/**
 * System takes care of updating all the entities (based on their component data)
 * @param apiSystem GameLib.API.System
 * @constructor
 */
GameLib.System.Render = function(
    apiSystem
) {

    GameLib.System.call(
        this,
        apiSystem
    );

};

GameLib.System.Render.prototype = Object.create(GameLib.System.prototype);
GameLib.System.Render.prototype.constructor = GameLib.System.Render;

GameLib.System.Render.prototype.start = function() {

	this.renderEntities = GameLib.EntityManager.Instance.query(
		[
			GameLib.D3.Viewport,
			GameLib.D3.Scene,
			GameLib.D3.Renderer,
			GameLib.D3.Camera
		]
	);

	this.renderEntities.map(
		function(entity) {
			var stats = entity.getFirstComponent(GameLib.D3.Stats);
			stats.resize();
			stats.domElement.instance.parentElement.appendChild(stats.instance.dom);
		}
	)
};

/**
 * Update script
 */
GameLib.System.Render.prototype.update = function() {

	this.renderEntities.map(

		function (renderEntity) {

			var stats = renderEntity.getFirstComponent(GameLib.D3.Stats);

			if (!stats.instance) {
				return;
			}

			var renderer = renderEntity.getFirstComponent(GameLib.D3.Renderer);
			var camera = renderEntity.getFirstComponent(GameLib.D3.Camera);
			var viewports = renderEntity.getComponents(GameLib.D3.Viewport);
			var scenes = renderEntity.getComponents(GameLib.D3.Scene);

			if (!renderer.instance) {
				return;
			}

			if (viewports.length > 1) {
				renderer.instance.autoClear = false;
			}

			if (scenes.length > 1) {
				renderer.instance.autoClear = false;
			}

			renderer.instance.clear();

			viewports.map(
				function (viewport) {

					renderer.instance.setViewport(
						viewport.x * renderer.width,
						viewport.y * renderer.height,
						viewport.width * renderer.width,
						viewport.height * renderer.height
					);

					function renderScene(scene) {

						if (!scene.instance) {
							return;
						}

						if (scene.activeCamera) {

							if (!scene.activeCamera.instance) {
								return;
							}

							renderer.instance.render(
								scene.instance,
								scene.activeCamera.instance
							);
						} else {

							if (!camera.instance) {
								return;
							}

							renderer.instance.render(
								scene.instance,
								camera.instance
							);
						}
					}

					if (viewport.scenes && viewport.scenes.length > 0) {
						viewport.scenes.map(renderScene);
					} else {
						scenes.map(renderScene);
					}
				}
			);

			stats.instance.end();
		}
	);

};

GameLib.System.Render.prototype.stop = function() {

	this.renderEntities.map(
		function(entity) {
			var stats = entity.getFirstComponent(GameLib.D3.Stats);
			stats.domElement.instance.parentElement.removeChild(stats.instance.dom);
		}
	);

	this.renderEntities	= [];
};