadPath')
+  }
+}

src/renderer/controllers/subtitles-controller.js

@@ -0,0 +1,134 @@
+const remote = require('@electron/remote')
+const fs = require('fs')
+const path = require('path')
+const parallel = require('run-parallel')
+
+const { dispatch } = require('../lib/dispatcher')
+
+module.exports = class SubtitlesController {
+  constructor (state) {
+    this.state = state
+  }
+
+  openSubtitles () {
+    const filenames = remote.dialog.showOpenDialogSync({
+      title: 'Select a subtitles file.',
+      filters: [{ name: 'Subtitles', extensions: ['vtt', 'srt'] }],
+      properties: ['openFile']
+    })
+    if (!Array.isArray(filenames)) return
+    this.addSubtitles(filenames, true)
+  }
+
+  selectSubtitle (ix) {
+    this.state.playing.subtitles.selectedIndex = ix
+  }
+
+  toggleSubtitlesMenu () {
+    const subtitles = this.state.playing.subtitles
+    subtitles.showMenu = !subtitles.showMenu
+  }
+
+  addSubtitles (files, autoSelect) {
+    // Subtitles are only supported when playing video files
+    if (this.state.playing.type !== 'video') return
+    if (files.length === 0) return
+    const subtitles = this.state.playing.subtitles
+
+    // Read the files concurrently, then add all resulting subtitle tracks
+    const tasks = files.map((file) => (cb) => loadSubtitle(file, cb))
+    parallel(tasks, (err, tracks) => {
+      if (err) return dispatch('error', err)
+
+      // No dupes allowed
+      tracks.forEach((track, i) => {
+        let trackIndex = subtitles.tracks.findIndex((t) =>
+          track.filePath === t.filePath)
+
+        // Add the track
+        if (trackIndex === -1) {
+          trackIndex = subtitles.tracks.push(track) - 1
+        }
+
+        // If we're auto-selecting a track, try to find one in the user's language
+        if (autoSelect && (i === 0 || isSystemLanguage(track.language))) {
+          subtitles.selectedIndex = trackIndex
+        }
+      })
+
+      // Finally, make sure no two tracks have the same label
+      relabelSubtitles(subtitles)
+    })
+  }
+
+  checkForSubtitles () {
+    if (this.state.playing.type !== 'video') return
+    const torrentSummary = this.state.getPlayingTorrentSummary()
+    if (!torrentSummary || !torrentSummary.progress) return
+
+    torrentSummary.progress.files.forEach((fp, ix) => {
+      if (fp.numPieces !== fp.numPiecesPresent) return // ignore incomplete files
+      const file = torrentSummary.files[ix]
+      if (!this.isSubtitle(file.name)) return
+      const filePath = path.join(torrentSummary.path, file.path)
+      this.addSubtitles([filePath], false)
+    })
+  }
+
+  isSubtitle (file) {
+    const name = typeof file === 'string' ? file : file.name
+    const ext = path.extname(name).toLowerCase()
+    return ext === '.srt' || ext === '.vtt'
+  }
+}
+
+function loadSubtitle (file, cb) {
+  // Lazy load to keep startup fast
+  const concat = require('simple-concat')
+  const LanguageDetect = require('languagedetect')
+  const srtToVtt = require('srt-to-vtt')
+
+  // Read the .SRT or .VTT file, parse it, add subtitle track
+  const filePath = file.path || file
+
+  const vttStream = fs.createReadStream(filePath).pipe(srtToVtt())
+
+  concat(vttStream, (err, buf) => {
+    if (err) return dispatch('error', 'Can\'t parse subtitles file.')
+
+    // Detect what language the subtitles are in
+    const vttContents = buf.toString().replace(/(.*-->.*)/g, '')
+    let langDetected = (new LanguageDetect()).detect(vttContents, 2)
+    langDetected = langDetected.length ? langDetected[0][0] : 'subtitle'
+    langDetected = langDetected.slice(0, 1).toUpperCase() + langDetected.slice(1)
+
+    const track = {
+      buffer: 'data:text/vtt;base64,' + buf.toString('base64'),
+      language: langDetected,
+      label: langDetected,
+      filePath
+    }
+
+    cb(null, track)
+  })
+}
+
+// Checks whether a language name like 'English' or 'German' matches the system
+// language, aka the current locale
+function isSystemLanguage (language) {
+  const iso639 = require('iso-639-1')
+  const osLangISO = window.navigator.language.split('-')[0] // eg 'en'
+  const langIso = iso639.getCode(language) // eg 'de' if language is 'German'
+  return langIso === osLangISO
+}
+
+// Make sure we don't have two subtitle tracks with the same label
+// Labels each track by language, eg 'German', 'English', 'English 2', ...
+function relabelSubtitles (subtitles) {
+  const counts = {}
+  subtitles.tracks.forEach(track => {
+    const lang = track.language
+    counts[lang] = (counts[lang] || 0) + 1
+    track.label = counts[lang] > 1 ? (lang + ' ' + counts[lang]) : lang
+  })
+}

src/renderer/controllers/torrent-controller.js

@@ -0,0 +1,186 @@
+const path = require('path')
+const { ipcRenderer } = require('electron')
+
+const TorrentSummary = require('../lib/torrent-summary')
+const sound = require('../lib/sound')
+const { dispatch } = require('../lib/dispatcher')
+
+module.exports = class TorrentController {
+  constructor (state) {
+    this.state = state
+  }
+
+  torrentParsed (torrentKey, infoHash, magnetURI) {
+    let torrentSummary = this.getTorrentSummary(torrentKey)
+    console.log('got infohash for %s torrent %s',
+      torrentSummary ? 'existing' : 'new', torrentKey)
+
+    if (!torrentSummary) {
+      const torrents = this.state.saved.torrents
+
+      // Check if an existing (non-active) torrent has the same info hash
+      if (torrents.find((t) => t.infoHash === infoHash)) {
+        ipcRenderer.send('wt-stop-torrenting', infoHash)
+        return dispatch('error', 'Cannot add duplicate torrent')
+      }
+
+      torrentSummary = {
+        torrentKey,
+        status: 'new'
+      }
+      torrents.unshift(torrentSummary)
+      sound.play('ADD')
+    }
+
+    torrentSummary.infoHash = infoHash
+    torrentSummary.magnetURI = magnetURI
+    dispatch('update')
+  }
+
+  torrentWarning (torrentKey, message) {
+    console.log('warning for torrent %s: %s', torrentKey, message)
+  }
+
+  torrentError (torrentKey, message) {
+    // TODO: WebTorrent needs semantic errors
+    if (message.startsWith('Cannot add duplicate torrent')) {
+      // Remove infohash from the message
+      message = 'Cannot add duplicate torrent'
+    }
+    dispatch('error', message)
+
+    const torrentSummary = this.getTorrentSummary(torrentKey)
+    if (torrentSummary) {
+      console.log('Pausing torrent %s due to error: %s', torrentSummary.infoHash, message)
+      torrentSummary.status = 'paused'
+      dispatch('update')
+    }
+  }
+
+  torrentMetadata (torrentKey, torrentInfo) {
+    // Summarize torrent
+    const torrentSummary = this.getTorrentSummary(torrentKey)
+    torrentSummary.status = 'downloading'
+    torrentSummary.name = torrentSummary.displayName || torrentInfo.name
+    torrentSummary.path = torrentInfo.path
+    // TODO: make torrentInfo immutable, save separately as torrentSummary.info
+    // For now, check whether torrentSummary.files has already been set:
+    const hasDetailedFileInfo = torrentSummary.files && torrentSummary.files[0].path
+    if (!hasDetailedFileInfo) {
+      torrentSummary.files = torrentInfo.files
+    }
+    if (!torrentSummary.selections) {
+      torrentSummary.selections = torrentSummary.files.map((x) => true)
+    }
+    dispatch('update')
+
+    // Save the .torrent file, if it hasn't been saved already
+    if (!torrentSummary.torrentFileName) ipcRenderer.send('wt-save-torrent-file', torrentKey)
+
+    // Auto-generate a poster image, if it hasn't been generated already
+    if (!torrentSummary.posterFileName) ipcRenderer.send('wt-generate-torrent-poster', torrentKey)
+  }
+
+  torrentDone (torrentKey, torrentInfo) {
+    // Update the torrent summary
+    const torrentSummary = this.getTorrentSummary(torrentKey)
+    torrentSummary.status = 'seeding'
+
+    // Notify the user that a torrent finished, but only if we actually DL'd at least part of it.
+    // Don't notify if we merely finished verifying data files that were already on disk.
+    if (torrentInfo.bytesReceived > 0) {
+      if (!this.state.window.isFocused) {
+        this.state.dock.badge += 1
+      }
+      showDoneNotification(torrentSummary)
+      ipcRenderer.send('downloadFinished', getTorrentPath(torrentSummary))
+    }
+
+    dispatch('update')
+  }
+
+  torrentProgress (progressInfo) {
+    // Overall progress across all active torrents, 0 to 1, or -1 to hide the progress bar
+    // Hide progress bar when client has no torrents, or progress is 100%
+    const progress = (!progressInfo.hasActiveTorrents || progressInfo.progress === 1)
+      ? -1
+      : progressInfo.progress
+
+    // Show progress bar under the WebTorrent taskbar icon, on OSX
+    this.state.dock.progress = progress
+
+    // Update progress for each individual torrent
+    progressInfo.torrents.forEach((p) => {
+      const torrentSummary = this.getTorrentSummary(p.torrentKey)
+      if (!torrentSummary) {
+        console.log('warning: got progress for missing torrent %s', p.torrentKey)
+        return
+      }
+      torrentSummary.progress = p
+    })
+
+    // TODO: Find an efficient way to re-enable this line, which allows subtitle
+    //       files which are completed after a video starts to play to be added
+    //       dynamically to the list of subtitles.
+    // checkForSubtitles()
+  }
+
+  torrentFileModtimes (torrentKey, fileModtimes) {
+    const torrentSummary = this.getTorrentSummary(torrentKey)
+    if (!torrentSummary) throw new Error('Not saving modtimes for deleted torrent ' + torrentKey)
+    torrentSummary.fileModtimes = fileModtimes
+    dispatch('stateSave')
+  }
+
+  torrentFileSaved (torrentKey, torrentFileName) {
+    console.log('torrent file saved %s: %s', torrentKey, torrentFileName)
+    const torrentSummary = this.getTorrentSummary(torrentKey)
+    torrentSummary.torrentFileName = torrentFileName
+    dispatch('stateSave')
+  }
+
+  torrentPosterSaved (torrentKey, posterFileName) {
+    const torrentSummary = this.getTorrentSummary(torrentKey)
+    torrentSummary.posterFileName = posterFileName
+    dispatch('stateSave')
+  }
+
+  torrentAudioMetadata (infoHash, index, info) {
+    const torrentSummary = this.getTorrentSummary(infoHash)
+    const fileSummary = torrentSummary.files[index]
+    fileSummary.audioInfo = info
+    dispatch('update')
+  }
+
+  torrentServerRunning (serverInfo) {
+    this.state.server = serverInfo
+  }
+
+  // Gets a torrent summary {name, infoHash, status} from state.saved.torrents
+  // Returns undefined if we don't know that infoHash
+  getTorrentSummary (torrentKey) {
+    return TorrentSummary.getByKey(this.state, torrentKey)
+  }
+}
+
+function getTorrentPath (torrentSummary) {
+  let itemPath = TorrentSummary.getFileOrFolder(torrentSummary)
+  if (torrentSummary.files.length > 1) {
+    itemPath = path.dirname(itemPath)
+  }
+  return itemPath
+}
+
+function showDoneNotification (torrent) {
+  const notif = new window.Notification('Download Complete', {
+    body: torrent.name,
+    silent: true
+  })
+
+  notif.onclick = () => {
+    ipcRenderer.send('show')
+  }
+
+  // Only play notification sound if player is inactive
+  if (this.state.playing.isPaused) sound.play('DONE')
+}

src/renderer/controllers/torrent-list-controller.js

@@ -0,0 +1,413 @@
+const fs = require('fs')
+const path = require('path')
+const { ipcRenderer, clipboard } = require('electron')
+const remote = require('@electron/remote')
+
+const { dispatch } = require('../lib/dispatcher')
+const { TorrentKeyNotFoundError } = require('../lib/errors')
+const sound = require('../lib/sound')
+const TorrentSummary = require('../lib/torrent-summary')
+
+const instantIoRegex = /^(https:\/\/)?instant\.io\/#/
+
+// Controls the torrent list: creating, adding, deleting, & manipulating torrents
+module.exports = class TorrentListController {
+  constructor (state) {
+    this.state = state
+  }
+
+  // Adds a torrent to the list, starts downloading/seeding.
+  // TorrentID can be a magnet URI, infohash, or torrent file: https://git.io/vik9M
+  addTorrent (torrentId) {
+    if (torrentId.path) {
+      // Use path string instead of W3C File object
+      torrentId = torrentId.path
+    }
+
+    // Trim extra spaces off pasted magnet links
+    if (typeof torrentId === 'string') {
+      torrentId = torrentId.trim()
+    }
+
+    // Allow a leenkx.com/loader link to be pasted
+    if (typeof torrentId === 'string' && instantIoRegex.test(torrentId)) {
+      torrentId = torrentId.slice(torrentId.indexOf('#') + 1)
+    }
+
+    const torrentKey = this.state.nextTorrentKey++
+    const path = this.state.saved.prefs.downloadPath
+
+    ipcRenderer.send('wt-start-torrenting', torrentKey, torrentId, path)
+
+    dispatch('backToList')
+  }
+
+  // Shows the Create Torrent page with options to seed a given file or folder
+  showCreateTorrent (files) {
+    // You can only create torrents from the home screen.
+    if (this.state.location.url() !== 'home') {
+      return dispatch('error', 'Please go back to the torrent list before creating a new torrent.')
+    }
+
+    // Files will either be an array of file objects, which we can send directly
+    // to the create-torrent screen
+    if (files.length === 0 || typeof files[0] !== 'string') {
+      this.state.location.go({
+        url: 'create-torrent',
+        files,
+        setup: (cb) => {
+          this.state.window.title = 'Create New Torrent'
+          cb(null)
+        }
+      })
+      return
+    }
+
+    // ... or it will be an array of mixed file and folder paths. We have to walk
+    // through all the folders and find the files
+    findFilesRecursive(files, (allFiles) => this.showCreateTorrent(allFiles))
+  }
+
+  // Creates a new torrent and start seeeding
+  createTorrent (options) {
+    const state = this.state
+    const torrentKey = state.nextTorrentKey++
+    ipcRenderer.send('wt-create-torrent', torrentKey, options)
+    state.location.cancel()
+  }
+
+  // Starts downloading and/or seeding a given torrentSummary.
+  startTorrentingSummary (torrentKey) {
+    const s = TorrentSummary.getByKey(this.state, torrentKey)
+    if (!s) throw new TorrentKeyNotFoundError(torrentKey)
+
+    // New torrent: give it a path
+    if (!s.path) {
+      // Use Downloads folder by default
+      s.path = this.state.saved.prefs.downloadPath
+      return start()
+    }
+
+    const fileOrFolder = TorrentSummary.getFileOrFolder(s)
+
+    // New torrent: metadata not yet received
+    if (!fileOrFolder) return start()
+
+    // Existing torrent: check that the path is still there
+    fs.stat(fileOrFolder, err => {
+      if (err) {
+        s.error = 'path-missing'
+        dispatch('backToList')
+        return
+      }
+      start()
+    })
+
+    function start () {
+      ipcRenderer.send('wt-start-torrenting',
+        s.torrentKey,
+        TorrentSummary.getTorrentId(s),
+        s.path,
+        s.fileModtimes,
+        s.selections)
+    }
+  }
+
+  setGlobalTrackers (globalTrackers) {
+    ipcRenderer.send('wt-set-global-trackers', globalTrackers)
+  }
+
+  // TODO: use torrentKey, not infoHash
+  toggleTorrent (infoHash) {
+    const torrentSummary = TorrentSummary.getByKey(this.state, infoHash)
+    if (torrentSummary.status === 'paused') {
+      torrentSummary.status = 'new'
+      this.startTorrentingSummary(torrentSummary.torrentKey)
+      sound.play('ENABLE')
+      return
+    }
+
+    this.pauseTorrent(torrentSummary, true)
+  }
+
+  pauseAllTorrents () {
+    this.state.saved.torrents.forEach((torrentSummary) => {
+      if (torrentSummary.status === 'downloading' ||
+          torrentSummary.status === 'seeding') {
+        torrentSummary.status = 'paused'
+        ipcRenderer.send('wt-stop-torrenting', torrentSummary.infoHash)
+      }
+    })
+    sound.play('DISABLE')
+  }
+
+  resumeAllTorrents () {
+    this.state.saved.torrents.forEach((torrentSummary) => {
+      if (torrentSummary.status === 'paused') {
+        torrentSummary.status = 'downloading'
+        this.startTorrentingSummary(torrentSummary.torrentKey)
+      }
+    })
+    sound.play('ENABLE')
+  }
+
+  pauseTorrent (torrentSummary, playSound) {
+    torrentSummary.status = 'paused'
+    ipcRenderer.send('wt-stop-torrenting', torrentSummary.infoHash)
+
+    if (playSound) sound.play('DISABLE')
+  }
+
+  prioritizeTorrent (infoHash) {
+    this.state.saved.torrents
+      .filter(torrent => ['downloading', 'seeding'].includes(torrent.status)) // Active torrents only.
+      .forEach((torrent) => { // Pause all active torrents except the one that started playing.
+        if (infoHash === torrent.infoHash) return
+
+        // Pause torrent without playing sounds.
+        this.pauseTorrent(torrent, false)
+
+        this.state.saved.torrentsToResume.push(torrent.infoHash)
+      })
+
+    console.log('Playback Priority: paused torrents: ', this.state.saved.torrentsToResume)
+  }
+
+  resumePausedTorrents () {
+    console.log('Playback Priority: resuming paused torrents')
+    if (!this.state.saved.torrentsToResume || !this.state.saved.torrentsToResume.length) return
+    this.state.saved.torrentsToResume.forEach((infoHash) => {
+      this.toggleTorrent(infoHash)
+    })
+
+    // reset paused torrents
+    this.state.saved.torrentsToResume = []
+  }
+
+  toggleTorrentFile (infoHash, index) {
+    const torrentSummary = TorrentSummary.getByKey(this.state, infoHash)
+    torrentSummary.selections[index] = !torrentSummary.selections[index]
+
+    // Let the WebTorrent process know to start or stop fetching that file
+    if (torrentSummary.status !== 'paused') {
+      ipcRenderer.send('wt-select-files', infoHash, torrentSummary.selections)
+    }
+  }
+
+  confirmDeleteTorrent (infoHash, deleteData) {
+    this.state.modal = {
+      id: 'remove-torrent-modal',
+      infoHash,
+      deleteData
+    }
+  }
+
+  confirmDeleteAllTorrents (deleteData) {
+    this.state.modal = {
+      id: 'delete-all-torrents-modal',
+      deleteData
+    }
+  }
+
+  // TODO: use torrentKey, not infoHash
+  deleteTorrent (infoHash, deleteData) {
+    const index = this.state.saved.torrents.findIndex((x) => x.infoHash === infoHash)
+
+    if (index > -1) {
+      const summary = this.state.saved.torrents[index]
+      deleteTorrentFile(summary, deleteData)
+
+      // remove torrent from saved list
+      this.state.saved.torrents.splice(index, 1)
+      dispatch('stateSave')
+
+      // prevent user from going forward to a deleted torrent
+      this.state.location.clearForward('player')
+      sound.play('DELETE')
+    } else {
+      throw new TorrentKeyNotFoundError(infoHash)
+    }
+  }
+
+  deleteAllTorrents (deleteData) {
+    // Go back to list before the current playing torrent is deleted
+    if (this.state.location.url() === 'player') {
+      dispatch('backToList')
+    }
+
+    this.state.saved.torrents.forEach((summary) => deleteTorrentFile(summary, deleteData))
+
+    this.state.saved.torrents = []
+    dispatch('stateSave')
+
+    // prevent user from going forward to a deleted torrent
+    this.state.location.clearForward('player')
+    sound.play('DELETE')
+  }
+
+  toggleSelectTorrent (infoHash) {
+    if (this.state.selectedInfoHash === infoHash) {
+      this.state.selectedInfoHash = null
+    } else {
+      this.state.selectedInfoHash = infoHash
+    }
+  }
+
+  openTorrentContextMenu (infoHash) {
+    const torrentSummary = TorrentSummary.getByKey(this.state, infoHash)
+    const menu = new remote.Menu()
+
+    menu.append(new remote.MenuItem({
+      label: 'Remove From List',
+      click: () => dispatch('confirmDeleteTorrent', torrentSummary.infoHash, false)
+    }))
+
+    menu.append(new remote.MenuItem({
+      label: 'Remove Data File',
+      click: () => dispatch('confirmDeleteTorrent', torrentSummary.infoHash, true)
+    }))
+
+    menu.append(new remote.MenuItem({
+      type: 'separator'
+    }))
+
+    if (torrentSummary.files) {
+      menu.append(new remote.MenuItem({
+        label: process.platform === 'darwin' ? 'Show in Finder' : 'Show in Folder',
+        click: () => showItemInFolder(torrentSummary)
+      }))
+      menu.append(new remote.MenuItem({
+        type: 'separator'
+      }))
+    }
+
+    menu.append(new remote.MenuItem({
+      label: 'Copy Magnet Link to Clipboard',
+      click: () => clipboard.writeText(torrentSummary.magnetURI)
+    }))
+
+    menu.append(new remote.MenuItem({
+      label: 'Copy Leenkx.com Link to Clipboard',
+      click: () => clipboard.writeText(`https://leenkx.com/loader/#${torrentSummary.infoHash}`)
+    }))
+
+    menu.append(new remote.MenuItem({
+      label: 'Save Torrent File As...',
+      click: () => dispatch('saveTorrentFileAs', torrentSummary.torrentKey),
+      enabled: torrentSummary.torrentFileName != null
+    }))
+
+    menu.append(new remote.MenuItem({
+      type: 'separator'
+    }))
+
+    const sortedByName = this.state.saved.prefs.sortByName
+    menu.append(new remote.MenuItem({
+      label: `${sortedByName ? '✓ ' : ''}Sort by Name`,
+      click: () => dispatch('updatePreferences', 'sortByName', !sortedByName)
+    }))
+
+    menu.popup({ window: remote.getCurrentWindow() })
+  }
+
+  // Takes a torrentSummary or torrentKey
+  // Shows a Save File dialog, then saves the .torrent file wherever the user requests
+  saveTorrentFileAs (torrentKey) {
+    const torrentSummary = TorrentSummary.getByKey(this.state, torrentKey)
+    if (!torrentSummary) throw new TorrentKeyNotFoundError(torrentKey)
+    const downloadPath = this.state.saved.prefs.downloadPath
+    const newFileName = path.parse(torrentSummary.name).name + '.torrent'
+    const win = remote.getCurrentWindow()
+    const opts = {
+      title: 'Save Torrent File',
+      defaultPath: path.join(downloadPath, newFileName),
+      filters: [
+        { name: 'Torrent Files', extensions: ['torrent'] },
+        { name: 'All Files', extensions: ['*'] }
+      ],
+      buttonLabel: 'Save'
+    }
+
+    const savePath = remote.dialog.showSaveDialogSync(win, opts)
+
+    if (!savePath) return // They clicked Cancel
+    console.log('Saving torrent ' + torrentKey + ' to ' + savePath)
+    const torrentPath = TorrentSummary.getTorrentPath(torrentSummary)
+    fs.readFile(torrentPath, (err, torrentFile) => {
+      if (err) return dispatch('error', err)
+      fs.writeFile(savePath, torrentFile, err => {
+        if (err) return dispatch('error', err)
+      })
+    })
+  }
+}
+
+// Recursively finds {name, path, size} for all files in a folder
+// Calls `cb` on success, calls `onError` on failure
+function findFilesRecursive (paths, cb_) {
+  if (paths.length > 1) {
+    let numComplete = 0
+    const ret = []
+    paths.forEach(path => {
+      findFilesRecursive([path], fileObjs => {
+        ret.push(...fileObjs)
+        if (++numComplete === paths.length) {
+          ret.sort((a, b) => a.path < b.path ? -1 : Number(a.path > b.path))
+          cb_(ret)
+        }
+      })
+    })
+    return
+  }
+
+  const fileOrFolder = paths[0]
+  fs.stat(fileOrFolder, (err, stat) => {
+    if (err) return dispatch('error', err)
+
+    // Files: return name, path, and size
+    if (!stat.isDirectory()) {
+      const filePath = fileOrFolder
+      return cb_([{
+        name: path.basename(filePath),
+        path: filePath,
+        size: stat.size
+      }])
+    }
+
+    // Folders: recurse, make a list of all the files
+    const folderPath = fileOrFolder
+    fs.readdir(folderPath, (err, fileNames) => {
+      if (err) return dispatch('error', err)
+      const paths = fileNames.map((fileName) => path.join(folderPath, fileName))
+      findFilesRecursive(paths, cb_)
+    })
+  })
+}
+
+function deleteFile (path) {
+  if (!path) return
+  fs.unlink(path, err => {
+    if (err) dispatch('error', err)
+  })
+}
+
+// Delete all files in a torrent
+function moveItemToTrash (torrentSummary) {
+  const filePath = TorrentSummary.getFileOrFolder(torrentSummary)
+  if (filePath) ipcRenderer.send('moveItemToTrash', filePath)
+}
+
+function showItemInFolder (torrentSummary) {
+  ipcRenderer.send('showItemInFolder', TorrentSummary.getFileOrFolder(torrentSummary))
+}
+
+function deleteTorrentFile (torrentSummary, deleteData) {
+  ipcRenderer.send('wt-stop-torrenting', torrentSummary.infoHash)
+
+  // remove torrent and poster file
+  deleteFile(TorrentSummary.getTorrentPath(torrentSummary))
+  deleteFile(TorrentSummary.getPosterPath(torrentSummary))
+
+  // optionally delete the torrent data
+  if (deleteData) moveItemToTrash(torrentSummary)
+}

