/*
 * Copyright (C)2005-2019 Haxe Foundation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

package haxe.io;

#if cpp
using cpp.NativeArray;
#end

class Bytes {
	public var length(default, null):Int;

	var b:BytesData;

	function new(length, b) {
		this.length = length;
		this.b = b;
		#if flash
		b.endian = flash.utils.Endian.LITTLE_ENDIAN;
		#end
	}

	/**
		Returns the byte at index `pos`.
	**/
	public inline function get(pos:Int):Int {
		#if neko
		return untyped $sget(b, pos);
		#elseif flash
		return b[pos];
		#elseif cpp
		return untyped b[pos];
		#elseif java
		return untyped b[pos] & 0xFF;
		#elseif python
		return python.Syntax.arrayAccess(b, pos);
		#else
		return b[pos];
		#end
	}

	/**
		Stores the given byte `v` at the given position `pos`.
	**/
	public inline function set(pos:Int, v:Int):Void {
		#if neko
		untyped $sset(b, pos, v);
		#elseif flash
		b[pos] = v;
		#elseif cpp
		untyped b[pos] = v;
		#elseif java
		b[pos] = cast v;
		#elseif cs
		b[pos] = cast v;
		#elseif python
		python.Syntax.arraySet(b, pos, v & 0xFF);
		#else
		b[pos] = v & 0xFF;
		#end
	}

	/**
		Copies `len` bytes from `src` into this instance.
		@param pos Zero-based location in `this` instance at which to start writing
			bytes.
		@param src Source `Bytes` instance from which to copy bytes.
		@param srcpos Zero-based location at `src` from which bytes will be copied.
		@param len Number of bytes to be copied.
	**/
	public function blit(pos:Int, src:Bytes, srcpos:Int, len:Int):Void {
		#if !neko
		if (pos < 0 || srcpos < 0 || len < 0 || pos + len > length || srcpos + len > src.length)
			throw Error.OutsideBounds;
		#end
		#if neko
		try
			untyped $sblit(b, pos, src.b, srcpos, len)
		catch (e:Dynamic)
			throw Error.OutsideBounds;
		#elseif flash
		b.position = pos;
		if (len > 0)
			b.writeBytes(src.b, srcpos, len);
		#elseif java
		java.lang.System.arraycopy(src.b, srcpos, b, pos, len);
		#elseif cs
		cs.system.Array.Copy(src.b, srcpos, b, pos, len);
		#elseif python
		python.Syntax.code("self.b[{0}:{0}+{1}] = src.b[srcpos:srcpos+{1}]", pos, len);
		#elseif cpp
		b.blit(pos, src.b, srcpos, len);
		#else
		var b1 = b;
		var b2 = src.b;
		if (b1 == b2 && pos > srcpos) {
			var i = len;
			while (i > 0) {
				i--;
				b1[i + pos] = b2[i + srcpos];
			}
			return;
		}
		for (i in 0...len)
			b1[i + pos] = b2[i + srcpos];
		#end
	}

	/**
		Sets `len` consecutive bytes starting from index `pos` of `this` instance
		to `value`.
	**/
	public function fill(pos:Int, len:Int, value:Int) {
		#if flash
		var v4 = value & 0xFF;
		v4 |= v4 << 8;
		v4 |= v4 << 16;
		b.position = pos;
		for (i in 0...len >> 2)
			b.writeUnsignedInt(v4);
		pos += len & ~3;
		for (i in 0...len & 3)
			set(pos++, value);
		#elseif cpp
		untyped __global__.__hxcpp_memory_memset(b, pos, len, value);
		#else
		for (i in 0...len)
			set(pos++, value);
		#end
	}

	/**
		Returns a new `Bytes` instance that contains a copy of `len` bytes of
		`this` instance, starting at index `pos`.
	**/
	public function sub(pos:Int, len:Int):Bytes {
		#if !neko
		if (pos < 0 || len < 0 || pos + len > length)
			throw Error.OutsideBounds;
		#end
		#if neko
		return try new Bytes(len, untyped __dollar__ssub(b, pos, len)) catch (e:Dynamic) throw Error.OutsideBounds;
		#elseif flash
		b.position = pos;
		var b2 = new flash.utils.ByteArray();
		b.readBytes(b2, 0, len);
		return new Bytes(len, b2);
		#elseif java
		var newarr = new java.NativeArray(len);
		java.lang.System.arraycopy(b, pos, newarr, 0, len);
		return new Bytes(len, newarr);
		#elseif cs
		var newarr = new cs.NativeArray(len);
		cs.system.Array.Copy(b, pos, newarr, 0, len);
		return new Bytes(len, newarr);
		#elseif python
		return new Bytes(len, python.Syntax.arrayAccess(b, pos, pos + len));
		#else
		return new Bytes(len, b.slice(pos, pos + len));
		#end
	}
	
	/**
		Returns `0` if the bytes of `this` instance and the bytes of `other` are
		identical.

