/* Copyright (c) 2006-2010 by OpenLayers Contributors (see authors.txt for 
 * full list of contributors). Published under the Clear BSD license.  
 * See http://svn.openlayers.org/trunk/openlayers/license.txt for the
 * full text of the license. */
 
 
/**
 * @requires OpenLayers/Util.js
 */
 
/**
 * Namespace: OpenLayers.Event
 * Utility functions for event handling.
 */
OpenLayers.Event = {
 
    /** 
     * Property: observers 
     * {Object} A hashtable cache of the event observers. Keyed by
     * element._eventCacheID 
     */
    observers: false,
    
    /** 
     * Constant: KEY_BACKSPACE 
     * {int} 
     */
    KEY_BACKSPACE: 8,
 
    /** 
     * Constant: KEY_TAB 
     * {int} 
     */
    KEY_TAB: 9,
 
    /** 
     * Constant: KEY_RETURN 
     * {int} 
     */
    KEY_RETURN: 13,
 
    /** 
     * Constant: KEY_ESC 
     * {int} 
     */
    KEY_ESC: 27,
 
    /** 
     * Constant: KEY_LEFT 
     * {int} 
     */
    KEY_LEFT: 37,
 
    /** 
     * Constant: KEY_UP 
     * {int} 
     */
    KEY_UP: 38,
 
    /** 
     * Constant: KEY_RIGHT 
     * {int} 
     */
    KEY_RIGHT: 39,
 
    /** 
     * Constant: KEY_DOWN 
     * {int} 
     */
    KEY_DOWN: 40,
 
    /** 
     * Constant: KEY_DELETE 
     * {int} 
     */
    KEY_DELETE: 46,
 
 
    /**
     * Method: element
     * Cross browser event element detection.
     * 
     * Parameters:
     * event - {Event} 
     * 
     * Returns:
     * {DOMElement} The element that caused the event 
     */
    element: function(event) {
        return event.target || event.srcElement;
    },
 
    /**
     * Method: isLeftClick
     * Determine whether event was caused by a left click. 
     *
     * Parameters:
     * event - {Event} 
     * 
     * Returns:
     * {Boolean}
     */
    isLeftClick: function(event) {
        return (((event.which) && (event.which == 1)) ||
                ((event.button) && (event.button == 1)));
    },
 
    /**
     * Method: isRightClick
     * Determine whether event was caused by a right mouse click. 
     *
     * Parameters:
     * event - {Event} 
     * 
     * Returns:
     * {Boolean}
     */
     isRightClick: function(event) {
        return (((event.which) && (event.which == 3)) ||
                ((event.button) && (event.button == 2)));
    },
     
    /**
     * Method: stop
     * Stops an event from propagating. 
     *
     * Parameters: 
     * event - {Event} 
     * allowDefault - {Boolean} If true, we stop the event chain but 
     *                               still allow the default browser 
     *                               behaviour (text selection, radio-button 
     *                               clicking, etc)
     *                               Default false
     */
    stop: function(event, allowDefault) {
        
        if (!allowDefault) { 
            if (event.preventDefault) {
                event.preventDefault();
            } else {
                event.returnValue = false;
            }
        }
                
        if (event.stopPropagation) {
            event.stopPropagation();
        } else {
            event.cancelBubble = true;
        }
    },
 
    /** 
     * Method: findElement
     * 
     * Parameters:
     * event - {Event} 
     * tagName - {String} 
     * 
     * Returns:
     * {DOMElement} The first node with the given tagName, starting from the
     * node the event was triggered on and traversing the DOM upwards
     */
    findElement: function(event, tagName) {
        var element = OpenLayers.Event.element(event);
        while (element.parentNode && (!element.tagName ||
              (element.tagName.toUpperCase() != tagName.toUpperCase()))){
            element = element.parentNode;
        }
        return element;
    },
 
    /** 
     * Method: observe
     * 
     * Parameters:
     * elementParam - {DOMElement || String} 
     * name - {String} 
     * observer - {function} 
     * useCapture - {Boolean} 
     */
    observe: function(elementParam, name, observer, useCapture) {
        var element = OpenLayers.Util.getElement(elementParam);
        useCapture = useCapture || false;
 
        if (name == 'keypress' &&
           (navigator.appVersion.match(/Konqueror|Safari|KHTML/)
           || element.attachEvent)) {
            name = 'keydown';
        }
 
        //if observers cache has not yet been created, create it
        if (!this.observers) {
            this.observers = {};
        }
 