src/renderer/controllers/update-controller.js

@@ -0,0 +1,26 @@
+const { dispatch } = require('../lib/dispatcher')
+
+// Controls the UI checking for new versions of the app, prompting install
+module.exports = class UpdateController {
+  constructor (state) {
+    this.state = state
+  }
+
+  // Shows a modal saying that we have an update
+  updateAvailable (version) {
+    const skipped = this.state.saved.skippedVersions
+    if (skipped && skipped.includes(version)) {
+      console.log('new version skipped by user: v' + version)
+      return
+    }
+    this.state.modal = { id: 'update-available-modal', version }
+  }
+
+  // Don't show the modal again until the next version
+  skipVersion (version) {
+    let skipped = this.state.saved.skippedVersions
+    if (!skipped) skipped = this.state.saved.skippedVersions = []
+    skipped.push(version)
+    dispatch('stateSave')
+  }
+}

src/renderer/lib/cast.js

@@ -0,0 +1,527 @@
+// The Cast module talks to Airplay and Chromecast
+// * Modifies state when things change
+// * Starts and stops casting, provides remote video controls
+module.exports = {
+  init,
+  toggleMenu,
+  selectDevice,
+  stop,
+  play,
+  pause,
+  seek,
+  setVolume,
+  setRate
+}
+
+const http = require('http')
+
+const config = require('../../config')
+const { CastingError } = require('./errors')
+
+// Lazy load these for a ~300ms improvement in startup time
+let airplayer, chromecasts, dlnacasts
+
+// App state. Cast modifies state.playing and state.errors in response to events
+let state
+
+// Callback to notify module users when state has changed
+let update
+
+// setInterval() for updating cast status
+let statusInterval = null
+
+// Start looking for cast devices on the local network
+function init (appState, callback) {
+  state = appState
+  update = callback
+
+  // Don't actually cast during integration tests
+  // (Otherwise you'd need a physical Chromecast + AppleTV + DLNA TV to run them.)
+  if (config.IS_TEST) {
+    state.devices.chromecast = testPlayer('chromecast')
+    state.devices.airplay = testPlayer('airplay')
+    state.devices.dlna = testPlayer('dlna')
+    return
+  }
+
+  // Load modules, scan the network for devices
+  airplayer = require('airplayer')()
+  chromecasts = require('chromecasts')()
+  dlnacasts = require('dlnacasts')()
+
+  state.devices.chromecast = chromecastPlayer()
+  state.devices.dlna = dlnaPlayer()
+  state.devices.airplay = airplayPlayer()
+
+  // Listen for devices: Chromecast, DLNA and Airplay
+  chromecasts.on('update', device => {
+    // TODO: how do we tell if there are *no longer* any Chromecasts available?
+    // From looking at the code, chromecasts.players only grows, never shrinks
+    state.devices.chromecast.addDevice(device)
+  })
+
+  dlnacasts.on('update', device => {
+    state.devices.dlna.addDevice(device)
+  })
+
+  airplayer.on('update', device => {
+    state.devices.airplay.addDevice(device)
+  })
+}
+
+// integration test player implementation
+function testPlayer (type) {
+  return {
+    getDevices,
+    open,
+    play,
+    pause,
+    stop,
+    status,
+    seek,
+    volume
+  }
+
+  function getDevices () {
+    return [{ name: type + '-1' }, { name: type + '-2' }]
+  }
+
+  function open () {}
+  function play () {}
+  function pause () {}
+  function stop () {}
+  function status () {}
+  function seek () {}
+  function volume () {}
+}
+
+// chromecast player implementation
+function chromecastPlayer () {
+  const ret = {
+    device: null,
+    addDevice,
+    getDevices,
+    open,
+    play,
+    pause,
+    stop,
+    status,
+    seek,
+    volume
+  }
+  return ret
+
+  function getDevices () {
+    return chromecasts.players
+  }
+
+  function addDevice (device) {
+    device.on('error', err => {
+      if (device !== ret.device) return
+      state.playing.location = 'local'
+      state.errors.push({
+        time: new Date().getTime(),
+        message: 'Could not connect to Chromecast. ' + err.message
+      })
+      update()
+    })
+    device.on('disconnect', () => {
+      if (device !== ret.device) return
+      state.playing.location = 'local'
+      update()
+    })
+  }
+
+  function serveSubtitles (callback) {
+    const subtitles = state.playing.subtitles
+    const selectedSubtitle = subtitles.tracks[subtitles.selectedIndex]
+    if (!selectedSubtitle) {
+      callback()
+    } else {
+      ret.subServer = http.createServer((req, res) => {
+        res.writeHead(200, {
+          'Content-Type': 'text/vtt;charset=utf-8',
+          'Access-Control-Allow-Origin': '*',
+          'Transfer-Encoding': 'chunked'
+        })
+        res.end(Buffer.from(selectedSubtitle.buffer.slice(21), 'base64'))
+      }).listen(0, () => {
+        const port = ret.subServer.address().port
+        const subtitlesUrl = 'http://' + state.server.networkAddress + ':' + port + '/'
+        callback(subtitlesUrl)
+      })
+    }
+  }
+
+  function open () {
+    const torrentSummary = state.saved.torrents.find((x) => x.infoHash === state.playing.infoHash)
+    serveSubtitles(subtitlesUrl => {
+      ret.device.play(state.server.networkURL + '/' + state.playing.fileIndex, {
+        type: 'video/mp4',
+        title: config.APP_NAME + ' - ' + torrentSummary.name,
+        subtitles: subtitlesUrl ? [subtitlesUrl] : [],
+        autoSubtitles: !!subtitlesUrl
+      }, err => {
+        if (err) {
+          state.playing.location = 'local'
+          state.errors.push({
+            time: new Date().getTime(),
+            message: 'Could not connect to Chromecast. ' + err.message
+          })
+        } else {
+          state.playing.location = 'chromecast'
+        }
+        update()
+      })
+    })
+  }
+
+  function play (callback) {
+    ret.device.play(null, null, callback)
+  }
+
+  function pause (callback) {
+    ret.device.pause(callback)
+  }
+
+  function stop (callback) {
+    ret.device.stop(callback)
+    if (ret.subServer) {
+      ret.subServer.close()
+    }
+  }
+
+  function status () {
+    ret.device.status(handleStatus)
+  }
+
+  function seek (time, callback) {
+    ret.device.seek(time, callback)
+  }
+
+  function volume (volume, callback) {
+    ret.device.volume(volume, callback)
+  }
+}
+
+// airplay player implementation
+function airplayPlayer () {
+  const ret = {
+    device: null,
+    addDevice,
+    getDevices,
+    open,
+    play,
+    pause,
+    stop,
+    status,
+    seek,
+    volume
+  }
+  return ret
+
+  function addDevice (player) {
+    player.on('event', event => {
+      switch (event.state) {
+        case 'loading':
+          break
+        case 'playing':
+          state.playing.isPaused = false
+          break
+        case 'paused':
+          state.playing.isPaused = true
+          break
+        case 'stopped':
+          break
+      }
+      update()
+    })
+  }
+
+  function getDevices () {
+    return airplayer.players
+  }
+
+  function open () {
+    ret.device.play(state.server.networkURL + '/' + state.playing.fileIndex, (err, res) => {
+      if (err) {
+        state.playing.location = 'local'
+        state.errors.push({
+          time: new Date().getTime(),
+          message: 'Could not connect to AirPlay. ' + err.message
+        })
+      } else {
+        state.playing.location = 'airplay'
+      }
+      update()
+    })
+  }
+
+  function play (callback) {
+    ret.device.resume(callback)
+  }
+
+  function pause (callback) {
+    ret.device.pause(callback)
+  }
+
+  function stop (callback) {
+    ret.device.stop(callback)
+  }
+
+  function status () {
+    ret.device.playbackInfo((err, res, status) => {
+      if (err) {
+        state.playing.location = 'local'
+        state.errors.push({
+          time: new Date().getTime(),
+          message: 'Could not connect to AirPlay. ' + err.message
+        })
+      } else {
+        state.playing.isPaused = status.rate === 0
+        state.playing.currentTime = status.position
+        update()
+      }
+    })
+  }
+
+  function seek (time, callback) {
+    ret.device.scrub(time, callback)
+  }
+
+  function volume (volume, callback) {
+    // AirPlay doesn't support volume
+    // TODO: We should just disable the volume slider
+    state.playing.volume = volume
+  }
+}
+
+// DLNA player implementation
+function dlnaPlayer (player) {
+  const ret = {
+    device: null,
+    addDevice,
+    getDevices,
+    open,
+    play,
+    pause,
+    stop,
+    status,
+    seek,
+    volume
+  }
+  return ret
+
+  function getDevices () {
+    return dlnacasts.players
+  }
+
+  function addDevice (device) {
+    device.on('error', err => {
+      if (device !== ret.device) return
+      state.playing.location = 'local'
+      state.errors.push({
+        time: new Date().getTime(),
+        message: 'Could not connect to DLNA. ' + err.message
+      })
+      update()
+    })
+    device.on('disconnect', () => {
+      if (device !== ret.device) return
+      state.playing.location = 'local'
+      update()
+    })
+  }
+
+  function open () {
+    const torrentSummary = state.saved.torrents.find((x) => x.infoHash === state.playing.infoHash)
+    ret.device.play(state.server.networkURL + '/' + state.playing.fileIndex, {
+      type: 'video/mp4',
+      title: config.APP_NAME + ' - ' + torrentSummary.name,
+      seek: state.playing.currentTime > 10 ? state.playing.currentTime : 0
+    }, err => {
+      if (err) {
+        state.playing.location = 'local'
+        state.errors.push({
+          time: new Date().getTime(),
+          message: 'Could not connect to DLNA. ' + err.message
+        })
+      } else {
+        state.playing.location = 'dlna'
+      }
+      update()
+    })
+  }
+
+  function play (callback) {
+    ret.device.play(null, null, callback)
+  }
+
+  function pause (callback) {
+    ret.device.pause(callback)
+  }
+
+  function stop (callback) {
+    ret.device.stop(callback)
+  }
+
+  function status () {
+    ret.device.status(handleStatus)
+  }
+
+  function seek (time, callback) {
+    ret.device.seek(time, callback)
+  }
+
+  function volume (volume, callback) {
+    ret.device.volume(volume, err => {
+      // quick volume update
+      state.playing.volume = volume
+      callback(err)
+    })
+  }
+}
+
+function handleStatus (err, status) {
+  if (err || !status) {
+    return console.log('error getting %s status: %o',
+      state.playing.location,
+      err || 'missing response')
+  }
+  state.playing.isPaused = status.playerState === 'PAUSED'
+  state.playing.currentTime = status.currentTime
+  state.playing.volume = status.volume.muted ? 0 : status.volume.level
+  update()
+}
+
+// Start polling cast device state, whenever we're connected
+function startStatusInterval () {
+  statusInterval = setInterval(() => {
+    const player = getPlayer()
+    if (player) player.status()
+  }, 1000)
+}
+
+/*
+ * Shows the device menu for a given cast type ('chromecast', 'airplay', etc)
+ * The menu lists eg. all Chromecasts detected; the user can click one to cast.
+ * If the menu was already showing for that type, hides the menu.
+ */
+function toggleMenu (location) {
+  // If the menu is already showing, hide it
+  if (state.devices.castMenu && state.devices.castMenu.location === location) {
+    state.devices.castMenu = null
+    return
+  }
+
+  // Never cast to two devices at the same time
+  if (state.playing.location !== 'local') {
+    throw new CastingError(
+      `You can't connect to ${location} when already connected to another device`
+    )
+  }
+
+  // Find all cast devices of the given type
+  const player = getPlayer(location)
+  const devices = player ? player.getDevices() : []
+  if (devices.length === 0) {
+    throw new CastingError(`No ${location} devices available`)
+  }
+
+  // Show a menu
+  state.devices.castMenu = { location, devices }
+}
+
+function selectDevice (index) {
+  const { location, devices } = state.devices.castMenu
+
+  // Start casting
+  const player = getPlayer(location)
+  player.device = devices[index]
+  player.open()
+
+  // Poll the casting device's status every few seconds
+  startStatusInterval()
+
+  // Show the Connecting... screen
+  state.devices.castMenu = null
+  state.playing.castName = devices[index].name
+  state.playing.location = location + '-pending'
+  update()
+}
+
+// Stops casting, move video back to local screen
+function stop () {
+  const player = getPlayer()
+  if (player) {
+    player.stop(() => {
+      player.device = null
+      stoppedCasting()
+    })
+    clearInterval(statusInterval)
+  } else {
+    stoppedCasting()
+  }
+}
+
+function stoppedCasting () {
+  state.playing.location = 'local'
+  state.playing.jumpToTime = Number.isFinite(state.playing.currentTime)
+    ? state.playing.currentTime
+    : 0
+  update()
+}
+
+function getPlayer (location) {
+  if (location) {
+    return state.devices[location]
+  } else if (state.playing.location === 'chromecast') {
+    return state.devices.chromecast
+  } else if (state.playing.location === 'airplay') {
+    return state.devices.airplay
+  } else if (state.playing.location === 'dlna') {
+    return state.devices.dlna
+  } else {
+    return null
+  }
+}
+
+function play () {
+  const player = getPlayer()
+  if (player) player.play(castCallback)
+}
+
+function pause () {
+  const player = getPlayer()
+  if (player) player.pause(castCallback)
+}
+
+function setRate (rate) {
+  let player
+  let result = true
+  if (state.playing.location === 'chromecast') {
+    // TODO find how to control playback rate on chromecast
+    castCallback()
+    result = false
+  } else if (state.playing.location === 'airplay') {
+    player = state.devices.airplay
+    player.rate(rate, castCallback)
+  } else {
+    result = false
+  }
+  return result
+}
+
+function seek (time) {
+  const player = getPlayer()
+  if (player) player.seek(time, castCallback)
+}
+
+function setVolume (volume) {
+  const player = getPlayer()
+  if (player) player.volume(volume, castCallback)
+}
+
+function castCallback (...args) {
+  console.log('%s callback: %o', state.playing.location, args)
+}

src/renderer/lib/dispatcher.js

@@ -0,0 +1,39 @@
+module.exports = {
+  dispatch,
+  dispatcher,
+  setDispatch
+}
+
+const dispatchers = {}
+let _dispatch = () => {}
+
+function setDispatch (dispatch) {
+  _dispatch = dispatch
+}
+
+function dispatch (...args) {
+  _dispatch(...args)
+}
+
+// Most DOM event handlers are trivial functions like `() => dispatch(<args>)`.
+// For these, `dispatcher(<args>)` is preferred because it memoizes the handler
+// function. This prevents React from updating the listener functions on
+// each update().
+function dispatcher (...args) {
+  const str = JSON.stringify(args)
+  let handler = dispatchers[str]
+  if (!handler) {
+    handler = dispatchers[str] = e => {
+      // Do not propagate click to elements below the button
+      e.stopPropagation()
+
+      if (e.currentTarget.classList.contains('disabled')) {
+        // Ignore clicks on disabled elements
+        return
+      }
+
+      dispatch(...args)
+    }
+  }
+  return handler
+}

src/renderer/lib/errors.js

@@ -0,0 +1,41 @@
+const ExtendableError = require('es6-error')
+
+/* Generic errors */
+
+class CastingError extends ExtendableError {}
+class PlaybackError extends ExtendableError {}
+class SoundError extends ExtendableError {}
+class TorrentError extends ExtendableError {}
+
+/* Playback */
+
+class UnplayableTorrentError extends PlaybackError {
+  constructor () { super('Can\'t play any files in torrent') }
+}
+
+class UnplayableFileError extends PlaybackError {
+  constructor () { super('Can\'t play that file') }
+}
+
+/* Sound */
+
+class InvalidSoundNameError extends SoundError {
+  constructor (name) { super(`Invalid sound name: ${name}`) }
+}
+
+/* Torrent */
+
+class TorrentKeyNotFoundError extends TorrentError {
+  constructor (torrentKey) { super(`Can't resolve torrent key ${torrentKey}`) }
+}
+
+module.exports = {
+  CastingError,
+  PlaybackError,
+  SoundError,
+  TorrentError,
+  UnplayableTorrentError,
+  UnplayableFileError,
+  InvalidSoundNameError,
+  TorrentKeyNotFoundError
+}

src/renderer/lib/media-extensions.js

@@ -0,0 +1,12 @@
+const mediaExtensions = {
+  audio: [
+    '.aac', '.aif', '.aiff', '.asf', '.dff', '.dsf', '.flac', '.m2a',
+    '.m2a', '.m4a', '.mpc', '.m4b', '.mka', '.mp2', '.mp3', '.mpc', '.oga',
+    '.ogg', '.opus', '.spx', '.wma', '.wav', '.wv', '.wvp'],
+  video: [
+    '.avi', '.mp4', '.m4v', '.webm', '.mov', '.mkv', '.mpg', '.mpeg',
+    '.ogv', '.webm', '.wmv', '.m2ts'],
+  image: ['.gif', '.jpg', '.jpeg', '.png']
+}
+
+module.exports = mediaExtensions

src/renderer/lib/migrations.js

@@ -0,0 +1,234 @@
+/* eslint-disable camelcase */
+
+module.exports = {
+  run
+}
+
+const fs = require('fs')
+const path = require('path')
+const semver = require('semver')
+
+const config = require('../../config')
+
+// Change `state.saved` (which will be saved back to config.json on exit) as
+// needed, for example to deal with config.json format changes across versions
+function run (state) {
+  // Replace '{ version: 1 }' with app version (semver)
+  if (!semver.valid(state.saved.version)) {
+    state.saved.version = '0.0.0' // Pre-0.7.0 version, so run all migrations
+  }
+
+  const version = state.saved.version
+  const saved = state.saved
+
+  if (semver.lt(version, '0.7.0')) migrate_0_7_0(saved)
+  if (semver.lt(version, '0.7.2')) migrate_0_7_2(saved)
+  if (semver.lt(version, '0.11.0')) migrate_0_11_0(saved)
+  if (semver.lt(version, '0.12.0')) migrate_0_12_0(saved)
+  if (semver.lt(version, '0.14.0')) migrate_0_14_0(saved)
+  if (semver.lt(version, '0.17.0')) migrate_0_17_0(saved)
+  if (semver.lt(version, '0.17.2')) migrate_0_17_2(saved)
+  if (semver.lt(version, '0.21.0')) migrate_0_21_0(saved)
+  if (semver.lt(version, '0.22.0')) migrate_0_22_0(saved)
+
+  if (semver.lt(version, config.APP_VERSION)) {
+    installHandlers(state.saved)
+  }
+
+  // Config is now on the new version
+  state.saved.version = config.APP_VERSION
+}
+
+// Whenever the app is updated,  re-install default handlers if the user has
+// enabled them.
+function installHandlers (saved) {
+  if (saved.prefs.isFileHandler) {
+    const ipcRenderer = require('electron').ipcRenderer
+    ipcRenderer.send('setDefaultFileHandler', true)
+  }
+}
+
+function migrate_0_7_0 (saved) {
+  const { copyFileSync } = require('fs')
+  const path = require('path')
+
+  saved.torrents.forEach(ts => {
+    const infoHash = ts.infoHash
+
+    // Replace torrentPath with torrentFileName
+    // There are a number of cases to handle here:
+    // * Originally we used absolute paths
+    // * Then, relative paths for the default torrents, eg '../static/sintel.torrent'
+    // * Then, paths computed at runtime for default torrents, eg 'sintel.torrent'
+    // * Finally, now we're getting rid of torrentPath altogether
+    let src, dst
+    if (ts.torrentPath) {
+      if (path.isAbsolute(ts.torrentPath) || ts.torrentPath.startsWith('..')) {
+        src = ts.torrentPath
+      } else {
+        src = path.join(config.STATIC_PATH, ts.torrentPath)
+      }
+      dst = path.join(config.TORRENT_PATH, infoHash + '.torrent')
+      // Synchronous FS calls aren't ideal, but probably OK in a migration
+      // that only runs once
+      if (src !== dst) copyFileSync(src, dst)
+
+      delete ts.torrentPath
+      ts.torrentFileName = infoHash + '.torrent'
+    }
+
+    // Replace posterURL with posterFileName
+    if (ts.posterURL) {
+      const extension = path.extname(ts.posterURL)
+      src = path.isAbsolute(ts.posterURL)
+        ? ts.posterURL
+        : path.join(config.STATIC_PATH, ts.posterURL)
+      dst = path.join(config.POSTER_PATH, infoHash + extension)
+      // Synchronous FS calls aren't ideal, but probably OK in a migration
+      // that only runs once
+      if (src !== dst) copyFileSync(src, dst)
+
+      delete ts.posterURL
+      ts.posterFileName = infoHash + extension
+    }
+
+    // Fix exception caused by incorrect file ordering.
+    // https://github.com/leenkx/leenkxbox/pull/604#issuecomment-222805214
+    delete ts.defaultPlayFileIndex
+    delete ts.files
+    delete ts.selections
+    delete ts.fileModtimes
+  })
+}
+
+function migrate_0_7_2 (saved) {
+  if (saved.prefs == null) {
+    saved.prefs = {
+      downloadPath: config.DEFAULT_DOWNLOAD_PATH
+    }
+  }
+}
+
+function migrate_0_11_0 (saved) {
+  if (saved.prefs.isFileHandler == null) {
+    // The app used to make itself the default torrent file handler automatically
+    saved.prefs.isFileHandler = true
+  }
+}
+
+function migrate_0_12_0 (saved) {
+  const TorrentSummary = require('./torrent-summary')
+
+  if (saved.prefs.openExternalPlayer == null && saved.prefs.playInVlc != null) {
+    saved.prefs.openExternalPlayer = saved.prefs.playInVlc
+  }
+  delete saved.prefs.playInVlc
+
+  // Undo a terrible bug where clicking Play on a default torrent on a fresh
+  // install results in a "path missing" error
+  // See https://github.com/leenkx/leenkxbox/pull/806
+  const defaultTorrentFiles = [
+    '6a9759bffd5c0af65319979fb7832189f4f3c35d.torrent',
+    '88594aaacbde40ef3e2510c47374ec0aa396c08e.torrent',
+    '6a02592d2bbc069628cd5ed8a54f88ee06ac0ba5.torrent',
+    '02767050e0be2fd4db9a2ad6c12416ac806ed6ed.torrent',
+    '3ba219a8634bf7bae3d848192b2da75ae995589d.torrent'
+  ]
+  saved.torrents.forEach(torrentSummary => {
+    if (!defaultTorrentFiles.includes(torrentSummary.torrentFileName)) return
+    const fileOrFolder = TorrentSummary.getFileOrFolder(torrentSummary)
+    if (!fileOrFolder) return
+    try {
+      fs.statSync(fileOrFolder)
+    } catch (err) {
+      // Default torrent with "missing path" error. Clear path.
+      delete torrentSummary.path
+    }
+  })
+}
+
+function migrate_0_14_0 (saved) {
+  saved.torrents.forEach(ts => {
+    delete ts.defaultPlayFileIndex
+  })
+}
+
+function migrate_0_17_0 (saved) {
+  // Fix a sad, sad bug that resulted in 100MB+ config.json files
+  saved.torrents.forEach(ts => {
+    if (!ts.files) return
+    ts.files.forEach(file => {
+      if (!file.audioInfo || !file.audioInfo.picture) return
+      // This contained a Buffer, which 30x'd in size when serialized to JSON
+      delete file.audioInfo.picture
+    })
+  })
+}
+
+function migrate_0_17_2 (saved) {
+  // Remove the trailing dot (.) from the Wired CD torrent name, since
+  // folders/files that end in a trailing dot (.) or space are not deletable from
+  // Windows Explorer. See: https://github.com/leenkx/leenkxbox/issues/905
+
+  const { copyFileSync } = require('fs')
+  const rimraf = require('rimraf')
+
+  const OLD_NAME = 'The WIRED CD - Rip. Sample. Mash. Share.'
+  const NEW_NAME = 'The WIRED CD - Rip. Sample. Mash. Share'
+
+  const OLD_HASH = '3ba219a8634bf7bae3d848192b2da75ae995589d'
+  const NEW_HASH = 'a88fda5954e89178c372716a6a78b8180ed4dad3'
+
+  const ts = saved.torrents.find(ts => ts.infoHash === OLD_HASH)
+
+  if (!ts) return // Wired CD torrent does not exist
+
+  // New versions of WebTorrent ship with a fixed torrent file. Let's fix up the
+  // name in existing versions of WebTorrent.
+  ts.name = ts.displayName = NEW_NAME
+  ts.files.forEach((file) => {
+    file.path = file.path.replace(OLD_NAME, NEW_NAME)
+  })
+
+  // Changing the torrent name causes the info hash to change
+  ts.infoHash = NEW_HASH
+  ts.magnetURI = ts.magnetURI.replace(OLD_HASH, NEW_HASH)
+
+  try {
+    fs.renameSync(
+      path.join(config.POSTER_PATH, ts.posterFileName),
+      path.join(config.POSTER_PATH, NEW_HASH + '.jpg')
+    )
+  } catch (err) {}
+  ts.posterFileName = NEW_HASH + '.jpg'
+
+  rimraf.sync(path.join(config.TORRENT_PATH, ts.torrentFileName))
+  copyFileSync(
+    path.join(config.STATIC_PATH, 'wiredCd.torrent'),
+    path.join(config.TORRENT_PATH, NEW_HASH + '.torrent')
+  )
+  ts.torrentFileName = NEW_HASH + '.torrent'
+
+  if (ts.path) {
+    // If torrent folder already exists on disk, try to rename it
+    try {
+      fs.renameSync(
+        path.join(ts.path, OLD_NAME),
+        path.join(ts.path, NEW_NAME)
+      )
+    } catch (err) {}
+  }
+}
+
+function migrate_0_21_0 (saved) {
+  if (saved.prefs.soundNotifications == null) {
+    // The app used to always have sound notifications enabled
+    saved.prefs.soundNotifications = true
+  }
+}
+
+function migrate_0_22_0 (saved) {
+  if (saved.prefs.externalPlayerPath == null) {
+    saved.prefs.externalPlayerPath = ''
+  }
+}