		Returns a negative value if the `length` of `this` instance is less than
		the `length` of `other`, or a positive value if the `length` of `this`
		instance is greater than the `length` of `other`.

		In case of equal `length`s, returns a negative value if the first different
		value in `other` is greater than the corresponding value in `this`
		instance; otherwise returns a positive value.
	**/
	public function compare(other:Bytes):Int {
		#if neko
		return untyped __dollar__compare(b, other.b);
		#elseif flash
		var len = (length < other.length) ? length : other.length;
		var b1 = b;
		var b2 = other.b;
		b1.position = 0;
		b2.position = 0;
		b1.endian = flash.utils.Endian.BIG_ENDIAN;
		b2.endian = flash.utils.Endian.BIG_ENDIAN;
		for (i in 0...len >> 2)
			if (b1.readUnsignedInt() != b2.readUnsignedInt()) {
				b1.position -= 4;
				b2.position -= 4;
				var d = b1.readUnsignedInt() - b2.readUnsignedInt();
				b1.endian = flash.utils.Endian.LITTLE_ENDIAN;
				b2.endian = flash.utils.Endian.LITTLE_ENDIAN;
				return d;
			}
		for (i in 0...len & 3)
			if (b1.readUnsignedByte() != b2.readUnsignedByte()) {
				b1.endian = flash.utils.Endian.LITTLE_ENDIAN;
				b2.endian = flash.utils.Endian.LITTLE_ENDIAN;
				return b1[b1.position - 1] - b2[b2.position - 1];
			}
		b1.endian = flash.utils.Endian.LITTLE_ENDIAN;
		b2.endian = flash.utils.Endian.LITTLE_ENDIAN;
		return length - other.length;
		// #elseif cs
		// TODO: memcmp if unsafe flag is on
		#elseif cpp
		return b.memcmp(other.b);
		#else
		var b1 = b;
		var b2 = other.b;
		var len = (length < other.length) ? length : other.length;
		for (i in 0...len)
			if (b1[i] != b2[i])
				return untyped b1[i] - b2[i];
		return length - other.length;
		#end
	}

	/**
		Returns the IEEE double-precision value at the given position `pos` (in
		little-endian encoding). Result is unspecified if `pos` is outside the
		bounds.
	**/
	#if (neko_v21 || (cpp && !cppia) || flash)
	inline
	#end
	public function getDouble(pos:Int):Float {
		#if neko_v21
		return untyped $sgetd(b, pos, false);
		#elseif flash
		b.position = pos;
		return b.readDouble();
		#elseif cpp
		if (pos < 0 || pos + 8 > length)
			throw Error.OutsideBounds;
		return untyped __global__.__hxcpp_memory_get_double(b, pos);
		#else
		return FPHelper.i64ToDouble(getInt32(pos), getInt32(pos + 4));
		#end
	}

	/**
		Returns the IEEE single-precision value at the given position `pos` (in
		little-endian encoding). Result is unspecified if `pos` is outside the
		bounds.
	**/
	#if (neko_v21 || (cpp && !cppia) || flash)
	inline
	#end
	public function getFloat(pos:Int):Float {
		#if neko_v21
		return untyped $sgetf(b, pos, false);
		#elseif flash
		b.position = pos;
		return b.readFloat();
		#elseif cpp
		if (pos < 0 || pos + 4 > length)
			throw Error.OutsideBounds;
		return untyped __global__.__hxcpp_memory_get_float(b, pos);
		#else
		return FPHelper.i32ToFloat(getInt32(pos));
		#end
	}

	/**
		Stores the given IEEE double-precision value `v` at the given position
		`pos` in little-endian encoding. Result is unspecified if writing outside
		of bounds.
	**/
	#if (neko_v21 || flash)
	inline
	#end
	public function setDouble(pos:Int, v:Float):Void {
		#if neko_v21
		untyped $ssetd(b, pos, v, false);
		#elseif neko
		untyped $sblit(b, pos, FPHelper._double_bytes(v, false), 0, 8);
		#elseif flash
		b.position = pos;
		b.writeDouble(v);
		#elseif cpp
		if (pos < 0 || pos + 8 > length)
			throw Error.OutsideBounds;
		untyped __global__.__hxcpp_memory_set_double(b, pos, v);
		#else
		var i = FPHelper.doubleToI64(v);
		setInt32(pos, i.low);
		setInt32(pos + 4, i.high);
		#end
	}

