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

        /**
         * 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 {
            return extension.indexOf(".dds") === 0;
        }

        /**
         * 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 {
            return rootUrl;
        }

        /**
         * 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> {
            return null;
        }

        /**
         * 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(imgs: string | ArrayBuffer | (string | ArrayBuffer)[], texture: InternalTexture, createPolynomials: boolean, onLoad: Nullable<(data?: any) => void>, onError: Nullable<(message?: string, exception?: any) => void>): void {
            var engine = texture.getEngine();
            var info: DDSInfo | undefined;
            var loadMipmap: boolean = false;
            if (Array.isArray(imgs)) {
                for (let index = 0; index < imgs.length; index++) {
                    let data = imgs[index];
                    info = DDSTools.GetDDSInfo(data);

                    texture.width = info.width;
                    texture.height = info.height;

                    loadMipmap = (info.isRGB || info.isLuminance || info.mipmapCount > 1) && texture.generateMipMaps;

                    engine._unpackFlipY(info.isCompressed);

                    DDSTools.UploadDDSLevels(engine, texture, data, info, loadMipmap, 6, -1, index);

                    if (!info.isFourCC && info.mipmapCount === 1) {
                        engine.generateMipMapsForCubemap(texture);
                    }
                }
            }
            else {
                var data = imgs;
                info = DDSTools.GetDDSInfo(data);

                texture.width = info.width;
                texture.height = info.height;

                if (createPolynomials) {
                    info.sphericalPolynomial = new SphericalPolynomial();
                }

                loadMipmap = (info.isRGB || info.isLuminance || info.mipmapCount > 1) && texture.generateMipMaps;
                engine._unpackFlipY(info.isCompressed);

                DDSTools.UploadDDSLevels(engine, texture, data, info, loadMipmap, 6);

                if (!info.isFourCC && info.mipmapCount === 1) {
                    engine.generateMipMapsForCubemap(texture);
                }
            }

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

            if (onLoad) {
                onLoad({ isDDS: true, width: texture.width, info, imgs, texture });
            }
        }

        /**
         * 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 info = DDSTools.GetDDSInfo(data);

            var loadMipmap = (info.isRGB || info.isLuminance || info.mipmapCount > 1) && texture.generateMipMaps && ((info.width >> (info.mipmapCount - 1)) === 1);
            callback(info.width, info.height, !loadMipmap, info.isFourCC, () => {
                DDSTools.UploadDDSLevels(texture.getEngine(), texture, data, info, loadMipmap, 1);
            });
        }
    }

    // Register the loader.
    Engine._TextureLoaders.push(new DDSTextureLoader());
}