/**

  * Copyright 2010 The Kuali Foundation Licensed under the

  * Educational Community License, Version 2.0 (the "License"); you may

  * not use this file except in compliance with the License. You may

  * obtain a copy of the License at

  *

  * http://www.osedu.org/licenses/ECL-2.0

  *

  * Unless required by applicable law or agreed to in writing,

  * software distributed under the License is distributed on an "AS IS"

  * BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express

  * or implied. See the License for the specific language governing

  * permissions and limitations under the License.

  */

 package org.kuali.student.common.ui.client.widgets.search;

 import org.kuali.student.common.ui.client.theme.Theme;

 import org.kuali.student.common.ui.client.widgets.KSButton;

 import org.kuali.student.common.ui.client.widgets.KSButtonAbstract.ButtonStyle;

 import org.kuali.student.common.ui.client.widgets.layout.HorizontalBlockFlowPanel;

 import org.kuali.student.common.ui.client.widgets.layout.VerticalFlowPanel;

 import com.google.gwt.animation.client.Animation;

 import com.google.gwt.event.dom.client.ClickEvent;

 import com.google.gwt.event.dom.client.ClickHandler;

 import com.google.gwt.user.client.DOM;

 import com.google.gwt.user.client.ui.Composite;

 import com.google.gwt.user.client.ui.DisclosurePanel;

 import com.google.gwt.user.client.ui.Image;

 import com.google.gwt.user.client.ui.SimplePanel;

 import com.google.gwt.user.client.ui.Widget;

 public class CollapsablePanel extends Composite {

         protected KSButton label;

         protected VerticalFlowPanel layout = new VerticalFlowPanel();

         protected HorizontalBlockFlowPanel linkPanel = new HorizontalBlockFlowPanel();

         protected SimplePanel content = new SimplePanel();

         protected ContentAnimation animation = new ContentAnimation();

         protected boolean isOpen = false;

         protected boolean withImages = true;

         protected ImagePosition imagePosition = ImagePosition.ALIGN_LEFT;

         public enum ImagePosition {

                 ALIGN_LEFT, ALIGN_RIGHT

         }

         protected Image closedImage = Theme.INSTANCE.getCommonImages().getDisclosureClosedIcon();

         protected Image openedImage = Theme.INSTANCE.getCommonImages().getDisclosureOpenedIcon();

         private ClickHandler openCloseClickHandler = new ClickHandler() {

                 @Override

                 public void onClick(ClickEvent event) {

                         if (CollapsablePanel.this.isOpen) {

                                 CollapsablePanel.this.close();

                         } else {

                                 CollapsablePanel.this.open();

                         }

                 }

         };

         private static class ContentAnimation extends Animation {

                 /**

                  * Whether the item is being opened or closed.

                  */

                 private boolean opening;

                 /**

                  * The {@link DisclosurePanel} being affected.

                  */

                 private CollapsablePanel curPanel;

                 /**

                  * Open or close the content.

                  * 

                  * @param panel

                  *            the panel to open or close

                  * @param animate

                  *            true to animate, false to open instantly

                  */

                 public void setOpen(CollapsablePanel panel, boolean animate) {

                         // Immediately complete previous open

                         cancel();

                         // Open the new item

                         if (animate) {

                                 curPanel = panel;

                                 opening = panel.isOpen;

                                 run(1000);

                         } else {

                                 panel.content.setVisible(panel.isOpen);

                                 if (panel.isOpen) {

                                         // Special treatment on the visible case to ensure LazyPanel

                                         // works

                                         panel.content.setVisible(true);

                                 }

                         }

                 }

                 @Override

                 protected void onComplete() {

                         if (!opening) {

                                 curPanel.content.setVisible(false);

                         }

                         DOM.setStyleAttribute(curPanel.content.getElement(), "height", "auto");

                         DOM.setStyleAttribute(curPanel.content.getElement(), "overflow", "visible");

                         curPanel = null;

