protected static function prepare_files( $type ) {

		$params['type']   = $type;
		$params['routes'] = self::get_routes_to_folder( $type );

		self::get_processed_files();

		foreach ( self::$data[ $type ] as $id => $file ) {

			$path = self::get_path_from_url( $file['url'] );

			$params['files'][ $id ] = basename( $file['url'] );
			$params['urls'][ $id ]  = $file['url'];
			$params['paths'][ $id ] = $path;

			if ( is_file( $path ) && self::is_modified_file( $path ) ) {
				unset( $params['urls'][ $id ] );
				continue;
			}

			$path = $params['routes']['path'] . $params['files'][ $id ];

			if ( is_file( $path ) ) {
				if ( self::is_modified_hash( $file['url'], $path ) ) {
					continue;
				}
				$params['paths'][ $id ] = $path;

			} elseif ( self::is_external_url( $file['url'] ) ) {
				continue;
			}

			unset( $params['urls'][ $id ] );
		}

		return $params;
	}