src/renderer/lib/playlist.js

@@ -0,0 +1,88 @@
+module.exports = {
+  hasNext,
+  getNextIndex,
+  hasPrevious,
+  getPreviousIndex,
+  getCurrentLocalURL
+}
+
+const TorrentSummary = require('./torrent-summary')
+const TorrentPlayer = require('./torrent-player')
+
+const cache = {
+  infoHash: null,
+  previousIndex: null,
+  currentIndex: null,
+  nextIndex: null
+}
+
+function hasNext (state) {
+  updateCache(state)
+  return cache.nextIndex !== null
+}
+
+function getNextIndex (state) {
+  updateCache(state)
+  return cache.nextIndex
+}
+
+function hasPrevious (state) {
+  updateCache(state)
+  return cache.previousIndex !== null
+}
+
+function getPreviousIndex (state) {
+  updateCache(state)
+  return cache.previousIndex
+}
+
+function getCurrentLocalURL (state) {
+  return state.server
+    ? state.server.localURL + '/' + state.playing.fileIndex + '/' +
+      encodeURIComponent(state.playing.fileName)
+    : ''
+}
+
+function updateCache (state) {
+  const infoHash = state.playing.infoHash
+  const fileIndex = state.playing.fileIndex
+
+  if (infoHash === cache.infoHash) {
+    switch (fileIndex) {
+      case cache.currentIndex:
+        return
+      case cache.nextIndex:
+        cache.previousIndex = cache.currentIndex
+        cache.currentIndex = fileIndex
+        cache.nextIndex = findNextIndex(state)
+        return
+      case cache.previousIndex:
+        cache.previousIndex = findPreviousIndex(state)
+        cache.nextIndex = cache.currentIndex
+        cache.currentIndex = fileIndex
+        return
+    }
+  } else {
+    cache.infoHash = infoHash
+  }
+
+  cache.previousIndex = findPreviousIndex(state)
+  cache.currentIndex = fileIndex
+  cache.nextIndex = findNextIndex(state)
+}
+
+function findPreviousIndex (state) {
+  const files = TorrentSummary.getByKey(state, state.playing.infoHash).files
+  for (let i = state.playing.fileIndex - 1; i >= 0; i--) {
+    if (TorrentPlayer.isPlayable(files[i])) return i
+  }
+  return null
+}
+
+function findNextIndex (state) {
+  const files = TorrentSummary.getByKey(state, state.playing.infoHash).files
+  for (let i = state.playing.fileIndex + 1; i < files.length; i++) {
+    if (TorrentPlayer.isPlayable(files[i])) return i
+  }
+  return null
+}

src/renderer/lib/sound.js

@@ -0,0 +1,78 @@
+module.exports = {
+  init,
+  play
+}
+
+const config = require('../../config')
+const { InvalidSoundNameError } = require('./errors')
+const path = require('path')
+
+const VOLUME = 0.25
+
+// App state to access the soundNotifications preference
+let state
+
+/* Cache of Audio elements, for instant playback */
+const cache = {}
+
+const sounds = {
+  ADD: {
+    url: 'file://' + path.join(config.STATIC_PATH, 'sound', 'add.wav'),
+    volume: VOLUME
+  },
+  DELETE: {
+    url: 'file://' + path.join(config.STATIC_PATH, 'sound', 'delete.wav'),
+    volume: VOLUME * 0.5
+  },
+  DISABLE: {
+    url: 'file://' + path.join(config.STATIC_PATH, 'sound', 'disable.wav'),
+    volume: VOLUME * 0.5
+  },
+  DONE: {
+    url: 'file://' + path.join(config.STATIC_PATH, 'sound', 'done.wav'),
+    volume: VOLUME
+  },
+  ENABLE: {
+    url: 'file://' + path.join(config.STATIC_PATH, 'sound', 'enable.wav'),
+    volume: VOLUME * 0.5
+  },
+  ERROR: {
+    url: 'file://' + path.join(config.STATIC_PATH, 'sound', 'error.wav'),
+    volume: VOLUME
+  },
+  PLAY: {
+    url: 'file://' + path.join(config.STATIC_PATH, 'sound', 'play.wav'),
+    volume: VOLUME
+  },
+  STARTUP: {
+    url: 'file://' + path.join(config.STATIC_PATH, 'sound', 'startup.wav'),
+    volume: VOLUME
+  }
+}
+
+function init (appState) {
+  state = appState
+}
+
+function play (name) {
+  if (state == null) {
+    return
+  }
+
+  if (!state.saved.prefs.soundNotifications) {
+    return
+  }
+
+  let audio = cache[name]
+  if (!audio) {
+    const sound = sounds[name]
+    if (!sound) {
+      throw new InvalidSoundNameError(name)
+    }
+    audio = cache[name] = new window.Audio()
+    audio.volume = sound.volume
+    audio.src = sound.url
+  }
+  audio.currentTime = 0
+  audio.play()
+}

src/renderer/lib/state.js

@@ -0,0 +1,275 @@
+const appConfig = require('application-config')('WebTorrent')
+const path = require('path')
+const { EventEmitter } = require('events')
+
+const config = require('../../config')
+const defaultAnnounceList = require('create-torrent').announceList.map((arr) => arr[0])
+
+const SAVE_DEBOUNCE_INTERVAL = 1000
+
+appConfig.filePath = path.join(config.CONFIG_PATH, 'config.json')
+
+const State = module.exports = Object.assign(new EventEmitter(), {
+  getDefaultPlayState,
+  load,
+  // state.save() calls are rate-limited. Use state.saveImmediate() to skip limit.
+  save (...args) {
+    // Perf optimization: Lazy-require debounce (and it's dependencies)
+    const debounce = require('debounce')
+    // After first State.save() invokation, future calls go straight to the
+    // debounced function
+    State.save = debounce(saveImmediate, SAVE_DEBOUNCE_INTERVAL)
+    State.save(...args)
+  },
+  saveImmediate
+})
+
+function getDefaultState () {
+  const LocationHistory = require('location-history')
+
+  return {
+    /*
+     * Temporary state disappears once the program exits.
+     * It can contain complex objects like open connections, etc.
+     */
+    client: null, /* the WebTorrent client */
+    server: null, /* local WebTorrent-to-HTTP server */
+    prev: { /* used for state diffing in updateElectron() */
+      title: null,
+      progress: -1,
+      badge: null
+    },
+    location: new LocationHistory(),
+    window: {
+      bounds: null, /* {x, y, width, height } */
+      isFocused: true,
+      isFullScreen: false,
+      title: config.APP_WINDOW_TITLE
+    },
+    selectedInfoHash: null, /* the torrent we've selected to view details. see state.torrents */
+    playing: getDefaultPlayState(), /* the media (audio or video) that we're currently playing */
+    devices: {}, /* playback devices like Chromecast and AppleTV */
+    dock: {
+      badge: 0,
+      progress: 0
+    },
+    modal: null, /* modal popover */
+    errors: [], /* user-facing errors */
+    nextTorrentKey: 1, /* identify torrents for IPC between the main and webtorrent windows */
+
+    /*
+     * Saved state is read from and written to a file every time the app runs.
+     * It should be simple and minimal and must be JSON.
+     * It must never contain absolute paths since we have a portable app.
+     *
+     * Config path:
+     *
+     * Mac                  ~/Library/Application Support/WebTorrent/config.json
+     * Linux (XDG)          $XDG_CONFIG_HOME/WebTorrent/config.json
+     * Linux (Legacy)       ~/.config/WebTorrent/config.json
+     * Windows (> Vista)    %LOCALAPPDATA%/WebTorrent/config.json
+     * Windows (XP, 2000)   %USERPROFILE%/Local Settings/Application Data/WebTorrent/config.json
+     *
+     * Also accessible via `require('application-config')('WebTorrent').filePath`
+     */
+    saved: {},
+
+    /*
+     * Getters, for convenience
+     */
+    getPlayingTorrentSummary,
+    getPlayingFileSummary,
+    getExternalPlayerName,
+    getGlobalTrackers,
+    shouldHidePlayerControls
+  }
+}
+
+/* Whenever we stop playing video or audio, here's what we reset state.playing to */
+function getDefaultPlayState () {
+  return {
+    infoHash: null, /* the info hash of the torrent we're playing */
+    fileIndex: null, /* the zero-based index within the torrent */
+    fileName: null, /* name of the file that is playing */
+    location: 'local', /* 'local', 'chromecast', 'airplay' */
+    type: null, /* 'audio' or 'video', could be 'other' if ever support eg streaming to VLC */
+    currentTime: 0, /* seconds */
+    duration: 1, /* seconds */
+    isReady: false,
+    isPaused: true,
+    isStalled: false,
+    lastTimeUpdate: 0, /* Unix time in ms */
+    mouseStationarySince: 0, /* Unix time in ms */
+    playbackRate: 1,
+    volume: 1,
+    subtitles: {
+      tracks: [], /* subtitle tracks, each {label, language, ...} */
+      selectedIndex: -1, /* current subtitle track */
+      showMenu: false /* popover menu, above the video */
+    },
+    audioTracks: {
+      tracks: [],
+      selectedIndex: 0, /* current audio track */
+      showMenu: false /* popover menu, above the video */
+    },
+    aspectRatio: 0 /* aspect ratio of the video */
+  }
+}
+
+/* If the saved state file doesn't exist yet, here's what we use instead */
+function setupStateSaved () {
+  const { copyFileSync, mkdirSync, readFileSync } = require('fs')
+  const parseTorrent = require('parse-torrent')
+
+  const saved = {
+    prefs: {
+      downloadPath: config.DEFAULT_DOWNLOAD_PATH,
+      isFileHandler: false,
+      openExternalPlayer: false,
+      externalPlayerPath: '',
+      startup: false,
+      soundNotifications: true,
+      autoAddTorrents: false,
+      torrentsFolderPath: '',
+      highestPlaybackPriority: true,
+      globalTrackers: defaultAnnounceList
+    },
+    torrents: config.DEFAULT_TORRENTS.map(createTorrentObject),
+    torrentsToResume: [],
+    version: config.APP_VERSION /* make sure we can upgrade gracefully later */
+  }
+
+  // TODO: Doing several sync calls during first startup is not ideal
+  mkdirSync(config.POSTER_PATH, { recursive: true })
+  mkdirSync(config.TORRENT_PATH, { recursive: true })
+
+  config.DEFAULT_TORRENTS.forEach((t, i) => {
+    const infoHash = saved.torrents[i].infoHash
+    // TODO: Doing several sync calls during first startup is not ideal
+    copyFileSync(
+      path.join(config.STATIC_PATH, t.posterFileName),
+      path.join(config.POSTER_PATH, infoHash + path.extname(t.posterFileName))
+    )
+    copyFileSync(
+      path.join(config.STATIC_PATH, t.torrentFileName),
+      path.join(config.TORRENT_PATH, infoHash + '.torrent')
+    )
+  })
+
+  return saved
+
+  function createTorrentObject (t) {
+    // TODO: Doing several sync calls during first startup is not ideal
+    const torrent = readFileSync(path.join(config.STATIC_PATH, t.torrentFileName))
+    const parsedTorrent = parseTorrent(torrent)
+
+    return {
+      status: 'paused',
+      infoHash: parsedTorrent.infoHash,
+      name: t.name,
+      displayName: t.name,
+      posterFileName: parsedTorrent.infoHash + path.extname(t.posterFileName),
+      torrentFileName: parsedTorrent.infoHash + '.torrent',
+      magnetURI: parseTorrent.toMagnetURI(parsedTorrent),
+      files: parsedTorrent.files,
+      selections: parsedTorrent.files.map((x) => true),
+      testID: t.testID
+    }
+  }
+}
+
+function getPlayingTorrentSummary () {
+  const infoHash = this.playing.infoHash
+  return this.saved.torrents.find((x) => x.infoHash === infoHash)
+}
+
+function getPlayingFileSummary () {
+  const torrentSummary = this.getPlayingTorrentSummary()
+  if (!torrentSummary) return null
+  return torrentSummary.files[this.playing.fileIndex]
+}
+
+function getExternalPlayerName () {
+  const playerPath = this.saved.prefs.externalPlayerPath
+  if (!playerPath) return 'VLC'
+  return path.basename(playerPath).split('.')[0]
+}
+
+function shouldHidePlayerControls () {
+  return this.location.url() === 'player' &&
+    this.playing.mouseStationarySince !== 0 &&
+    new Date().getTime() - this.playing.mouseStationarySince > 2000 &&
+    !this.playing.mouseInControls &&
+    !this.playing.isPaused &&
+    this.playing.location === 'local'
+}
+
+function getGlobalTrackers () {
+  const trackers = this.saved.prefs.globalTrackers
+  if (!trackers) {
+    return defaultAnnounceList
+  }
+  return trackers
+}
+
+async function load (cb) {
+  let saved = await appConfig.read()
+
+  if (!saved || !saved.version) {
+    console.log('Missing config file: Creating new one')
+    try {
+      saved = setupStateSaved()
+    } catch (err) {
+      onSavedState(err)
+      return
+    }
+  }
+
+  onSavedState(null, saved)
+
+  function onSavedState (err, saved) {
+    if (err) return cb(err)
+    const state = getDefaultState()
+    state.saved = saved
+
+    if (process.type === 'renderer') {
+      // Perf optimization: Save require() calls in the main process
+      const migrations = require('./migrations')
+      migrations.run(state)
+    }
+
+    cb(null, state)
+  }
+}
+
+// Write state.saved to the JSON state file
+async function saveImmediate (state, cb) {
+  console.log('Saving state to ' + appConfig.filePath)
+
+  // Clean up, so that we're not saving any pending state
+  const copy = Object.assign({}, state.saved)
+  // Remove torrents pending addition to the list, where we haven't finished
+  // reading the torrent file or file(s) to seed & don't have an infohash
+  copy.torrents = copy.torrents
+    .filter((x) => x.infoHash)
+    .map(x => {
+      const torrent = {}
+      for (const key in x) {
+        if (key === 'progress' || key === 'torrentKey') {
+          continue // Don't save progress info or key for the webtorrent process
+        }
+        if (key === 'error') {
+          continue // Don't save error states
+        }
+        torrent[key] = x[key]
+      }
+      return torrent
+    })
+
+  try {
+    await appConfig.write(copy)
+    State.emit('stateSaved')
+  } catch (err) {
+    console.error(err)
+  }
+}

src/renderer/lib/telemetry.js

@@ -0,0 +1,222 @@
+// Collects anonymous usage stats and uncaught errors
+// Reports back so that we can improve WebTorrent Desktop
+module.exports = {
+  init,
+  send,
+  logUncaughtError,
+  logPlayAttempt
+}
+
+const remote = require('@electron/remote')
+
+const config = require('../../config')
+
+let telemetry
+
+function init (state) {
+  telemetry = state.saved.telemetry
+
+  // First app run
+  if (!telemetry) {
+    const crypto = require('crypto')
+    telemetry = state.saved.telemetry = {
+      userID: crypto.randomBytes(32).toString('hex') // 256-bit random ID
+    }
+    reset()
+  }
+}
+
+function send (state) {
+  const now = new Date()
+  telemetry.version = config.APP_VERSION
+  telemetry.timestamp = now.toISOString()
+  telemetry.localTime = now.toTimeString()
+  telemetry.screens = getScreenInfo()
+  telemetry.system = getSystemInfo()
+  telemetry.torrentStats = getTorrentStats(state)
+  telemetry.approxNumTorrents = telemetry.torrentStats.approxCount
+
+  if (!config.IS_PRODUCTION) {
+    // Development: telemetry used only for local debugging
+    // Empty uncaught errors, etc at the start of every run
+    return reset()
+  }
+
+  const get = require('simple-get')
+
+  const opts = {
+    url: config.TELEMETRY_URL,
+    body: telemetry,
+    json: true
+  }
+
+  get.post(opts, (err, res) => {
+    if (err) return console.error('Error sending telemetry', err)
+    if (res.statusCode !== 200) {
+      return console.error(`Error sending telemetry, status code: ${res.statusCode}`)
+    }
+    console.log('Sent telemetry')
+    reset()
+  })
+}
+
+function reset () {
+  telemetry.uncaughtErrors = []
+  telemetry.playAttempts = {
+    minVersion: config.APP_VERSION,
+    total: 0,
+    success: 0,
+    error: 0,
+    external: 0,
+    abandoned: 0
+  }
+}
+
+// Track screen resolution
+function getScreenInfo () {
+  return remote.screen.getAllDisplays().map((screen) => ({
+    width: screen.size.width,
+    height: screen.size.height,
+    scaleFactor: screen.scaleFactor
+  }))
+}
+
+// Track basic system info like OS version and amount of RAM
+function getSystemInfo () {
+  const os = require('os')
+  return {
+    osPlatform: process.platform,
+    osRelease: os.type() + ' ' + os.release(),
+    architecture: os.arch(),
+    systemArchitecture: config.OS_SYSARCH,
+    totalMemoryMB: roundPow2(os.totalmem() / (1 << 20)),
+    numCores: os.cpus().length
+  }
+}
+
+// Get stats like the # of torrents currently active, # in list, total size
+function getTorrentStats (state) {
+  const count = state.saved.torrents.length
+  let sizeMB = 0
+  const byStatus = {
+    new: { count: 0, sizeMB: 0 },
+    downloading: { count: 0, sizeMB: 0 },
+    seeding: { count: 0, sizeMB: 0 },
+    paused: { count: 0, sizeMB: 0 }
+  }
+
+  // First, count torrents & total file size
+  for (const torrent of state.saved.torrents) {
+    const stat = byStatus[torrent.status]
+    if (!torrent || !torrent.files || !stat) continue
+    stat.count++
+
+    for (const file of torrent.files) {
+      if (!file || !file.length) continue
+      const fileSizeMB = file.length / (1 << 20)
+      sizeMB += fileSizeMB
+      stat.sizeMB += fileSizeMB
+    }
+  }
+
+  // Then, round all the counts and sums to the nearest power of 2
+  const ret = roundTorrentStats({ count, sizeMB })
+  ret.byStatus = {
+    new: roundTorrentStats(byStatus.new),
+    downloading: roundTorrentStats(byStatus.downloading),
+    seeding: roundTorrentStats(byStatus.seeding),
+    paused: roundTorrentStats(byStatus.paused)
+  }
+  return ret
+}
+
+function roundTorrentStats (stats) {
+  return {
+    approxCount: roundPow2(stats.count),
+    approxSizeMB: roundPow2(stats.sizeMB)
+  }
+}
+
+// Rounds to the nearest power of 2, for privacy and easy bucketing.
+// Rounds 35 to 32, 70 to 64, 5 to 4, 1 to 1, 0 to 0.
+// Supports nonnegative numbers only.
+function roundPow2 (n) {
+  if (n <= 0) return 0
+  // Otherwise, return 1, 2, 4, 8, etc by rounding in log space
+  const log2 = Math.log(n) / Math.log(2)
+  return 2 ** Math.round(log2)
+}
+
+// An uncaught error happened in the main process or in one of the windows
+function logUncaughtError (procName, e) {
+  // Not initialized yet? Ignore.
+  // Hopefully uncaught errors immediately on startup are fixed in dev
+  if (!telemetry) return
+
+  let message
+  let stack = ''
+  if (e == null) {
+    message = 'Unexpected undefined error'
+  } else if (e.error) {
+    // Uncaught Javascript errors (window.onerror), err is an ErrorEvent
+    if (!e.error.message) {
+      message = 'Unexpected ErrorEvent.error: ' + Object.keys(e.error).join(' ')
+    } else {
+      message = e.error.message
+      stack = e.error.stack
+    }
+  } else if (e.message) {
+    // err is either an Error or a plain object {message, stack}
+    message = e.message
+    stack = e.stack
+  } else {
+    // Resource errors (captured element.onerror), err is an Event
+    if (!e.target) {
+      message = 'Unexpected unknown error'
+    } else if (!e.target.error) {
+      message = 'Unexpected resource loading error: ' + getElemString(e.target)
+    } else {
+      message = 'Resource error ' + getElemString(e.target) + ': ' + e.target.error.code
+    }
+  }
+
+  if (typeof stack !== 'string') stack = 'Unexpected stack: ' + stack
+  if (typeof message !== 'string') message = 'Unexpected message: ' + message
+
+  // Remove the first part of each file path in the stack trace.
+  // - Privacy: remove personal info like C:\Users\<full name>
+  // - Aggregation: this lets us find which stacktraces occur often
+  stack = stack.replace(/\(.*app.asar/g, '(...')
+  stack = stack.replace(/at .*app.asar/g, 'at ...')
+
+  // We need to POST the telemetry object, make sure it stays < 100kb
+  if (telemetry.uncaughtErrors.length > 20) return
+  if (message.length > 1000) message = message.substring(0, 1000)
+  if (stack.length > 1000) stack = stack.substring(0, 1000)
+
+  // Log the app version *at the time of the error*
+  const version = config.APP_VERSION
+
+  telemetry.uncaughtErrors.push({ process: procName, message, stack, version })
+}
+
+// Turns a DOM element into a string, eg "DIV.my-class.visible"
+function getElemString (elem) {
+  let ret = elem.tagName
+  try {
+    ret += '.' + Array.from(elem.classList).join('.')
+  } catch (err) {}
+  return ret
+}
+
+// The user pressed play. Did it work, display an error,
+// open an external player or did user abandon the attempt?
+function logPlayAttempt (result) {
+  if (!['success', 'error', 'external', 'abandoned'].includes(result)) {
+    return console.error('Unknown play attempt result', result)
+  }
+
+  const attempts = telemetry.playAttempts
+  attempts.total = (attempts.total || 0) + 1
+  attempts[result] = (attempts[result] || 0) + 1
+}

