/*
    * Ext GWT 2.2.0 - Ext for GWT
    * Copyright(c) 2007-2010, Ext JS, LLC.
    * licensing@extjs.com
    * 
    * http://extjs.com/license
    */
   package com.extjs.gxt.ui.client.fx;
   
  import com.extjs.gxt.ui.client.Style;
  import com.extjs.gxt.ui.client.core.El;
  import com.extjs.gxt.ui.client.core.XDOM;
  import com.extjs.gxt.ui.client.event.BaseObservable;
  import com.extjs.gxt.ui.client.event.ComponentEvent;
  import com.extjs.gxt.ui.client.event.DragEvent;
  import com.extjs.gxt.ui.client.event.DragListener;
  import com.extjs.gxt.ui.client.event.Events;
  import com.extjs.gxt.ui.client.event.Listener;
  import com.extjs.gxt.ui.client.event.PreviewEvent;
  import com.extjs.gxt.ui.client.util.BaseEventPreview;
  import com.extjs.gxt.ui.client.util.Rectangle;
  import com.extjs.gxt.ui.client.widget.Component;
  import com.extjs.gxt.ui.client.widget.Shim;
  import com.google.gwt.event.dom.client.KeyCodes;
  import com.google.gwt.user.client.DOM;
  import com.google.gwt.user.client.Element;
  import com.google.gwt.user.client.Event;
  import com.google.gwt.user.client.Window;
  
  /**
   * Adds drag behavior to any widget. Drag operations can be initiated from the
   * widget itself, or another widget, such as the header in a dialog.
   * 
   * <p/>
   * It is possible to specify event targets that will be ignored. If the target
   * element has a 'x-nodrag' style it will not trigger a drag operation.
   * 
   * <dl>
   * <dt><b>Events:</b></dt>
   * 
   * <dd><b>DragStart</b> : DragEvent(draggable, component, event) <br>
   * <div>Fires after a drag has started.</div>
   * <ul>
   * <li>draggable : this</li>
   * <li>component : drag component</li>
   * <li>event : the dom event</li>
   * </ul>
   * </dd>
   * 
   * <dd><b>DragMove</b> : DragEvent(draggable, component, event)<br>
   * <div>Fires after the mouse moves.</div>
   * <li>draggable : this</li>
   * <li>component : drag component</li>
   * <li>event : the dom event</li>
   * </ul>
   * </dd>
   * 
   * <dd><b>DragCancel</b> : DragEvent(draggable, component, event)<br>
   * <div>Fires after a drag has been cancelled.</div>
   * <ul>
   * <li>draggable : this</li>
   * <li>component : drag component</li>
   * <li>event : the dom event</li>
   * </ul>
   * </dd>
   * 
   * <dd><b>DragEnd</b> : DragEvent(draggable, component, event) <br>
   * <div>Fires after a drag has ended.</div>
   * <ul>
   * <li>draggable : this</li>
   * <li>component : drag widget</li>
   * <li>event : the dom event</li>
   * </ul>
   * </dd>
   * </dl>
   */
  public class Draggable extends BaseObservable {
  
    protected int conX, conY, conWidth, conHeight;
    protected int dragStartX, dragStartY;
    protected int lastX, lastY;
    protected Rectangle startBounds;
    protected El proxyEl;
  
    // config
    private boolean updateZIndex = true;
    private boolean sizeProxyToSource = true;
    private boolean constrainHorizontal;
    private boolean moveAfterProxyDrag = true;
    private boolean constrainVertical;
    private boolean constrainClient = true;
    private boolean useProxy = true;
    private int xLeft = Style.DEFAULT, xRight = Style.DEFAULT;
    private int xTop = Style.DEFAULT, xBottom = Style.DEFAULT;
    private String proxyStyle = "x-drag-proxy";
    private Component container;
    private Component dragWidget;
    private Component handle;
    private boolean dragging;
   private boolean enabled = true;
   private int clientWidth, clientHeight;
   private BaseEventPreview preview;
   private DragEvent dragEvent;
   private int startDragDistance = 2;
   private Listener<ComponentEvent> listener;
 
