// Configuration Vars //

TreeMenu.SymbolTag = 'span';			// symbol inserted at beginning of <LI> tags
TreeMenu.SymbolTag = '';			// uncomment to disable insertion of symbols
//TreeMenu.SymbolTag = 'img';			// uncomment to use IMG tags for symbols
//TreeMenu.SymbolSrcItem = '';			// url to assign to IMG src attribute of an item
//TreeMenu.SymbolSrcClose = '';			// url to assign to IMG src attribute upon close
//TreeMenu.SymbolSrcOpen = '';			// url to assign to IMG src attribute upon open

TreeMenu.OmitSymbols = false;			// don't insert symbol but do adjust them

TreeMenu.SymbolClassItem  = 'symbol-item';
TreeMenu.SymbolClassClose = 'symbol-close';
TreeMenu.SymbolClassOpen  = 'symbol-open';

TreeMenu.ClassItem  = 'item';			// class name added to <LI> tag's class
TreeMenu.ClassClose = 'close';			// class name added to <LI> tag's class
TreeMenu.ClassOpen  = 'open';			// class name added to <LI> tag's class
TreeMenu.ClassLast  = 'last';			// added to last <LI> and symbol tags' classes

TreeMenu.CookieSaveStates = true;		// flag to use a cookie to save menu state
TreeMenu.CookieExpire = 1;			// days before cookie saving menu states expires

TreeMenu.SetupMenu = true;			// scan document objects to initialize menu

TreeMenu.Singular = false;			// restrict open menus to only one per level

/////// End of Configuration Variables ///////////////////

function make_tree_menu(id,omit_symbols,no_save_state,singular,no_setup) {
	var m = new TreeMenu(id);
	if (omit_symbols) m.OmitSymbols = true;
	if (no_save_state) m.CookieSaveStates = false;
	if (singular) m.Singular = true;
	if (no_setup) m.SetupMenu = false;
	// Setup menus if we are inserting symbols or restoring menu open/close states.
	if (m.SetupMenu) m.setup_symbols();
	return m;
}

/*
 * TreeNavMod
 */

function TreeMenu(ul_id) {			// object constructor

	this.top_ul_id = ul_id;
	this.top_ul = document.getElementById(ul_id);

	this.configure();

	// Register menu
	TreeMenu.menus[ul_id] = this;

	return this;
}

/*
 * TreeMenu Class Variables
 */

TreeMenu.menus = [];				// list of defined menus

/*
 * TreeMenu Class Methods
 */

TreeMenu.toggle = function(e) {
	e = TreeMenu.get_ref(e);
	var m = TreeMenu.menus[TreeMenu.get_top_ul(e).id];
	var li = TreeMenu.get_li(e);
	var ul = li.getElementsByTagName("UL")[0];
	if (ul.style.display == "block") {
		m.hide_menu(ul,li,e);
	}
	else {
		if (m.Singular) m.hide_menus_except(li);
		m.show_menu(ul,li,e);
	}

	m.save_menu_states();
}

TreeMenu.show = function(ul) {
	ul = TreeMenu.get_ref(ul);
	var top_ul = TreeMenu.get_top_ul(ul);
	if (! top_ul) return;
	var m = TreeMenu.menus[top_ul.id];
	var li = TreeMenu.get_li(ul);
	m.show_menu(ul,li);
}

TreeMenu.hide = function(ul) {
	ul = TreeMenu.get_ref(ul);
	var top_ul = TreeMenu.get_top_ul(ul);
	if (! top_ul) return;
	var m = TreeMenu.menus[top_ul.id];
	var li = TreeMenu.get_li(ul);
	m.hide_menu(ul,li);
}

TreeMenu.show_all = function(ul) {
	// Show all menus under ul.
	ul = TreeMenu.get_ref(ul);
	var uls = ul.getElementsByTagName("UL");
	for (i = 0; i < uls.length; i++) {
		TreeMenu.show(uls[i]);
	}
}

