(function(){

var EXTUTIL = Ext.util, 
    TOARRAY = Ext.toArray, 
    EACH = Ext.each, 
    ISOBJECT = Ext.isObject
    TRUE = true,
    FALSE = false;
/**
 * @class Ext.util.Observable
 * Abstract base class that provides a common interface for publishing events. Subclasses are expected to
 * to have a property "events" with all the events defined.

 * For example:
 * 

 Employee = function(name){
    this.name = name;
    this.addEvents({
        "fired" : true,
        "quit" : true
    });
 }
 Ext.extend(Employee, Ext.util.Observable);

 */
EXTUTIL.Observable = function(){
    
/**
     * @cfg {Object} listeners (optional) A config object containing one or more event handlers to be added to this
     * object during initialization.  This should be a valid listeners config object as specified in the
     * {@link #addListener} example for attaching multiple handlers at once.
     */
    var me = this, e = me.events;
    if(me.listeners){
        me.on(me.listeners);
        delete me.listeners;
    }
    me.events = e || {};
};

EXTUTIL.Observable.prototype = function(){
	var filterOptRe = /^(?:scope|delay|buffer|single)$/, toLower = function(s){
        return s.toLowerCase();    
    };
		
	return {
	    
/**
	     * 
Fires the specified event with the passed parameters (minus the event name).
         * 
An event may be set to bubble up an Observable parent hierarchy (See {@link Ext.Component#getBubbleTarget})
         * by calling {@link #enableBubble}.
	     * @param {String} eventName The name of the event to fire.
	     * @param {Object...} args Variable number of parameters are passed to handlers.
	     * @return {Boolean} returns false if any of the handlers return false otherwise it returns true.
	     */
	
	    fireEvent : function(){
	        var a = TOARRAY(arguments),
	        	ename = toLower(a[0]),
	        	me = this,
				ret = TRUE,
	        	ce = me.events[ename],
	        	q,
				c;
            if (me.eventsSuspended === TRUE) {            
	            if (q = me.suspendedEventsQueue) {
	                q.push(a);
	            }
            }
            else if(ISOBJECT(ce) && ce.bubble){
				if(ce.fire.apply(ce, a.slice(1)) === FALSE) {
					return FALSE;
				}
                c = me.getBubbleTarget && me.getBubbleTarget();
				if(c && c.enableBubble) {
					c.enableBubble(ename);
					return c.fireEvent.apply(c, a);
				}
	        }
            else {            
	            if (ISOBJECT(ce)) {
	                a.shift();
	                ret = ce.fire.apply(ce, a);
	            }
	        }
	        return ret;
	    },
	
	    
/**
	     * Appends an event handler to this component
	     * @param {String}   eventName The type of event to listen for
	     * @param {Function} handler The method the event invokes
	     * @param {Object}   scope (optional) The scope in which to execute the handler
	     * function. The handler function's "this" context.
	     * @param {Object}   options (optional) An object containing handler configuration
	     * properties. This may contain any of the following properties:

	     * 
scope : Object
The scope in which to execute the handler function. The handler function's "this" context.
	     * 
delay : Number
The number of milliseconds to delay the invocation of the handler after the event fires.
	     * 
single : Boolean
True to add a handler to handle just the next firing of the event, and then remove itself.
	     * 
buffer : Number
Causes the handler to be scheduled to run in an {@link Ext.util.DelayedTask} delayed
	     * by the specified number of milliseconds. If the event fires again within that time, the original
	     * handler is not invoked, but the new handler is scheduled in its place.
	     * 
target : Observable
Only call the handler if the event was fired on the target Observable, not
	     * if the event was bubbled up from a child Observable.
	     * 


	     * 

	     * Combining Options

	     * Using the options argument, it is possible to combine different types of listeners:

	     * 

	     * A normalized, delayed, one-time listener that auto stops the event and passes a custom argument (forumId)
	     * 

	el.on('click', this.onClick, this, {
	    single: true,
	    delay: 100,
	    forumId: 4
	});
	     * 