	/**
		Stores the given IEEE single-precision value `v` at the given position
		`pos` in little-endian encoding. Result is unspecified if writing outside
		of bounds.
	**/
	#if (neko_v21 || flash)
	inline
	#end
	public function setFloat(pos:Int, v:Float):Void {
		#if neko_v21
		untyped $ssetf(b, pos, v, false);
		#elseif neko
		untyped $sblit(b, pos, FPHelper._float_bytes(v, false), 0, 4);
		#elseif flash
		b.position = pos;
		b.writeFloat(v);
		#elseif cpp
		if (pos < 0 || pos + 4 > length)
			throw Error.OutsideBounds;
		untyped __global__.__hxcpp_memory_set_float(b, pos, v);
		#else
		setInt32(pos, FPHelper.floatToI32(v));
		#end
	}

	/**
		Returns the 16-bit unsigned integer at the given position `pos` (in
		little-endian encoding).
	**/
	public inline function getUInt16(pos:Int):Int {
		#if neko_v21
		return untyped $sget16(b, pos, false);
		#else
		return get(pos) | (get(pos + 1) << 8);
		#end
	}

	/**
		Stores the given 16-bit unsigned integer `v` at the given position `pos`
		(in little-endian encoding).
	**/
	public inline function setUInt16(pos:Int, v:Int):Void {
		#if neko_v21
		untyped $sset16(b, pos, v, false);
		#else
		set(pos, v);
		set(pos + 1, v >> 8);
		#end
	}

	/**
		Returns the 32-bit integer at the given position `pos` (in little-endian
		encoding).
	**/
	public inline function getInt32(pos:Int):Int {
		#if neko_v21
		return untyped $sget32(b, pos, false);
		#elseif python
		var v = get(pos) | (get(pos + 1) << 8) | (get(pos + 2) << 16) | (get(pos + 3) << 24);
		return if (v & 0x80000000 != 0) v | 0x80000000 else v;
		#elseif lua
		var v = get(pos) | (get(pos + 1) << 8) | (get(pos + 2) << 16) | (get(pos + 3) << 24);
		return lua.Boot.clampInt32(if (v & 0x80000000 != 0) v | 0x80000000 else v);
		#else
		return get(pos) | (get(pos + 1) << 8) | (get(pos + 2) << 16) | (get(pos + 3) << 24);
		#end
	}

	/**
		Returns the 64-bit integer at the given position `pos` (in little-endian
		encoding).
	**/
	public inline function getInt64(pos:Int):haxe.Int64 {
		return haxe.Int64.make(getInt32(pos + 4), getInt32(pos));
	}

	/**
		Stores the given 32-bit integer `v` at the given position `pos` (in
		little-endian encoding).
	**/
	public inline function setInt32(pos:Int, v:Int):Void {
		#if neko_v21
		untyped $sset32(b, pos, v, false);
		#else
		set(pos, v);
		set(pos + 1, v >> 8);
		set(pos + 2, v >> 16);
		set(pos + 3, v >>> 24);
		#end
	}

	/**
		Stores the given 64-bit integer `v` at the given position `pos` (in
		little-endian encoding).
	**/
	public inline function setInt64(pos:Int, v:haxe.Int64):Void {
		setInt32(pos, v.low);
		setInt32(pos + 4, v.high);
	}

