/* custom extensions to the DOM api */
Element.addMethods({

  addInterface: function(element, objectInterface) {
    element = $(element);
    Object.extend(element, objectInterface);
    if (element.bind)
      element.bind();
  },

  childNodesWithTag: function(element, tagName) {
    element = $(element);
    var matchingNodes = new Array();
    var tagName = tagName.toUpperCase();
    
    for (var i = 0; i < element.childNodes.length; i++) {
      if (typeof(element.childNodes[i]) == "object"
	  && element.childNodes[i].tagName
	  && element.childNodes[i].tagName.toUpperCase() == tagName)
	matchingNodes.push(element.childNodes[i]);
    }

    return matchingNodes;
  },

  removeClassName: function(element, className) {
    element = $(element);
    var classStr = '' + element.readAttribute('class');

    position = classStr.indexOf(className, 0);
    while (position > -1) {
      classStr1 = classStr.substring(0, position); 
      classStr2 = classStr.substring(position + 10, classStr.length);
      classStr = classStr1 + classStr2;
      position = classStr.indexOf(className, 0);
    }
    
    element.setAttribute('class', classStr);
  },

  getParentWithTagName: function(element, tagName) {
    element = $(element);
    var currentElement = element;
    tagName = tagName.toUpperCase();
    
    currentElement = currentElement.parentNode;
    while (currentElement
	   && currentElement.tagName != tagName) {
      currentElement = currentElement.parentNode;
    }
    
    return currentElement;
  },

  cascadeLeftOffset: function(element) {
    element = $(element);
    var currentElement = element;
    
    var offset = 0;
    while (currentElement) {
      offset += currentElement.offsetLeft;
      currentElement = currentElement.getParentWithTagName("div");
    }
    
    return offset;
  },

  cascadeTopOffset: function(element) {
    element = $(element);
    var currentElement = element;
    var offset = 0;
    
    var i = 0;
    
    while (currentElement
	   && currentElement instanceof HTMLElement) {
      offset += currentElement.offsetTop;
      currentElement = currentElement.parentNode;
      i++;
    }
    
    return offset;
  },
 
  dump: function(element, additionalInfo, additionalKeys) {
    element = $(element);
    var id = element.getAttribute("id");
    var nclass = element.getAttribute("class");
    
    var str = element.tagName;
    if (id)
      str += "; id = " + id;
    if (nclass)
      str += "; class = " + nclass;
    
    if (additionalInfo)
      str += "; " + additionalInfo;
    
    if (additionalKeys)
      for (var i = 0; i < additionalKeys.length; i++) {
	var value = element.getAttribute(additionalKeys[i]);
	if (value)
	  str += "; " + additionalKeys[i] + " = " + value;
      }
    
    log (str);
  },

  getSelectedNodes: function(element) {
    element = $(element);
    var selArray = new Array();
    
    for (var i = 0; i < element.childNodes.length; i++) {
      node = element.childNodes.item(i);
      if (node.nodeType == 1
	  && isNodeSelected(node))
	selArray.push(node);
    }
    
    return selArray;
  },

  getSelectedNodesId: function(element) {
    element = $(element);
    var selArray = new Array();
    
    for (var i = 0; i < element.childNodes.length; i++) {
      node = element.childNodes.item(i);
      if (node.nodeType == 1
	  && isNodeSelected(node))
	selArray.push(node.getAttribute("id"));
    }

    return selArray;
  },

  onContextMenu: function(element, event) {
    element = $(element);
    var popup = element.sogoContextMenu;

    if (document.currentPopupMenu)
      hideMenu(event, document.currentPopupMenu);
    
    var menuTop = event.pageY;
    var menuLeft = event.pageX;
    var heightDiff = (window.innerHeight
		      - (menuTop + popup.offsetHeight));
    if (heightDiff < 0)
      menuTop += heightDiff;
    
    var leftDiff = (window.innerWidth
		    - (menuLeft + popup.offsetWidth));
    if (leftDiff < 0)
      menuLeft -= popup.offsetWidth;
    
    popup.style.top = menuTop + "px;";
    popup.style.left = menuLeft + "px;";
    popup.style.visibility = "visible;";
    
    document.currentPopupMenu = popup;
    Event.observe(document.body, "click", onBodyClickMenuHandler);
  },

  attachMenu: function(element, menuName) {
    element = $(element);
    element.sogoContextMenu = $(menuName);
    Event.observe(element, "contextmenu", element.onContextMenu.bindAsEventListener(element));
  },

  select: function(element) {
    element = $(element);
    element.addClassName('_selected');
  },

  deselect: function(element) {
    element = $(element);
    element.removeClassName('_selected');
  },

  deselectAll: function (element) {
    element = $(element);
    for (var i = 0; i < element.childNodes.length; i++) {
      var node = element.childNodes.item(i);
      if (node.nodeType == 1)
	node.deselect();
    }
  }

});