   /**
    * Creates a new draggable instance.
    * 
    * @param dragComponent the component to be dragged
    */
   public Draggable(Component dragComponent) {
     this(dragComponent, dragComponent);
   }
 
   /**
    * Create a new draggable instance.
    * 
    * @param dragComponent the component to be dragged
    * @param handle the component drags will be initiated from
    */
   public Draggable(final Component dragComponent, final Component handle) {
     listener = new Listener<ComponentEvent>() {
       public void handleEvent(ComponentEvent ce) {
         onMouseDown(ce);
       }
     };
     this.dragWidget = dragComponent;
     this.handle = handle;
 
     handle.addListener(Events.OnMouseDown, listener);
 
     preview = new BaseEventPreview() {
 
       @Override
       public boolean onPreview(PreviewEvent event) {
         event.preventDefault();
         switch (event.getEventTypeInt()) {
           case Event.ONKEYDOWN:
             if (dragging && event.getKeyCode() == KeyCodes.KEY_ESCAPE) {
               cancelDrag();
             }
             break;
           case Event.ONMOUSEMOVE:
             onMouseMove(event.getEvent());
             break;
           case Event.ONMOUSEUP:
             stopDrag(event.getEvent());
             break;
         }
         return true;
       }
 
     };
     preview.setAutoHide(false);
 
     handle.sinkEvents(Event.ONMOUSEDOWN);
   }
 
   /**
    * Adds a listener to receive drag events.
    * 
    * @param listener the drag listener to be added
    */
   public void addDragListener(DragListener listener) {
     addListener(Events.DragStart, listener);
     addListener(Events.DragMove, listener);
     addListener(Events.DragCancel, listener);
     addListener(Events.DragEnd, listener);
   }
 
   /**
    * Cancels the drag if running.
    */
   public void cancelDrag() {
     preview.remove();
     if (dragging) {
       dragging = false;
       if (isUseProxy()) {
         proxyEl.disableTextSelection(false);
         proxyEl.setVisibility(false);
         proxyEl.remove();
       } else {
         dragWidget.el().setPagePosition(startBounds.x, startBounds.y);
       }
 
       fireEvent(Events.DragCancel, new DragEvent(this));
       afterDrag();
     }
   }
 
   /**
    * Returns the drag container.
    * 
    * @return the drag container
    */
   public Component getContainer() {
     return container;
   }
 
   /**
    * Returns the drag handle.
    * 
    * @return the drag handle
    */
   public Component getDragHandle() {
     return handle;
   }
 
   /**
    * Returns the widget being dragged.
    * 
    * @return the drag widget
    */
   public Component getDragWidget() {
     return dragWidget;
   }
 
   /**
    * Returns the proxy style.
    * 
    * @return the proxy style
    */
   public String getProxyStyle() {
     return proxyStyle;
   }
 
   /**
    * Returns the number of pixels the cursor must move before dragging begins.
    * 
    * @return the distance in pixels
    */
   public int getStartDragDistance() {
     return startDragDistance;
   }
 
   /**
    * Returns true if drag is constrained to the viewport.
    * 
    * @return the constrain client state
    */
   public boolean isConstrainClient() {
     return constrainClient;
   }
 
   /**
    * Returns true if horizontal movement is constrained.
    * 
    * @return the horizontal constrain state
    */
   public boolean isConstrainHorizontal() {
     return constrainHorizontal;
   }
 
   /**
    * Returns true if vertical movement is constrained.
    * 
    * @return true if vertical movement is constrained
    */
   public boolean isConstrainVertical() {
     return constrainVertical;
   }
 
   /**
    * Returns <code>true</code> if a drag is in progress.
    * 
    * @return the drag state
    */
   public boolean isDragging() {
     return dragging;
   }
 
   /**
    * Returns <code>true</code> if enabled.
    * 
    * @return the enable state
    */
   public boolean isEnabled() {
     return enabled;
   }
 
   /**
    * Returns true if the drag widget is moved after a proxy drag.
    * 
    * @return the move after proxy state
    */
   public boolean isMoveAfterProxyDrag() {
     return moveAfterProxyDrag;
   }
 
