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

PIXI.BaseTextureCache = {};
PIXI.texturesToUpdate = [];
PIXI.texturesToDestroy = [];

PIXI.BaseTextureCacheIdGenerator = 0;

/**
 * A texture stores the information that represents an image. All textures have a base texture
 *
 * @class BaseTexture
 * @uses EventTarget
 * @constructor
 * @param source {String} the source object (image or canvas)
 */
PIXI.BaseTexture = function(source, scaleMode)
{
    PIXI.EventTarget.call( this );

    /**
     * [read-only] The width of the base texture set when the image has loaded
     *
     * @property width
     * @type Number
     * @readOnly
     */
    this.width = 100;

    /**
     * [read-only] The height of the base texture set when the image has loaded
     *
     * @property height
     * @type Number
     * @readOnly
     */
    this.height = 100;

    /**
     * The scale mode to apply when scaling this texture
     * @property scaleMode
     * @type PIXI.scaleModes
     * @default PIXI.scaleModes.LINEAR
     */
    this.scaleMode = scaleMode || PIXI.scaleModes.DEFAULT;

    /**
     * [read-only] Describes if the base texture has loaded or not
     *
     * @property hasLoaded
     * @type Boolean
     * @readOnly
     */
    this.hasLoaded = false;

    /**
     * The source that is loaded to create the texture
     *
     * @property source
     * @type Image
     */
    this.source = source;

    if(!source)return;

    if(this.source instanceof Image || this.source instanceof HTMLImageElement)
    {
        if(this.source.complete)
        {
            this.hasLoaded = true;
            this.width = this.source.width;
            this.height = this.source.height;

            PIXI.texturesToUpdate.push(this);
        }
        else
        {

            var scope = this;
            this.source.onload = function() {

                scope.hasLoaded = true;
                scope.width = scope.source.width;
                scope.height = scope.source.height;

                // add it to somewhere...
                PIXI.texturesToUpdate.push(scope);
                scope.dispatchEvent( { type: 'loaded', content: scope } );
            };
            //this.image.src = imageUrl;
        }
    }
    else
    {
        this.hasLoaded = true;
        this.width = this.source.width;
        this.height = this.source.height;

        PIXI.texturesToUpdate.push(this);
    }

    this.imageUrl = null;
    this._powerOf2 = false;

    //TODO will be used for futer pixi 1.5...
    this.id = PIXI.BaseTextureCacheIdGenerator++;

    // used for webGL
    this._glTextures = [];

};

PIXI.BaseTexture.prototype.constructor = PIXI.BaseTexture;

/**
 * Destroys this base texture
 *
 * @method destroy
 */
PIXI.BaseTexture.prototype.destroy = function()
{
    if(this.source instanceof Image)
    {
        if (this.imageUrl in PIXI.BaseTextureCache)
            delete PIXI.BaseTextureCache[this.imageUrl];
        this.imageUrl = null;
        this.source.src = null;
    }
    this.source = null;
    PIXI.texturesToDestroy.push(this);
};

/**
 *
 *
 * @method destroy
 */

PIXI.BaseTexture.prototype.updateSourceImage = function(newSrc)
{
    this.hasLoaded = false;
    this.source.src = null;
    this.source.src = newSrc;
};

/**
 * Helper function that returns a base texture based on an image url
 * If the image is not in the base texture cache it will be created and loaded
 *
 * @static
 * @method fromImage
 * @param imageUrl {String} The image url of the texture
 * @return BaseTexture
 */
PIXI.BaseTexture.fromImage = function(imageUrl, crossorigin, scaleMode)
{
    var baseTexture = PIXI.BaseTextureCache[imageUrl];
    crossorigin = !crossorigin;

    if(!baseTexture)
    {
        // new Image() breaks tex loading in some versions of Chrome.
        // See https://code.google.com/p/chromium/issues/detail?id=238071
        var image = new Image();//document.createElement('img');
        if (crossorigin)
        {
            image.crossOrigin = '';
        }
        image.src = imageUrl;
        baseTexture = new PIXI.BaseTexture(image, scaleMode);
        baseTexture.imageUrl = imageUrl;
        PIXI.BaseTextureCache[imageUrl] = baseTexture;
    }

    return baseTexture;
};

PIXI.BaseTexture.fromCanvas = function(canvas, scaleMode)
{
    if(!canvas._pixiId)
    {
        canvas._pixiId = 'canvas_' + PIXI.TextureCacheIdGenerator++;
    }

    var baseTexture = PIXI.BaseTextureCache[canvas._pixiId];

    if(!baseTexture)
    {
        baseTexture = new PIXI.BaseTexture(canvas, scaleMode);
        PIXI.BaseTextureCache[canvas._pixiId] = baseTexture;
    }

    return baseTexture;
};