/* 
*  Mouse wheel support for OS X - implemented in javascript because Adobe
*  hasn't implemented it in the mac version of Flash Player  >:(
*  
*  Copyright (c) 2007-2008 Ali Rantakari ( http://hasseg.org/blog )
*  
*  Requires related ActionScript 3 class:
*  org.hasseg.externalMouseWheel.ExternalMouseWheelSupport
*  
*  
*  Changelog:
*  ---------------------------------------------------------------------------------
*  VERSION 1.0 (Ali Rantakari)
*  July 2007
*  
*  - Initial implementation
*  
*  
*  ---------------------------------------------------------------------------------
*  VERSION 1.5 (Changes by Pavel Fljot, http://inreflected.com)
*  Jan 2008
*  
*  - Added statement to support Safari under Windows
*  
*  
*  ---------------------------------------------------------------------------------
*  VERSION 2.0 (Changes by Ali Rantakari)
*  Apr 2008
*  
*  - Changed structure of JavaScript so that everything is encapsulated
*    inside one top-level function
*  - Added support for modifier keys (ctrl (i.e. command on a Mac,) alt, shift)
*  - Fixed code for determining coordinates on different (recent) browsers
*  - Added support for registering multiple Flash objects and their container DIVs
*  
*  
*  ---------------------------------------------------
*  This code is licensed under the MIT License:
*  
*  Permission is hereby granted, free of charge, to any person obtaining a copy
*  of this software and associated documentation files (the "Software"), to deal
*  in the Software without restriction, including without limitation the rights
*  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
*  copies of the Software, and to permit persons to whom the Software is
*  furnished to do so, subject to the following conditions:
*  
*  The above copyright notice and this permission notice shall be included in
*  all copies or substantial portions of the Software.
*  
*  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
*  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
*  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
*  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
*  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
*  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
*  THE SOFTWARE.
*/

var extMouseWheel = function () {
    // let's not allow other deltas than +/- 3 because that's what flash player does:
    var keepDeltaAtPlusMinusThree = true;


    // an associative array, where the keys are the ids of flash
    // objects that have registered for the mouse wheel support, and
    // the values their respective container div elements.
    var f = [];




    // helper function courtesy of the Adobe peepz
    var thisMovie = function (movieName) {
        if (navigator.appName.indexOf("Microsoft") != -1) {
            return window[movieName];
        } else {
            return document[movieName];
        }
    }

    // helper functions for getting the position of
    // an element
    // from:  http://blog.firetree.net/2005/07/04/javascript-find-position/
    var findPosX = function (obj) {
        var curleft = 0;
        if (obj.offsetParent)
            while (1) {
                curleft += obj.offsetLeft;
                if (!obj.offsetParent)
                    break;
                obj = obj.offsetParent;
            }
        else if (obj.x)
            curleft += obj.x;
        return curleft;
    }
    var findPosY = function (obj) {
        var curtop = 0;
        if (obj.offsetParent)
            while (1) {
                curtop += obj.offsetTop;
                if (!obj.offsetParent)
                    break;
                obj = obj.offsetParent;
            }
        else if (obj.y)
            curtop += obj.y;
        return curtop;
    }

    // helper function for searching the user-agent string
    var uaContains = function (str) {
        return (navigator.userAgent.indexOf(str) != -1);
    }






    // Handler for mouse wheel event:
    var onWheelHandler = function (event) {
        var delta = 0;
        if (!event) event = window.event;
        if (event.wheelDelta) {
            // Safari
            delta = event.wheelDelta / 120;
            if (window.opera) delta = -delta;
        }
        else if (event.detail) // Firefox
            delta = -event.detail * 3;

        if (keepDeltaAtPlusMinusThree) {
            if (delta > 0) delta = 3;
            else if (delta == 0) delta = 0;
            else delta = -3;
        }

        if (delta) {

            var thisFlashMovieId = null;
            for (var j in f)
                if (f[j] != null && f[j] == event.currentTarget) thisFlashMovieId = j;

            var thisMouse;

            if (uaContains("Camino"))
                thisMouse = { x: event.layerX, y: event.layerY };
            else if (uaContains('Firefox'))
                thisMouse = { x: (event.layerX - findPosX(event.currentTarget)), y: (event.layerY - findPosY(event.currentTarget)) };
            else
                thisMouse = { x: event.offsetX, y: event.offsetY };

            thisMouse.ctrlKey = (uaContains('Mac')) ? (event.metaKey || event.ctrlKey) : event.ctrlKey;
            thisMouse.altKey = event.altKey;
            thisMouse.shiftKey = event.shiftKey;
            thisMouse.buttonDown = false;

            if (thisMovie(thisFlashMovieId).dispatchExternalMouseWheelEvent)
                thisMovie(thisFlashMovieId).dispatchExternalMouseWheelEvent(delta, thisMouse.x, thisMouse.y,
																			thisMouse.ctrlKey, thisMouse.altKey,
																			thisMouse.shiftKey, thisMouse.buttonDown);
        };

        // Prevent default actions caused by mouse wheel
        if (event.preventDefault) event.preventDefault();
        event.returnValue = false;

    }









    return {
        // initialize mouse wheel capturing by setting the listener
        // (this is called from within the Flash app):
        initCaptureFor: function (aFlashObjectId) {

            if (uaContains('Mac') || uaContains('Safari') || uaContains('Firefox')) {
                
                // find flash object's div container
                var parentdiv = document.getElementById(aFlashObjectId).parentNode;

                while (parentdiv != null && parentdiv.nodeName != "DIV")
                    parentdiv = parentdiv.parentNode;

                
                if (parentdiv != undefined && parentdiv != null) {
                    f[aFlashObjectId] = parentdiv;

                    if (parentdiv.addEventListener) parentdiv.addEventListener('DOMMouseScroll', onWheelHandler, false); // Firefox
                    parentdiv.onmousewheel = onWheelHandler; // Safari

                    return true;
                }
                else
                    return false;
            }
            else
                return false;
        }
    };

} ();