   /**
    * Returns true if the proxy element is sized to match the drag widget.
    * 
    * @return the size proxy to source state
    */
   public boolean isSizeProxyToSource() {
     return sizeProxyToSource;
   }
 
   /**
    * Returns true if the z-index is updated after a drag.
    * 
    * @return the update z-index state
    */
   public boolean isUpdateZIndex() {
     return updateZIndex;
   }
 
   /**
    * Returns true if proxy element is enabled.
    * 
    * @return the use proxy state
    */
   public boolean isUseProxy() {
     return useProxy;
   }
 
   /**
    * Removes the drag handles.
    */
   public void release() {
     cancelDrag();
     handle.removeListener(Events.OnMouseDown, listener);
   }
 
   /**
    * Removes a previously added listener.
    * 
    * @param listener the listener to be removed
    */
   public void removeDragListener(DragListener listener) {
     if (hasListeners()) {
       removeListener(Events.DragStart, listener);
       removeListener(Events.DragMove, listener);
       removeListener(Events.DragCancel, listener);
       removeListener(Events.DragEnd, listener);
     }
   }
 
   /**
    * True to set constrain movement to the viewport (defaults to true).
    * 
    * @param constrainClient true to constrain to viewport
    */
   public void setConstrainClient(boolean constrainClient) {
     this.constrainClient = constrainClient;
   }
 
   /**
    * True to stop horizontal movement (defaults to false).
    * 
    * @param constrainHorizontal true to stop horizontal movement
    */
   public void setConstrainHorizontal(boolean constrainHorizontal) {
     this.constrainHorizontal = constrainHorizontal;
   }
 
   /**
    * True to stop vertical movement (defaults to false).
    * 
    * @param constrainVertical true to stop vertical movement
    */
   public void setConstrainVertical(boolean constrainVertical) {
     this.constrainVertical = constrainVertical;
   }
 
   /**
    * Specifies a container to which the drag widget is constrained.
    * 
    * @param container the container
    */
   public void setContainer(Component container) {
     this.container = container;
   }
 
   /**
    * Enables dragging if the argument is <code>true</code>, and disables it
    * otherwise.
    * 
    * @param enabled the new enabled state
    */
   public void setEnabled(boolean enabled) {
     this.enabled = enabled;
   }
 
   /**
    * True to move source widget after a proxy drag (defaults to true).
    * 
    * @param moveAfterProxyDrag true to move after a proxy drag
    */
   public void setMoveAfterProxyDrag(boolean moveAfterProxyDrag) {
     this.moveAfterProxyDrag = moveAfterProxyDrag;
   }
 
   /**
    * Sets the proxy element.
    * 
    * @param element the proxy element
    */
   public void setProxy(El element) {
     proxyEl = element;
   }
 
   /**
    * Sets the style name used for proxy drags (defaults to 'my-drag-proxy').
    * 
    * @param proxyStyle the proxy style
    */
   public void setProxyStyle(String proxyStyle) {
     this.proxyStyle = proxyStyle;
   }
 
   /**
    * True to set proxy dimensions the same as the drag widget (defaults to
    * true).
    * 
    * @param sizeProxyToSource true to update proxy size
    */
   public void setSizeProxyToSource(boolean sizeProxyToSource) {
     this.sizeProxyToSource = sizeProxyToSource;
   }
 
   /**
    * Specifies how far the cursor must move after mousedown to start dragging
    * (defaults to 2).
    * 
    * @param startDragDistance the start distance in pixels
    */
   public void setStartDragDistance(int startDragDistance) {
     this.startDragDistance = startDragDistance;
   }
 
   /**
    * True if the CSS z-index should be updated on the widget being dragged.
    * Setting this value to <code>true</code> will ensure that the dragged
    * element is always displayed over all other widgets (defaults to true).
    * 
    * @param updateZIndex true update the z-index
    */
   public void setUpdateZIndex(boolean updateZIndex) {
     this.updateZIndex = updateZIndex;
   }
 
   /**
    * True to use a proxy widget during drag operation (defaults to true).
    * 
    * @param useProxy true use a proxy
    */
   public void setUseProxy(boolean useProxy) {
     this.useProxy = useProxy;
   }
 
