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

/**
 * The xml loader is used to load in XML bitmap font data ('xml' or 'fnt')
 * To generate the data you can use http://www.angelcode.com/products/bmfont/
 * This loader will also load the image file as the data.
 * When loaded this class will dispatch a 'loaded' event
 *
 * @class BitmapFontLoader
 * @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.BitmapFontLoader = 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(/[^\/]*$/, '');

    /**
     * [read-only] The texture of the bitmap font
     *
     * @property baseUrl
     * @type String
     */
    this.texture = null;
};

// constructor
PIXI.BitmapFontLoader.prototype.constructor = PIXI.BitmapFontLoader;

/**
 * Loads the XML font data
 *
 * @method load
 */
PIXI.BitmapFontLoader.prototype.load = function()
{
    this.ajaxRequest = new XMLHttpRequest();
    var scope = this;
    this.ajaxRequest.onreadystatechange = function()
    {
        scope.onXMLLoaded();
    };

    this.ajaxRequest.open('GET', this.url, true);
    if (this.ajaxRequest.overrideMimeType) this.ajaxRequest.overrideMimeType('application/xml');
    this.ajaxRequest.send(null);
};

/**
 * Invoked when XML file is loaded, parses the data
 *
 * @method onXMLLoaded
 * @private
 */
PIXI.BitmapFontLoader.prototype.onXMLLoaded = function()
{
    if (this.ajaxRequest.readyState === 4)
    {
        if (this.ajaxRequest.status === 200 || window.location.protocol.indexOf('http') === -1)
        {
            var textureUrl = this.baseUrl + this.ajaxRequest.responseXML.getElementsByTagName('page')[0].attributes.getNamedItem('file').nodeValue;
            var image = new PIXI.ImageLoader(textureUrl, this.crossorigin);
            this.texture = image.texture.baseTexture;

            var data = {};
            var info = this.ajaxRequest.responseXML.getElementsByTagName('info')[0];
            var common = this.ajaxRequest.responseXML.getElementsByTagName('common')[0];
            data.font = info.attributes.getNamedItem('face').nodeValue;
            data.size = parseInt(info.attributes.getNamedItem('size').nodeValue, 10);
            data.lineHeight = parseInt(common.attributes.getNamedItem('lineHeight').nodeValue, 10);
            data.chars = {};

            //parse letters
            var letters = this.ajaxRequest.responseXML.getElementsByTagName('char');

            for (var i = 0; i < letters.length; i++)
            {
                var charCode = parseInt(letters[i].attributes.getNamedItem('id').nodeValue, 10);

                var textureRect = new PIXI.Rectangle(
                    parseInt(letters[i].attributes.getNamedItem('x').nodeValue, 10),
                    parseInt(letters[i].attributes.getNamedItem('y').nodeValue, 10),
                    parseInt(letters[i].attributes.getNamedItem('width').nodeValue, 10),
                    parseInt(letters[i].attributes.getNamedItem('height').nodeValue, 10)
                );

                data.chars[charCode] = {
                    xOffset: parseInt(letters[i].attributes.getNamedItem('xoffset').nodeValue, 10),
                    yOffset: parseInt(letters[i].attributes.getNamedItem('yoffset').nodeValue, 10),
                    xAdvance: parseInt(letters[i].attributes.getNamedItem('xadvance').nodeValue, 10),
                    kerning: {},
                    texture: PIXI.TextureCache[charCode] = new PIXI.Texture(this.texture, textureRect)

                };
            }

            //parse kernings
            var kernings = this.ajaxRequest.responseXML.getElementsByTagName('kerning');
            for (i = 0; i < kernings.length; i++)
            {
                var first = parseInt(kernings[i].attributes.getNamedItem('first').nodeValue, 10);
                var second = parseInt(kernings[i].attributes.getNamedItem('second').nodeValue, 10);
                var amount = parseInt(kernings[i].attributes.getNamedItem('amount').nodeValue, 10);

                data.chars[second].kerning[first] = amount;

            }

            PIXI.BitmapText.fonts[data.font] = data;

            var scope = this;
            image.addEventListener('loaded', function() {
                scope.onLoaded();
            });
            image.load();
        }
    }
};

/**
 * Invoked when all files are loaded (xml/fnt and texture)
 *
 * @method onLoaded
 * @private
 */
PIXI.BitmapFontLoader.prototype.onLoaded = function()
{
    this.dispatchEvent({type: 'loaded', content: this});
};