/**
 * The way to use RaytracingWorkerRenderer is similar to RaytracingRenderer
 * except that it is simply a coordinator for workers. The workers compute
 * the pixel values and this renderer simply paints it to the Canvas. As such,
 * it is simply a renderer.
 *
 * TODO
 * - serialize scene and hand it to workers
 * - pass worker path as option
 *
 * @author zz85 / http://github.com/zz85
 */

THREE.RaytracingWorkerRenderer = function ( parameters ) {

	console.log( 'THREE.RaytracingWorkerRenderer', THREE.REVISION );

	parameters = parameters || {};

	var scope = this;
	var pool = [];

	var canvas = document.createElement( 'canvas' );
	var context = canvas.getContext( '2d', {
		alpha: parameters.alpha === true
	} );

	var maxRecursionDepth = 3;

	var canvasWidth, canvasHeight;
	var canvasWidthHalf, canvasHeightHalf;

	var clearColor = new THREE.Color( 0x000000 );

	this.domElement = canvas;

	this.autoClear = true;

	var workers = parameters.workers || navigator.hardwareConcurrency || 4;
	var blockSize = parameters.blockSize || 64;

	console.log('%cSpinning off ' + workers + ' Workers ', 'font-size: 20px; background: black; color: white; font-family: monospace;');

	for (var i = 0; i < workers; i++) {

		var worker = new Worker('js/renderers/RaytracingWorker.js');

		worker.onmessage = function(e) {
			var data = e.data;

			if (!data) return;

			if (data.blockSize) {
				var d = data.data;
				var imagedata = new ImageData(new Uint8ClampedArray(d), data.blockSize, data.blockSize);
				context.putImageData( imagedata, data.blockX, data.blockY );
			} else if (data.type == 'complete') {
				// TODO can terminate workers after all is done?
				console.log('Worker ' + data.worker, data.time / 1000, (Date.now() - reallyThen) / 1000 + ' s');

				renderNext(this);
			}

		}

		worker.color = new THREE.Color().setHSL(i / workers, 0.8, 0.8).getHexString();
		pool.push(worker);

	}

	this.setClearColor = function ( color, alpha ) {

		clearColor.set( color );

	};

	this.setPixelRatio = function () {};

	this.setSize = function ( width, height ) {

		canvas.width = width;
		canvas.height = height;

		canvasWidth = canvas.width;
		canvasHeight = canvas.height;

		canvasWidthHalf = Math.floor( canvasWidth / 2 );
		canvasHeightHalf = Math.floor( canvasHeight / 2 );

		context.fillStyle = 'white';

		pool.forEach( function( p, i ) {

			p.postMessage({

				init: [ width, height ],
				worker: i,
				workers: pool.length,
				blockSize: blockSize,
				initScene: initScene.toString()

			});

		});

	};

	this.setSize( canvas.width, canvas.height );

	this.clear = function () {

	};

	//

	var nextBlock, totalBlocks, xblocks, yblocks;

	function renderNext(worker) {
		var current = nextBlock++;
		if (nextBlock > totalBlocks) {
			return scope.dispatchEvent( { type: "complete" } );
		}

		var blockX = (current % xblocks) * blockSize;
		var blockY = (current / xblocks | 0) * blockSize;

		worker.postMessage({
			render: true,
			x: blockX,
			y: blockY
		});

		context.fillStyle = '#' + worker.color;

		context.fillRect( blockX, blockY, blockSize, blockSize );
	}

	this.render = function ( scene, camera ) {

		var sceneJSON = scene.toJSON();
		var cameraJSON = camera.toJSON();

		pool.forEach(function(worker) {
			worker.postMessage({
				scene: sceneJSON,
				camera: cameraJSON
			});
		});

		context.clearRect( 0, 0, canvasWidth, canvasHeight );
		reallyThen = Date.now();

		xblocks = Math.ceil(canvasWidth / blockSize);
		yblocks = Math.ceil(canvasHeight / blockSize);
		nextBlock = 0;
		totalBlocks = xblocks * yblocks;

		pool.forEach(renderNext);

	};

};

THREE.EventDispatcher.prototype.apply( THREE.RaytracingWorkerRenderer.prototype );