/**

  * 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;

 import java.util.Arrays;

 import java.util.List;

 import com.google.gwt.dom.client.Element;

 import com.google.gwt.dom.client.NativeEvent;

 import com.google.gwt.dom.client.NodeList;

 import com.google.gwt.dom.client.Style.Overflow;

 import com.google.gwt.dom.client.Style.Unit;

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

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

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

 import com.google.gwt.event.logical.shared.ResizeEvent;

 import com.google.gwt.event.logical.shared.ResizeHandler;

 import com.google.gwt.event.shared.HandlerRegistration;

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

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

 import com.google.gwt.user.client.Event.NativePreviewEvent;

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

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

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

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

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

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

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

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

 /**

  * A KSLightBox is a dialog box that lays out its contents as follows using a

  * {@link DockLayoutPanel}:<br/>

  * <br />

  * ------------------<br/>

  * HEADER (either static caption / header widget that is not part of the scrollable area)<br/>

  * ------------------<br/>

  * CONTENT (part of the scrollable area that will fill available space)<br/>

  * ------------------<br/>

  * BUTTONS (static button area that is not part of the scrollable area)<br/>

  * ------------------<br/>

  * <br/>

  * 

  * The size of the dock panel will determine the size of the lightbox. Thus only the dock

  * panel size will need to be set.<br/>

  * The size of the dock panel is usually determined dynamically when the lightbox is

  * displayed, but you can also statically set it with one of the 'setSize' methods.<br/>

  * If you however set the size statically, the lightbox won't resize.<br/>

  * If you're making use of the <b>static sizes, the non-caption header and displaying the

  * buttons</b>, don't set the height of the dialog smaller than about 155px. Otherwise

  * there's too little space left for the content and the content (even if its just one line 

  * of text) will be displayed in a scroll panel.

  * 

  */

 public class KSLightBox extends DialogBox {

     private static final List<String> FOCUSABLE_TAGS = Arrays.asList("INPUT", "SELECT", "BUTTON", "TEXTAREA");

     /**

      * An enum that specifies predefined width and height values (in pixels) for the

      * lightbox.

      */

     public enum Size {

         SMALL(400, 155), MEDIUM(550, 340), LARGE(600, 400);

         private int width;

         private int height;

         Size(int width, int height) {

             this.width = width;

             this.height = height;

         }

         public int getWidth() {

             return width;

         }

         public int getHeight() {

             return height;

         }

     }

     private enum LightBoxStyle {

         LIGHT_BOX {

             public String toString() {

                 return "ks-lightbox";

             }

         },

         MAIN_PANEL {

             public String toString() {

                 return "ks-lightbox-mainPanel";

             }

         },

         TITLE_PANEL {

             public String toString() {

                 return "ks-lightbox-titlePanel";

             }

         },

         SCROLL_PANEL {

             public String toString() {

                 return "ks-lightbox-scrollPanel";

             }

         },

         BUTTON_PANEL {

             public String toString() {

                 return "ks-lightbox-buttonPanel";

             }

         },

         CLOSE_LINK {

             public String toString() {

                 return "ks-lightbox-closeLink";

             }

         },

         CLOSE_LINK_WITH_CAPTION {

             public String toString() {

                 return "ks-lightbox-closeLink-with-Caption";

             }

         }

     }

     //Resizing variables

     private int maxWidth = 800;

     private int maxHeight = 0;

     private int minWidth = 400;

     private int minHeight = 200;

     private int permWidth = -1;

     private int permHeight = -1;

     //DockLayoutPanel sizes

     private static final int BUTTON_HEIGHT = 40;//'px' units (specified in mainPanel's constructor)

     private static final int NON_CAPTION_HEIGHT = 40;//'px' units (specified in mainPanel's constructor)

     private DockLayoutPanel mainPanel = new DockLayoutPanel(Unit.PX);

     private FlowPanel closeLinkPanel = new FlowPanel();

     private SimplePanel titlePanel = new SimplePanel();

     private ScrollPanel scrollPanel = new ScrollPanel();

     private SimplePanel contentPanel = new SimplePanel();

     private FlowPanel buttonPanel = new FlowPanel();

     private Anchor closeLink = new Anchor();

     private KSDialogResizeHandler resizeHandler = new KSDialogResizeHandler();

     private HandlerRegistration resizeHandlerRegistrater;

     public KSLightBox() {

         getCaption().asWidget().setVisible(false);

         init();