src/renderer/lib/time.js

@@ -0,0 +1,20 @@
+module.exports = {
+  calculateEta
+}
+
+function calculateEta (missing, downloadSpeed) {
+  if (downloadSpeed === 0 || missing === 0) return
+
+  const rawEta = missing / downloadSpeed
+  const hours = Math.floor(rawEta / 3600) % 24
+  const minutes = Math.floor(rawEta / 60) % 60
+  const seconds = Math.floor(rawEta % 60)
+
+  // Only display hours and minutes if they are greater than 0 but always
+  // display minutes if hours is being displayed
+  const hoursStr = hours ? hours + ' h' : ''
+  const minutesStr = (hours || minutes) ? minutes + ' min' : ''
+  const secondsStr = seconds + ' s'
+
+  return `${hoursStr} ${minutesStr} ${secondsStr} remaining`
+}

src/renderer/lib/torrent-player.js

@@ -0,0 +1,53 @@
+module.exports = {
+  isPlayable,
+  isVideo,
+  isAudio,
+  isTorrent,
+  isMagnetLink,
+  isPlayableTorrentSummary
+}
+
+const path = require('path')
+
+const mediaExtensions = require('./media-extensions')
+
+// Checks whether a fileSummary or file path is audio/video that we can play,
+// based on the file extension
+function isPlayable (file) {
+  return isVideo(file) || isAudio(file)
+}
+
+// Checks whether a fileSummary or file path is playable video
+function isVideo (file) {
+  return mediaExtensions.video.includes(getFileExtension(file))
+}
+
+// Checks whether a fileSummary or file path is playable audio
+function isAudio (file) {
+  return mediaExtensions.audio.includes(getFileExtension(file))
+}
+
+// Checks if the argument is either:
+// - a string that's a valid filename ending in .torrent
+// - a file object where obj.name is ends in .torrent
+// - a string that's a magnet link (magnet://...)
+function isTorrent (file) {
+  return isTorrentFile(file) || isMagnetLink(file)
+}
+
+function isTorrentFile (file) {
+  return getFileExtension(file) === '.torrent'
+}
+
+function isMagnetLink (link) {
+  return typeof link === 'string' && /^(stream-)?magnet:/.test(link)
+}
+
+function getFileExtension (file) {
+  const name = typeof file === 'string' ? file : file.name
+  return path.extname(name).toLowerCase()
+}
+
+function isPlayableTorrentSummary (torrentSummary) {
+  return torrentSummary.files && torrentSummary.files.some(isPlayable)
+}

src/renderer/lib/torrent-poster.js

@@ -0,0 +1,182 @@
+module.exports = torrentPoster
+
+const captureFrame = require('capture-frame')
+const path = require('path')
+
+const mediaExtensions = require('./media-extensions')
+
+const msgNoSuitablePoster = 'Cannot generate a poster from any files in the torrent'
+
+function torrentPoster (torrent, cb) {
+  // First, try to use a poster image if available
+  const posterFile = torrent.files.filter(file => /^poster\.(jpg|png|gif)$/.test(file.name))[0]
+  if (posterFile) return extractPoster(posterFile, cb)
+
+  // 'score' each media type based on total size present in torrent
+  const bestScore = ['audio', 'video', 'image'].map(mediaType => ({
+    type: mediaType,
+    size: calculateDataLengthByExtension(torrent, mediaExtensions[mediaType])
+  })).sort((a, b) => b.size - a.size)[0] // sort descending on size
+
+  if (bestScore.size === 0) {
+    // Admit defeat, no video, audio or image had a significant presence
+    return cb(new Error(msgNoSuitablePoster))
+  }
+
+  // Based on which media type is dominant we select the corresponding poster function
+  switch (bestScore.type) {
+    case 'audio':
+      return torrentPosterFromAudio(torrent, cb)
+    case 'image':
+      return torrentPosterFromImage(torrent, cb)
+    case 'video':
+      return torrentPosterFromVideo(torrent, cb)
+  }
+}
+
+/**
+ * Calculate the total data size of file matching one of the provided extensions
+ * @param torrent
+ * @param extensions List of extension to match
+ * @returns {number} total size, of matches found (>= 0)
+ */
+function calculateDataLengthByExtension (torrent, extensions) {
+  const files = filterOnExtension(torrent, extensions)
+  if (files.length === 0) return 0
+  return files
+    .map(file => file.length)
+    .reduce((a, b) => a + b)
+}
+
+/**
+ * Get the largest file of a given torrent, filtered by provided extension
+ * @param torrent Torrent to search in
+ * @param extensions Extension whitelist filter
+ * @returns Torrent file object
+ */
+function getLargestFileByExtension (torrent, extensions) {
+  const files = filterOnExtension(torrent, extensions)
+  if (files.length === 0) return undefined
+  return files.reduce((a, b) => a.length > b.length ? a : b)
+}
+
+/**
+ * Filter file on a list extension, can be used to find al image files
+ * @param torrent Torrent to filter files from
+ * @param extensions File extensions to filter on
+ * @returns {Array} Array of torrent file objects matching one of the given extensions
+ */
+function filterOnExtension (torrent, extensions) {
+  return torrent.files.filter(file => {
+    const extname = path.extname(file.name).toLowerCase()
+    return extensions.indexOf(extname) !== -1
+  })
+}
+
+/**
+ * Returns a score how likely the file is suitable as a poster
+ * @param imgFile File object of an image
+ * @returns {number} Score, higher score is a better match
+ */
+function scoreAudioCoverFile (imgFile) {
+  const fileName = path.basename(imgFile.name, path.extname(imgFile.name)).toLowerCase()
+  const relevanceScore = {
+    cover: 80,
+    folder: 80,
+    album: 80,
+    front: 80,
+    back: 20,
+    spectrogram: -80
+  }
+
+  for (const keyword in relevanceScore) {
+    if (fileName === keyword) {
+      return relevanceScore[keyword]
+    }
+    if (fileName.indexOf(keyword) !== -1) {
+      return relevanceScore[keyword]
+    }
+  }
+  return 0
+}
+
+function torrentPosterFromAudio (torrent, cb) {
+  const imageFiles = filterOnExtension(torrent, mediaExtensions.image)
+
+  if (imageFiles.length === 0) return cb(new Error(msgNoSuitablePoster))
+
+  const bestCover = imageFiles.map(file => ({
+    file,
+    score: scoreAudioCoverFile(file)
+  })).reduce((a, b) => {
+    if (a.score > b.score) {
+      return a
+    }
+    if (b.score > a.score) {
+      return b
+    }
+    // If score is equal, pick the largest file, aiming for highest resolution
+    if (a.file.length > b.file.length) {
+      return a
+    }
+    return b
+  })
+
+  const extname = path.extname(bestCover.file.name)
+  bestCover.file.getBuffer((err, buf) => cb(err, buf, extname))
+}
+
+function torrentPosterFromVideo (torrent, cb) {
+  const file = getLargestFileByExtension(torrent, mediaExtensions.video)
+
+  const index = torrent.files.indexOf(file)
+
+  const server = torrent.createServer(0)
+  server.listen(0, onListening)
+
+  function onListening () {
+    const port = server.address().port
+    const url = 'http://localhost:' + port + '/' + index
+    const video = document.createElement('video')
+    video.addEventListener('canplay', onCanPlay)
+
+    video.volume = 0
+    video.src = url
+    video.play()
+
+    function onCanPlay () {
+      video.removeEventListener('canplay', onCanPlay)
+      video.addEventListener('seeked', onSeeked)
+
+      video.currentTime = Math.min((video.duration || 600) * 0.03, 60)
+    }
+
+    function onSeeked () {
+      video.removeEventListener('seeked', onSeeked)
+
+      const frame = captureFrame(video)
+      const buf = frame && frame.image
+
+      // unload video element
+      video.pause()
+      video.src = ''
+      video.load()
+
+      server.destroy()
+
+      if (buf.length === 0) return cb(new Error(msgNoSuitablePoster))
+
+      cb(null, buf, '.jpg')
+    }
+  }
+}
+
+function torrentPosterFromImage (torrent, cb) {
+  const file = getLargestFileByExtension(torrent, mediaExtensions.image)
+  extractPoster(file, cb)
+}
+
+function extractPoster (file, cb) {
+  const extname = path.extname(file.name)
+  file.getBuffer((err, buf) => cb(err, buf, extname))
+}

src/renderer/lib/torrent-summary.js

@@ -0,0 +1,58 @@
+module.exports = {
+  getPosterPath,
+  getTorrentPath,
+  getByKey,
+  getTorrentId,
+  getFileOrFolder
+}
+
+const path = require('path')
+const config = require('../../config')
+
+// Expects a torrentSummary
+// Returns an absolute path to the torrent file, or null if unavailable
+function getTorrentPath (torrentSummary) {
+  if (!torrentSummary || !torrentSummary.torrentFileName) return null
+  return path.join(config.TORRENT_PATH, torrentSummary.torrentFileName)
+}
+
+// Expects a torrentSummary
+// Returns an absolute path to the poster image, or null if unavailable
+function getPosterPath (torrentSummary) {
+  if (!torrentSummary || !torrentSummary.posterFileName) return null
+  const posterPath = path.join(config.POSTER_PATH, torrentSummary.posterFileName)
+  // Work around a Chrome bug (reproduced in vanilla Chrome, not just Electron):
+  // Backslashes in URLS in CSS cause bizarre string encoding issues
+  return posterPath.replace(/\\/g, '/')
+}
+
+// Expects a torrentSummary
+// Returns a torrentID: filename, magnet URI, or infohash
+function getTorrentId (torrentSummary) {
+  const s = torrentSummary
+  if (s.torrentFileName) { // Load torrent file from disk
+    return getTorrentPath(s)
+  } else { // Load torrent from DHT
+    return s.magnetURI || s.infoHash
+  }
+}
+
+// Expects a torrentKey or infoHash
+// Returns the corresponding torrentSummary, or undefined
+function getByKey (state, torrentKey) {
+  if (!torrentKey) return undefined
+  return state.saved.torrents.find((x) =>
+    x.torrentKey === torrentKey || x.infoHash === torrentKey)
+}
+
+// Returns the path to either the file (in a single-file torrent) or the root
+// folder (in  multi-file torrent)
+// WARNING: assumes that multi-file torrents consist of a SINGLE folder.
+// TODO: make this assumption explicit, enforce it in the `create-torrent`
+// module. Store root folder explicitly to avoid hacky path processing below.
+function getFileOrFolder (torrentSummary) {
+  const ts = torrentSummary
+  if (!ts.path || !ts.files || ts.files.length === 0) return null
+  const dirname = ts.files[0].path.split(path.sep)[0]
+  return path.join(ts.path, dirname)
+}

