/**
 * Adds mousewheel event support
 * @module event
 * @submodule event-mousewheel
 */
var DOM_MOUSE_SCROLL = 'DOMMouseScroll',
    fixArgs = function(args) {
        var a = Y.Array(args, 0, true), target;
        if (Y.UA.gecko) {
            a[0] = DOM_MOUSE_SCROLL;
            target = Y.config.win;
        } else {
            target = Y.config.doc;
        }

        if (a.length < 3) {
            a[2] = target;
        } else {
            a.splice(2, 0, target);
        }

        return a;
    };

/**
 * Mousewheel event.  This listener is automatically attached to the
 * correct target, so one should not be supplied.  Mouse wheel 
 * direction and velocity is stored in the 'wheelDelta' field.
 * @event mousewheel
 * @param type {string} 'mousewheel'
 * @param fn {function} the callback to execute
 * @param context optional context object
 * @param args 0..n additional arguments to provide to the listener.
 * @return {EventHandle} the detach handle
 * @for YUI
 */
Y.Env.evt.plugins.mousewheel = {
    on: function() {
        return Y.Event._attach(fixArgs(arguments));
    },

    detach: function() {
        return Y.Event.detach.apply(Y.Event, fixArgs(arguments));
    }
};