	/**
		Returns the `len`-bytes long string stored at the given position `pos`,
		interpreted with the given `encoding` (UTF-8 by default).
	**/
	public function getString(pos:Int, len:Int, ?encoding:Encoding):String {
		if (encoding == null)
			encoding == UTF8;
		#if !neko
		if (pos < 0 || len < 0 || pos + len > length)
			throw Error.OutsideBounds;
		#end
		#if neko
		return try new String(untyped __dollar__ssub(b, pos, len)) catch (e:Dynamic) throw Error.OutsideBounds;
		#elseif flash
		b.position = pos;
		return encoding == RawNative ? b.readMultiByte(len, "unicode") : b.readUTFBytes(len);
		#elseif cpp
		var result:String = "";
		untyped __global__.__hxcpp_string_of_bytes(b, result, pos, len);
		return result;
		#elseif cs
		switch (encoding) {
			case UTF8 | null:
				return cs.system.text.Encoding.UTF8.GetString(b, pos, len);
			case RawNative:
				return cs.system.text.Encoding.Unicode.GetString(b, pos, len);
		}
		#elseif java
		try {
			switch (encoding) {
				case UTF8 | null:
					return new String(b, pos, len, "UTF-8");
				case RawNative:
					return new String(b, pos, len, "UTF-16LE");
			}
		} catch (e:Dynamic) {
			throw e;
		}
		#elseif python
		return python.Syntax.code("self.b[{0}:{0}+{1}].decode('UTF-8','replace')", pos, len);
		#elseif lua
		if (b.length - pos <= lua.Boot.MAXSTACKSIZE) {
			var end:Int = cast Math.min(b.length, pos + len) - 1;
			return lua.NativeStringTools.char(lua.TableTools.unpack(untyped b, pos, end));
		} else {
			var tbl:lua.Table<Int, String> = lua.Table.create();
			for (idx in pos...pos + len) {
				lua.Table.insert(tbl, lua.NativeStringTools.char(b[idx]));
			}
			return lua.Table.concat(tbl, '');
		}
		#else
		var s = "";
		var b = b;
		var fcc = String.fromCharCode;
		var i = pos;
		var max = pos + len;
		// utf8-decode and utf16-encode
		while (i < max) {
			var c = b[i++];
			if (c < 0x80) {
				if (c == 0)
					break;
				s += fcc(c);
			} else if (c < 0xE0)
				s += fcc(((c & 0x3F) << 6) | (b[i++] & 0x7F));
			else if (c < 0xF0) {
				var c2 = b[i++];
				s += fcc(((c & 0x1F) << 12) | ((c2 & 0x7F) << 6) | (b[i++] & 0x7F));
			} else {
				var c2 = b[i++];
				var c3 = b[i++];
				var u = ((c & 0x0F) << 18) | ((c2 & 0x7F) << 12) | ((c3 & 0x7F) << 6) | (b[i++] & 0x7F);
				// surrogate pair
				s += fcc((u >> 10) + 0xD7C0);
				s += fcc((u & 0x3FF) | 0xDC00);
			}
		}
		return s;
		#end
	}

	@:deprecated("readString is deprecated, use getString instead")
	@:noCompletion
	public inline function readString(pos:Int, len:Int):String {
		return getString(pos, len);
	}

	/**
		Returns a `String` representation of the bytes interpreted as UTF-8.
	**/
	public function toString():String {
		#if neko
		return new String(untyped __dollar__ssub(b, 0, length));
		#elseif flash
		b.position = 0;
		return b.toString();
		#elseif cs
		return cs.system.text.Encoding.UTF8.GetString(b, 0, length);
		#elseif java
		try {
			return new String(b, 0, length, "UTF-8");
		} catch (e:Dynamic)
			throw e;
		#else
		return getString(0, length);
		#end
	}

	/**
		Returns a hexadecimal `String` representation of the bytes of `this`
		instance.
	**/
	public function toHex():String {
		var s = new StringBuf();
		var chars = [];
		var str = "0123456789abcdef";
		for (i in 0...str.length)
			chars.push(str.charCodeAt(i));
		for (i in 0...length) {
			var c = get(i);
			s.addChar(chars[c >> 4]);
			s.addChar(chars[c & 15]);
		}
		return s.toString();
	}

	/**
		Returns the bytes of `this` instance as `BytesData`.
	**/
	public inline function getData():BytesData {
		return b;
	}

	/**
		Returns a new `Bytes` instance with the given `length`. The values of the
		bytes are not initialized and may not be zero.
	**/
	public static function alloc(length:Int):Bytes {
		#if neko
		return new Bytes(length, untyped __dollar__smake(length));
		#elseif flash
		var b = new flash.utils.ByteArray();
		b.length = length;
		return new Bytes(length, b);
		#elseif cpp
		var a = new BytesData();
		if (length > 0)
			cpp.NativeArray.setSize(a, length);
		return new Bytes(length, a);
		#elseif cs
		return new Bytes(length, new cs.NativeArray(length));
		#elseif java
		return new Bytes(length, new java.NativeArray(length));
		#elseif python
		return new Bytes(length, new python.Bytearray(length));
		#else
		var a = new Array();
		for (i in 0...length)
			a.push(0);
		return new Bytes(length, a);
		#end
	}