src/renderer/main.js

@@ -0,0 +1,607 @@
+/**
+ * Perf optimization: Hook into require() to modify how certain modules load:
+ *
+ * - `inline-style-prefixer` (used by `material-ui`) takes ~40ms. It is not
+ *   actually used because auto-prefixing is disabled with
+ *   `darkBaseTheme.userAgent = false`. Return a fake object.
+ */
+const Module = require('module')
+const _require = Module.prototype.require
+Module.prototype.require = function (id) {
+  if (id === 'inline-style-prefixer') return {}
+  return _require.apply(this, arguments)
+}
+
+console.time('init')
+
+// Perf optimization: Start asynchronously read on config file before all the
+// blocking require() calls below.
+
+const State = require('./lib/state')
+State.load(onState)
+
+const createGetter = require('fn-getter')
+const debounce = require('debounce')
+const dragDrop = require('drag-drop')
+const electron = require('electron')
+const fs = require('fs')
+const React = require('react')
+const ReactDOM = require('react-dom')
+
+const config = require('../config')
+const telemetry = require('./lib/telemetry')
+const sound = require('./lib/sound')
+const TorrentPlayer = require('./lib/torrent-player')
+
+// Perf optimization: Needed immediately, so do not lazy load it below
+const TorrentListController = require('./controllers/torrent-list-controller')
+
+const App = require('./pages/app')
+
+// Electron apps have two processes: a main process (node) runs first and starts
+// a renderer process (essentially a Chrome window). We're in the renderer process,
+// and this IPC channel receives from and sends messages to the main process
+const ipcRenderer = electron.ipcRenderer
+
+// Yo-yo pattern: state object lives here and percolates down thru all the views.
+// Events come back up from the views via dispatch(...)
+require('./lib/dispatcher').setDispatch(dispatch)
+
+// From dispatch(...), events are sent to one of the controllers
+let controllers = null
+
+// This dependency is the slowest-loading, so we lazy load it
+let Cast = null
+
+// All state lives in state.js. `state.saved` is read from and written to a file.
+// All other state is ephemeral. First we load state.saved then initialize the app.
+let state
+
+// Root React component
+let app
+
+// Called once when the application loads. (Not once per window.)
+// Connects to the torrent networks, sets up the UI and OS integrations like
+// the dock icon and drag+drop.
+function onState (err, _state) {
+  if (err) return onError(err)
+
+  // Make available for easier debugging
+  state = window.state = _state
+  window.dispatch = dispatch
+
+  telemetry.init(state)
+  sound.init(state)
+
+  // Log uncaught JS errors
+  window.addEventListener(
+    'error', (e) => telemetry.logUncaughtError('window', e), true /* capture */
+  )
+
+  // Create controllers
+  controllers = {
+    media: createGetter(() => {
+      const MediaController = require('./controllers/media-controller')
+      return new MediaController(state)
+    }),
+    playback: createGetter(() => {
+      const PlaybackController = require('./controllers/playback-controller')
+      return new PlaybackController(state, config, update)
+    }),
+    prefs: createGetter(() => {
+      const PrefsController = require('./controllers/prefs-controller')
+      return new PrefsController(state, config)
+    }),
+    subtitles: createGetter(() => {
+      const SubtitlesController = require('./controllers/subtitles-controller')
+      return new SubtitlesController(state)
+    }),
+    audioTracks: createGetter(() => {
+      const AudioTracksController = require('./controllers/audio-tracks-controller')
+      return new AudioTracksController(state)
+    }),
+    torrent: createGetter(() => {
+      const TorrentController = require('./controllers/torrent-controller')
+      return new TorrentController(state)
+    }),
+    torrentList: createGetter(() => new TorrentListController(state)),
+    update: createGetter(() => {
+      const UpdateController = require('./controllers/update-controller')
+      return new UpdateController(state)
+    }),
+    folderWatcher: createGetter(() => {
+      const FolderWatcherController = require('./controllers/folder-watcher-controller')
+      return new FolderWatcherController()
+    })
+  }
+
+  // Add first page to location history
+  state.location.go({
+    url: 'home',
+    setup: (cb) => {
+      state.window.title = config.APP_WINDOW_TITLE
+      cb(null)
+    }
+  })
+
+  // Give global trackers
+  setGlobalTrackers()
+
+  // Restart everything we were torrenting last time the app ran
+  resumeTorrents()
+
+  // Initialize ReactDOM
+  ReactDOM.render(
+    <App state={state} ref={elem => { app = elem }} />,
+    document.querySelector('#body')
+  )
+
+  // Calling update() updates the UI given the current state
+  // Do this at least once a second to give every file in every torrentSummary
+  // a progress bar and to keep the cursor in sync when playing a video
+  setInterval(update, 1000)
+
+  // Listen for messages from the main process
+  setupIpc()
+
+  // Drag and drop files/text to start torrenting or seeding
+  dragDrop('body', {
+    onDrop: onOpen,
+    onDropText: onOpen
+  })
+
+  // ...same thing if you paste a torrent
+  document.addEventListener('paste', onPaste)
+
+  // Add YouTube style hotkey shortcuts
+  window.addEventListener('keydown', onKeydown)
+
+  const debouncedFullscreenToggle = debounce(() => {
+    dispatch('toggleFullScreen')
+  }, 1000, true)
+
+  document.addEventListener('wheel', event => {
+    // ctrlKey detects pinch to zoom, http://crbug.com/289887
+    if (event.ctrlKey) {
+      event.preventDefault()
+      debouncedFullscreenToggle()
+    }
+  })
+
+  // ...focus and blur. Needed to show correct dock icon text ('badge') in OSX
+  window.addEventListener('focus', onFocus)
+  window.addEventListener('blur', onBlur)
+
+  if (electron.remote.getCurrentWindow().isVisible()) {
+    sound.play('STARTUP')
+  }
+
+  // To keep app startup fast, some code is delayed.
+  window.setTimeout(delayedInit, config.DELAYED_INIT)
+
+  // Done! Ideally we want to get here < 500ms after the user clicks the app
+  console.timeEnd('init')
+}
+
+// Runs a few seconds after the app loads, to avoid slowing down startup time
+function delayedInit () {
+  telemetry.send(state)
+
+  // Send telemetry data every 12 hours, for users who keep the app running
+  // for extended periods of time
+  setInterval(() => telemetry.send(state), 12 * 3600 * 1000)
+
+  // Warn if the download dir is gone, eg b/c an external drive is unplugged
+  checkDownloadPath()
+
+  // ...window visibility state.
+  document.addEventListener('webkitvisibilitychange', onVisibilityChange)
+  onVisibilityChange()
+
+  lazyLoadCast()
+}
+
+// Lazily loads Chromecast and Airplay support
+function lazyLoadCast () {
+  if (!Cast) {
+    Cast = require('./lib/cast')
+    Cast.init(state, update) // Search the local network for Chromecast and Airplays
+  }
+  return Cast
+}
+
+// React loop:
+// 1. update() - recompute the virtual DOM, diff, apply to the real DOM
+// 2. event - might be a click or other DOM event, or something external
+// 3. dispatch - the event handler calls dispatch(), main.js sends it to a controller
+// 4. controller - the controller handles the event, changing the state object
+function update () {
+  controllers.playback().showOrHidePlayerControls()
+  app.setState(state)
+  updateElectron()
+}
+
+// Some state changes can't be reflected in the DOM, instead we have to
+// tell the main process to update the window or OS integrations
+function updateElectron () {
+  if (state.window.title !== state.prev.title) {
+    state.prev.title = state.window.title
+    ipcRenderer.send('setTitle', state.window.title)
+  }
+  if (state.dock.progress.toFixed(2) !== state.prev.progress.toFixed(2)) {
+    state.prev.progress = state.dock.progress
+    ipcRenderer.send('setProgress', state.dock.progress)
+  }
+  if (state.dock.badge !== state.prev.badge) {
+    state.prev.badge = state.dock.badge
+    ipcRenderer.send('setBadge', state.dock.badge || 0)
+  }
+}
+
+const dispatchHandlers = {
+  // Torrent list: creating, deleting, selecting torrents
+  openTorrentFile: () => ipcRenderer.send('openTorrentFile'),
+  openFiles: () => ipcRenderer.send('openFiles'), /* shows the open file dialog */
+  openTorrentAddress: () => { state.modal = { id: 'open-torrent-address-modal' } },
+
+  addTorrent: (torrentId) => controllers.torrentList().addTorrent(torrentId),
+  showCreateTorrent: (paths) => controllers.torrentList().showCreateTorrent(paths),
+  createTorrent: (options) => controllers.torrentList().createTorrent(options),
+  toggleTorrent: (infoHash) => controllers.torrentList().toggleTorrent(infoHash),
+  pauseAllTorrents: () => controllers.torrentList().pauseAllTorrents(),
+  resumeAllTorrents: () => controllers.torrentList().resumeAllTorrents(),
+  toggleTorrentFile: (infoHash, index) =>
+    controllers.torrentList().toggleTorrentFile(infoHash, index),
+  confirmDeleteTorrent: (infoHash, deleteData) =>
+    controllers.torrentList().confirmDeleteTorrent(infoHash, deleteData),
+  deleteTorrent: (infoHash, deleteData) =>
+    controllers.torrentList().deleteTorrent(infoHash, deleteData),
+  openTorrentListContextMenu: () => onPaste(),
+  confirmDeleteAllTorrents: (deleteData) =>
+    controllers.torrentList().confirmDeleteAllTorrents(deleteData),
+  deleteAllTorrents: (deleteData) =>
+    controllers.torrentList().deleteAllTorrents(deleteData),
+  toggleSelectTorrent: (infoHash) =>
+    controllers.torrentList().toggleSelectTorrent(infoHash),
+  openTorrentContextMenu: (infoHash) =>
+    controllers.torrentList().openTorrentContextMenu(infoHash),
+  startTorrentingSummary: (torrentKey) =>
+    controllers.torrentList().startTorrentingSummary(torrentKey),
+  saveTorrentFileAs: (torrentKey) =>
+    controllers.torrentList().saveTorrentFileAs(torrentKey),
+  prioritizeTorrent: (infoHash) => controllers.torrentList().prioritizeTorrent(infoHash),
+  resumePausedTorrents: () => controllers.torrentList().resumePausedTorrents(),
+
+  // Playback
+  playFile: (infoHash, index) => controllers.playback().playFile(infoHash, index),
+  playPause: () => controllers.playback().playPause(),
+  nextTrack: () => controllers.playback().nextTrack(),
+  previousTrack: () => controllers.playback().previousTrack(),
+  skip: (time) => controllers.playback().skip(time),
+  skipTo: (time) => controllers.playback().skipTo(time),
+  preview: (x) => controllers.playback().preview(x),
+  clearPreview: () => controllers.playback().clearPreview(),
+  changePlaybackRate: (dir) => controllers.playback().changePlaybackRate(dir),
+  changeVolume: (delta) => controllers.playback().changeVolume(delta),
+  setVolume: (vol) => controllers.playback().setVolume(vol),
+  openPath: (infoHash, index) => controllers.playback().openPath(infoHash, index),
+
+  // Subtitles
+  openSubtitles: () => controllers.subtitles().openSubtitles(),
+  selectSubtitle: (index) => controllers.subtitles().selectSubtitle(index),
+  toggleSubtitlesMenu: () => controllers.subtitles().toggleSubtitlesMenu(),
+  checkForSubtitles: () => controllers.subtitles().checkForSubtitles(),
+  addSubtitles: (files, autoSelect) => controllers.subtitles().addSubtitles(files, autoSelect),
+
+  // Audio Tracks
+  selectAudioTrack: (index) => controllers.audioTracks().selectAudioTrack(index),
+  toggleAudioTracksMenu: () => controllers.audioTracks().toggleAudioTracksMenu(),
+
+  // Local media: <video>, <audio>, external players
+  mediaStalled: () => controllers.media().mediaStalled(),
+  mediaError: (err) => controllers.media().mediaError(err),
+  mediaSuccess: () => controllers.media().mediaSuccess(),
+  mediaTimeUpdate: () => controllers.media().mediaTimeUpdate(),
+  mediaMouseMoved: () => controllers.media().mediaMouseMoved(),
+  mediaControlsMouseEnter: () => controllers.media().controlsMouseEnter(),
+  mediaControlsMouseLeave: () => controllers.media().controlsMouseLeave(),
+  openExternalPlayer: () => controllers.media().openExternalPlayer(),
+  externalPlayerNotFound: () => controllers.media().externalPlayerNotFound(),
+
+  // Remote casting: Chromecast, Airplay, etc
+  toggleCastMenu: (deviceType) => lazyLoadCast().toggleMenu(deviceType),
+  selectCastDevice: (index) => lazyLoadCast().selectDevice(index),
+  stopCasting: () => lazyLoadCast().stop(),
+
+  // Preferences screen
+  preferences: () => controllers.prefs().show(),
+  updatePreferences: (key, value) => controllers.prefs().update(key, value),
+  checkDownloadPath,
+  updateGlobalTrackers: (trackers) => setGlobalTrackers(trackers),
+  startFolderWatcher: () => controllers.folderWatcher().start(),
+  stopFolderWatcher: () => controllers.folderWatcher().stop(),
+
+  // Update (check for new versions on Linux, where there's no auto updater)
+  updateAvailable: (version) => controllers.update().updateAvailable(version),
+  skipVersion: (version) => controllers.update().skipVersion(version),
+
+  // Navigation between screens (back, forward, ESC, etc)
+  exitModal: () => { state.modal = null },
+  backToList,
+  escapeBack,
+  back: () => state.location.back(),
+  forward: () => state.location.forward(),
+  cancel: () => state.location.cancel(),
+
+  // Controlling the window
+  setDimensions,
+  toggleFullScreen: (setTo) => ipcRenderer.send('toggleFullScreen', setTo),
+  setTitle: (title) => { state.window.title = title },
+  resetTitle: () => { state.window.title = config.APP_WINDOW_TITLE },
+
+  // Everything else
+  onOpen,
+  error: onError,
+  uncaughtError: (proc, err) => telemetry.logUncaughtError(proc, err),
+  stateSave: () => State.save(state),
+  stateSaveImmediate: () => State.saveImmediate(state),
+  update: () => {} // No-op, just trigger an update
+}
+
+// Events from the UI never modify state directly. Instead they call dispatch()
+function dispatch (action, ...args) {
+  // Log dispatch calls, for debugging, but don't spam
+  if (!['mediaMouseMoved', 'mediaTimeUpdate', 'update'].includes(action)) {
+    console.log('dispatch: %s %o', action, args)
+  }
+
+  const handler = dispatchHandlers[action]
+  if (handler) handler(...args)
+  else console.error('Missing dispatch handler: ' + action)
+
+  // Update the virtual DOM, unless it's just a mouse move event
+  if (action !== 'mediaMouseMoved' ||
+      controllers.playback().showOrHidePlayerControls()) {
+    update()
+  }
+}
+
+// Listen to events from the main and webtorrent processes
+function setupIpc () {
+  ipcRenderer.on('log', (e, ...args) => console.log(...args))
+  ipcRenderer.on('error', (e, ...args) => console.error(...args))
+
+  ipcRenderer.on('dispatch', (e, ...args) => dispatch(...args))
+
+  ipcRenderer.on('fullscreenChanged', onFullscreenChanged)
+  ipcRenderer.on('windowBoundsChanged', onWindowBoundsChanged)
+
+  const tc = controllers.torrent()
+  ipcRenderer.on('wt-parsed', (e, ...args) => tc.torrentParsed(...args))
+  ipcRenderer.on('wt-metadata', (e, ...args) => tc.torrentMetadata(...args))
+  ipcRenderer.on('wt-done', (e, ...args) => tc.torrentDone(...args))
+  ipcRenderer.on('wt-done', () => controllers.torrentList().resumePausedTorrents())
+  ipcRenderer.on('wt-warning', (e, ...args) => tc.torrentWarning(...args))
+  ipcRenderer.on('wt-error', (e, ...args) => tc.torrentError(...args))
+
+  ipcRenderer.on('wt-progress', (e, ...args) => tc.torrentProgress(...args))
+  ipcRenderer.on('wt-file-modtimes', (e, ...args) => tc.torrentFileModtimes(...args))
+  ipcRenderer.on('wt-file-saved', (e, ...args) => tc.torrentFileSaved(...args))
+  ipcRenderer.on('wt-poster', (e, ...args) => tc.torrentPosterSaved(...args))
+  ipcRenderer.on('wt-audio-metadata', (e, ...args) => tc.torrentAudioMetadata(...args))
+  ipcRenderer.on('wt-server-running', (e, ...args) => tc.torrentServerRunning(...args))
+
+  ipcRenderer.on('wt-uncaught-error', (e, err) => telemetry.logUncaughtError('webtorrent', err))
+
+  ipcRenderer.send('ipcReady')
+
+  State.on('stateSaved', () => ipcRenderer.send('stateSaved'))
+}
+
+// Quits any modal popovers and returns to the torrent list screen
+function backToList () {
+  // Exit any modals and screens with a back button
+  state.modal = null
+  state.location.backToFirst(() => {
+    // If we were already on the torrent list, scroll to the top
+    const contentTag = document.querySelector('.content')
+    if (contentTag) contentTag.scrollTop = 0
+  })
+}
+
+// Quits modals, full screen, or goes back. Happens when the user hits ESC
+function escapeBack () {
+  if (state.modal) {
+    dispatch('exitModal')
+  } else if (state.window.isFullScreen) {
+    dispatch('toggleFullScreen')
+  } else {
+    dispatch('back')
+  }
+}
+
+function setGlobalTrackers () {
+  controllers.torrentList().setGlobalTrackers(state.getGlobalTrackers())
+}
+
+// Starts all torrents that aren't paused on program startup
+function resumeTorrents () {
+  state.saved.torrents
+    .map((torrentSummary) => {
+      // Torrent keys are ephemeral, reassigned each time the app runs.
+      // On startup, give all torrents a key, even the ones that are paused.
+      torrentSummary.torrentKey = state.nextTorrentKey++
+      return torrentSummary
+    })
+    .filter((s) => s.status !== 'paused')
+    .forEach((s) => controllers.torrentList().startTorrentingSummary(s.torrentKey))
+}
+
+// Set window dimensions to match video dimensions or fill the screen
+function setDimensions (dimensions) {
+  // Don't modify the window size if it's already maximized
+  if (electron.remote.getCurrentWindow().isMaximized()) {
+    state.window.bounds = null
+    return
+  }
+
+  // Save the bounds of the window for later. See restoreBounds()
+  state.window.bounds = {
+    x: window.screenX,
+    y: window.screenY,
+    width: window.outerWidth,
+    height: window.outerHeight
+  }
+  state.window.wasMaximized = electron.remote.getCurrentWindow().isMaximized
+
+  // Limit window size to screen size
+  const screenWidth = window.screen.width
+  const screenHeight = window.screen.height
+  const aspectRatio = dimensions.width / dimensions.height
+  const scaleFactor = Math.min(
+    Math.min(screenWidth / dimensions.width, 1),
+    Math.min(screenHeight / dimensions.height, 1)
+  )
+  const width = Math.max(
+    Math.floor(dimensions.width * scaleFactor),
+    config.WINDOW_MIN_WIDTH
+  )
+  const height = Math.max(
+    Math.floor(dimensions.height * scaleFactor),
+    config.WINDOW_MIN_HEIGHT
+  )
+
+  ipcRenderer.send('setAspectRatio', aspectRatio)
+  ipcRenderer.send('setBounds', { contentBounds: true, x: null, y: null, width, height })
+  state.playing.aspectRatio = aspectRatio
+}
+
+// Called when the user adds files (.torrent, files to seed, subtitles) to the app
+// via any method (drag-drop, drag to app icon, command line)
+function onOpen (files) {
+  if (!Array.isArray(files)) files = [files]
+
+  // File API seems to transform "magnet:?foo" in "magnet:///?foo"
+  // this is a sanitization
+  files = files.map(file => {
+    if (typeof file !== 'string') return file
+    return file.replace(/^magnet:\/+\?/i, 'magnet:?')
+  })
+
+  const url = state.location.url()
+  const allTorrents = files.every(TorrentPlayer.isTorrent)
+  const allSubtitles = files.every(controllers.subtitles().isSubtitle)
+
+  if (allTorrents) {
+    // Drop torrents onto the app: go to home screen, add torrents, no matter what
+    dispatch('backToList')
+    // All .torrent files? Add them.
+    files.forEach((file) => controllers.torrentList().addTorrent(file))
+  } else if (url === 'player' && allSubtitles) {
+    // Drop subtitles onto a playing video: add subtitles
+    controllers.subtitles().addSubtitles(files, true)
+  } else if (url === 'home') {
+    // Drop files onto home screen: show Create Torrent
+    state.modal = null
+    controllers.torrentList().showCreateTorrent(files)
+  } else {
+    // Drop files onto any other screen: show error
+    return onError('Please go back to the torrent list before creating a new torrent.')
+  }
+
+  update()
+}
+
+function onError (err) {
+  console.error(err.stack || err)
+  sound.play('ERROR')
+  state.errors.push({
+    time: new Date().getTime(),
+    message: err.message || err
+  })
+
+  update()
+}
+
+const editableHtmlTags = new Set(['input', 'textarea'])
+
+function onPaste (e) {
+  if (e && editableHtmlTags.has(e.target.tagName.toLowerCase())) return
+  controllers.torrentList().addTorrent(electron.clipboard.readText())
+
+  update()
+}
+
+function onKeydown (e) {
+  // prevent event fire on user input elements
+  if (editableHtmlTags.has(e.target.tagName.toLowerCase())) return
+
+  const key = e.key
+
+  if (key === 'ArrowLeft') {
+    dispatch('skip', -5)
+  } else if (key === 'ArrowRight') {
+    dispatch('skip', 5)
+  } else if (key === 'ArrowUp') {
+    dispatch('changeVolume', 0.1)
+  } else if (key === 'ArrowDown') {
+    dispatch('changeVolume', -0.1)
+  } else if (key === 'j') {
+    dispatch('skip', -10)
+  } else if (key === 'l') {
+    dispatch('skip', 10)
+  } else if (key === 'k') {
+    dispatch('playPause')
+  } else if (key === '>') {
+    dispatch('changePlaybackRate', 1)
+  } else if (key === '<') {
+    dispatch('changePlaybackRate', -1)
+  } else if (key === 'f') {
+    dispatch('toggleFullScreen')
+  }
+
+  update()
+}
+
+function onFocus (e) {
+  state.window.isFocused = true
+  state.dock.badge = 0
+  update()
+}
+
+function onBlur () {
+  state.window.isFocused = false
+  update()
+}
+
+function onVisibilityChange () {
+  state.window.isVisible = !document.hidden
+}
+
+function onFullscreenChanged (e, isFullScreen) {
+  state.window.isFullScreen = isFullScreen
+  if (!isFullScreen) {
+    // Aspect ratio gets reset in fullscreen mode, so restore it (Mac)
+    ipcRenderer.send('setAspectRatio', state.playing.aspectRatio)
+  }
+
+  update()
+}
+
+function onWindowBoundsChanged (e, newBounds) {
+  if (state.location.url() !== 'player') {
+    state.saved.bounds = newBounds
+    dispatch('stateSave')
+  }
+}
+
+function checkDownloadPath () {
+  fs.stat(state.saved.prefs.downloadPath, (err, stat) => {
+    if (err) {
+      state.downloadPathStatus = 'missing'
+      return console.error(err)
+    }
+    if (stat.isDirectory()) state.downloadPathStatus = 'ok'
+    else state.downloadPathStatus = 'missing'
+  })
+}

src/renderer/pages/app.js

@@ -0,0 +1,132 @@
+const colors = require('material-ui/styles/colors')
+const createGetter = require('fn-getter')
+const React = require('react')
+
+const darkBaseTheme = require('material-ui/styles/baseThemes/darkBaseTheme').default
+const getMuiTheme = require('material-ui/styles/getMuiTheme').default
+const MuiThemeProvider = require('material-ui/styles/MuiThemeProvider').default
+
+const Header = require('../components/header')
+
+// Perf optimization: Needed immediately, so do not lazy load it below
+const TorrentListPage = require('./torrent-list-page')
+
+const Views = {
+  home: createGetter(() => TorrentListPage),
+  player: createGetter(() => require('./player-page')),
+  'create-torrent': createGetter(() => require('./create-torrent-page')),
+  preferences: createGetter(() => require('./preferences-page'))
+}
+
+const Modals = {
+  'open-torrent-address-modal': createGetter(
+    () => require('../components/open-torrent-address-modal')
+  ),
+  'remove-torrent-modal': createGetter(() => require('../components/remove-torrent-modal')),
+  'update-available-modal': createGetter(() => require('../components/update-available-modal')),
+  'unsupported-media-modal': createGetter(() => require('../components/unsupported-media-modal')),
+  'delete-all-torrents-modal':
+      createGetter(() => require('../components/delete-all-torrents-modal'))
+}
+
+const fontFamily = process.platform === 'win32'
+  ? '"Segoe UI", sans-serif'
+  : 'BlinkMacSystemFont, "Helvetica Neue", Helvetica, sans-serif'
+
+darkBaseTheme.fontFamily = fontFamily
+darkBaseTheme.userAgent = false
+darkBaseTheme.palette.primary1Color = colors.grey50
+darkBaseTheme.palette.primary2Color = colors.grey50
+darkBaseTheme.palette.primary3Color = colors.grey600
+darkBaseTheme.palette.accent1Color = colors.redA200
+darkBaseTheme.palette.accent2Color = colors.redA400
+darkBaseTheme.palette.accent3Color = colors.redA100
+
+let darkMuiTheme
+let lightMuiTheme
+
+class App extends React.Component {
+  render () {
+    const state = this.props.state
+
+    // Hide player controls while playing video, if the mouse stays still for a while
+    // Never hide the controls when:
+    // * The mouse is over the controls or we're scrubbing (see CSS)
+    // * The video is paused
+    // * The video is playing remotely on Chromecast or Airplay
+    const hideControls = state.shouldHidePlayerControls()
+
+    const cls = [
+      'view-' + state.location.url(), /* e.g. view-home, view-player */
+      'is-' + process.platform /* e.g. is-darwin, is-win32, is-linux */
+    ]
+    if (state.window.isFullScreen) cls.push('is-fullscreen')
+    if (state.window.isFocused) cls.push('is-focused')
+    if (hideControls) cls.push('hide-video-controls')
+
+    if (!darkMuiTheme) {
+      darkMuiTheme = getMuiTheme(darkBaseTheme)
+    }
+
+    return (
+      <MuiThemeProvider muiTheme={darkMuiTheme}>
+        <div className={'app ' + cls.join(' ')}>
+          <Header state={state} />
+          {this.getErrorPopover()}
+          <div key='content' className='content'>{this.getView()}</div>
+          {this.getModal()}
+        </div>
+      </MuiThemeProvider>
+    )
+  }
+
+  getErrorPopover () {
+    const state = this.props.state
+    const now = new Date().getTime()
+    const recentErrors = state.errors.filter((x) => now - x.time < 5000)
+    const hasErrors = recentErrors.length > 0
+
+    const errorElems = recentErrors.map((error, i) => <div key={i} className='error'>{error.message}</div>)
+    return (
+      <div
+        key='errors'
+        className={'error-popover ' + (hasErrors ? 'visible' : 'hidden')}
+      >
+        <div key='title' className='title'>Error</div>
+        {errorElems}
+      </div>
+    )
+  }
+
+  getModal () {
+    const state = this.props.state
+    if (!state.modal) return
+
+    if (!lightMuiTheme) {
+      const lightBaseTheme = require('material-ui/styles/baseThemes/lightBaseTheme').default
+      lightBaseTheme.fontFamily = fontFamily
+      lightBaseTheme.userAgent = false
+      lightMuiTheme = getMuiTheme(lightBaseTheme)
+    }
+
+    const ModalContents = Modals[state.modal.id]()
+    return (
+      <MuiThemeProvider muiTheme={lightMuiTheme}>
+        <div key='modal' className='modal'>
+          <div key='modal-background' className='modal-background' />
+          <div key='modal-content' className='modal-content'>
+            <ModalContents state={state} />
+          </div>
+        </div>
+      </MuiThemeProvider>
+    )
+  }
+
+  getView () {
+    const state = this.props.state
+    const View = Views[state.location.url()]()
+    return (<View state={state} />)
+  }
+}
+
+module.exports = App

src/renderer/pages/create-torrent-page.js

@@ -0,0 +1,227 @@
+const createTorrent = require('create-torrent')
+const path = require('path')
+const prettyBytes = require('prettier-bytes')
+const React = require('react')
+
+const { dispatch, dispatcher } = require('../lib/dispatcher')
+
+const FlatButton = require('material-ui/FlatButton').default
+const RaisedButton = require('material-ui/RaisedButton').default
+const TextField = require('material-ui/TextField').default
+const Checkbox = require('material-ui/Checkbox').default
+
+const CreateTorrentErrorPage = require('../components/create-torrent-error-page')
+const Heading = require('../components/heading')
+const ShowMore = require('../components/show-more')
+
+// Shows a basic UI to create a torrent, from an already-selected file or folder.
+// Includes a "Show Advanced..." button and more advanced UI.
+class CreateTorrentPage extends React.Component {
+  constructor (props) {
+    super(props)
+
+    const state = this.props.state
+    const info = state.location.current()
+
+    // First, extract the base folder that the files are all in
+    let pathPrefix = info.folderPath
+    if (!pathPrefix) {
+      pathPrefix = info.files.map((x) => x.path).reduce(findCommonPrefix)
+      if (!pathPrefix.endsWith('/') && !pathPrefix.endsWith('\\')) {
+        pathPrefix = path.dirname(pathPrefix)
+      }
+    }
+
+    // Then, exclude .DS_Store and other dotfiles
+    const files = info.files
+      .filter((f) => !containsDots(f.path, pathPrefix))
+      .map((f) => ({ name: f.name, path: f.path, size: f.size }))
+    if (files.length === 0) return (<CreateTorrentErrorPage state={state} />)
+
+    // Then, use the name of the base folder (or sole file, for a single file torrent)
+    // as the default name. Show all files relative to the base folder.
+    let defaultName, basePath
+    if (files.length === 1) {
+      // Single file torrent: /a/b/foo.jpg -> torrent name 'foo.jpg', path '/a/b'
+      defaultName = files[0].name
+      basePath = pathPrefix
+    } else {
+      // Multi file torrent: /a/b/{foo, bar}.jpg -> torrent name 'b', path '/a'
+      defaultName = path.basename(pathPrefix)
+      basePath = path.dirname(pathPrefix)
+    }
+
+    // Default trackers
+    const trackers = createTorrent.announceList.join('\n')
+
+    this.state = {
+      comment: '',
+      isPrivate: false,
+      pathPrefix,
+      basePath,
+      defaultName,
+      files,
+      trackers
+    }
+
+    // Create React event handlers only once
+    this.handleSetIsPrivate = (_, isPrivate) => this.setState({ isPrivate })
+    this.handleSetComment = (_, comment) => this.setState({ comment })
+    this.handleSetTrackers = (_, trackers) => this.setState({ trackers })
+    this.handleSubmit = handleSubmit.bind(this)
+  }
+
+  render () {
+    const files = this.state.files
+
+    // Sanity check: show the number of files and total size
+    const numFiles = files.length
+    const totalBytes = files
+      .map((f) => f.size)
+      .reduce((a, b) => a + b, 0)
+    const torrentInfo = `${numFiles} files, ${prettyBytes(totalBytes)}`
+
+    return (
+      <div className='create-torrent'>
+        <Heading level={1}>Create torrent {this.state.defaultName}</Heading>
+        <div className='torrent-info'>{torrentInfo}</div>
+        <div className='torrent-attribute'>
+          <label>Path:</label>
+          <div>{this.state.pathPrefix}</div>
+        </div>
+        <ShowMore
+          style={{
+            marginBottom: 10
+          }}
+          hideLabel='Hide advanced settings...'
+          showLabel='Show advanced settings...'
+        >
+          {this.renderAdvanced()}
+        </ShowMore>
+        <div className='float-right'>
+          <FlatButton
+            className='control cancel'
+            label='Cancel'
+            style={{
+              marginRight: 10
+            }}
+            onClick={dispatcher('cancel')}
+          />
+          <RaisedButton
+            className='control create-torrent-button'
+            label='Create Torrent'
+            primary
+            onClick={this.handleSubmit}
+          />
+        </div>
+      </div>
+    )
+  }
+
+  // Renders everything after clicking Show Advanced...:
+  // * Is Private? (private torrents, not announced to DHT)
+  // * Announce list (trackers)
+  // * Comment
+  renderAdvanced () {
+    // Create file list
+    const maxFileElems = 100
+    const files = this.state.files
+    const fileElems = files.slice(0, maxFileElems).map((file, i) => {
+      const relativePath = path.relative(this.state.pathPrefix, file.path)
+      return (<div key={i}>{relativePath}</div>)
+    })
+    if (files.length > maxFileElems) {
+      fileElems.push(<div key='more'>+ {files.length - maxFileElems} more</div>)
+    }
+
+    // Align the text fields
+    const textFieldStyle = { width: '' }
+    const textareaStyle = { margin: 0 }
+
+    return (
+      <div key='advanced' className='create-torrent-advanced'>
+        <div key='private' className='torrent-attribute'>
+          <label>Private:</label>
+          <Checkbox
+            className='torrent-is-private control'
+            style={{ display: '' }}
+            checked={this.state.isPrivate}
+            onCheck={this.handleSetIsPrivate}
+          />
+        </div>
+        <div key='trackers' className='torrent-attribute'>
+          <label>Trackers:</label>
+          <TextField
+            className='torrent-trackers control'
+            style={textFieldStyle}
+            textareaStyle={textareaStyle}
+            multiLine
+            rows={2}
+            rowsMax={10}
+            value={this.state.trackers}
+            onChange={this.handleSetTrackers}
+          />
+        </div>
+        <div key='comment' className='torrent-attribute'>
+          <label>Comment:</label>
+          <TextField
+            className='torrent-comment control'
+            style={textFieldStyle}
+            textareaStyle={textareaStyle}
+            hintText='Optionally describe your torrent...'
+            multiLine
+            rows={2}
+            rowsMax={10}
+            value={this.state.comment}
+            onChange={this.handleSetComment}
+          />
+        </div>
+        <div key='files' className='torrent-attribute'>
+          <label>Files:</label>
+          <div>{fileElems}</div>
+        </div>
+      </div>
+    )
+  }
+}
+
+function handleSubmit () {
+  const announceList = this.state.trackers
+    .split('\n')
+    .map((s) => s.trim())
+    .filter((s) => s !== '')
+  const options = {
+    // We can't let the user choose their own name if we want WebTorrent
+    // to use the files in place rather than creating a new folder.
+    name: this.state.defaultName,
+    path: this.state.basePath,
+    files: this.state.files,
+    announce: announceList,
+    comment: this.state.comment.trim()
+  }
+
+  // If torrent is not private, leave private flag unset. This ensures that
+  // the torrent info hash will match the result generated by other tools,
+  // including webtorrent-cli.
+  if (this.state.isPrivate) options.private = true
+
+  dispatch('createTorrent', options)
+}
+
+// Finds the longest common prefix
+function findCommonPrefix (a, b) {
+  let i
+  for (i = 0; i < a.length && i < b.length; i++) {
+    if (a.charCodeAt(i) !== b.charCodeAt(i)) break
+  }
+  if (i === a.length) return a
+  if (i === b.length) return b
+  return a.substring(0, i)
+}
+
+function containsDots (path, pathPrefix) {
+  const suffix = path.substring(pathPrefix.length).replace(/\\/g, '/')
+  return ('/' + suffix).includes('/.')
+}
+
+module.exports = CreateTorrentPage

