/**
 * 
 */  
URL = function (url) {
    this.scheme = null;
    this.host   = null;
    this.port   = null;
    this.path   = null;
    this.args   = {};
    this.anchor = null;
  
    if (arguments.length > 0) this.set(url);   
}   
  
/**  
 * thisURL() parses the current window.location and returns a URL object  
 */  
URL.thisURL = function () {   
    return new URL(window.location.href);   
}   
  
URL.prototype = new Object();   
  
/**  
 * set() parses a url and sets the properties of the URL object  
 */  
URL.prototype.set = function (url) {   
    var p;   
    if (p = this.parseURL(url)) {   
        this.scheme = p['scheme'];   
        this.host   = p['host'];   
        this.port   = p['port'];   
        this.path   = p['path'];   
        this.args   = this.parseArgs(p['args']);   
        this.anchor = p['anchor'];   
    }   
}   
  
/**  
 * removeArg() is used remove a specified argument from the URL object arguments  
 */  
URL.prototype.removeArg = function (k) {   
    if (k && String(k.constructor) == String(Array)) { // TODO: Change to use is_array   
        var t = this.args;   
        for (var i=0; i < k.length-1; i++) {   
            if (typeof t[k[i]] != 'undefined') { // TODO: Change to use isset   
                t = t[k[i]];   
            } else {   
                return false;   
            }   
        }   
        delete t[k[k.length-1]];   
        return true;   
    } else if (typeof this.args[k] != 'undefined') { // TODO: Change to use isset   
        delete this.args[k];   
        return true;   
    }   
  
    return false;   
}   
  
/**  
 * addArg() is used to add an argument with specified value to the URL object arguments  
 */  
URL.prototype.addArg = function (k, v, o) {   
    if (k && String(k.constructor) == String(Array)) { // TODO: Change to use is_array   
        var t = this.args;   
        for (var i=0; i < k.length-1; i++) {   
            if (typeof t[k[i]] == 'undefined') t[k[i]] = {};   
            t = t[k[i]];   
        }   
        if (o || typeof t[k[k.length-1]] == 'undefined') t[k[k.length-1]] = v; // TODO: Change to use isset   
    } else if (o || typeof this.args[k] == 'undefined') { // TODO: Change to use isset   
        this.args[k] = v;   
        return true;   
    }   
  
    return false;   
}   
  
/**  
 * parseURL() parses the specified url and returns an object containing the various components  
 */  
URL.prototype.parseURL = function (url) {   
    // TODO: Add support for ftp username   
    var p = {}, m;   
    if (m = url.match(/((s?ftp|https?):\/\/)?([^\/:]+)?(:([0-9]+))?([^\?#]+)?(\?([^#]+))?(#(.+))?/)) {
        p['scheme'] = (m[2]  ? m[2] : 'http');   
        p['host']   = (m[3]  ? m[3] : window.location.host);   
        p['port']   = (m[5]  ? m[5] : null);   
        p['path']   = (m[6]  ? m[6] : null);   
        p['args']   = (m[8]  ? m[8] : null);   
        p['anchor'] = (m[10] ? m[10] : null);   
  
        return p;   
    }   
  
    return false;   
}   
  
/**  
 * parseArgs() parses a query string and returns an object containing the parsed data  
 */  
URL.prototype.parseArgs = function (s) {   
    var a = {};   
    if (s && s.length) {   
        var kp, kv;   
        var p;   
        if ((kp = s.split('&')) && kp.length) {   
            for (var i=0; i < kp.length; i++) {   
                if ((kv = kp[i].split('=')) && kv.length == 2) {   
                    if (p = kv[0].split(/(\[|\]\[|\])/)) {   
                        for (var z=0; z < p.length; z++) {   
                            if (p[z] == ']' || p[z] == '[' || p[z] == '][') {   
                                p.splice(z, 1);   
                            }   
                        }   
                        var t = a;   
                        for (var o=0; o < p.length-1; o++) {   
                            if (typeof t[p[o]] == 'undefined') t[p[o]] = {}; // TODO: Change this to isset   
                            t = t[p[o]];   
                        }   
                        t[p[p.length-1]] = kv[1];   
                    } else {   
                        a[kv[0]] = kv[1];   
                    }   
                }   
            }   
        }   
    }   
  
    return a;   
}   
  
/**  
 * toArgs() takes an object and returns a query string  
 */  
URL.prototype.toArgs = function (a, p) {   
    if (arguments.length < 2) p = '';   
    if (a && typeof a == 'object') { // TODO: Change this to use is_object   
        var s = '';   
        for (i in a) {   
            if (typeof a[i] != 'function') {   
                if (s.length) s+= '&';   
                if (typeof a[i] == 'object') { // TODO: Change this to use is_object   
                    var k = (p.length ? p+'['+i+']' : i);   
                    s+= this.toArgs(a[i], k);   
                } else { // TODO: Change this to use is_function   
                    s+= p+(p.length && i != '' ? '[' : '')+i+(p.length && i != '' ? ']' : '')+'='+a[i];   
                }   
            }   
        }   
        return s;   
    }   
  
    return '';   
}   
  
/**  
 * toAbsolute() returns a string containing the absolute URL for the current URL object  
 */  
URL.prototype.toAbsolute = function () {   
    var s = '';   
    if (this.scheme != null) s+= this.scheme+'://';   
    if (this.host != null) s+= this.host;   
    if (this.port != null) s+= ':'+this.port;   
    s+= this.toRelative();   
  
    return s;   
}   
  
/**  
 * toRelative() returns a string containing the relative URL for the current URL object  
 */  
URL.prototype.toRelative = function () {   
    var s = '';   
    if (this.path != null)
      s+= this.path;   
    var a = this.toArgs(this.args);   
    if (a.length)
    	s+= '?' + a;   
    if (this.anchor != null)
    	s+= '#' + this.anchor;   
  
    return s;   
}   
  
/**  
 * isHost() is used to determine whether the host in the URL object matches the current host  
 */  
URL.prototype.isHost = function () {   
    var u = URL.thisURL();   
    return (this.host == null || this.host == u.host ? true : false);   
}   
  
/**  
 * toString() returns a string containing the current URL object as a URL  
 */  
URL.prototype.toString = function () {   
    return (this.isHost() ? this.toRelative() : this.toAbsolute());   
}