   /**
    * Constrains the horizontal travel.
    * 
    * @param left the number of pixels the element can move to the left
    * @param right the number of pixels the element can move to the right
    */
   public void setXConstraint(int left, int right) {
     xLeft = left;
     xRight = right;
   }
 
   /**
    * Constrains the vertical travel.
    * 
    * @param top the number of pixels the element can move to the up
    * @param bottom the number of pixels the element can move to the down
    */
   public void setYConstraint(int top, int bottom) {
     xTop = top;
     xBottom = bottom;
   }
 
   protected void afterDrag() {
     XDOM.getBodyEl().removeStyleName("x-unselectable");
     XDOM.getBodyEl().removeStyleName("x-dd-cursor");
     Shim.get().uncover();
   }
 
   protected El createProxy() {
     proxyEl = new El(DOM.createDiv());
     proxyEl.setVisibility(false);
     proxyEl.dom.setClassName(getProxyStyle());
     proxyEl.disableTextSelection(true);
     return proxyEl;
   }
 
   protected void onMouseDown(ComponentEvent ce) {
     if (!enabled || ce.getEvent().getButton() != Event.BUTTON_LEFT) {
       return;
     }
     Element target = ce.getTarget();
     String s = DOM.getElementProperty(target, "className");
     if (s != null && s.indexOf("x-nodrag") != -1) {
       return;
     }
 
     // still allow text selection, prevent drag of other elements
     if ((!"input".equalsIgnoreCase(ce.getTarget().getTagName()) && !"textarea".equalsIgnoreCase(ce.getTarget().getTagName()))
         || ce.getTarget().getPropertyBoolean("disabled")) {
       ce.preventDefault();
     }
 
     startBounds = dragWidget.el().getBounds();
 
     dragStartX = ce.getClientX();
     dragStartY = ce.getClientY();
 
     preview.add();
 
     clientWidth = Window.getClientWidth() + XDOM.getBodyScrollLeft();
     clientHeight = Window.getClientHeight() + XDOM.getBodyScrollTop();
 
     if (container != null) {
       conX = container.getAbsoluteLeft();
       conY = container.getAbsoluteTop();
       conWidth = container.getOffsetWidth();
       conHeight = container.getOffsetHeight();
     }
 
     if (startDragDistance == 0) {
       startDrag(ce.getEvent());
     }
 
   }
 
   protected void onMouseMove(Event event) {
     Element elem = event.getEventTarget().cast();
     // elem.getClassName throwing GWT exception when dragged component is over
     // SVG / VML
     if (hasAttribute(elem, "class")) {
    	  /* begin laaglu */
 //      String cls = ((Element) event.getEventTarget().cast()).getClassName();
         String cls = El.getClassName(((Element) event.getEventTarget().cast()));
       /* end laaglu */
 
       if (cls != null && cls.contains("x-insert")) {
         return;
       }
     }
 
     int x = DOM.eventGetClientX(event);
     int y = DOM.eventGetClientY(event);
 
     if (!dragging && (Math.abs(dragStartX - x) > startDragDistance || Math.abs(dragStartY - y) > startDragDistance)) {
       startDrag(event);
     }
 
     if (dragging) {
       int left = constrainHorizontal ? startBounds.x : startBounds.x + (x - dragStartX);
       int top = constrainVertical ? startBounds.y : startBounds.y + (y - dragStartY);
 
       if (constrainClient) {
         if (!constrainHorizontal) {
           int width = startBounds.width;
           left = Math.max(left, 0);
           left = Math.max(0, Math.min(clientWidth - width, left));
         }
         if (!constrainVertical) {
           top = Math.max(top, 0);
           int height = startBounds.height;
           if (Math.min(clientHeight - height, top) > 0) {
             top = Math.max(2, Math.min(clientHeight - height, top));
           }
         }
       }
 