src/renderer/pages/player-page.js

@@ -0,0 +1,993 @@
+/* globals MediaMetadata */
+
+const React = require('react')
+const BitField = require('bitfield').default
+const prettyBytes = require('prettier-bytes')
+
+const TorrentSummary = require('../lib/torrent-summary')
+const Playlist = require('../lib/playlist')
+const { dispatch, dispatcher } = require('../lib/dispatcher')
+const config = require('../../config')
+const { calculateEta } = require('../lib/time')
+
+// Shows a streaming video player. Standard features + Chromecast + Airplay
+module.exports = class Player extends React.Component {
+  render () {
+    // Show the video as large as will fit in the window, play immediately
+    // If the video is on Chromecast or Airplay, show a title screen instead
+    const state = this.props.state
+    const showVideo = state.playing.location === 'local'
+    const showControls = state.playing.location !== 'external'
+    return (
+      <div
+        className='player'
+        onWheel={handleVolumeWheel}
+        onMouseMove={dispatcher('mediaMouseMoved')}
+      >
+        {showVideo ? renderMedia(state) : renderCastScreen(state)}
+        {showControls ? renderPlayerControls(state) : null}
+      </div>
+    )
+  }
+
+  onComponentWillUnmount () {
+    // Unload the media element so that Chromium stops trying to fetch data
+    const tag = document.querySelector('audio,video')
+    if (!tag) return
+    tag.pause()
+    tag.src = ''
+    tag.load()
+    navigator.mediaSession.metadata = null
+  }
+}
+
+// Handles volume change by wheel
+function handleVolumeWheel (e) {
+  dispatch('changeVolume', (-e.deltaY | e.deltaX) / 500)
+}
+
+function renderMedia (state) {
+  if (!state.server) return
+
+  // Unfortunately, play/pause can't be done just by modifying HTML.
+  // Instead, grab the DOM node and play/pause it if necessary
+  // Get the <video> or <audio> tag
+  const mediaElement = document.querySelector(state.playing.type)
+  if (mediaElement !== null) {
+    if (navigator.mediaSession.metadata === null && mediaElement.played.length !== 0) {
+      navigator.mediaSession.metadata = new MediaMetadata({
+        title: state.playing.fileName
+      })
+      navigator.mediaSession.setActionHandler('pause', () => {
+        dispatch('playPause')
+      })
+      navigator.mediaSession.setActionHandler('play', () => {
+        dispatch('playPause')
+      })
+      if (Playlist.hasNext(state)) {
+        navigator.mediaSession.setActionHandler('nexttrack', () => {
+          dispatch('nextTrack')
+        })
+      }
+      if (Playlist.hasPrevious(state)) {
+        navigator.mediaSession.setActionHandler('previoustrack', () => {
+          dispatch('previousTrack')
+        })
+      }
+    }
+
+    if (state.playing.isPaused && !mediaElement.paused) {
+      mediaElement.pause()
+    } else if (!state.playing.isPaused && mediaElement.paused) {
+      mediaElement.play()
+    }
+    // When the user clicks or drags on the progress bar, jump to that position
+    if (state.playing.jumpToTime != null) {
+      mediaElement.currentTime = state.playing.jumpToTime
+      state.playing.jumpToTime = null
+    }
+    if (state.playing.playbackRate !== mediaElement.playbackRate) {
+      mediaElement.playbackRate = state.playing.playbackRate
+    }
+    // Recover previous volume
+    if (state.previousVolume !== null && isFinite(state.previousVolume)) {
+      mediaElement.volume = state.previousVolume
+      state.previousVolume = null
+    }
+
+    // Set volume
+    if (state.playing.setVolume !== null && isFinite(state.playing.setVolume)) {
+      mediaElement.volume = state.playing.setVolume
+      state.playing.setVolume = null
+    }
+
+    // Switch to the newly added subtitle track, if available
+    const tracks = mediaElement.textTracks || []
+    for (let j = 0; j < tracks.length; j++) {
+      const isSelectedTrack = j === state.playing.subtitles.selectedIndex
+      tracks[j].mode = isSelectedTrack ? 'showing' : 'hidden'
+    }
+
+    // Save video position
+    const file = state.getPlayingFileSummary()
+    file.currentTime = state.playing.currentTime = mediaElement.currentTime
+    file.duration = state.playing.duration = mediaElement.duration
+
+    // Save selected subtitle
+    if (state.playing.subtitles.selectedIndex !== -1) {
+      const index = state.playing.subtitles.selectedIndex
+      file.selectedSubtitle = state.playing.subtitles.tracks[index].filePath
+    } else if (file.selectedSubtitle != null) {
+      delete file.selectedSubtitle
+    }
+
+    // Switch to selected audio track
+    const audioTracks = mediaElement.audioTracks || []
+    for (let j = 0; j < audioTracks.length; j++) {
+      const isSelectedTrack = j === state.playing.audioTracks.selectedIndex
+      audioTracks[j].enabled = isSelectedTrack
+    }
+
+    state.playing.volume = mediaElement.volume
+  }
+
+  // Add subtitles to the <video> tag
+  const trackTags = []
+  if (state.playing.subtitles.selectedIndex >= 0) {
+    state.playing.subtitles.tracks.forEach((track, i) => {
+      const isSelected = state.playing.subtitles.selectedIndex === i
+      trackTags.push(
+        <track
+          key={i}
+          default={isSelected}
+          label={track.label}
+          kind='subtitles'
+          src={track.buffer}
+        />
+      )
+    })
+  }
+
+  // Create the <audio> or <video> tag
+  const MediaTagName = state.playing.type
+  const mediaTag = (
+    <MediaTagName
+      src={Playlist.getCurrentLocalURL(state)}
+      onDoubleClick={dispatcher('toggleFullScreen')}
+      onClick={dispatcher('playPause')}
+      onLoadedMetadata={onLoadedMetadata}
+      onEnded={onEnded}
+      onStalled={dispatcher('mediaStalled')}
+      onError={dispatcher('mediaError')}
+      onTimeUpdate={dispatcher('mediaTimeUpdate')}
+      onEncrypted={dispatcher('mediaEncrypted')}
+    >
+      {trackTags}
+    </MediaTagName>
+  )
+
+  // Show the media.
+  return (
+    <div
+      key='letterbox'
+      className='letterbox'
+      onMouseMove={dispatcher('mediaMouseMoved')}
+    >
+      {mediaTag}
+      {renderOverlay(state)}
+    </div>
+  )
+
+  function onLoadedMetadata (e) {
+    const mediaElement = e.target
+
+    // check if we can decode video and audio track
+    if (state.playing.type === 'video') {
+      if (mediaElement.videoTracks.length === 0) {
+        dispatch('mediaError', 'Video codec unsupported')
+      }
+
+      if (mediaElement.audioTracks.length === 0) {
+        dispatch('mediaError', 'Audio codec unsupported')
+      }
+
+      dispatch('mediaSuccess')
+
+      const dimensions = {
+        width: mediaElement.videoWidth,
+        height: mediaElement.videoHeight
+      }
+
+      // As soon as we know the video dimensions, resize the window
+      dispatch('setDimensions', dimensions)
+
+      // set audioTracks
+      const tracks = []
+      for (let i = 0; i < mediaElement.audioTracks.length; i++) {
+        tracks.push({
+          label: mediaElement.audioTracks[i].label || `Track ${i + 1}`,
+          language: mediaElement.audioTracks[i].language
+        })
+      }
+
+      state.playing.audioTracks.tracks = tracks
+      state.playing.audioTracks.selectedIndex = 0
+    }
+
+    // check if we can decode audio track
+    if (state.playing.type === 'audio') {
+      if (mediaElement.audioTracks.length === 0) {
+        dispatch('mediaError', 'Audio codec unsupported')
+      }
+
+      dispatch('mediaSuccess')
+    }
+  }
+
+  function onEnded () {
+    if (Playlist.hasNext(state)) {
+      dispatch('nextTrack')
+    } else {
+      // When the last video completes, pause the video instead of looping
+      state.playing.isPaused = true
+      if (state.window.isFullScreen) dispatch('toggleFullScreen')
+    }
+  }
+}
+
+function renderOverlay (state) {
+  const elems = []
+  const audioMetadataElem = renderAudioMetadata(state)
+  const spinnerElem = renderLoadingSpinner(state)
+  if (audioMetadataElem) elems.push(audioMetadataElem)
+  if (spinnerElem) elems.push(spinnerElem)
+
+  // Video fills the window, centered with black bars if necessary
+  // Audio gets a static poster image and a summary of the file metadata.
+  let style
+  if (state.playing.type === 'audio') {
+    style = { backgroundImage: cssBackgroundImagePoster(state) }
+  } else if (elems.length !== 0) {
+    style = { backgroundImage: cssBackgroundImageDarkGradient() }
+  } else {
+    // Video playing, so no spinner. No overlay needed
+    return
+  }
+
+  return (
+    <div key='overlay' className='media-overlay-background' style={style}>
+      <div className='media-overlay'>{elems}</div>
+    </div>
+  )
+}
+
+/**
+ * Render track or disk number string
+ * @param common metadata.common part
+ * @param key should be either 'track' or 'disk'
+ * @return track or disk number metadata as JSX block
+ */
+function renderTrack (common, key) {
+  // Audio metadata: track-number
+  if (common[key] && common[key].no) {
+    let str = `${common[key].no}`
+    if (common[key].of) {
+      str += ` of ${common[key].of}`
+    }
+    const style = { textTransform: 'capitalize' }
+    return (
+      <div className={`audio-${key}`}>
+        <label style={style}>{key}</label> {str}
+      </div>
+    )
+  }
+}
+
+function renderAudioMetadata (state) {
+  const fileSummary = state.getPlayingFileSummary()
+  if (!fileSummary.audioInfo) return
+  const common = fileSummary.audioInfo.common || {}
+
+  // Get audio track info
+  const title = common.title ? common.title : fileSummary.name
+
+  // Show a small info box in the middle of the screen with title/album/etc
+  const elems = []
+
+  // Audio metadata: artist(s)
+  const artist = common.artist || common.albumartist
+  if (artist) {
+    elems.push((
+      <div key='artist' className='audio-artist'>
+        <label>Artist</label>{artist}
+      </div>
+    ))
+  }
+
+  // Audio metadata: disk & track-number
+  const count = ['track', 'disk']
+  count.forEach(key => {
+    const nrElem = renderTrack(common, key)
+    if (nrElem) {
+      elems.push(nrElem)
+    }
+  })
+
+  // Audio metadata: album
+  if (common.album) {
+    elems.push((
+      <div key='album' className='audio-album'>
+        <label>Album</label>{common.album}
+      </div>
+    ))
+  }
+
+  // Audio metadata: year
+  if (common.year) {
+    elems.push((
+      <div key='year' className='audio-year'>
+        <label>Year</label>{common.year}
+      </div>
+    ))
+  }
+
+  // Audio metadata: release information (label & catalog-number)
+  if (common.label || common.catalognumber) {
+    const releaseInfo = []
+    if (common.label && common.catalognumber &&
+      common.label.length === common.catalognumber.length) {
+      // Assume labels & catalog-numbers are pairs
+      for (let n = 0; n < common.label.length; ++n) {
+        releaseInfo.push(common.label[0] + ' / ' + common.catalognumber[n])
+      }
+    } else {
+      if (common.label) {
+        releaseInfo.push(...common.label)
+      }
+      if (common.catalognumber) {
+        releaseInfo.push(...common.catalognumber)
+      }
+    }
+    elems.push((
+      <div key='release' className='audio-release'>
+        <label>Release</label>{releaseInfo.join(', ')}
+      </div>
+    ))
+  }
+
+  // Audio metadata: format
+  const format = []
+  fileSummary.audioInfo.format = fileSummary.audioInfo.format || ''
+  if (fileSummary.audioInfo.format.container) {
+    format.push(fileSummary.audioInfo.format.container)
+  }
+  if (fileSummary.audioInfo.format.codec &&
+    fileSummary.audioInfo.format.container !== fileSummary.audioInfo.format.codec) {
+    format.push(fileSummary.audioInfo.format.codec)
+  }
+  if (fileSummary.audioInfo.format.bitrate) {
+    format.push(Math.round(fileSummary.audioInfo.format.bitrate / 1000) + ' kbit/s') // 128 kbit/s
+  }
+  if (fileSummary.audioInfo.format.sampleRate) {
+    format.push(Math.round(fileSummary.audioInfo.format.sampleRate / 100) / 10 + ' kHz')
+  }
+  if (fileSummary.audioInfo.format.bitsPerSample) {
+    format.push(fileSummary.audioInfo.format.bitsPerSample + '-bit')
+  }
+  if (format.length > 0) {
+    elems.push((
+      <div key='format' className='audio-format'>
+        <label>Format</label>{format.join(', ')}
+      </div>
+    ))
+  }
+
+  // Audio metadata: comments
+  if (common.comment) {
+    elems.push((
+      <div key='comments' className='audio-comments'>
+        <label>Comments</label>{common.comment.join(' / ')}
+      </div>
+    ))
+  }
+
+  // Align the title with the other info, if available. Otherwise, center title
+  const emptyLabel = (<label />)
+  elems.unshift((
+    <div key='title' className='audio-title'>
+      {elems.length ? emptyLabel : undefined}{title}
+    </div>
+  ))
+
+  return (<div key='audio-metadata' className='audio-metadata'>{elems}</div>)
+}
+
+function renderLoadingSpinner (state) {
+  if (state.playing.isPaused) return
+  const isProbablyStalled = state.playing.isStalled ||
+    (new Date().getTime() - state.playing.lastTimeUpdate > 2000)
+  if (!isProbablyStalled) return
+
+  const prog = state.getPlayingTorrentSummary().progress || {}
+  let fileProgress = 0
+  if (prog.files) {
+    const file = prog.files[state.playing.fileIndex]
+    fileProgress = Math.floor(100 * file.numPiecesPresent / file.numPieces)
+  }
+
+  return (
+    <div key='loading' className='media-stalled'>
+      <div key='loading-spinner' className='loading-spinner' />
+      <div key='loading-progress' className='loading-status ellipsis'>
+        <span><span className='progress'>{fileProgress}%</span> downloaded</span>
+        <span> ↓ {prettyBytes(prog.downloadSpeed || 0)}/s</span>
+        <span> ↑ {prettyBytes(prog.uploadSpeed || 0)}/s</span>
+      </div>
+    </div>
+  )
+}
+
+function renderCastScreen (state) {
+  let castIcon, castType, isCast
+  if (state.playing.location.startsWith('chromecast')) {
+    castIcon = 'cast_connected'
+    castType = 'Chromecast'
+    isCast = true
+  } else if (state.playing.location.startsWith('airplay')) {
+    castIcon = 'airplay'
+    castType = 'AirPlay'
+    isCast = true
+  } else if (state.playing.location.startsWith('dlna')) {
+    castIcon = 'tv'
+    castType = 'DLNA'
+    isCast = true
+  } else if (state.playing.location === 'external') {
+    castIcon = 'tv'
+    castType = state.getExternalPlayerName()
+    isCast = false
+  } else if (state.playing.location === 'error') {
+    castIcon = 'error_outline'
+    castType = 'Unable to Play'
+    isCast = false
+  }
+
+  const isStarting = state.playing.location.endsWith('-pending')
+  const castName = state.playing.castName
+  const fileName = state.getPlayingFileSummary().name || ''
+  let castStatus
+  if (isCast && isStarting) castStatus = 'Connecting to ' + castName + '...'
+  else if (isCast && !isStarting) castStatus = 'Connected to ' + castName
+  else castStatus = ''
+
+  const prog = state.getPlayingTorrentSummary().progress || {}
+
+  // Show a nice title image, if possible
+  const style = {
+    backgroundImage: cssBackgroundImagePoster(state)
+  }
+
+  function renderEta (total, downloaded) {
+    const missing = (total || 0) - (downloaded || 0)
+    const downloadSpeed = prog.downloadSpeed || 0
+    if (downloadSpeed === 0 || missing === 0) return
+
+    const etaStr = calculateEta(missing, downloadSpeed)
+
+    return (<span>{etaStr}</span>)
+  }
+
+  function renderDownloadProgress () {
+    if (!prog.files) return
+
+    const fileProg = prog.files[state.playing.fileIndex]
+    const fileProgress = fileProg.numPiecesPresent / fileProg.numPieces
+    const fileLength = state.getPlayingFileSummary().length
+    const fileDownloaded = fileProgress * fileLength
+
+    const progress = Math.round(100 * fileProgress)
+    const total = prettyBytes(fileLength)
+    const completed = prettyBytes(fileDownloaded)
+
+    const downloadSpeed = prettyBytes(prog.downloadSpeed || 0)
+    const uploadSpeed = prettyBytes(prog.uploadSpeed || 0)
+
+    let sizes
+    if (fileProgress < 1) {
+      sizes = <span> | {completed} / {total}</span>
+    } else {
+      sizes = <span> | {completed}</span>
+    }
+
+    return (
+      <div key='download-progress'>
+        <span className='progress'>{progress}% downloaded {sizes}</span>
+        <br />
+        <span>↓ {downloadSpeed}/s ↑ {uploadSpeed}/s | {prog.numPeers || 0} peer(s)</span>
+        <br />
+        {renderEta(fileLength, fileDownloaded)}
+      </div>
+    )
+  }
+
+  return (
+    <div key='cast' className='letterbox' style={style}>
+      <div className='cast-screen'>
+        <i className='icon'>{castIcon}</i>
+        <div key='type' className='cast-type'>{castType}</div>
+        <div key='status' className='cast-status'>{castStatus}</div>
+        <div key='name' className='name'>{fileName}</div>
+        {renderDownloadProgress()}
+      </div>
+    </div>
+  )
+}
+
+function renderCastOptions (state) {
+  if (!state.devices.castMenu) return
+
+  const { location, devices } = state.devices.castMenu
+  const player = state.devices[location]
+
+  const items = devices.map((device, ix) => {
+    const isSelected = player.device === device
+    const name = device.name
+    return (
+      <li key={ix} onClick={dispatcher('selectCastDevice', ix)}>
+        <i className='icon'>{isSelected ? 'radio_button_checked' : 'radio_button_unchecked'}</i>
+        {' '}
+        {name}
+      </li>
+    )
+  })
+
+  return (
+    <ul key='cast-options' className='options-list'>
+      {items}
+    </ul>
+  )
+}
+
+function renderSubtitleOptions (state) {
+  const subtitles = state.playing.subtitles
+  if (!subtitles.tracks.length || !subtitles.showMenu) return
+
+  const items = subtitles.tracks.map((track, ix) => {
+    const isSelected = state.playing.subtitles.selectedIndex === ix
+    return (
+      <li key={ix} onClick={dispatcher('selectSubtitle', ix)}>
+        <i className='icon'>{'radio_button_' + (isSelected ? 'checked' : 'unchecked')}</i>
+        {track.label}
+      </li>
+    )
+  })
+
+  const noneSelected = state.playing.subtitles.selectedIndex === -1
+  const noneClass = 'radio_button_' + (noneSelected ? 'checked' : 'unchecked')
+  return (
+    <ul key='subtitle-options' className='options-list'>
+      {items}
+      <li onClick={dispatcher('selectSubtitle', -1)}>
+        <i className='icon'>{noneClass}</i>
+        None
+      </li>
+    </ul>
+  )
+}
+
+function renderAudioTrackOptions (state) {
+  const audioTracks = state.playing.audioTracks
+  if (!audioTracks.tracks.length || !audioTracks.showMenu) return
+
+  const items = audioTracks.tracks.map((track, ix) => {
+    const isSelected = state.playing.audioTracks.selectedIndex === ix
+    return (
+      <li key={ix} onClick={dispatcher('selectAudioTrack', ix)}>
+        <i className='icon'>{'radio_button_' + (isSelected ? 'checked' : 'unchecked')}</i>
+        {track.label}
+      </li>
+    )
+  })
+
+  return (
+    <ul key='audio-track-options' className='options-list'>
+      {items}
+    </ul>
+  )
+}
+
+function renderPlayerControls (state) {
+  const positionPercent = 100 * state.playing.currentTime / state.playing.duration
+  const playbackCursorStyle = { left: 'calc(' + positionPercent + '% - 3px)' }
+  const captionsClass = state.playing.subtitles.tracks.length === 0
+    ? 'disabled'
+    : state.playing.subtitles.selectedIndex >= 0
+      ? 'active'
+      : ''
+  const multiAudioClass = state.playing.audioTracks.tracks.length > 1
+    ? 'active'
+    : 'disabled'
+  const prevClass = Playlist.hasPrevious(state) ? '' : 'disabled'
+  const nextClass = Playlist.hasNext(state) ? '' : 'disabled'
+
+  const elements = [
+    renderPreview(state),
+
+    <div key='playback-bar' className='playback-bar'>
+      {renderLoadingBar(state)}
+      <div
+        key='cursor'
+        className='playback-cursor'
+        style={playbackCursorStyle}
+      />
+      <div
+        key='scrub-bar'
+        className='scrub-bar'
+        draggable='true'
+        onMouseMove={handleScrubPreview}
+        onMouseOut={clearPreview}
+        onDragStart={handleDragStart}
+        onClick={handleScrub}
+        onDrag={handleScrub}
+      />
+    </div>,
+
+    <i
+      key='skip-previous'
+      className={'icon skip-previous float-left ' + prevClass}
+      onClick={dispatcher('previousTrack')}
+      role='button'
+      aria-label='Previous track'
+    >
+      skip_previous
+    </i>,
+
+    <i
+      key='play'
+      className='icon play-pause float-left'
+      onClick={dispatcher('playPause')}
+      role='button'
+      aria-label={state.playing.isPaused ? 'Play' : 'Pause'}
+    >
+      {state.playing.isPaused ? 'play_arrow' : 'pause'}
+    </i>,
+
+    <i
+      key='skip-next'
+      className={'icon skip-next float-left ' + nextClass}
+      onClick={dispatcher('nextTrack')}
+      role='button'
+      aria-label='Next track'
+    >
+      skip_next
+    </i>,
+
+    <i
+      key='fullscreen'
+      className='icon fullscreen float-right'
+      onClick={dispatcher('toggleFullScreen')}
+      role='button'
+      aria-label={state.window.isFullScreen ? 'Exit full screen' : 'Enter full screen'}
+    >
+      {state.window.isFullScreen ? 'fullscreen_exit' : 'fullscreen'}
+    </i>
+  ]
+
+  if (state.playing.type === 'video') {
+    // Show closed captions icon
+    elements.push((
+      <i
+        key='subtitles'
+        className={'icon closed-caption float-right ' + captionsClass}
+        onClick={handleSubtitles}
+        role='button'
+        aria-label='Closed captions'
+      >
+        closed_caption
+      </i>
+    ), (
+      <i
+        key='audio-tracks'
+        className={'icon multi-audio float-right ' + multiAudioClass}
+        onClick={handleAudioTracks}
+      >
+        library_music
+      </i>
+    ))
+  }
+
+  // If we've detected a Chromecast or AppleTV, the user can play video there
+  const castTypes = ['chromecast', 'airplay', 'dlna']
+  const isCastingAnywhere = castTypes.some(
+    (castType) => state.playing.location.startsWith(castType))
+
+  // Add the cast buttons. Icons for each cast type, connected/disconnected:
+  const buttonIcons = {
+    chromecast: { true: 'cast_connected', false: 'cast' },
+    airplay: { true: 'airplay', false: 'airplay' },
+    dlna: { true: 'tv', false: 'tv' }
+  }
+  castTypes.forEach(castType => {
+    // Do we show this button (eg. the Chromecast button) at all?
+    const isCasting = state.playing.location.startsWith(castType)
+    const player = state.devices[castType]
+    if ((!player || player.getDevices().length === 0) && !isCasting) return
+
+    // Show the button. Three options for eg the Chromecast button:
+    let buttonClass, buttonHandler
+    if (isCasting) {
+      // Option 1: we are currently connected to Chromecast. Button stops the cast.
+      buttonClass = 'active'
+      buttonHandler = dispatcher('stopCasting')
+    } else if (isCastingAnywhere) {
+      // Option 2: we are currently connected somewhere else. Button disabled.
+      buttonClass = 'disabled'
+      buttonHandler = undefined
+    } else {
+      // Option 3: we are not connected anywhere. Button opens Chromecast menu.
+      buttonClass = ''
+      buttonHandler = dispatcher('toggleCastMenu', castType)
+    }
+    const buttonIcon = buttonIcons[castType][isCasting]
+
+    elements.push((
+      <i
+        key={castType}
+        className={'icon device float-right ' + buttonClass}
+        onClick={buttonHandler}
+      >
+        {buttonIcon}
+      </i>
+    ))
+  })
+
+  // Render volume slider
+  const volume = state.playing.volume
+  const volumeIcon = 'volume_' + (
+    volume === 0
+      ? 'off'
+      : volume < 0.3
+        ? 'mute'
+        : volume < 0.6
+          ? 'down'
+          : 'up'
+  )
+  const volumeStyle = {
+    background: '-webkit-gradient(linear, left top, right top, ' +
+      'color-stop(' + (volume * 100) + '%, #eee), ' +
+      'color-stop(' + (volume * 100) + '%, #727272))'
+  }
+
+  elements.push((
+    <div key='volume' className='volume float-left'>
+      <i
+        className='icon volume-icon float-left'
+        onMouseDown={handleVolumeMute}
+        role='button'
+        aria-label='Mute'
+      >
+        {volumeIcon}
+      </i>
+      <input
+        className='volume-slider float-right'
+        type='range' min='0' max='1' step='0.05'
+        value={volume}
+        onChange={handleVolumeScrub}
+        style={volumeStyle}
+      />
+    </div>
+  ))
+
+  // Show video playback progress
+  const currentTimeStr = formatTime(state.playing.currentTime, state.playing.duration)
+  const durationStr = formatTime(state.playing.duration, state.playing.duration)
+  elements.push((
+    <span key='time' className='time float-left'>
+      {currentTimeStr} / {durationStr}
+    </span>
+  ))
+
+  // Render playback rate
+  if (state.playing.playbackRate !== 1) {
+    elements.push((
+      <span key='rate' className='rate float-left'>
+        {state.playing.playbackRate}x
+      </span>
+    ))
+  }
+
+  const emptyImage = new window.Image(0, 0)
+  emptyImage.src = 'data:image/gif;base64,R0lGODlhAQABAAD/ACwAAAAAAQABAAACADs%3D'
+  function handleDragStart (e) {
+    if (e.dataTransfer) {
+      const dt = e.dataTransfer
+      // Prevent the cursor from changing, eg to a green + icon on Mac
+      dt.effectAllowed = 'none'
+      // Prevent ghost image
+      dt.setDragImage(emptyImage, 0, 0)
+    }
+  }
+
+  // Handles a scrub hover (preview another position in the video)
+  function handleScrubPreview (e) {
+    // Only show for videos
+    if (!e.clientX || state.playing.type !== 'video') return
+    dispatch('mediaMouseMoved')
+    dispatch('preview', e.clientX)
+  }
+
+  function clearPreview () {
+    if (state.playing.type !== 'video') return
+    dispatch('clearPreview')
+  }
+
+  // Handles a click or drag to scrub (jump to another position in the video)
+  function handleScrub (e) {
+    if (!e.clientX) return
+    dispatch('mediaMouseMoved')
+    const windowWidth = document.querySelector('body').clientWidth
+    const fraction = e.clientX / windowWidth
+    const position = fraction * state.playing.duration /* seconds */
+    dispatch('skipTo', position)
+  }
+
+  // Handles volume muting and Unmuting
+  function handleVolumeMute () {
+    if (state.playing.volume === 0.0) {
+      dispatch('setVolume', 1.0)
+    } else {
+      dispatch('setVolume', 0.0)
+    }
+  }
+
+  // Handles volume slider scrub
+  function handleVolumeScrub (e) {
+    dispatch('setVolume', e.target.value)
+  }
+
+  function handleSubtitles (e) {
+    if (!state.playing.subtitles.tracks.length || e.ctrlKey || e.metaKey) {
+      // if no subtitles available select it
+      dispatch('openSubtitles')
+    } else {
+      dispatch('toggleSubtitlesMenu')
+    }
+  }
+
+  function handleAudioTracks () {
+    dispatch('toggleAudioTracksMenu')
+  }
+
+  return (
+    <div
+      key='controls' className='controls'
+      onMouseEnter={dispatcher('mediaControlsMouseEnter')}
+      onMouseLeave={dispatcher('mediaControlsMouseLeave')}
+    >
+      {elements}
+      {renderCastOptions(state)}
+      {renderSubtitleOptions(state)}
+      {renderAudioTrackOptions(state)}
+    </div>
+  )
+}
+
+function renderPreview (state) {
+  const { previewXCoord = null } = state.playing
+
+  // Calculate time from x-coord as fraction of track width
+  const windowWidth = document.querySelector('body').clientWidth
+  const fraction = previewXCoord / windowWidth
+  const time = fraction * state.playing.duration /* seconds */
+
+  const height = 70
+  let width = 0
+
+  const previewEl = document.querySelector('video#preview')
+  if (previewEl !== null && previewXCoord !== null) {
+    previewEl.currentTime = time
+
+    // Auto adjust width to maintain video aspect ratio
+    width = Math.floor((previewEl.videoWidth / previewEl.videoHeight) * height)
+  }
+
+  // Center preview window on mouse cursor,
+  // while avoiding falling off the left or right edges
+  const xPos = Math.min(Math.max(previewXCoord - (width / 2), 5), windowWidth - width - 5)
+
+  return (
+    <div
+      key='preview' style={{
+        position: 'absolute',
+        bottom: 50,
+        left: xPos,
+        display: previewXCoord == null && 'none' // Hide preview when XCoord unset
+      }}
+    >
+      <div style={{ width, height, backgroundColor: 'black' }}>
+        <video
+          src={Playlist.getCurrentLocalURL(state)}
+          id='preview'
+          style={{ border: '1px solid lightgrey', borderRadius: 2 }}
+        />
+      </div>
+      <p
+        style={{
+          textAlign: 'center', margin: 5, textShadow: '0 0 2px rgba(0,0,0,.5)', color: '#eee'
+        }}
+      >
+        {formatTime(time, state.playing.duration)}
+      </p>
+    </div>
+  )
+}
+
+// Renders the loading bar. Shows which parts of the torrent are loaded, which
+// can be 'spongey' / non-contiguous
+function renderLoadingBar (state) {
+  if (config.IS_TEST) return // Don't integration test the loading bar. Screenshots won't match.
+
+  const torrentSummary = state.getPlayingTorrentSummary()
+  if (!torrentSummary.progress) {
+    return null
+  }
+
+  // Find all contiguous parts of the torrent which are loaded
+  const prog = torrentSummary.progress
+  const fileProg = prog.files[state.playing.fileIndex]
+
+  if (!fileProg) return null
+
+  const parts = []
+  let lastPiecePresent = false
+  for (let i = fileProg.startPiece; i <= fileProg.endPiece; i++) {
+    const partPresent = BitField.prototype.get.call(prog.bitfield, i)
+    if (partPresent && !lastPiecePresent) {
+      parts.push({ start: i - fileProg.startPiece, count: 1 })
+    } else if (partPresent) {
+      parts[parts.length - 1].count++
+    }
+    lastPiecePresent = partPresent
+  }
+
+  // Output some bars to show which parts of the file are loaded
+  const loadingBarElems = parts.map((part, i) => {
+    const style = {
+      left: (100 * part.start / fileProg.numPieces) + '%',
+      width: (100 * part.count / fileProg.numPieces) + '%'
+    }
+
+    return (<div key={i} className='loading-bar-part' style={style} />)
+  })
+
+  return (<div key='loading-bar' className='loading-bar'>{loadingBarElems}</div>)
+}
+
+// Returns the CSS background-image string for a poster image + dark vignette
+function cssBackgroundImagePoster (state) {
+  const torrentSummary = state.getPlayingTorrentSummary()
+  const posterPath = TorrentSummary.getPosterPath(torrentSummary)
+  if (!posterPath) return ''
+  return cssBackgroundImageDarkGradient() + `, url('${posterPath}')`
+}
+
+function cssBackgroundImageDarkGradient () {
+  return 'radial-gradient(circle at center, ' +
+    'rgba(0,0,0,0.4) 0%, rgba(0,0,0,1) 100%)'
+}
+
+function formatTime (time, total) {
+  if (typeof time !== 'number' || Number.isNaN(time)) {
+    return '0:00'
+  }
+
+  const totalHours = Math.floor(total / 3600)
+  const totalMinutes = Math.floor(total / 60)
+  const hours = Math.floor(time / 3600)
+  let minutes = Math.floor(time % 3600 / 60)
+  if (totalMinutes > 9 && minutes < 10) {
+    minutes = '0' + minutes
+  }
+  const seconds = `0${Math.floor(time % 60)}`.slice(-2)
+
+  return (totalHours > 0 ? hours + ':' : '') + minutes + ':' + seconds
+}