TreeMenu.hide_all = function(ul) {
	// Hide all menus under ul.
	ul = TreeMenu.get_ref(ul);
	var uls = ul.getElementsByTagName("UL");
	for (i = 0; i < uls.length; i++) {
		TreeMenu.hide(uls[i]);
	}
}

TreeMenu.save_state = function(ul) {
	// Reset menu to original settings.
	ul = TreeMenu.get_ref(ul);
	var m = TreeMenu.menus[TreeMenu.get_top_ul(ul).id];
	m.save_menu_states();
}

TreeMenu.reset = function(ul) {
	// Reset menu to original settings.
	ul = TreeMenu.get_ref(ul);
	var m = TreeMenu.menus[TreeMenu.get_top_ul(ul).id];
	m.reset_menu_states();
}

// Private methods
TreeMenu.get_ref = function(id) {
        if (typeof id == "string") return document.getElementById(id);
	return id;
}

TreeMenu.get_top_ul = function(e) {
	while (e && (e.nodeName != 'UL' || ! e.id || ! TreeMenu.menus[e.id])) e = e.parentNode;
	return e;

}

TreeMenu.get_li = function(e) {
	while (e && e.nodeName != 'LI') e = e.parentNode;
	return e;
}


/*
 * TreeMenu Object Methods
 */

TreeMenu.prototype.configure = function() {

        // Assign global class settings (capitalized variables) to object settings.

        var v,c;
        for (v in TreeMenu) {
                c = v.substr(0,1);
                if (c == c.toUpperCase()) {
                        this[v] = TreeMenu[v];
                }
        }
}

TreeMenu.prototype.setup_symbols = function() {

	// Insert open/close symbols at the beginning of the menu items
	// and open or close menus like they were previously.

	var states = this.get_menu_states();

	var index = 0;
	var ul, li, symbol, islast = false;
	var ul_elements, li_elements = this.top_ul.getElementsByTagName("LI");
	for(var i=0; i < li_elements.length; i++) {
		li = li_elements[i];

		if (this.ClassLast) islast = this.is_last_item(li);

		ul_elements = li.getElementsByTagName("UL");
		if(ul_elements.length > 0) {
			// Submenus
			if (this.SymbolTag && ! this.OmitSymbols) {
				symbol = document.createElement(this.SymbolTag);
				if (this.ClassLast && islast) symbol.className = this.ClassLast;
				symbol.onclick = function() { TreeMenu.toggle(this); };
				li.insertBefore(symbol, li.firstChild);
			}

			ul = ul_elements[0];
			if (states[index] == '1') this.show_menu(ul,li);
			else                      this.hide_menu(ul,li);
			index++;
		}
		else {
			// Menu item
			if (this.SymbolTag && ! this.OmitSymbols) {
				symbol = document.createElement(this.SymbolTag);
				if (this.SymbolClassItem)
					symbol.className = this.SymbolClassItem;
				if (this.SymbolSrcItem)
					symbol.src = this.SymbolSrcItem;
				if (this.ClassLast && islast)
					symbol.className += ' ' + this.ClassLast;
				li.insertBefore(symbol, li.firstChild);
			}

			if (this.ClassItem) li.className += ' ' + this.ClassItem;
		}

		if (islast) li.className += ' ' + this.ClassLast;
	}
}

TreeMenu.prototype.is_last_item = function(e) {
	// Check if element is the last LI element in the list.
	e = e.nextSibling;
	// Get next element (Mozilla puts text nodes at same level here).
	while (e && e.nodeType != 1) e = e.nextSibling;
	return e ? false : true;
}

TreeMenu.prototype.get_menu_states = function() {
	var cookie = getCookie("tm_" + this.top_ul_id);
	if (cookie) return cookie.split('x');
	return [];
}