       if (container != null) {
         int width = startBounds.width;
         int height = startBounds.height;
         if (!constrainHorizontal) {
           left = Math.max(left, conX);
           left = Math.min(conX + conWidth - width, left);
         }
         if (!constrainVertical) {
           top = Math.min(conY + conHeight - height, top);
           top = Math.max(top, conY);
         }
       }
       if (!constrainHorizontal) {
         if (xLeft != Style.DEFAULT) {
           left = Math.max(startBounds.x - xLeft, left);
         }
         if (xRight != Style.DEFAULT) {
           left = Math.min(startBounds.x + xRight, left);
         }
       }
 
       if (!constrainVertical) {
         if (xTop != Style.DEFAULT) {
           top = Math.max(startBounds.y - xTop, top);
         }
         if (xBottom != Style.DEFAULT) {
           top = Math.min(startBounds.y + xBottom, top);
         }
       }
 
       lastX = left;
       lastY = top;
 
       dragEvent.setSource(this);
       dragEvent.setComponent(dragWidget);
       dragEvent.setEvent(event);
       dragEvent.setCancelled(false);
       dragEvent.setX(lastX);
       dragEvent.setY(lastY);
       fireEvent(Events.DragMove, dragEvent);
 
       if (dragEvent.isCancelled()) {
         cancelDrag();
         return;
       }
 
       int tl = dragEvent.getX() != lastX ? dragEvent.getX() : lastX;
       int tt = dragEvent.getY() != lastY ? dragEvent.getY() : lastY;
       if (useProxy) {
         proxyEl.setPagePosition(tl, tt);
       } else {
         dragWidget.el().setPagePosition(tl, tt);
       }
     }
 
   }
 
   protected void startDrag(Event event) {
     DragEvent de = new DragEvent(this);
     de.setComponent(dragWidget);
     de.setEvent(event);
     de.setX(startBounds.x);
     de.setY(startBounds.y);
 
     if (fireEvent(Events.DragStart, de)) {
       dragging = true;
       XDOM.getBodyEl().addStyleName("x-unselectable");
       XDOM.getBodyEl().addStyleName("x-dd-cursor");
       dragWidget.el().makePositionable();
 
       event.preventDefault();
 
       Shim.get().cover(true);
 
       lastX = startBounds.x;
       lastY = startBounds.y;
 
       if (dragEvent == null) {
         dragEvent = new DragEvent(this);
       }
 
       if (useProxy) {
         if (proxyEl == null) {
           createProxy();
         }
         if (container == null) {
           XDOM.getBody().appendChild(proxyEl.dom);
         } else {
           container.el().appendChild(proxyEl.dom);
         }
         proxyEl.setVisibility(true);
         proxyEl.setZIndex(XDOM.getTopZIndex());
         proxyEl.makePositionable(true);
 
         if (sizeProxyToSource) {
           proxyEl.setBounds(startBounds);
         } else {
           proxyEl.setXY(startBounds.x, startBounds.y);
         }
 
         // did listeners change size?
         if (de.getHeight() > 0 && de.getWidth() > 0) {
           proxyEl.setSize(de.getWidth(), de.getHeight(), true);
         } else if (de.getHeight() > 0) {
           proxyEl.setHeight(de.getHeight(), true);
         } else if (de.getWidth() > 0) {
           proxyEl.setWidth(de.getWidth(), true);
         }
       } else if (updateZIndex) {
         dragWidget.setZIndex(XDOM.getTopZIndex());
       }
     } else {
       cancelDrag();
     }
   }
 
   protected void stopDrag(Event event) {
     preview.remove();
     if (dragging) {
       dragging = false;
       if (isUseProxy()) {
         if (isMoveAfterProxyDrag()) {
           Rectangle rect = proxyEl.getBounds();
           dragWidget.el().setPagePosition(rect.x, rect.y);
         }
         proxyEl.setVisibility(false);
         proxyEl.disableTextSelection(false);
         proxyEl.remove();
       }
       DragEvent de = new DragEvent(this);
       de.setComponent(dragWidget);
       de.setEvent(event);
       de.setX(lastX);
       de.setY(lastY);
       fireEvent(Events.DragEnd, de);
       afterDrag();
     }
   }
 
   private native boolean hasAttribute(Element elem, String name) /*-{
     return elem.hasAttribute ? elem.hasAttribute(name) : true;
   }-*/;
 
 }