        //if not already assigned, make a new unique cache ID
        if (!element._eventCacheID) {
            var idPrefix = "eventCacheID_";
            if (element.id) {
                idPrefix = element.id + "_" + idPrefix;
            }
            element._eventCacheID = OpenLayers.Util.createUniqueID(idPrefix);
        }
 
        var cacheID = element._eventCacheID;
 
        //if there is not yet a hash entry for this element, add one
        if (!this.observers[cacheID]) {
            this.observers[cacheID] = [];
        }
 
        //add a new observer to this element's list
        this.observers[cacheID].push({
            'element': element,
            'name': name,
            'observer': observer,
            'useCapture': useCapture
        });
 
        //add the actual browser event listener
        if (element.addEventListener) {
            element.addEventListener(name, observer, useCapture);
        } else if (element.attachEvent) {
            element.attachEvent('on' + name, observer);
        }
    },
 
    /** 
     * Method: stopObservingElement
     * Given the id of an element to stop observing, cycle through the 
     *   element's cached observers, calling stopObserving on each one, 
     *   skipping those entries which can no longer be removed.
     * 
     * parameters:
     * elementParam - {DOMElement || String} 
     */
    stopObservingElement: function(elementParam) {
        var element = OpenLayers.Util.getElement(elementParam);
        var cacheID = element._eventCacheID;
 
        this._removeElementObservers(OpenLayers.Event.observers[cacheID]);
    },
 
    /**
     * Method: _removeElementObservers
     *
     * Parameters:
     * elementObservers - {Array(Object)} Array of (element, name, 
     *                                         observer, usecapture) objects, 
     *                                         taken directly from hashtable
     */
    _removeElementObservers: function(elementObservers) {
        if (elementObservers) {
            for(var i = elementObservers.length-1; i >= 0; i--) {
                var entry = elementObservers[i];
                var args = new Array(entry.element,
                                     entry.name,
                                     entry.observer,
                                     entry.useCapture);
                var removed = OpenLayers.Event.stopObserving.apply(this, args);
            }
        }
    },
 
    /**
     * Method: stopObserving
     * 
     * Parameters:
     * elementParam - {DOMElement || String} 
     * name - {String} 
     * observer - {function} 
     * useCapture - {Boolean} 
     *  
     * Returns:
     * {Boolean} Whether or not the event observer was removed
     */
    stopObserving: function(elementParam, name, observer, useCapture) {
        useCapture = useCapture || false;
    
        var element = OpenLayers.Util.getElement(elementParam);
        var cacheID = element._eventCacheID;
 
        if (name == 'keypress') {
            if ( navigator.appVersion.match(/Konqueror|Safari|KHTML/) || 
                 element.detachEvent) {
              name = 'keydown';
            }
        }
 
        // find element's entry in this.observers cache and remove it
        var foundEntry = false;
        var elementObservers = OpenLayers.Event.observers[cacheID];
        if (elementObservers) {
    
            // find the specific event type in the element's list
            var i=0;
            while(!foundEntry && i < elementObservers.length) {
                var cacheEntry = elementObservers[i];
    
                if ((cacheEntry.name == name) &&
                    (cacheEntry.observer == observer) &&
                    (cacheEntry.useCapture == useCapture)) {
    
                    elementObservers.splice(i, 1);
                    if (elementObservers.length == 0) {
                        delete OpenLayers.Event.observers[cacheID];
                    }
                    foundEntry = true;
                    break; 
                }
                i++;           
            }
        }
    
        //actually remove the event listener from browser
        if (foundEntry) {
            if (element.removeEventListener) {
                element.removeEventListener(name, observer, useCapture);
            } else if (element && element.detachEvent) {
                element.detachEvent('on' + name, observer);
            }
        }
        return foundEntry;
    },
    
    /** 
     * Method: unloadCache
     * Cycle through all the element entries in the events cache and call
     *   stopObservingElement on each. 
     */
    unloadCache: function() {
        // check for OpenLayers.Event before checking for observers, because
        // OpenLayers.Event may be undefined in IE if no map instance was
        // created
        if (OpenLayers.Event && OpenLayers.Event.observers) {
            for (var cacheID in OpenLayers.Event.observers) {
                var elementObservers = OpenLayers.Event.observers[cacheID];
                OpenLayers.Event._removeElementObservers.apply(this, 
                                                           [elementObservers]);
            }
            OpenLayers.Event.observers = false;
        }
    },
 
    CLASS_NAME: "OpenLayers.Event"
};
 
/* prevent memory leaks in IE */
OpenLayers.Event.observe(window, 'unload', OpenLayers.Event.unloadCache, false);
 
