package iron.culling;

class TemporalState {

	public var visibleLastFrame: haxe.ds.IntMap<Bool>;
	public var visibleLastShadow: haxe.ds.IntMap<Bool>;
	public var frameLastTested: haxe.ds.IntMap<Int>;
	public var occlusionConfidence: haxe.ds.IntMap<Int>;
	public var capacity: Int = 0;
	public var frameCount: Int = 0;

	public function new() {
		visibleLastFrame = new haxe.ds.IntMap<Bool>();
		visibleLastShadow = new haxe.ds.IntMap<Bool>();
		frameLastTested = new haxe.ds.IntMap<Int>();
		occlusionConfidence = new haxe.ds.IntMap<Int>();
	}

	public function ensureCapacity(cap: Int) {
		if (capacity < cap) capacity = cap;
	}

	public inline function wasVisibleLastFrame(i: Int): Bool {
		return visibleLastFrame.exists(i);
	}

	public inline function wasVisibleShadowLastFrame(i: Int): Bool {
		return visibleLastShadow.exists(i);
	}

	public inline function needsTest(i: Int, maxSkipFrames: Int): Bool {
		if (visibleLastFrame.exists(i)) return false; // assumed visible
		var lastTested = frameLastTested.get(i);
		if (lastTested == null) return true;
		return frameCount - lastTested >= maxSkipFrames;
	}

	public inline function needsVisibleReTest(i: Int, retestInterval: Int): Bool {
		var lastTested = frameLastTested.get(i);
		if (lastTested == null) return true;
		return frameCount - lastTested >= retestInterval;
	}

	public inline function setVisible(i: Int, visible: Bool) {
		if (visible) {
			visibleLastFrame.set(i, true);
			occlusionConfidence.remove(i);
		} else {
			visibleLastFrame.remove(i);
			var conf = occlusionConfidence.get(i);
			occlusionConfidence.set(i, conf == null ? 1 : Std.int(Math.min(255, conf + 1)));
		}
	}

	public inline function markTested(i: Int) {
		frameLastTested.set(i, frameCount);
	}

	public inline function setVisibleShadow(i: Int, visible: Bool) {
		if (visible) visibleLastShadow.set(i, true);
		else visibleLastShadow.remove(i);
	}

	public inline function advanceFrame() {
		frameCount++;
	}

	public function clear() {
		visibleLastFrame = new haxe.ds.IntMap<Bool>();
		visibleLastShadow = new haxe.ds.IntMap<Bool>();
		frameLastTested = new haxe.ds.IntMap<Int>();
		occlusionConfidence = new haxe.ds.IntMap<Int>();
	}

	public inline function getConfidence(i: Int): Int {
		var c = occlusionConfidence.get(i);
		return c == null ? 0 : c;
	}
}