/**

  * 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 java.util.ArrayList;

 import java.util.List;

 import org.kuali.student.common.ui.client.reporting.ReportExportWidget;

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

 import org.kuali.student.common.ui.client.util.ExportElement;

 import org.kuali.student.common.ui.client.util.ExportUtils;

 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.field.layout.element.SpanPanel;

 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 implements ReportExportWidget {

     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);

     }

     @Override

     public boolean isExportElement() {

         return true;

     }

     @Override

     public List<ExportElement> getExportElementSubset(ExportElement parent) {

         return ExportUtils.getDetailsForWidget(this.content.getWidget(), parent.getViewName(), parent.getSectionName());

     }

     @Override

     public String getExportFieldValue() {

         String text = null;

         for (int i = 0; i < this.linkPanel.getWidgetCount(); i++) {

             Widget child = this.linkPanel.getWidget(i);

             if (child instanceof SpanPanel) {

                 SpanPanel header = (SpanPanel) child;

                 text = header.getText();

             }

         }

         return text;

     }

 }