// FIXME: Remove this in 3.0. In 3.0, Event.stop will no longer be provided
// by OpenLayers.
if (window.Event) {
    OpenLayers.Util.applyDefaults(window.Event, OpenLayers.Event);
} else {
    var Event = OpenLayers.Event;
}
 
/**
 * Class: OpenLayers.Events
 */
OpenLayers.Events = OpenLayers.Class({
 
    /** 
     * Constant: BROWSER_EVENTS
     * {Array(String)} supported events 
     */
    BROWSER_EVENTS: [
        "mouseover", "mouseout",
        "mousedown", "mouseup", "mousemove", 
        "click", "dblclick", "rightclick", "dblrightclick",
        "resize", "focus", "blur"
    ],
 
    /** 
     * Property: listeners 
     * {Object} Hashtable of Array(Function): events listener functions  
     */
    listeners: null,
 
    /** 
     * Property: object 
     * {Object}  the code object issuing application events 
     */
    object: null,
 
    /** 
     * Property: element 
     * {DOMElement}  the DOM element receiving browser events 
     */
    element: null,
 
    /** 
     * Property: eventTypes 
     * {Array(String)}  list of support application events 
     */
    eventTypes: null,
 
    /** 
     * Property: eventHandler 
     * {Function}  bound event handler attached to elements 
     */
    eventHandler: null,
 
    /** 
     * APIProperty: fallThrough 
     * {Boolean} 
     */
    fallThrough: null,
 
    /** 
     * APIProperty: includeXY
     * {Boolean} Should the .xy property automatically be created for browser
     *    mouse events? In general, this should be false. If it is true, then
     *    mouse events will automatically generate a '.xy' property on the 
     *    event object that is passed. (Prior to OpenLayers 2.7, this was true
     *    by default.) Otherwise, you can call the getMousePosition on the
     *    relevant events handler on the object available via the 'evt.object'
     *    property of the evt object. So, for most events, you can call:
     *    function named(evt) { 
     *        this.xy = this.object.events.getMousePosition(evt) 
     *    } 
     *
     *    This option typically defaults to false for performance reasons:
     *    when creating an events object whose primary purpose is to manage
     *    relatively positioned mouse events within a div, it may make
     *    sense to set it to true.
     *
     *    This option is also used to control whether the events object caches
     *    offsets. If this is false, it will not: the reason for this is that
     *    it is only expected to be called many times if the includeXY property
     *    is set to true. If you set this to true, you are expected to clear 
     *    the offset cache manually (using this.clearMouseCache()) if:
     *        the border of the element changes
     *        the location of the element in the page changes
    */
    includeXY: false,      
 
    /**
     * Method: clearMouseListener
     * A version of <clearMouseCache> that is bound to this instance so that
     *     it can be used with <OpenLayers.Event.observe> and
     *     <OpenLayers.Event.stopObserving>.
     */
    clearMouseListener: null,
 
    /**
     * Constructor: OpenLayers.Events
     * Construct an OpenLayers.Events object.
     *
     * Parameters:
     * object - {Object} The js object to which this Events object  is being
     * added element - {DOMElement} A dom element to respond to browser events
     * eventTypes - {Array(String)} Array of custom application events 
     * fallThrough - {Boolean} Allow events to fall through after these have
     *                         been handled?
     * options - {Object} Options for the events object.
     */
    initialize: function (object, element, eventTypes, fallThrough, options) {
        OpenLayers.Util.extend(this, options);
        this.object     = object;
        this.fallThrough = fallThrough;
        this.listeners  = {};
 
        // keep a bound copy of handleBrowserEvent() so that we can
        // pass the same function to both Event.observe() and .stopObserving()
        this.eventHandler = OpenLayers.Function.bindAsEventListener(
            this.handleBrowserEvent, this
        );
        
        // to be used with observe and stopObserving
        this.clearMouseListener = OpenLayers.Function.bind(
            this.clearMouseCache, this
        );
 
        // if eventTypes is specified, create a listeners list for each 
        // custom application event.
        this.eventTypes = [];
        if (eventTypes != null) {
            for (var i=0, len=eventTypes.length; i<len; i++) {
                this.addEventType(eventTypes[i]);
            }
        }
        
        // if a dom element is specified, add a listeners list 
        // for browser events on the element and register them
        if (element != null) {
            this.attachToElement(element);
        }
    },
 
    /**
     * APIMethod: destroy
     */
    destroy: function () {
        if (this.element) {
            OpenLayers.Event.stopObservingElement(this.element);
            if(this.element.hasScrollEvent) {
                OpenL