module BABYLON {
    /**
     * Implementation of the KTX Texture Loader.
     */
    class KTXTextureLoader implements IInternalTextureLoader {
        /**
         * Defines wether the loader supports cascade loading the different faces.
         */
        public readonly supportCascades = false;

        /**
         * This returns if the loader support the current file information.
         * @param extension defines the file extension of the file being loaded
         * @param textureFormatInUse defines the current compressed format in use iun the engine
         * @param fallback defines the fallback internal texture if any
         * @param isBase64 defines whether the texture is encoded as a base64
         * @param isBuffer defines whether the texture data are stored as a buffer
         * @returns true if the loader can load the specified file
         */
        public canLoad(extension: string, textureFormatInUse: Nullable<string>, fallback: Nullable<InternalTexture>, isBase64: boolean, isBuffer: boolean): boolean {
            if (textureFormatInUse && !isBase64 && !fallback && !isBuffer) {
                return true;
            }
            return false;
        }

        /**
         * Transform the url before loading if required.
         * @param rootUrl the url of the texture
         * @param textureFormatInUse defines the current compressed format in use iun the engine
         * @returns the transformed texture
         */
        public transformUrl(rootUrl: string, textureFormatInUse: Nullable<string>): string {
            var lastDot = rootUrl.lastIndexOf('.');
            return (lastDot > -1 ? rootUrl.substring(0, lastDot) : rootUrl) + textureFormatInUse;
        }

        /**
         * Gets the fallback url in case the load fail. This can return null to allow the default fallback mecanism to work
         * @param rootUrl the url of the texture
         * @param textureFormatInUse defines the current compressed format in use iun the engine
         * @returns the fallback texture
         */
        public getFallbackTextureUrl(rootUrl: string, textureFormatInUse: Nullable<string>): Nullable<string> {
            // remove the format appended to the rootUrl in the original createCubeTexture call.
            var exp = new RegExp("" + textureFormatInUse! + "$");
            return rootUrl.replace(exp, "");
        }

        /**
         * Uploads the cube texture data to the WebGl Texture. It has alreday been bound.
         * @param data contains the texture data
         * @param texture defines the BabylonJS internal texture
         * @param createPolynomials will be true if polynomials have been requested
         * @param onLoad defines the callback to trigger once the texture is ready
         * @param onError defines the callback to trigger in case of error
         */
        public loadCubeData(data: string | ArrayBuffer | (string | ArrayBuffer)[], texture: InternalTexture, createPolynomials: boolean, onLoad: Nullable<(data?: any) => void>, onError: Nullable<(message?: string, exception?: any) => void>): void {
            if (Array.isArray(data)) {
                return;
            }

            var engine = texture.getEngine();
            var ktx = new KhronosTextureContainer(data, 6);

            var loadMipmap = ktx.numberOfMipmapLevels > 1 && texture.generateMipMaps;

            engine._unpackFlipY(true);

            ktx.uploadLevels(texture, texture.generateMipMaps);

            texture.width = ktx.pixelWidth;
            texture.height = ktx.pixelHeight;

            engine._setCubeMapTextureParams(loadMipmap);
            texture.isReady = true;
        }

        /**
         * Uploads the 2D texture data to the WebGl Texture. It has alreday been bound once in the callback.
         * @param data contains the texture data
         * @param texture defines the BabylonJS internal texture
         * @param callback defines the method to call once ready to upload
         */
        public loadData(data: ArrayBuffer, texture: InternalTexture, 
            callback: (width: number, height: number, loadMipmap: boolean, isCompressed: boolean, done: () => void) => void): void {
            var ktx = new KhronosTextureContainer(data, 1);

            callback(ktx.pixelWidth, ktx.pixelHeight, false, true, () => {
                ktx.uploadLevels(texture, texture.generateMipMaps);
            });
        }
    }

    // Register the loader.
    Engine._TextureLoaders.unshift(new KTXTextureLoader());
}