/**
 * Event.simulate(@element, eventName[, options]) -> Element
 *
 * - @element: element to fire event on
 * - eventName: name of event to fire (only MouseEvents and HTMLEvents interfaces are supported)
 * - options: optional object to fine-tune event properties - pointerX, pointerY, ctrlKey, etc.
 *
 *    $('foo').simulate('click'); // => fires "click" event on an element with id=foo
 *
 **/
(function() {

    var eventMatchers = {
        'HTMLEvents': /^(?:load|unload|abort|error|select|change|submit|reset|focus|blur|resize|scroll)$/,
        'MouseEvents': /^(?:click|mouse(?:down|up|over|move|out))$/
    }
    var defaultOptions = {
        pointerX: 0,
        pointerY: 0,
        button: 0,
        ctrlKey: false,
        altKey: false,
        shiftKey: false,
        metaKey: false,
        bubbles: true,
        cancelable: true
    }

    Event.simulate = function(element, eventName) {
        var options = Object.extend(Object.clone(defaultOptions), arguments[2] || { });
        var oEvent, eventType = null;

        element = $(element);

        for (var name in eventMatchers) {
            if (eventMatchers[name].test(eventName)) {
                eventType = name;
                break;
            }
        }

        if (!eventType)
            throw new SyntaxError('Only HTMLEvents and MouseEvents interfaces are supported');

        if (document.createEvent) {
            oEvent = document.createEvent(eventType);
            if (eventType == 'HTMLEvents') {
                oEvent.initEvent(eventName, options.bubbles, options.cancelable);
            } else {
                oEvent.initMouseEvent(eventName, options.bubbles, options.cancelable, document.defaultView, options.button, options.pointerX, options.pointerY, options.pointerX, options.pointerY, options.ctrlKey, options.altKey, options.shiftKey, options.metaKey, options.button, element);
            }
            element.dispatchEvent(oEvent);
        } else {
            options.clientX = options.pointerX;
            options.clientY = options.pointerY;
            oEvent = Object.extend(document.createEventObject(), options);
            element.fireEvent('on' + eventName, oEvent);
        }
        return element;
    }

    Element.addMethods({ simulate: Event.simulate });
})()