	     * Attaching multiple handlers in 1 call

	      * The method also allows for a single argument to be passed which is a config object containing properties
	     * which specify multiple handlers.
	     * 

	     * 

	foo.on({
	    'click' : {
	        fn: this.onClick,
	        scope: this,
	        delay: 100
	    },
	    'mouseover' : {
	        fn: this.onMouseOver,
	        scope: this
	    },
	    'mouseout' : {
	        fn: this.onMouseOut,
	        scope: this
	    }
	});
	     * 

	     * Or a shorthand syntax:

	     * 

	foo.on({
	    'click' : this.onClick,
	    'mouseover' : this.onMouseOver,
	    'mouseout' : this.onMouseOut,
	     scope: this
	});
	     */
	    addListener : function(eventName, fn, scope, o){
		    var me = this,
		    	e,
		    	oe,
		    	isF,
			ce;
	        if (ISOBJECT(eventName)) {
	            o = eventName;
	            for (e in o){		            
		            oe = o[e];
	                if (!filterOptRe.test(e)) {	                
		                me.addListener(e, oe.fn || oe, oe.scope || o.scope, oe.fn ? oe : o);              
	                }
	            }            
	        } else {	        
		        eventName = toLower(eventName);
			    ce = me.events[eventName] || TRUE;
		    	if (typeof ce == "boolean") {	            
		            me.events[eventName] = ce = new EXTUTIL.Event(me, eventName);
		        }
		        ce.addListener(fn, scope, ISOBJECT(o) ? o : {});
	    	}
	    },
	
	    
/**
	     * Removes a listener
	     * @param {String}   eventName     The type of event to listen for
	     * @param {Function} handler        The handler to remove
	     * @param {Object}   scope  (optional) The scope (this object) for the handler
	     */
	    removeListener : function(eventName, fn, scope){
	        var ce = this.events[toLower(eventName)];
	        if (ISOBJECT(ce)) {
	            ce.removeListener(fn, scope);
	        }
	    },
	
	    
/**
	     * Removes all listeners for this object
	     */
	    purgeListeners : function(){
		    var events = this.events,
		    	evt,
		    	key;		    	
	        for(key in events){
		        evt = events[key];
	            if(ISOBJECT(evt)){
                    evt.clearListeners();               
                }
	        }
	    },	    
	
	    
/**
	     * Used to define events on this Observable
	     * @param {Object} object The object with the events defined
	     */
	    addEvents : function(o){
		    var me = this;
		    me.events = me.events || {};        
	        if (typeof o == 'string') {            
		        EACH(arguments, function(a) {
			        me.events[a] = me.events[a] || TRUE;
	            });
	        } else {
	            Ext.applyIf(me.events, o);
	        }
	    },
	
	    
/**
	     * Checks to see if this object has any listeners for a specified event
	     * @param {String} eventName The name of the event to check for
	     * @return {Boolean} True if the event is being listened for, else false
	     */
	    hasListener : function(eventName){
	        var e = this.events[eventName];
	        return ISOBJECT(e) && e.listeners.length > 0;
	    },
	
	    
/**
	     * Suspend the firing of all events. (see {@link #resumeEvents})
	     * @param queueSuspended {Boolean} Pass as true to queue up suspended events to be fired
	     * after the {@link #resumeEvents} call instead of discarding all suspended events;
	     */
	    suspendEvents : function(queueSuspended){
	        this.eventsSuspended = TRUE;
	        if (queueSuspended){
                this.suspendedEventsQueue = [];         
            }
	    },
	
