// Variables used for "Draggable IFrame" (DIF) functions
var DIF_dragging = false;
var DIF_iframeBeingDragged = "";
var DIF_iframeObjects = new Object();
var DIF_iframeWindows = new Object();
var DIF_iframeMouseDownLeft = new Object();
var DIF_iframeMouseDownTop = new Object();
var DIF_pageMouseDownLeft = new Object();
var DIF_pageMouseDownTop = new Object();
var DIF_handles = new Object();
var DIF_highestZIndex = 99;
var DIF_raiseSelectedIframe = false;
var DIF_allowDragOffScreen = false;

// Set to true to always raise the dragged iframe to top zIndex
function bringSelectedIframeToTop(val) {
  DIF_raiseSelectedIframe = val;
}

// Set to try to allow iframes to be dragged off the top/left of the document
function allowDragOffScreen(val) {
  DIF_allowDragOffScreen = val;
}

// Method to be used by iframe content document to specify what object can be draggable in the window
function addHandle(o, win) {
  if (arguments.length == 2 && win == window) {
    // JS is included in the iframe who has a handle, search up the chain to find a parent window that this one is dragged in
    var p = win;
    while (p = p.parent) {
      if (p.addHandle) { p.addHandle(o, win, true); return; }
      if (p == win.top) { return; } // Already reached the top, stop looking
    }
    return; // If it reaches here, there is no parent with the addHandle function defined, so this frame can't be dragged!
  }
  var topRef = win;
  var topRefStr = "window";
  while (topRef.parent && topRef.parent != window) {
    topRef = topRef.parent;
    topRefStr = topRefStr + ".parent";
  }
  // Add handlers to child window
  if (typeof (win.DIF_mainHandlersAdded) == "undefined" || !win.DIF_mainHandlersAdded) {
    // This is done in a funky way to make Netscape happy
    with (win) {
      eval("function OnMouseDownHandler(evt) { if(typeof(evt)=='undefined'){evt=event;}" + topRefStr + ".parent.DIF_begindrag(evt, " + topRefStr + ") }");
      eval("document.onmousedown = OnMouseDownHandler;");
      eval("function OnMouseUpHandler(evt) { if(typeof(evt)=='undefined'){evt=event;}" + topRefStr + ".parent.DIF_enddrag(evt, " + topRefStr + ") }");
      eval("document.onmouseup = OnMouseUpHandler;");
      eval("function OnMouseMoveHandler(evt) { if(typeof(evt)=='undefined'){evt=event;}" + topRefStr + ".parent.DIF_iframemove(evt, " + topRefStr + ") }");
      eval("document.onmousemove = OnMouseMoveHandler;");
      win.DIF_handlersAdded = true;
      win.DIF_mainHandlersAdded = true;
    }
  }
  // Add handler to this window
  if (typeof (window.DIF_handlersAdded) != "undefined" || !window.DIF_handlersAdded) {
    eval("function OnMouseMoveHandler(evt) { if(typeof(evt)=='undefined'){evt=event;}DIF_mouseMove(evt, window) }");
    eval("document.onmousemove = OnMouseMoveHandler;");
    window.DIF_handlersAdded = true;
  }
  var name = DIF_getIframeId(topRef);
  if (DIF_handles[name] == null) {
    // Initialize relative positions for mouse down events
    DIF_handles[name] = new Array();
    DIF_iframeMouseDownLeft[name] = 0;
    DIF_iframeMouseDownTop[name] = 0;
    DIF_pageMouseDownLeft[name] = 0;
    DIF_pageMouseDownTop[name] = 0;
  }
  DIF_handles[name][DIF_handles[name].length] = o;
}

// Generalized function to get position of an event (like mousedown, mousemove, etc)
function DIF_getEventPosition(evt) {
  var pos = new Object();
  pos.x = 0;
  pos.y = 0;
  if (!evt) {
    evt = window.event;
  }
  if (typeof (evt.pageX) == 'number') {
    pos.x = evt.pageX;
    pos.y = evt.pageY;
  }
  else {
    pos.x = evt.clientX;
    pos.y = evt.clientY;
    if (!top.opera) {
      if ((!window.document.compatMode) || (window.document.compatMode == 'BackCompat')) {
        pos.x += window.document.body.scrollLeft;
        pos.y += window.document.body.scrollTop;
      }
      else {
        pos.x += window.document.documentElement.scrollLeft;
        pos.y += window.document.documentElement.scrollTop;
      }
    }
  }
  return pos;
}