src/renderer/pages/preferences-page.js

@@ -0,0 +1,336 @@
+const React = require('react')
+const PropTypes = require('prop-types')
+
+const colors = require('material-ui/styles/colors')
+const Checkbox = require('material-ui/Checkbox').default
+const RaisedButton = require('material-ui/RaisedButton').default
+const TextField = require('material-ui/TextField').default
+const Heading = require('../components/heading')
+const PathSelector = require('../components/path-selector')
+
+const { dispatch } = require('../lib/dispatcher')
+const config = require('../../config')
+
+class PreferencesPage extends React.Component {
+  constructor (props) {
+    super(props)
+
+    this.handleDownloadPathChange =
+      this.handleDownloadPathChange.bind(this)
+
+    this.handleOpenExternalPlayerChange =
+      this.handleOpenExternalPlayerChange.bind(this)
+
+    this.handleExternalPlayerPathChange =
+      this.handleExternalPlayerPathChange.bind(this)
+
+    this.handleStartupChange =
+      this.handleStartupChange.bind(this)
+
+    this.handleSoundNotificationsChange =
+      this.handleSoundNotificationsChange.bind(this)
+
+    this.handleSetGlobalTrackers =
+      this.handleSetGlobalTrackers.bind(this)
+
+    const globalTrackers = this.props.state.getGlobalTrackers().join('\n')
+
+    this.state = {
+      globalTrackers
+    }
+  }
+
+  downloadPathSelector () {
+    return (
+      <Preference>
+        <PathSelector
+          dialog={{
+            title: 'Select download directory',
+            properties: ['openDirectory']
+          }}
+          onChange={this.handleDownloadPathChange}
+          title='Download location'
+          value={this.props.state.saved.prefs.downloadPath}
+        />
+      </Preference>
+    )
+  }
+
+  handleDownloadPathChange (filePath) {
+    dispatch('updatePreferences', 'downloadPath', filePath)
+  }
+
+  openExternalPlayerCheckbox () {
+    return (
+      <Preference>
+        <Checkbox
+          className='control'
+          checked={!this.props.state.saved.prefs.openExternalPlayer}
+          label='Play torrent media files using LeenkxBox'
+          onCheck={this.handleOpenExternalPlayerChange}
+        />
+      </Preference>
+    )
+  }
+
+  handleOpenExternalPlayerChange (e, isChecked) {
+    dispatch('updatePreferences', 'openExternalPlayer', !isChecked)
+  }
+
+  highestPlaybackPriorityCheckbox () {
+    return (
+      <Preference>
+        <Checkbox
+          className='control'
+          checked={this.props.state.saved.prefs.highestPlaybackPriority}
+          label='Highest Playback Priority'
+          onCheck={this.handleHighestPlaybackPriorityChange}
+        />
+        <p>Pauses all active torrents to allow playback to use all of the available bandwidth.</p>
+      </Preference>
+    )
+  }
+
+  handleHighestPlaybackPriorityChange (e, isChecked) {
+    dispatch('updatePreferences', 'highestPlaybackPriority', isChecked)
+  }
+
+  externalPlayerPathSelector () {
+    const playerPath = this.props.state.saved.prefs.externalPlayerPath
+    const playerName = this.props.state.getExternalPlayerName()
+
+    const description = this.props.state.saved.prefs.openExternalPlayer
+      ? `Torrent media files will always play in ${playerName}.`
+      : `Torrent media files will play in ${playerName} if LeenkxBox cannot play them.`
+
+    return (
+      <Preference>
+        <p>{description}</p>
+        <PathSelector
+          dialog={{
+            title: 'Select media player app',
+            properties: ['openFile']
+          }}
+          onChange={this.handleExternalPlayerPathChange}
+          title='External player'
+          value={playerPath}
+        />
+      </Preference>
+    )
+  }
+
+  handleExternalPlayerPathChange (filePath) {
+    dispatch('updatePreferences', 'externalPlayerPath', filePath)
+  }
+
+  autoAddTorrentsCheckbox () {
+    return (
+      <Preference>
+        <Checkbox
+          className='control'
+          checked={this.props.state.saved.prefs.autoAddTorrents}
+          label='Watch for new .torrent files and add them immediately'
+          onCheck={(e, value) => { this.handleAutoAddTorrentsChange(e, value) }}
+        />
+      </Preference>
+    )
+  }
+
+  handleAutoAddTorrentsChange (e, isChecked) {
+    const torrentsFolderPath = this.props.state.saved.prefs.torrentsFolderPath
+    if (isChecked && !torrentsFolderPath) {
+      alert('Select a torrents folder first.') // eslint-disable-line
+      e.preventDefault()
+      return
+    }
+
+    dispatch('updatePreferences', 'autoAddTorrents', isChecked)
+
+    if (isChecked) {
+      dispatch('startFolderWatcher')
+      return
+    }
+
+    dispatch('stopFolderWatcher')
+  }
+
+  torrentsFolderPathSelector () {
+    const torrentsFolderPath = this.props.state.saved.prefs.torrentsFolderPath
+
+    return (
+      <Preference>
+        <PathSelector
+          dialog={{
+            title: 'Select folder to watch for new torrents',
+            properties: ['openDirectory']
+          }}
+          onChange={this.handleTorrentsFolderPathChange}
+          title='Folder to watch'
+          value={torrentsFolderPath}
+        />
+      </Preference>
+    )
+  }
+
+  handleTorrentsFolderPathChange (filePath) {
+    dispatch('updatePreferences', 'torrentsFolderPath', filePath)
+  }
+
+  setDefaultAppButton () {
+    const isFileHandler = this.props.state.saved.prefs.isFileHandler
+    if (isFileHandler) {
+      return (
+        <Preference>
+          <p>LeenkxBox is your default torrent app. Hooray!</p>
+        </Preference>
+      )
+    }
+    return (
+      <Preference>
+        <p>LeenkxBox is not currently the default torrent app.</p>
+        <RaisedButton
+          className='control'
+          onClick={this.handleSetDefaultApp}
+          label='Make LeenkxBox the default'
+        />
+      </Preference>
+    )
+  }
+
+  handleStartupChange (e, isChecked) {
+    dispatch('updatePreferences', 'startup', isChecked)
+  }
+
+  setStartupCheckbox () {
+    if (config.IS_PORTABLE) {
+      return
+    }
+
+    return (
+      <Preference>
+        <Checkbox
+          className='control'
+          checked={this.props.state.saved.prefs.startup}
+          label='Open LeenkxBox on startup'
+          onCheck={this.handleStartupChange}
+        />
+      </Preference>
+    )
+  }
+
+  soundNotificationsCheckbox () {
+    return (
+      <Preference>
+        <Checkbox
+          className='control'
+          checked={this.props.state.saved.prefs.soundNotifications}
+          label='Enable sounds'
+          onCheck={this.handleSoundNotificationsChange}
+        />
+      </Preference>
+    )
+  }
+
+  handleSoundNotificationsChange (e, isChecked) {
+    dispatch('updatePreferences', 'soundNotifications', isChecked)
+  }
+
+  handleSetDefaultApp () {
+    dispatch('updatePreferences', 'isFileHandler', true)
+  }
+
+  setGlobalTrackers () {
+    // Align the text fields
+    const textFieldStyle = { width: '100%' }
+    const textareaStyle = { margin: 0 }
+
+    return (
+      <Preference>
+        <TextField
+          className='torrent-trackers control'
+          style={textFieldStyle}
+          textareaStyle={textareaStyle}
+          multiLine
+          rows={2}
+          rowsMax={10}
+          value={this.state.globalTrackers}
+          onChange={this.handleSetGlobalTrackers}
+        />
+      </Preference>
+    )
+  }
+
+  handleSetGlobalTrackers (e, globalTrackers) {
+    this.setState({ globalTrackers })
+
+    const announceList = globalTrackers
+      .split('\n')
+      .map((s) => s.trim())
+      .filter((s) => s !== '')
+
+    dispatch('updatePreferences', 'globalTrackers', announceList)
+    dispatch('updateGlobalTrackers', announceList)
+  }
+
+  render () {
+    const style = {
+      color: colors.grey400,
+      marginLeft: 25,
+      marginRight: 25
+    }
+    return (
+      <div style={style}>
+        <PreferencesSection title='Folders'>
+          {this.downloadPathSelector()}
+          {this.autoAddTorrentsCheckbox()}
+          {this.torrentsFolderPathSelector()}
+        </PreferencesSection>
+        <PreferencesSection title='Playback'>
+          {this.openExternalPlayerCheckbox()}
+          {this.externalPlayerPathSelector()}
+          {this.highestPlaybackPriorityCheckbox()}
+        </PreferencesSection>
+        <PreferencesSection title='Default torrent app'>
+          {this.setDefaultAppButton()}
+        </PreferencesSection>
+        <PreferencesSection title='General'>
+          {this.setStartupCheckbox()}
+          {this.soundNotificationsCheckbox()}
+        </PreferencesSection>
+        <PreferencesSection title='Trackers'>
+          {this.setGlobalTrackers()}
+        </PreferencesSection>
+      </div>
+    )
+  }
+}
+
+class PreferencesSection extends React.Component {
+  static get propTypes () {
+    return {
+      title: PropTypes.string
+    }
+  }
+
+  render () {
+    const style = {
+      marginBottom: 25,
+      marginTop: 25
+    }
+    return (
+      <div style={style}>
+        <Heading level={2}>{this.props.title}</Heading>
+        {this.props.children}
+      </div>
+    )
+  }
+}
+
+class Preference extends React.Component {
+  render () {
+    const style = { marginBottom: 10 }
+    return (<div style={style}>{this.props.children}</div>)
+  }
+}
+
+module.exports = PreferencesPage

