/**
 * @author Mat Groves http://matgroves.com/ @Doormat23
 */

/**
 * The sprite sheet loader is used to load in JSON sprite sheet data
 * To generate the data you can use http://www.codeandweb.com/texturepacker and publish the "JSON" format
 * There is a free version so thats nice, although the paid version is great value for money.
 * It is highly recommended to use Sprite sheets (also know as texture atlas") as it means sprite"s can be batched and drawn together for highly increased rendering speed.
 * Once the data has been loaded the frames are stored in the PIXI texture cache and can be accessed though PIXI.Texture.fromFrameId() and PIXI.Sprite.fromFromeId()
 * This loader will also load the image file that the Spritesheet points to as well as the data.
 * When loaded this class will dispatch a "loaded" event
 *
 * @class SpriteSheetLoader
 * @uses EventTarget
 * @constructor
 * @param url {String} The url of the sprite sheet JSON file
 * @param crossorigin {Boolean} Whether requests should be treated as crossorigin
 */

PIXI.SpriteSheetLoader = function (url, crossorigin) {
	/*
	 * i use texture packer to load the assets..
	 * http://www.codeandweb.com/texturepacker
	 * make sure to set the format as "JSON"
	 */
	PIXI.EventTarget.call(this);

	/**
	 * The url of the bitmap font data
	 *
	 * @property url
	 * @type String
	 */
	this.url = url;

	/**
	 * Whether the requests should be treated as cross origin
	 *
	 * @property crossorigin
	 * @type Boolean
	 */
	this.crossorigin = crossorigin;

	/**
	 * [read-only] The base url of the bitmap font data
	 *
	 * @property baseUrl
	 * @type String
	 * @readOnly
	 */
	this.baseUrl = url.replace(/[^\/]*$/, "");

    /**
     * The texture being loaded
     *
     * @property texture
     * @type Texture
     */
    this.texture = null;

    /**
     * The frames of the sprite sheet
     *
     * @property frames
     * @type Object
     */
	this.frames = {};
};

// constructor
PIXI.SpriteSheetLoader.prototype.constructor = PIXI.SpriteSheetLoader;

/**
 * This will begin loading the JSON file
 *
 * @method load
 */
PIXI.SpriteSheetLoader.prototype.load = function () {
	var scope = this;
	var jsonLoader = new PIXI.JsonLoader(this.url, this.crossorigin);
	jsonLoader.addEventListener("loaded", function (event) {
		scope.json = event.content.json;
		scope.onJSONLoaded();
	});
	jsonLoader.load();
};

/**
 * Invoke when JSON file is loaded
 *
 * @method onJSONLoaded
 * @private
 */
PIXI.SpriteSheetLoader.prototype.onJSONLoaded = function () {
	var scope = this;
	var textureUrl = this.baseUrl + this.json.meta.image;
	var image = new PIXI.ImageLoader(textureUrl, this.crossorigin);
	var frameData = this.json.frames;

	this.texture = image.texture.baseTexture;
	image.addEventListener("loaded", function (event) {
		scope.onLoaded();
	});

	for (var i in frameData) {
		var rect = frameData[i].frame;
		if (rect) {
			PIXI.TextureCache[i] = new PIXI.Texture(this.texture, {
				x: rect.x,
				y: rect.y,
				width: rect.w,
				height: rect.h
			});
			if (frameData[i].trimmed) {
				//var realSize = frameData[i].spriteSourceSize;
				PIXI.TextureCache[i].realSize = frameData[i].spriteSourceSize;
				PIXI.TextureCache[i].trim.x = 0; // (realSize.x / rect.w)
				// calculate the offset!
			}
		}
	}

	image.load();
};
/**
 * Invoke when all files are loaded (json and texture)
 *
 * @method onLoaded
 * @private
 */
PIXI.SpriteSheetLoader.prototype.onLoaded = function () {
	this.dispatchEvent({
		type: "loaded",
		content: this
	});
};