// Gets the ID of a frame given a reference to a window object.
// Also stores a reference to the IFRAME object and it's window object
function DIF_getIframeId(win) {
  // Loop through the window's IFRAME objects looking for a matching window object
  var iframes = document.getElementsByTagName("IFRAME");
  for (var i = 0; i < iframes.length; i++) {
    var o = iframes.item(i);
    var w = null;
    if (o.contentWindow) {
      // For IE5.5 and IE6
      w = o.contentWindow;
    }
    else if (window.frames && window.frames[o.id].window) {
      w = window.frames[o.id];
    }
    if (w == win) {
      DIF_iframeWindows[o.id] = win;
      DIF_iframeObjects[o.id] = o;
      return o.id;
    }
  }
  return null;
}

// Gets the page x, y coordinates of the iframe (or any object)
function DIF_getObjectXY(o) {
  var res = new Object();
  res.x = 0; res.y = 0;
  if (o != null) {
    res.x = o.style.left.substring(0, o.style.left.indexOf("px"));
    res.y = o.style.top.substring(0, o.style.top.indexOf("px"));
  }
  return res;
}

// Function to get the src element clicked for non-IE browsers
function getSrcElement(e) {
  var tgt = e.target;
  while (tgt.nodeType != 1) { tgt = tgt.parentNode; }
  return tgt;
}

// Check if object clicked is a 'handle' - walk up the node tree if required
function isHandleClicked(handle, objectClicked) {
  if (handle == objectClicked) { return true; }
  while (objectClicked.parentNode != null) {
    if (objectClicked == handle) {
      return true;
    }
    objectClicked = objectClicked.parentNode;
  }
  return false;
}

// Called when user clicks an iframe that has a handle in it to begin dragging
function DIF_begindrag(e, win) {
  // Get the IFRAME ID that was clicked on
  var iframename = DIF_getIframeId(win);
  if (iframename == null) { return; }
  // Make sure that this IFRAME has a handle and that the handle was clicked
  if (DIF_handles[iframename] == null || DIF_handles[iframename].length < 1) {
    return;
  }
  var isHandle = false;
  var t = e.srcElement || getSrcElement(e);
  for (var i = 0; i < DIF_handles[iframename].length; i++) {
    if (isHandleClicked(DIF_handles[iframename][i], t)) {
      isHandle = true;
      break;
    }
  }
  if (!isHandle) { return false; }
  DIF_iframeBeingDragged = iframename;
  if (DIF_raiseSelectedIframe) {
    DIF_iframeObjects[DIF_iframeBeingDragged].style.zIndex = DIF_highestZIndex++;
  }
  DIF_dragging = true;
  var pos = DIF_getEventPosition(e);
  DIF_iframeMouseDownLeft[DIF_iframeBeingDragged] = pos.x;
  DIF_iframeMouseDownTop[DIF_iframeBeingDragged] = pos.y;
  var o = DIF_getObjectXY(DIF_iframeObjects[DIF_iframeBeingDragged]);

  DIF_pageMouseDownLeft[DIF_iframeBeingDragged] = o.x - 0 + pos.x;
  DIF_pageMouseDownTop[DIF_iframeBeingDragged] = o.y - 0 + pos.y;

}

// Called when mouse button is released after dragging an iframe
function DIF_enddrag(e) {
  DIF_dragging = false;
  DIF_iframeBeingDragged = "";
}

// Called when mouse moves in the main window
function DIF_mouseMove(e) {
  if (DIF_dragging) {
    var pos = DIF_getEventPosition(e);
    DIF_drag(pos.x - DIF_pageMouseDownLeft[DIF_iframeBeingDragged], pos.y - DIF_pageMouseDownTop[DIF_iframeBeingDragged]);
  }
}

// Called when mouse moves in the IFRAME window
function DIF_iframemove(e) {
  if (DIF_dragging) {
    var pos = DIF_getEventPosition(e);
    DIF_drag(pos.x - DIF_iframeMouseDownLeft[DIF_iframeBeingDragged], pos.y - DIF_iframeMouseDownTop[DIF_iframeBeingDragged]);
  }
}

// Function which actually moves of the iframe object on the screen
function DIF_drag(x, y) {
  var o = DIF_getObjectXY(DIF_iframeObjects[DIF_iframeBeingDragged]);
  // Don't drag it off the top or left of the screen?
  var newPositionX = o.x - 0 + x;
  var newPositionY = o.y - 0 + y;
  if (!DIF_allowDragOffScreen) {
    if (newPositionX < 0) { newPositionX = 0; }
    if (newPositionY < 0) { newPositionY = 0; }
  }

  if (newPositionX < 400 && newPositionY < 1500) {
    DIF_iframeObjects[DIF_iframeBeingDragged].style.left = newPositionX + "px";
    DIF_iframeObjects[DIF_iframeBeingDragged].style.top = newPositionY + "px";
    DIF_pageMouseDownLeft[DIF_iframeBeingDragged] += x;
    DIF_pageMouseDownTop[DIF_iframeBeingDragged] += y;
  }
}