module wdCb{
    var SPLITPATH_REGEX =
        /^(\/?|)([\s\S]*?)((?:\.{1,2}|[^\/]+?|)(\.[^.\/]*|))(?:[\/]*)$/;

    //reference from
    //https://github.com/cookfront/learn-note/blob/master/blog-backup/2014/nodejs-path.md
    export class PathUtils{
        public static basename(path:string, ext?:string){
            var f = this._splitPath(path)[2];
            // TODO: make this comparison case-insensitive on windows?
            if (ext && f.substr(-1 * ext.length) === ext) {
                f = f.substr(0, f.length - ext.length);
            }
            return f;

        }

        public static changeExtname(pathStr:string, extname:string) {
            var extname = extname || "",
                index = pathStr.indexOf("?"),
                tempStr = "";

            if (index > 0) {
                tempStr = pathStr.substring(index);
                pathStr = pathStr.substring(0, index);
            }

            index = pathStr.lastIndexOf(".");

            if (index < 0){
              return pathStr + extname + tempStr;
            }

            return pathStr.substring(0, index) + extname + tempStr;
        }

        public static changeBasename(pathStr:string, basename:string, isSameExt:boolean = false) {
            var index = null,
                tempStr = null,
                ext = null;

            if (basename.indexOf(".") == 0){
              return this.changeExtname(pathStr, basename);
            }

            index = pathStr.indexOf("?");
            tempStr = "";
            ext = isSameExt ? this.extname(pathStr) : "";

            if (index > 0) {
                tempStr = pathStr.substring(index);
                pathStr = pathStr.substring(0, index);
            }

            index = pathStr.lastIndexOf("/");
            index = index <= 0 ? 0 : index + 1;

            return pathStr.substring(0, index) + basename + ext + tempStr;
        }

        public static extname(path:string){
            return this._splitPath(path)[3];
        }

        public static dirname(path:string){
            var result = this._splitPath(path),
                root = result[0],
                dir = result[1];

            if (!root && !dir) {
                //no dirname whatsoever
                return '.';
            }

            if (dir) {
                //it has a dirname, strip trailing slash
                dir = dir.substr(0, dir.length - 1);
            }

            return root + dir;
        }

        private static _splitPath(fileName:string){
            return SPLITPATH_REGEX.exec(fileName).slice(1);
        }
    }
}