                 }

                 @Override

                 protected void onStart() {

                         super.onStart();

                         DOM.setStyleAttribute(curPanel.content.getElement(), "overflow", "hidden");

                         if (opening) {

                                 curPanel.content.setVisible(true);

                                 // Special treatment on the visible case to ensure LazyPanel works

                                 curPanel.content.setVisible(true);

                         }

                 }

                 @Override

                 protected void onUpdate(double progress) {

                         int scrollHeight = DOM.getElementPropertyInt(curPanel.content.getElement(), "scrollHeight");

                         int height = (int) (progress * scrollHeight);

                         if (!opening) {

                                 height = scrollHeight - height;

                         }

                         height = Math.max(height, 1);

                         DOM.setStyleAttribute(curPanel.content.getElement(), "height", height + "px");

                         DOM.setStyleAttribute(curPanel.content.getElement(), "width", "auto");

                 }

         }

         protected CollapsablePanel(){                

         }

         public CollapsablePanel(String label, Widget content, boolean isOpen) {

                 init(getButtonLabel(label), content, isOpen, true, ImagePosition.ALIGN_RIGHT);

         }

         public CollapsablePanel(String label, Widget content, boolean isOpen, boolean withImages) {

                 init(getButtonLabel(label), content, isOpen, withImages, ImagePosition.ALIGN_RIGHT);

         }

         public CollapsablePanel(String label, Widget content, boolean isOpen, boolean withImages, ImagePosition imagePosition) {

                 init(getButtonLabel(label), content, isOpen, withImages, imagePosition);

         }

         public CollapsablePanel(Widget label, Widget content, boolean isOpen, boolean withImages, ImagePosition imagePosition) {

                 init(label, content, isOpen, withImages, imagePosition);

         }

         protected void init(Widget label, Widget content, boolean isOpen, boolean withImages, ImagePosition imagePosition) {

                 this.isOpen = isOpen;

                 this.withImages = withImages;

                 this.imagePosition = imagePosition;                

                 this.content.setWidget(content);

                 if (this.imagePosition == ImagePosition.ALIGN_RIGHT){

                         linkPanel.add(label);

                 }

                 if (this.withImages){

                         linkPanel.add(closedImage);

                         linkPanel.add(openedImage);

                         setImageState();

                 }

                 if (this.imagePosition == ImagePosition.ALIGN_LEFT){

                         linkPanel.add(label);

                 }

                 if (!isOpen) {

                         this.content.setVisible(false);

                 }

                 closedImage.addClickHandler(openCloseClickHandler);

                 openedImage.addClickHandler(openCloseClickHandler);

                 layout.add(linkPanel);

                 layout.add(this.content);

                 closedImage.addStyleName("ks-image-middle-alignment");

                 openedImage.addStyleName("ks-image-middle-alignment");

                 content.addStyleName("top-padding");

                 this.initWidget(layout);

         }

         protected KSButton getButtonLabel(String labelString){

                 label = new KSButton(labelString, ButtonStyle.DEFAULT_ANCHOR);                                

                 label.addClickHandler(openCloseClickHandler);                

                 return label;

         }

         /**

          * If the widget was initialized with a string label, it will return a KSButton.

          * If the widget was initialized with a label widget, it will return the label widget.

          * @return

          */

         public KSButton getLabel() {

                 return label;

         }

         public Widget getLabelWidget() {

                 return label;

         }

         public boolean isOpen() {

                 return isOpen;

         }

         public void open() {

                 isOpen = true;

                 if (withImages) {

                         setImageState();

                 }

                 animation.setOpen(this, true);

         }

         public void close() {

                 isOpen = false;

                 if (withImages) {

                         setImageState();

                 }

                 animation.setOpen(this, true);

         }

         /**

          * Update the image state to display opened/closed image based in isOpen() status

          */

         protected void setImageState(){

                 closedImage.setVisible(!isOpen);

                 openedImage.setVisible(isOpen);                                                

         }

 }