src/renderer/pages/torrent-list-page.js

@@ -0,0 +1,414 @@
+const React = require('react')
+const prettyBytes = require('prettier-bytes')
+
+const Checkbox = require('material-ui/Checkbox').default
+const LinearProgress = require('material-ui/LinearProgress').default
+
+const TorrentSummary = require('../lib/torrent-summary')
+const TorrentPlayer = require('../lib/torrent-player')
+const { dispatcher } = require('../lib/dispatcher')
+const { calculateEta } = require('../lib/time')
+
+module.exports = class TorrentList extends React.Component {
+  render () {
+    const state = this.props.state
+
+    const contents = []
+    if (state.downloadPathStatus === 'missing') {
+      contents.push(
+        <div key='torrent-missing-path'>
+          <p>Download path missing: {state.saved.prefs.downloadPath}</p>
+          <p>Check that all drives are connected?</p>
+          <p>Alternatively, choose a new download path
+            in <a href='#' onClick={dispatcher('preferences')}>Preferences</a>
+          </p>
+        </div>
+      )
+    }
+    const torrentElems = state.saved.torrents.map(
+      (torrentSummary) => this.renderTorrent(torrentSummary)
+    )
+    contents.push(...torrentElems)
+    contents.push(
+      <div key='torrent-placeholder' className='torrent-placeholder'>
+        <span className='ellipsis'>Drop a torrent file here or paste a magnet link</span>
+      </div>
+    )
+
+    return (
+      <div
+        key='torrent-list'
+        className='torrent-list'
+        onContextMenu={dispatcher('openTorrentListContextMenu')}
+      >
+        {contents}
+      </div>
+    )
+  }
+
+  renderTorrent (torrentSummary) {
+    const state = this.props.state
+    const infoHash = torrentSummary.infoHash
+    const isSelected = infoHash && state.selectedInfoHash === infoHash
+
+    // Background image: show some nice visuals, like a frame from the movie, if possible
+    const style = {}
+    if (torrentSummary.posterFileName) {
+      const gradient = 'linear-gradient(to bottom, rgba(0, 0, 0, 0.4) 0%, rgba(0, 0, 0, 0.4) 100%)'
+      const posterPath = TorrentSummary.getPosterPath(torrentSummary)
+      style.backgroundImage = `${gradient}, url('${posterPath}')`
+    }
+
+    // Foreground: name of the torrent, basic info like size, play button,
+    // cast buttons if available, and delete
+    const classes = ['torrent']
+    if (isSelected) classes.push('selected')
+    if (!infoHash) classes.push('disabled')
+    if (!torrentSummary.torrentKey) throw new Error('Missing torrentKey')
+    return (
+      <div
+        id={torrentSummary.testID && ('torrent-' + torrentSummary.testID)}
+        key={torrentSummary.torrentKey}
+        style={style}
+        className={classes.join(' ')}
+        onContextMenu={infoHash && dispatcher('openTorrentContextMenu', infoHash)}
+        onClick={infoHash && dispatcher('toggleSelectTorrent', infoHash)}
+      >
+        {this.renderTorrentMetadata(torrentSummary)}
+        {infoHash ? this.renderTorrentButtons(torrentSummary) : null}
+        {isSelected ? this.renderTorrentDetails(torrentSummary) : null}
+        <hr />
+      </div>
+    )
+  }
+
+  // Show name, download status, % complete
+  renderTorrentMetadata (torrentSummary) {
+    const name = torrentSummary.name || 'Loading torrent...'
+    const elements = [(
+      <div key='name' className='name ellipsis'>{name}</div>
+    )]
+
+    // If it's downloading/seeding then show progress info
+    const prog = torrentSummary.progress
+    let progElems
+    if (torrentSummary.error) {
+      progElems = [getErrorMessage(torrentSummary)]
+    } else if (torrentSummary.status !== 'paused' && prog) {
+      progElems = [
+        renderDownloadCheckbox(),
+        renderTorrentStatus(),
+        renderProgressBar(),
+        renderPercentProgress(),
+        renderTotalProgress(),
+        renderPeers(),
+        renderSpeeds(),
+        renderEta()
+      ]
+    } else {
+      progElems = [
+        renderDownloadCheckbox(),
+        renderTorrentStatus()
+      ]
+    }
+    elements.push(
+      <div key='progress-info' className='ellipsis'>
+        {progElems}
+      </div>
+    )
+
+    return (<div key='metadata' className='metadata'>{elements}</div>)
+
+    function renderDownloadCheckbox () {
+      const infoHash = torrentSummary.infoHash
+      const isActive = ['downloading', 'seeding'].includes(torrentSummary.status)
+      return (
+        <Checkbox
+          key='download-button'
+          className={'control download ' + torrentSummary.status}
+          style={{
+            display: 'inline-block',
+            width: 32
+          }}
+          iconStyle={{
+            width: 20,
+            height: 20
+          }}
+          checked={isActive}
+          onClick={stopPropagation}
+          onCheck={dispatcher('toggleTorrent', infoHash)}
+        />
+      )
+    }
+
+    function renderProgressBar () {
+      const progress = Math.floor(100 * prog.progress)
+      const styles = {
+        wrapper: {
+          display: 'inline-block',
+          marginRight: 8
+        },
+        progress: {
+          height: 8,
+          width: 30
+        }
+      }
+      return (
+        <div key='progress-bar' style={styles.wrapper}>
+          <LinearProgress style={styles.progress} mode='determinate' value={progress} />
+        </div>
+      )
+    }
+
+    function renderPercentProgress () {
+      const progress = Math.floor(100 * prog.progress)
+      return (<span key='percent-progress'>{progress}%</span>)
+    }
+
+    function renderTotalProgress () {
+      const downloaded = prettyBytes(prog.downloaded)
+      const total = prettyBytes(prog.length || 0)
+      if (downloaded === total) {
+        return (<span key='total-progress'>{downloaded}</span>)
+      } else {
+        return (<span key='total-progress'>{downloaded} / {total}</span>)
+      }
+    }
+
+    function renderPeers () {
+      if (prog.numPeers === 0) return
+      const count = prog.numPeers === 1 ? 'peer' : 'peers'
+      return (<span key='peers'>{prog.numPeers} {count}</span>)
+    }
+
+    function renderSpeeds () {
+      let str = ''
+      if (prog.downloadSpeed > 0) str += ' ↓ ' + prettyBytes(prog.downloadSpeed) + '/s'
+      if (prog.uploadSpeed > 0) str += ' ↑ ' + prettyBytes(prog.uploadSpeed) + '/s'
+      if (str === '') return
+      return (<span key='download'>{str}</span>)
+    }
+
+    function renderEta () {
+      const downloaded = prog.downloaded
+      const total = prog.length || 0
+      const missing = total - downloaded
+      const downloadSpeed = prog.downloadSpeed
+      if (downloadSpeed === 0 || missing === 0) return
+
+      const etaStr = calculateEta(missing, downloadSpeed)
+
+      return (<span key='eta'>{etaStr}</span>)
+    }
+
+    function renderTorrentStatus () {
+      let status
+      if (torrentSummary.status === 'paused') {
+        if (!torrentSummary.progress) status = ''
+        else if (torrentSummary.progress.progress === 1) status = 'Not seeding'
+        else status = 'Paused'
+      } else if (torrentSummary.status === 'downloading') {
+        if (!torrentSummary.progress) status = ''
+        else if (!torrentSummary.progress.ready) status = 'Verifying'
+        else status = 'Downloading'
+      } else if (torrentSummary.status === 'seeding') {
+        status = 'Seeding'
+      } else { // torrentSummary.status is 'new' or something unexpected
+        status = ''
+      }
+      return (<span key='torrent-status'>{status}</span>)
+    }
+  }
+
+  // Download button toggles between torrenting (DL/seed) and paused
+  // Play button starts streaming the torrent immediately, unpausing if needed
+  renderTorrentButtons (torrentSummary) {
+    const infoHash = torrentSummary.infoHash
+
+    // Only show the play/dowload buttons for torrents that contain playable media
+    let playButton
+    if (!torrentSummary.error && TorrentPlayer.isPlayableTorrentSummary(torrentSummary)) {
+      playButton = (
+        <i
+          key='play-button'
+          title='Start streaming'
+          className='icon play'
+          onClick={dispatcher('playFile', infoHash)}
+        >
+          play_circle_outline
+        </i>
+      )
+    }
+
+    return (
+      <div className='torrent-controls'>
+        {playButton}
+        <i
+          key='delete-button'
+          className='icon delete'
+          title='Remove torrent'
+          onClick={dispatcher('confirmDeleteTorrent', infoHash, false)}
+        >
+          close
+        </i>
+      </div>
+    )
+  }
+
+  // Show files, per-file download status and play buttons, and so on
+  renderTorrentDetails (torrentSummary) {
+    let filesElement
+    if (torrentSummary.error || !torrentSummary.files) {
+      let message = ''
+      if (torrentSummary.error === 'path-missing') {
+        // Special case error: this torrent's download dir or file is missing
+        message = 'Missing path: ' + TorrentSummary.getFileOrFolder(torrentSummary)
+      } else if (torrentSummary.error) {
+        // General error for this torrent: just show the message
+        message = torrentSummary.error.message || torrentSummary.error
+      } else if (torrentSummary.status === 'paused') {
+        // No file info, no infohash, and we're not trying to download from the DHT
+        message = 'Failed to load torrent info. Click the download button to try again...'
+      } else {
+        // No file info, no infohash, trying to load from the DHT
+        message = 'Downloading torrent info...'
+      }
+      filesElement = (
+        <div key='files' className='files warning'>
+          {message}
+        </div>
+      )
+    } else {
+      // We do know the files. List them and show download stats for each one
+      const sortByName = this.props.state.saved.prefs.sortByName
+      const collator = new Intl.Collator(undefined, { numeric: true, sensitivity: 'base' })
+      let fileRows = torrentSummary.files
+        .filter((file) => !file.path.includes('/.____padding_file/'))
+        .map((file, index) => ({ file, index }))
+
+      if (sortByName) {
+        fileRows = fileRows.sort((a, b) => collator.compare(a.file.name, b.file.name))
+      }
+
+      fileRows = fileRows.map((obj) => this.renderFileRow(torrentSummary, obj.file, obj.index))
+
+      filesElement = (
+        <div key='files' className='files'>
+          <table>
+            <tbody>
+              {fileRows}
+            </tbody>
+          </table>
+        </div>
+      )
+    }
+
+    return (
+      <div key='details' className='torrent-details'>
+        {filesElement}
+      </div>
+    )
+  }
+
+  // Show a single torrentSummary file in the details view for a single torrent
+  renderFileRow (torrentSummary, file, index) {
+    // First, find out how much of the file we've downloaded
+    // Are we even torrenting it?
+    const isSelected = torrentSummary.selections && torrentSummary.selections[index]
+    let isDone = false // Are we finished torrenting it?
+    let progress = ''
+    if (torrentSummary.progress && torrentSummary.progress.files &&
+        torrentSummary.progress.files[index]) {
+      const fileProg = torrentSummary.progress.files[index]
+      isDone = fileProg.numPiecesPresent === fileProg.numPieces
+      progress = Math.floor(100 * fileProg.numPiecesPresent / fileProg.numPieces) + '%'
+    }
+
+    // Second, for media files where we saved our position, show how far we got
+    let positionElem
+    if (file.currentTime) {
+      // Radial progress bar. 0% = start from 0:00, 270% = 3/4 of the way thru
+      positionElem = this.renderRadialProgressBar(file.currentTime / file.duration)
+    }
+
+    // Finally, render the file as a table row
+    const isPlayable = TorrentPlayer.isPlayable(file)
+    const infoHash = torrentSummary.infoHash
+    let icon
+    let handleClick
+    if (isPlayable) {
+      icon = 'play_arrow' /* playable? add option to play */
+      handleClick = dispatcher('playFile', infoHash, index)
+    } else {
+      icon = 'description' /* file icon, opens in OS default app */
+      handleClick = isDone
+        ? dispatcher('openPath', infoHash, index)
+        : (e) => e.stopPropagation() // noop if file is not ready
+    }
+    // TODO: add a css 'disabled' class to indicate that a file cannot be opened/streamed
+    let rowClass = ''
+    if (!isSelected) rowClass = 'disabled' // File deselected, not being torrented
+    if (!isDone && !isPlayable) rowClass = 'disabled' // Can't open yet, can't stream
+    return (
+      <tr key={index} onClick={handleClick}>
+        <td className={'col-icon ' + rowClass}>
+          {positionElem}
+          <i className='icon'>{icon}</i>
+        </td>
+        <td className={'col-name ' + rowClass}>
+          {file.name}
+        </td>
+        <td className={'col-progress ' + rowClass}>
+          {isSelected ? progress : ''}
+        </td>
+        <td className={'col-size ' + rowClass}>
+          {prettyBytes(file.length)}
+        </td>
+        <td
+          className='col-select'
+          onClick={dispatcher('toggleTorrentFile', infoHash, index)}
+        >
+          <i className='icon deselect-file'>{isSelected ? 'close' : 'add'}</i>
+        </td>
+      </tr>
+    )
+  }
+
+  renderRadialProgressBar (fraction, cssClass) {
+    const rotation = 360 * fraction
+    const transformFill = { transform: 'rotate(' + (rotation / 2) + 'deg)' }
+    const transformFix = { transform: 'rotate(' + rotation + 'deg)' }
+
+    return (
+      <div key='radial-progress' className={'radial-progress ' + cssClass}>
+        <div className='circle'>
+          <div className='mask full' style={transformFill}>
+            <div className='fill' style={transformFill} />
+          </div>
+          <div className='mask half'>
+            <div className='fill' style={transformFill} />
+            <div className='fill fix' style={transformFix} />
+          </div>
+        </div>
+        <div className='inset' />
+      </div>
+    )
+  }
+}
+
+function stopPropagation (e) {
+  e.stopPropagation()
+}
+
+function getErrorMessage (torrentSummary) {
+  const err = torrentSummary.error
+  if (err === 'path-missing') {
+    return (
+      <span key='path-missing'>
+        Path missing.<br />
+        Fix and restart the app, or delete the torrent.
+      </span>
+    )
+  }
+  return 'Error'
+}

src/renderer/webtorrent.js

@@ -0,0 +1,434 @@
+// To keep the UI snappy, we run WebTorrent in its own hidden window, a separate
+// process from the main window.
+console.time('init')
+
+const crypto = require('crypto')
+const util = require('util')
+const { ipcRenderer } = require('electron')
+const fs = require('fs')
+const mm = require('music-metadata')
+const networkAddress = require('network-address')
+const path = require('path')
+const WebTorrent = require('webtorrent')
+
+const config = require('../config')
+const { TorrentKeyNotFoundError } = require('./lib/errors')
+const torrentPoster = require('./lib/torrent-poster')
+
+/**
+ * WebTorrent version.
+ */
+const VERSION = require('../../package.json').version
+
+/**
+ * Version number in Azureus-style. Generated from major and minor semver version.
+ * For example:
+ *   '0.16.1' -> '0016'
+ *   '1.2.5' -> '0102'
+ */
+const VERSION_STR = VERSION
+  .replace(/\d*./g, v => `0${v % 100}`.slice(-2))
+  .slice(0, 4)
+
+/**
+ * Version prefix string (used in peer ID). WebTorrent uses the Azureus-style
+ * encoding: '-', two characters for client id ('WW'), four ascii digits for version
+ * number, '-', followed by random numbers.
+ * For example:
+ *   '-WW0102-'...
+ */
+const VERSION_PREFIX = '-WD' + VERSION_STR + '-'
+
+/**
+ * Generate an ephemeral peer ID each time.
+ */
+const PEER_ID = Buffer.from(VERSION_PREFIX + crypto.randomBytes(9).toString('base64'))
+
+// Connect to the WebTorrent and BitTorrent networks. WebTorrent Desktop is a hybrid
+// client, as explained here: https://webtorrent.io/faq
+let client = window.client = new WebTorrent({ peerId: PEER_ID })
+
+// WebTorrent-to-HTTP streaming sever
+let server = null
+
+// Used for diffing, so we only send progress updates when necessary
+let prevProgress = null
+
+init()
+
+function init () {
+  listenToClientEvents()
+
+  ipcRenderer.on('wt-set-global-trackers', (e, globalTrackers) =>
+    setGlobalTrackers(globalTrackers))
+  ipcRenderer.on('wt-start-torrenting', (e, torrentKey, torrentID, path, fileModtimes, selections) =>
+    startTorrenting(torrentKey, torrentID, path, fileModtimes, selections))
+  ipcRenderer.on('wt-stop-torrenting', (e, infoHash) =>
+    stopTorrenting(infoHash))
+  ipcRenderer.on('wt-create-torrent', (e, torrentKey, options) =>
+    createTorrent(torrentKey, options))
+  ipcRenderer.on('wt-save-torrent-file', (e, torrentKey) =>
+    saveTorrentFile(torrentKey))
+  ipcRenderer.on('wt-generate-torrent-poster', (e, torrentKey) =>
+    generateTorrentPoster(torrentKey))
+  ipcRenderer.on('wt-get-audio-metadata', (e, infoHash, index) =>
+    getAudioMetadata(infoHash, index))
+  ipcRenderer.on('wt-start-server', (e, infoHash) =>
+    startServer(infoHash))
+  ipcRenderer.on('wt-stop-server', () =>
+    stopServer())
+  ipcRenderer.on('wt-select-files', (e, infoHash, selections) =>
+    selectFiles(infoHash, selections))
+
+  ipcRenderer.send('ipcReadyWebTorrent')
+
+  window.addEventListener('error', (e) =>
+    ipcRenderer.send('wt-uncaught-error', { message: e.error.message, stack: e.error.stack }),
+  true)
+
+  setInterval(updateTorrentProgress, 1000)
+  console.timeEnd('init')
+}
+
+function listenToClientEvents () {
+  client.on('warning', (err) => ipcRenderer.send('wt-warning', null, err.message))
+  client.on('error', (err) => ipcRenderer.send('wt-error', null, err.message))
+}
+
+// Sets the default trackers
+function setGlobalTrackers (globalTrackers) {
+  globalThis.WEBTORRENT_ANNOUNCE = globalTrackers
+}
+
+// Starts a given TorrentID, which can be an infohash, magnet URI, etc.
+// Returns a WebTorrent object. See https://git.io/vik9M
+function startTorrenting (torrentKey, torrentID, path, fileModtimes, selections) {
+  console.log('starting torrent %s: %s', torrentKey, torrentID)
+
+  const torrent = client.add(torrentID, {
+    path,
+    fileModtimes
+  })
+  torrent.key = torrentKey
+
+  // Listen for ready event, progress notifications, etc
+  addTorrentEvents(torrent)
+
+  // Only download the files the user wants, not necessarily all files
+  torrent.once('ready', () => selectFiles(torrent, selections))
+}
+
+function stopTorrenting (infoHash) {
+  console.log('--- STOP TORRENTING: ', infoHash)
+  const torrent = client.get(infoHash)
+  if (torrent) torrent.destroy()
+}
+
+// Create a new torrent, start seeding
+function createTorrent (torrentKey, options) {
+  console.log('creating torrent', torrentKey, options)
+  const paths = options.files.map((f) => f.path)
+  const torrent = client.seed(paths, options)
+  torrent.key = torrentKey
+  addTorrentEvents(torrent)
+  ipcRenderer.send('wt-new-torrent')
+}
+
+function addTorrentEvents (torrent) {
+  torrent.on('warning', (err) =>
+    ipcRenderer.send('wt-warning', torrent.key, err.message))
+  torrent.on('error', (err) =>
+    ipcRenderer.send('wt-error', torrent.key, err.message))
+  torrent.on('infoHash', () =>
+    ipcRenderer.send('wt-parsed', torrent.key, torrent.infoHash, torrent.magnetURI))
+  torrent.on('metadata', torrentMetadata)
+  torrent.on('ready', torrentReady)
+  torrent.on('done', torrentDone)
+
+  function torrentMetadata () {
+    const info = getTorrentInfo(torrent)
+    ipcRenderer.send('wt-metadata', torrent.key, info)
+
+    updateTorrentProgress()
+  }
+
+  function torrentReady () {
+    const info = getTorrentInfo(torrent)
+    ipcRenderer.send('wt-ready', torrent.key, info)
+    ipcRenderer.send('wt-ready-' + torrent.infoHash, torrent.key, info)
+
+    updateTorrentProgress()
+  }
+
+  function torrentDone () {
+    const info = getTorrentInfo(torrent)
+    ipcRenderer.send('wt-done', torrent.key, info)
+
+    updateTorrentProgress()
+
+    torrent.getFileModtimes((err, fileModtimes) => {
+      if (err) return onError(err)
+      ipcRenderer.send('wt-file-modtimes', torrent.key, fileModtimes)
+    })
+  }
+}
+
+// Produces a JSON saveable summary of a torrent
+function getTorrentInfo (torrent) {
+  return {
+    infoHash: torrent.infoHash,
+    magnetURI: torrent.magnetURI,
+    name: torrent.name,
+    path: torrent.path,
+    files: torrent.files.map(getTorrentFileInfo),
+    bytesReceived: torrent.received
+  }
+}
+
+// Produces a JSON saveable summary of a file in a torrent
+function getTorrentFileInfo (file) {
+  return {
+    name: file.name,
+    length: file.length,
+    path: file.path
+  }
+}
+
+// Every time we resolve a magnet URI, save the torrent file so that we can use
+// it on next startup. Starting with the full torrent metadata will be faster
+// than re-fetching it from peers using ut_metadata.
+function saveTorrentFile (torrentKey) {
+  const torrent = getTorrent(torrentKey)
+  const torrentPath = path.join(config.TORRENT_PATH, torrent.infoHash + '.torrent')
+
+  fs.access(torrentPath, fs.constants.R_OK, err => {
+    const fileName = torrent.infoHash + '.torrent'
+    if (!err) {
+      // We've already saved the file
+      return ipcRenderer.send('wt-file-saved', torrentKey, fileName)
+    }
+
+    // Otherwise, save the .torrent file, under the app config folder
+    fs.mkdir(config.TORRENT_PATH, { recursive: true }, _ => {
+      fs.writeFile(torrentPath, torrent.torrentFile, err => {
+        if (err) return console.log('error saving torrent file %s: %o', torrentPath, err)
+        console.log('saved torrent file %s', torrentPath)
+        return ipcRenderer.send('wt-file-saved', torrentKey, fileName)
+      })
+    })
+  })
+}
+
+// Save a JPG that represents a torrent.
+// Auto chooses either a frame from a video file, an image, etc
+function generateTorrentPoster (torrentKey) {
+  const torrent = getTorrent(torrentKey)
+  torrentPoster(torrent, (err, buf, extension) => {
+    if (err) return console.log('error generating poster: %o', err)
+    // save it for next time
+    fs.mkdir(config.POSTER_PATH, { recursive: true }, err => {
+      if (err) return console.log('error creating poster dir: %o', err)
+      const posterFileName = torrent.infoHash + extension
+      const posterFilePath = path.join(config.POSTER_PATH, posterFileName)
+      fs.writeFile(posterFilePath, buf, err => {
+        if (err) return console.log('error saving poster: %o', err)
+        // show the poster
+        ipcRenderer.send('wt-poster', torrentKey, posterFileName)
+      })
+    })
+  })
+}
+
+function updateTorrentProgress () {
+  const progress = getTorrentProgress()
+  // TODO: diff torrent-by-torrent, not once for the whole update
+  if (prevProgress && util.isDeepStrictEqual(progress, prevProgress)) {
+    return /* don't send heavy object if it hasn't changed */
+  }
+  ipcRenderer.send('wt-progress', progress)
+  prevProgress = progress
+}
+
+function getTorrentProgress () {
+  // First, track overall progress
+  const progress = client.progress
+  const hasActiveTorrents = client.torrents.some(torrent => torrent.progress !== 1)
+
+  // Track progress for every file in each torrent
+  // TODO: ideally this would be tracked by WebTorrent, which could do it
+  // more efficiently than looping over torrent.bitfield
+  const torrentProg = client.torrents.map(torrent => {
+    const fileProg = torrent.files && torrent.files.map(file => {
+      const numPieces = file._endPiece - file._startPiece + 1
+      let numPiecesPresent = 0
+      for (let piece = file._startPiece; piece <= file._endPiece; piece++) {
+        if (torrent.bitfield.get(piece)) numPiecesPresent++
+      }
+      return {
+        startPiece: file._startPiece,
+        endPiece: file._endPiece,
+        numPieces,
+        numPiecesPresent
+      }
+    })
+    return {
+      torrentKey: torrent.key,
+      ready: torrent.ready,
+      progress: torrent.progress,
+      downloaded: torrent.downloaded,
+      downloadSpeed: torrent.downloadSpeed,
+      uploadSpeed: torrent.uploadSpeed,
+      numPeers: torrent.numPeers,
+      length: torrent.length,
+      bitfield: torrent.bitfield,
+      files: fileProg
+    }
+  })
+
+  return {
+    torrents: torrentProg,
+    progress,
+    hasActiveTorrents
+  }
+}
+
+function startServer (infoHash) {
+  const torrent = client.get(infoHash)
+  if (torrent.ready) startServerFromReadyTorrent(torrent)
+  else torrent.once('ready', () => startServerFromReadyTorrent(torrent))
+}
+
+function startServerFromReadyTorrent (torrent) {
+  if (server) return
+
+  // start the streaming torrent-to-http server
+  server = torrent.createServer()
+  server.listen(0, () => {
+    const port = server.address().port
+    const urlSuffix = ':' + port
+    const info = {
+      torrentKey: torrent.key,
+      localURL: 'http://localhost' + urlSuffix,
+      networkURL: 'http://' + networkAddress() + urlSuffix,
+      networkAddress: networkAddress()
+    }
+
+    ipcRenderer.send('wt-server-running', info)
+    ipcRenderer.send('wt-server-' + torrent.infoHash, info)
+  })
+}
+
+function stopServer () {
+  if (!server) return
+  server.destroy()
+  server = null
+}
+
+console.log('Initializing...')
+
+function getAudioMetadata (infoHash, index) {
+  const torrent = client.get(infoHash)
+  const file = torrent.files[index]
+
+  // Set initial matadata to display the filename first.
+  const metadata = { title: file.name }
+  ipcRenderer.send('wt-audio-metadata', infoHash, index, metadata)
+
+  const options = {
+    native: false,
+    skipCovers: true,
+    fileSize: file.length,
+    observer: () => {
+      ipcRenderer.send('wt-audio-metadata', infoHash, index, {
+        common: metadata.common,
+        format: metadata.format
+      })
+    }
+  }
+  const onMetadata = file.done
+    // If completed; use direct file access
+    ? mm.parseFile(path.join(torrent.path, file.path), options)
+    // otherwise stream
+    : mm.parseStream(file.createReadStream(), file.name, options)
+
+  onMetadata
+    .then(
+      metadata => {
+        ipcRenderer.send('wt-audio-metadata', infoHash, index, metadata)
+        console.log(`metadata for file='${file.name}' completed.`)
+      },
+      err => {
+        console.log(
+          `error getting audio metadata for ${infoHash}:${index}`,
+          err
+        )
+      }
+    )
+}
+
+function selectFiles (torrentOrInfoHash, selections) {
+  // Get the torrent object
+  let torrent
+  if (typeof torrentOrInfoHash === 'string') {
+    torrent = client.get(torrentOrInfoHash)
+  } else {
+    torrent = torrentOrInfoHash
+  }
+  if (!torrent) {
+    throw new Error('selectFiles: missing torrent ' + torrentOrInfoHash)
+  }
+
+  // Selections not specified?
+  // Load all files. We still need to replace the default whole-torrent
+  // selection with individual selections for each file, so we can
+  // select/deselect files later on
+  if (!selections) {
+    selections = new Array(torrent.files.length).fill(true)
+  }
+
+  // Selections specified incorrectly?
+  if (selections.length !== torrent.files.length) {
+    throw new Error('got ' + selections.length + ' file selections, ' +
+      'but the torrent contains ' + torrent.files.length + ' files')
+  }
+
+  // Remove default selection (whole torrent)
+  torrent.deselect(0, torrent.pieces.length - 1, false)
+
+  // Add selections (individual files)
+  selections.forEach((selection, i) => {
+    const file = torrent.files[i]
+    if (selection) {
+      file.select()
+    } else {
+      console.log('deselecting file ' + i + ' of torrent ' + torrent.name)
+      file.deselect()
+    }
+  })
+}
+
+// Gets a WebTorrent handle by torrentKey
+// Throws an Error if we're not currently torrenting anything w/ that key
+function getTorrent (torrentKey) {
+  const ret = client.torrents.find((x) => x.key === torrentKey)
+  if (!ret) throw new TorrentKeyNotFoundError(torrentKey)
+  return ret
+}
+
+function onError (err) {
+  console.log(err)
+}
+
+// TODO: remove this once the following bugs are fixed:
+// https://bugs.chromium.org/p/chromium/issues/detail?id=490143
+// https://github.com/electron/electron/issues/7212
+window.testOfflineMode = () => {
+  console.log('Test, going OFFLINE')
+  client = window.client = new WebTorrent({
+    peerId: PEER_ID,
+    tracker: false,
+    dht: false,
+    webSeeds: false
+  })
+  listenToClientEvents()
+}