	    
/**
	     * Resume firing events. (see {@link #suspendEvents})
	     * If events were suspended using the queueSuspended parameter, then all
	     * events fired during event suspension will be sent to any listeners now.
	     */
	    resumeEvents : function(){
		    var me = this;
	        me.eventsSuspended = !delete me.suspendedEventQueue;        
	        EACH(me.suspendedEventsQueue, function(e) {
	            me.fireEvent.apply(me, e);
	        });     
	    }
	}
}();

var OBSERVABLE = EXTUTIL.Observable.prototype;
/**
 * Appends an event handler to this element (shorthand for addListener)
 * @param {String}   eventName     The type of event to listen for
 * @param {Function} handler        The method the event invokes
 * @param {Object}   scope (optional) The scope in which to execute the handler
 * function. The handler function's "this" context.
 * @param {Object}   options  (optional)
 * @method
 */
OBSERVABLE.on = OBSERVABLE.addListener;
/**
 * Removes a listener (shorthand for removeListener)
 * @param {String}   eventName     The type of event to listen for
 * @param {Function} handler        The handler to remove
 * @param {Object}   scope  (optional) The scope (this object) for the handler
 * @method
 */
OBSERVABLE.un = OBSERVABLE.removeListener;

/**
 * Removes all added captures from the Observable.
 * @param {Observable} o The Observable to release
 * @static
 */
EXTUTIL.Observable.releaseCapture = function(o){
    o.fireEvent = OBSERVABLE.fireEvent;
};

function createTargeted(h, o, scope){
    return function(){
        if(o.target == arguments[0]){
            h.apply(scope, TOARRAY(arguments));
        }
    };
};

function createBuffered(h, o, scope){
    var task = new EXTUTIL.DelayedTask();
    return function(){
        task.delay(o.buffer, h, scope, TOARRAY(arguments));
    };
}
    
function createSingle(h, e, fn, scope){
    return function(){
        e.removeListener(fn, scope);
        return h.apply(scope, arguments);
    };
}
    
function createDelayed(h, o, scope){
    return function(){
        var args = TOARRAY(arguments);
        (function(){
            h.apply(scope, args);
        }).defer(o.delay || 10);
    };
};

EXTUTIL.Event = function(obj, name){
    this.name = name;
    this.obj = obj;
    this.listeners = [];
};

EXTUTIL.Event.prototype = {
    addListener : function(fn, scope, options){
        var me = this,
        	l;
        scope = scope || me.obj;
        if(!me.isListening(fn, scope)){
            l = me.createListener(fn, scope, options);
            if(me.firing){ // if we are currently firing this event, don't disturb the listener loop	                                
                me.listeners = me.listeners.slice(0);                
            }
            me.listeners.push(l);
        }
    },

    createListener: function(fn, scope, o){
        o = o || {}, scope = scope || this.obj;
        var l = {
            fn: fn,
            scope: scope,
            options: o
        }, h = fn;
        if(o.target){
            h = createTargeted(h, o, scope);
        }
        if(o.delay){
            h = createDelayed(h, o, scope);
        }
        if(o.single){
            h = createSingle(h, this, fn, scope);
        }
        if(o.buffer){
            h = createBuffered(h, o, scope);
        }
        l.fireFn = h;
        return l;
    },

    findListener : function(fn, scope){ 
        var s, ret = -1                    
        EACH(this.listeners, function(l, i) {
            s = l.scope;
            if(l.fn == fn && (s == scope || s == this.obj)){
                ret = i;
                return FALSE;
            }
        },
        this);
        return ret;
    },

    isListening : function(fn, scope){
        return this.findListener(fn, scope) != -1;
    },

    removeListener : function(fn, scope){
        var index,
        	me = this,
        	ret = FALSE;
        if((index = me.findListener(fn, scope)) != -1){                
            if (me.firing) {
                me.listeners = me.listeners.slice(0);
            }
            me.listeners.splice(index, 1);
            ret = TRUE;
        }
        return ret;
    },

    clearListeners : function(){
        this.listeners = [];
    },

    fire : function(){
        var me = this,            	            	
        	args = TOARRAY(arguments),
        	ret = TRUE;                                                 
        
        EACH(me.listeners, function(l) {
            me.firing = TRUE;
            if (l.fireFn.apply(l.scope || me.obj || window, args) === FALSE) {
                return ret = me.firing = FALSE;
            }
        });
        me.firing = FALSE;
        return ret;
    }
};
})();