///// EventPublisher Class
/////////////////////////////////////////////////////////
//
// The EventPublisher class allows objects to fire events (and other objects to
// subscribe handlers to those events). The events can be fired either
// synchronously or asynchonously (depending on how the handlers register themselves),
// and may pass optional arguments to the handlers.

EventPublisher = Class.create();
EventPublisher.prototype = {
    initialize: function() {
    },

    // pass the asynch flag (true/false) as the 3rd argument, or omit it to default to false
    attachEventHandler: function(eventName, handler) {
        // using an event cache array to track all handlers for proper cleanup
        if (this.allEvents == null)
            this.allEvents = new Array();
        // loop through the event cache to prevent adding duplicates
        var len = this.allEvents.length;
        var foundEvent = false;
        for (var i = 0; i < len; i++) {
            if (this.allEvents[i] == eventName) {
                foundEvent = true;
                break;
            }
        }
        if (!foundEvent)
            this.allEvents.push(eventName);

        eventName = eventName + "_evt"; // appending _evt to event name to avoid collisions
        if (this[eventName] == null)
            this[eventName] = new Array();

        //create a custom object containing the handler method and the asynch flag
        var asynchVar = arguments.length > 2 ? arguments[1] : false;
        var handlerObj = {
            method: handler,
            asynch: asynchVar
        };

        this[eventName].push(handlerObj);
    },

    // Removes a single handler from a specific event
    removeEventHandler: function(eventName, handler) {
        eventName = eventName + "_evt"; // appending _evt to event name to avoid collisions
        if (this[eventName] != null)
            this[eventName] = this[eventName].reject(function(obj) { return obj.method == handler; });
    },

    // Removes all handlers from a single event
    clearEventHandlers: function(eventName) {
        eventName = eventName + "_evt"; // appending _evt to event name to avoid collisions
        this[eventName] = null;
    },

    // Removes all handlers from ALL events
    clearAllEventHandlers: function() {
        if (this.allEvents) {
            var len = this.allEvents.length;
            for (var i = 0; i < len; i++) {
                this.clearEventHandlers(this.allEvents[i]);
            }
        }
    },

    //to pass arguments to the handlers, include a 2nd argument (anonymous object that can contain whatever you want)
    fireEvent: function(eventName) {
        var evtName = eventName + "_evt"; // appending _evt to event name to avoid collisions
        if (this[evtName] != null) {
            var len = this[evtName].length; //optimization

            for (var i = 0; i < len; i++)
            {
                try
                {
                    if (arguments.length > 1)
                    {
                        if (this[evtName][i].asynch)
                        {
                            var eventArgs = arguments[1];
                            var method = this[evtName][i].method.bind(this);
                            setTimeout(function() { method(eventArgs)}.bind(this), 10);
                        }
                        else this[evtName][i].method(arguments[1]);
                    } else {
                        if (this[evtName][i].asynch)
                        {
                            var eventHandler = this[evtName][i].method;
                            setTimeout(eventHandler, 1);
                        }
                        else
                            if (this && this[evtName] && this[evtName][i] && this[evtName][i].method)
                                this[evtName][i].method();
                    }
                }
                catch (e) {
                    if (this.id) {
                        alert("error: error in " + this.id + ".fireevent():\n\nevent name: " + eventName + "\n\nerror message: " + e.message);
                    } else {
                        alert("error: error in [unknown object].fireevent():\n\nevent name: " + eventName + "\n\nerror message: " + e.message);
                    }
                }
            }
        }
    }
};