/**
 * @class Ext.menu.MenuMgr
 * Provides a common registry of all menu items on a page so that they can be easily accessed by id.
 * @singleton
 */
Ext.menu.MenuMgr = function(){
   var menus, active, groups = {}, attached = false, lastShow = new Date();

   // private - called when first menu is created
   function init(){
       menus = {};
       active = new Ext.util.MixedCollection();
       Ext.getDoc().addKeyListener(27, function(){
           if(active.length > 0){
               hideAll();
           }
       });
   }

   // private
   function hideAll(){
       if(active && active.length > 0){
           var c = active.clone();
           c.each(function(m){
               m.hide();
           });
       }
   }

   // private
   function onHide(m){
       active.remove(m);
       if(active.length < 1){
           Ext.getDoc().un("mousedown", onMouseDown);
           attached = false;
       }
   }

   // private
   function onShow(m){
       var last = active.last();
       lastShow = new Date();
       active.add(m);
       if(!attached){
           Ext.getDoc().on("mousedown", onMouseDown);
           attached = true;
       }
       if(m.parentMenu){
          m.getEl().setZIndex(parseInt(m.parentMenu.getEl().getStyle("z-index"), 10) + 3);
          m.parentMenu.activeChild = m;
       }else if(last && last.isVisible()){
          m.getEl().setZIndex(parseInt(last.getEl().getStyle("z-index"), 10) + 3);
       }
   }

   // private
   function onBeforeHide(m){
       if(m.activeChild){
           m.activeChild.hide();
       }
       if(m.autoHideTimer){
           clearTimeout(m.autoHideTimer);
           delete m.autoHideTimer;
       }
   }

   // private
   function onBeforeShow(m){
       var pm = m.parentMenu;
       if(!pm && !m.allowOtherMenus){
           hideAll();
       }else if(pm && pm.activeChild){
           pm.activeChild.hide();
       }
   }

   // private
   function onMouseDown(e){
       if(lastShow.getElapsed() > 50 && active.length > 0 && !e.getTarget(".x-menu")){
           hideAll();
       }
   }

   // private
   function onBeforeCheck(mi, state){
       if(state){
           var g = groups[mi.group];
           for(var i = 0, l = g.length; i < l; i++){
               if(g[i] != mi){
                   g[i].setChecked(false);
               }
           }
       }
   }

   return {

       
/**
        * Hides all menus that are currently visible
        */
       hideAll : function(){
            hideAll();  
       },

       // private
       register : function(menu){
           if(!menus){
               init();
           }
           menus[menu.id] = menu;
           menu.on("beforehide", onBeforeHide);
           menu.on("hide", onHide);
           menu.on("beforeshow", onBeforeShow);
           menu.on("show", onShow);
           var g = menu.group;
           if(g && menu.events["checkchange"]){
               if(!groups[g]){
                   groups[g] = [];
               }
               groups[g].push(menu);
               menu.on("checkchange", onCheck);
           }
       },

        
/**
         * Returns a {@link Ext.menu.Menu} object
         * @param {String/Object} menu The string menu id, an existing menu object reference, or a Menu config that will
         * be used to generate and return a new Menu instance.
         * @return {Ext.menu.Menu} The specified menu, or null if none are found
         */
       get : function(menu){
           if(typeof menu == "string"){ // menu id
               if(!menus){  // not initialized, no menus to return
                   return null;
               }
               return menus[menu];
           }else if(menu.events){  // menu instance
               return menu;
           }else if(typeof menu.length == 'number'){ // array of menu items?
               return new Ext.menu.Menu({items:menu});
           }else{ // otherwise, must be a config
               return Ext.create(menu, 'menu');
           }
       },

       // private
       unregister : function(menu){
           delete menus[menu.id];
           menu.un("beforehide", onBeforeHide);
           menu.un("hide", onHide);
           menu.un("beforeshow", onBeforeShow);
           menu.un("show", onShow);
           var g = menu.group;
           if(g && menu.events["checkchange"]){
               groups[g].remove(menu);
               menu.un("checkchange", onCheck);
           }
       },

       // private
       registerCheckable : function(menuItem){
           var g = menuItem.group;
           if(g){
               if(!groups[g]){
                   groups[g] = [];
               }
               groups[g].push(menuItem);
               menuItem.on("beforecheckchange", onBeforeCheck);
           }
       },

       // private
       unregisterCheckable : function(menuItem){
           var g = menuItem.group;
           if(g){
               groups[g].remove(menuItem);
               menuItem.un("beforecheckchange", onBeforeCheck);
           }
       },

       getCheckedItem : function(groupId){
           var g = groups[groupId];
           if(g){
               for(var i = 0, l = g.length; i < l; i++){
                   if(g[i].checked){
                       return g[i];
                   }
               }
           }
           return null;
       },

       setCheckedItem : function(groupId, itemId){
           var g = groups[groupId];
           if(g){
               for(var i = 0, l = g.length; i < l; i++){
                   if(g[i].id == itemId){
                       g[i].setChecked(true);
                   }
               }
           }
           return null;
       }
   };
}();