	/**
		Returns the `Bytes` representation of the given `String`, using the
		specified encoding (UTF-8 by default).
	**/
	@:pure
	public static function ofString(s:String, ?encoding:Encoding):Bytes {
		#if neko
		return new Bytes(s.length, untyped __dollar__ssub(s.__s, 0, s.length));
		#elseif flash
		var b = new flash.utils.ByteArray();
		if (encoding == RawNative)
			b.writeMultiByte(s, "unicode")
		else
			b.writeUTFBytes(s);
		return new Bytes(b.length, b);
		#elseif cpp
		var a = new BytesData();
		untyped __global__.__hxcpp_bytes_of_string(a, s);
		return new Bytes(a.length, a);
		#elseif cs
		var b = switch (encoding) {
			case UTF8 | null:
				cs.system.text.Encoding.UTF8.GetBytes(s);
			case RawNative:
				cs.system.text.Encoding.Unicode.GetBytes(s);
		};
		return new Bytes(b.Length, b);
		#elseif java
		try {
			var b:BytesData = switch (encoding) {
				case UTF8 | null:
					@:privateAccess s.getBytes("UTF-8");
				case RawNative:
					@:privateAccess s.getBytes("UTF-16LE");
			};
			return new Bytes(b.length, b);
		} catch (e:Dynamic) {
			throw e;
		}
		#elseif python
		var b:BytesData = new python.Bytearray(s, "UTF-8");
		return new Bytes(b.length, b);
		#elseif lua
		var bytes = [
			for (i in 0...lua.NativeStringTools.len(s)) {
				lua.NativeStringTools.byte(s, i + 1);
			}
		];
		return new Bytes(bytes.length, bytes);
		#else
		var a = new Array();
		// utf16-decode and utf8-encode
		var i = 0;
		while (i < s.length) {
			var c:Int = StringTools.fastCodeAt(s, i++);
			// surrogate pair
			if (0xD800 <= c && c <= 0xDBFF)
				c = (c - 0xD7C0 << 10) | (StringTools.fastCodeAt(s, i++) & 0x3FF);
			if (c <= 0x7F)
				a.push(c);
			else if (c <= 0x7FF) {
				a.push(0xC0 | (c >> 6));
				a.push(0x80 | (c & 63));
			} else if (c <= 0xFFFF) {
				a.push(0xE0 | (c >> 12));
				a.push(0x80 | ((c >> 6) & 63));
				a.push(0x80 | (c & 63));
			} else {
				a.push(0xF0 | (c >> 18));
				a.push(0x80 | ((c >> 12) & 63));
				a.push(0x80 | ((c >> 6) & 63));
				a.push(0x80 | (c & 63));
			}
		}
		return new Bytes(a.length, a);
		#end
	}

	/**
		Returns the `Bytes` representation of the given `BytesData`.
	**/
	public static function ofData(b:BytesData) {
		#if flash
		return new Bytes(b.length, b);
		#elseif neko
		return new Bytes(untyped __dollar__ssize(b), b);
		#elseif cs
		return new Bytes(b.Length, b);
		#else
		return new Bytes(b.length, b);
		#end
	}

	/**
		Converts the given hexadecimal `String` to `Bytes`. `s` must be a string of
		even length consisting only of hexadecimal digits. For example:
		`"0FDA14058916052309"`.
	**/
	public static function ofHex(s:String):Bytes {
		var len:Int = s.length;
		if ((len & 1) != 0)
			throw "Not a hex string (odd number of digits)";
		var ret:Bytes = Bytes.alloc(len >> 1);
		for (i in 0...ret.length) {
			var high = StringTools.fastCodeAt(s, i * 2);
			var low = StringTools.fastCodeAt(s, i * 2 + 1);
			high = (high & 0xF) + ((high & 0x40) >> 6) * 9;
			low = (low & 0xF) + ((low & 0x40) >> 6) * 9;
			ret.set(i, ((high << 4) | low) & 0xFF);
		}

		return ret;
	}

	/**
		Reads the `pos`-th byte of the given `b` bytes, in the most efficient way
		possible. Behavior when reading outside of the available data is
		unspecified.
	**/
	public inline static function fastGet(b:BytesData, pos:Int):Int {
		#if neko
		return untyped __dollar__sget(b, pos);
		#elseif flash
		return b[pos];
		#elseif cpp
		return untyped b.unsafeGet(pos);
		#elseif java
		return untyped b[pos] & 0xFF;
		#else
		return b[pos];
		#end
	}
}