     }

     public KSLightBox(boolean addCloseLink) {

         getCaption().asWidget().setVisible(false);

         init();

         closeLink.setVisible(addCloseLink);

     }

     public KSLightBox(String title) {

         init();

         setText(title);

     }

     public KSLightBox(String title, Size size) {

         init();

         setText(title);

         setSize(size);

     }

     private void init() {

         mainPanel.setStyleName(LightBoxStyle.MAIN_PANEL.toString());

         titlePanel.setStyleName(LightBoxStyle.TITLE_PANEL.toString());

         closeLink.setStyleName(LightBoxStyle.CLOSE_LINK.toString());

         scrollPanel.setStyleName(LightBoxStyle.SCROLL_PANEL.toString());

         buttonPanel.setStyleName(LightBoxStyle.BUTTON_PANEL.toString());

         setGlassEnabled(true);

         super.setWidget(mainPanel);

         mainPanel.addNorth(closeLinkPanel, 1);

         mainPanel.addNorth(titlePanel, 0);

         mainPanel.addSouth(buttonPanel, BUTTON_HEIGHT);

         mainPanel.add(scrollPanel);

         closeLinkPanel.add(closeLink);

         //parent element sets overflow to hidden, must reset overflow to visible to show the 'closeLink'

         Element titlePanelContainer = mainPanel.getWidgetContainerElement(closeLinkPanel);

         titlePanelContainer.getStyle().setOverflow(Overflow.VISIBLE);

         scrollPanel.add(contentPanel);

         installResizeHandler();

         //super.

         closeLink.addClickHandler(new ClickHandler() {

             @Override

             public void onClick(ClickEvent event) {

                 hide();

             }

         });

         super.setStyleName(LightBoxStyle.LIGHT_BOX.toString());

     }

     public void setCloseLinkVisible(boolean visible) {

         closeLink.setVisible(visible);

     }

     public void removeCloseLink() {

         closeLink.setVisible(false);

     }

     public HandlerRegistration addCloseLinkClickHandler(ClickHandler clickHandler) {

         return closeLink.addClickHandler(clickHandler);

     }

     /**

      * Sets the header that will be displayed at the top of the lightbox.<br/>

      * Please note: This header will not be displayed in the caption, but in the actual

      * lightbox content area.

      * @param widget The header widget.

      */

     public void setNonCaptionHeader(Widget widget) {

         titlePanel.setWidget(widget);

         mainPanel.setWidgetSize(titlePanel, NON_CAPTION_HEIGHT);

         mainPanel.forceLayout();

     }

     @Override

     public void setText(String text) {

         super.setText(text);

         getCaption().asWidget().setVisible(true);

         //Style needed to reposition the 'closeLink'

         closeLink.addStyleName(LightBoxStyle.CLOSE_LINK_WITH_CAPTION.toString());

     }

     /**

      * Removes all the buttons at the bottom of the lightbox.

      */

     public void clearButtons() {

         buttonPanel.clear();

     }

     /**

      * Adds a button to the bottom of the lightbox.

      */

     public void addButton(Widget button) {

         button.addStyleName("ks-button-spacing");

         buttonPanel.add(button);

     }

     /**

      * Adds a {@link org.kuali.student.common.ui.client.widgets.field.layout.button.ButtonGroup} to the button panel at the bottom of the lightbox. 

      * @param group

      */

     @SuppressWarnings("rawtypes")

     public void addButtonGroup(org.kuali.student.common.ui.client.widgets.field.layout.button.ButtonGroup group) {

         buttonPanel.add(group);

     }

     /**

      * Adds a {@link org.kuali.student.common.ui.client.widgets.buttongroups.ButtonGroup} to the button panel at the bottom of the lightbox.

      * @param group

      */

     @SuppressWarnings("rawtypes")

     public void addButtonGroup(org.kuali.student.common.ui.client.widgets.buttongroups.ButtonGroup group) {

         buttonPanel.add(group);

     }

     public void showButtons(boolean show) {

         buttonPanel.setVisible(show);

         if (show) {

             mainPanel.setWidgetSize(buttonPanel, BUTTON_HEIGHT);

         } else {

             mainPanel.setWidgetSize(buttonPanel, 0);

         }

         mainPanel.forceLayout();

     }

     /**

      * Set the maximum width in pixels that this dialog will grow to.<br />

      * Please note: If the lightbox's size was set explicitly, this call will have no

      * effect.