TreeMenu.prototype.save_menu_states = function() {

	// Save all menu and submenu open/close states in a cookie

	if (! this.CookieSaveStates) return;

	var states = [];
	var ul_elements, li_elements = this.top_ul.getElementsByTagName("LI");
	for(var i=0; i < li_elements.length; i++) {
		ul_elements = li_elements[i].getElementsByTagName("UL");
		if (ul_elements.length > 0) {
			states[states.length] = ul_elements[0].style.display == "block" ? 1 : 0;
		}
	}

	var expire_date = new Date((new Date().getTime()) + this.CookieExpire*24*60*60*1000);
	setCookie("tm_" + this.top_ul_id, states.join('x'), expire_date, '/');
}

TreeMenu.prototype.reset_menu_states = function() {

	// Reset all menu and submenu open/close states  (delete cookie)

	var expire_date = new Date((new Date().getTime()) - 1000);		// set to past time
	setCookie("tm_" + this.top_ul_id, '', expire_date, '/');
}

TreeMenu.prototype.add_remove_class = function(e,add_class,remove_class) {
	if (e) {
		if (remove_class)
			e.className = e.className.replace(remove_class,'');
		if (add_class && ! e.className.match( (new RegExp("\\b"+add_class+"(\\s.*)?")) ) ) {
			e.className += ' ' + add_class;
		}
	}
}

TreeMenu.prototype.show_menu = function(ul,li,e) {
	ul.style.display = 'block';

	this.add_remove_class(li,this.ClassOpen,this.ClassClose);

	if (this.SymbolTag) {
		var symbol = li.getElementsByTagName(this.SymbolTag)[0];
		this.add_remove_class(symbol,this.SymbolClassOpen,this.SymbolClassClose);
		if (this.SymbolSrcOpen) symbol.src = this.SymbolSrcOpen;
	}

	// Following case is for toggle buttons disassociated with menu structure.
	this.add_remove_class(e,this.SymbolClassOpen,this.SymbolClassClose);
}

TreeMenu.prototype.hide_menu = function(ul,li,e) {
	ul.style.display = 'none';

	this.add_remove_class(li,this.ClassClose,this.ClassOpen);

	if (this.SymbolTag) {
		var symbol = li.getElementsByTagName(this.SymbolTag)[0];
		this.add_remove_class(symbol,this.SymbolClassClose,this.SymbolClassOpen);
		if (this.SymbolSrcClose) symbol.src = this.SymbolSrcClose;
	}

	// Following case is for toggle buttons disassociated with menu structure.
	this.add_remove_class(e,this.SymbolClassClose,this.SymbolClassOpen);
}

TreeMenu.prototype.hide_menus_except = function(li) {
	// Hide other menus at same level as li.
	var n;
	var re = new RegExp('\\b' + this.ClassOpen + '\\b');
	for (var i = 0; i < li.parentNode.childNodes.length; i++) {
		n = li.parentNode.childNodes[i];
		if (n == li || n.nodeType != 1) continue;
		if (n.className.match(re)) this.hide_menu(n.getElementsByTagName("UL")[0],n);
	}
}

/*
 * Classic Cookie functions
 */

function setCookie(name, value, expires, path, domain, secure) {
	document.cookie	= name + "=" + escape(value) +
	  (expires	? "; expires=" + expires.toGMTString()	: "") +
	  (path		? "; path=" + path			: "") +
	  (domain	? "; domain=" + domain			: "") +
	  (secure	? "; secure"				: "");
}

function getCookie(name) {
	var dc = document.cookie;
	var prefix = name + "=";
	var begin = dc.indexOf("; " + prefix);
	if (begin == -1) {
		begin = dc.indexOf(prefix);
		if (begin != 0) return null;
	}
	else {
		begin += 2;
	}
	var end = document.cookie.indexOf(";", begin);
	if (end == -1) end = dc.length;
	return unescape(dc.substring(begin + prefix.length, end));
}