      * 

      * @param width The dialog's maximum width in pixels.

      */

     public void setMaxWidth(int width) {

         this.maxWidth = width;

     }

     /**

      * Set the maximum height in pixels that this dialog will grow to.<br />

      * Please note: If the lightbox's size was set explicitly, this call will have no

      * effect.

      * 

      * @param height The dialog's maximum height in pixels.

      */

     public void setMaxHeight(int height) {

         this.maxHeight = height;

     }

     /**

      * Set the width and height of the lightbox in pixels.<br/>

      * Please note: These values will not be affected by resizing. Thus the lightbox will

      * remain the specified size, irrespective of resizing.

      * 

      * @param width The specified width in pixels.

      * @param height The specified height in pixels.

      */

     public void setSize(int width, int height) {

         mainPanel.setSize(width + "px", width + "px");

         this.permHeight = height;

         this.permWidth = width;

     }

     /**

      * Set the width and height of the lightbox in pixels using the {@link Size} enum.

      * 

      * @param size A predefined dialog size.

      */

     public void setSize(Size size) {

         setSize(size.getWidth(), size.getHeight());

     }

     @Override

     public void setWidget(Widget content) {

         contentPanel.setWidget(content);

     }

     @Override

     public Widget getWidget() {

         return contentPanel.getWidget();

     }

     @Override

     public void hide() {

         super.hide();

         uninstallResizeHandler();

     }

     @Override

     public void show() {

         resizeDialog();

         installResizeHandler();

         super.show();

         super.center();

         grabFocus();

     }

     private void resizeDialog() {

         int width = maxWidth;

         int height = maxHeight;

         //Width calculation

         if (permWidth != -1) {

             width = permWidth;

         } else {

             if (Window.getClientWidth() < 850) {

                 width = Window.getClientWidth() - 160;

             }

             if (width > maxWidth) {

                 width = maxWidth;

             }

             if (width < minWidth) {

                 width = minWidth;

             }

         }

         //Height calculation

         if (permHeight != -1) {

             height = permHeight;

         } else {

             height = Window.getClientHeight() - 160;

             if (height > maxHeight && maxHeight != 0) {

                 height = maxHeight;

             }

             if (height < minHeight) {

                 height = minHeight;

             }

         }

         if (width > 0 && height > 0) {

             mainPanel.setSize(width + "px", height + "px");

         }

     }

     private void grabFocus() {

         Widget mainContent = contentPanel.getWidget();

         NodeList<Element> nodeList = mainContent.getElement().getElementsByTagName("*");

         for (int i = 0; i < nodeList.getLength(); i++) {

             Element e = nodeList.getItem(i);

             if (FOCUSABLE_TAGS.contains(e.getTagName().toUpperCase())) {

                 e.focus();

                 return;

             }

         }

     }

     @Override

     protected void onPreviewNativeEvent(NativePreviewEvent preview) {

         super.onPreviewNativeEvent(preview);

         NativeEvent evt = preview.getNativeEvent();

         if (evt.getType().equals("keydown")) {

             switch (evt.getKeyCode()) {

                 case KeyCodes.KEY_ESCAPE:

                     hide();

                     break;

             }

         }

     }

     public void uninstallResizeHandler() {

         if (resizeHandlerRegistrater != null) {

             resizeHandlerRegistrater.removeHandler();

             resizeHandlerRegistrater = null;

         }

     }

     public void installResizeHandler() {

         if (resizeHandlerRegistrater == null) {

             resizeHandlerRegistrater = Window.addResizeHandler(resizeHandler);

         }

     }

     class KSDialogResizeHandler implements ResizeHandler {

         @SuppressWarnings("deprecation")

         @Override

         public void onResize(ResizeEvent event) {

             DeferredCommand.addCommand(new Command() {

                 @Override

                 public void execute() {

                     resizeDialog();

                     int left = (Window.getClientWidth() - getOffsetWidth()) >> 1;

                     int top = (Window.getClientHeight() - getOffsetHeight()) >> 1;

                     setPopupPosition(Math.max(Window.getScrollLeft() + left, 0), Math.max(

                             Window.getScrollTop() + top, 0));

                 }

             });

         }

     }

 }