/**
    * This file Copyright (c) 2010-2015 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.ui.vaadin.gwt.client.layout.thumbnaillayout.widget;
  
  import info.magnolia.ui.vaadin.gwt.client.layout.CssRule;
  import info.magnolia.ui.vaadin.gwt.client.layout.thumbnaillayout.connector.LazyThumbnailLayoutConnector.ThumbnailService;
  import info.magnolia.ui.vaadin.gwt.client.layout.thumbnaillayout.shared.ThumbnailData;
  import info.magnolia.ui.vaadin.gwt.client.pinch.MagnoliaPinchMoveEvent;
  import info.magnolia.ui.vaadin.gwt.client.pinch.MagnoliaPinchRecognizer;
  
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  import com.google.gwt.dom.client.Style.Position;
  import com.google.gwt.dom.client.Style.Unit;
  import com.google.gwt.event.dom.client.ScrollEvent;
  import com.google.gwt.event.dom.client.ScrollHandler;
  import com.google.gwt.event.logical.shared.ValueChangeEvent;
  import com.google.gwt.event.logical.shared.ValueChangeHandler;
  import com.google.gwt.user.client.DOM;
  import com.google.gwt.user.client.Event;
  import com.google.gwt.user.client.Timer;
  import com.google.gwt.user.client.ui.FlowPanel;
  import com.google.gwt.user.client.ui.ScrollPanel;
  import com.googlecode.mgwt.dom.client.recognizer.pinch.UIObjectToOffsetProvider;
  import com.googlecode.mgwt.dom.client.recognizer.tap.MultiTapRecognizer;
  import com.googlecode.mgwt.ui.client.widget.touch.TouchDelegate;
  import com.vaadin.client.ComputedStyle;
  import com.vaadin.client.ServerConnector;
  
  /**
   * Client side impl of lazy asset thumbnails layout.
   */
  public class LazyThumbnailLayoutWidget extends FlowPanel {
  
      private static final int QUERY_TIMER_DELAY = 250;
  
      private static final int MIN_WIDTH = 50;
  
      private static final int MAX_WIDTH = 230;
  
      private int thumbnailWidth = 0;
  
      private int thumbnailHeight = 0;
  
      private int thumbnailAmount = 0;
  
      private ThumbnailWidget selectedThumbnail = null;
  
      private final List<ThumbnailWidget> thumbnails = new ArrayList<ThumbnailWidget>();
  
      private final List<ThumbnailWidget> thumbnailStubs = new ArrayList<ThumbnailWidget>();
  
      private final ScrollPanel scroller = new ScrollPanel();
  
      private final Slider thumbnailSizeSlider = new Slider();
  
      private final CssRule thumbnailImageStyle = CssRule.create(".thumbnail-image");
  
      private final CssRule thumbnailStyle = CssRule.create(".thumbnail");
  
      private final FlowPanel imageContainer = new FlowPanel();
  
      private ThumbnailService thumbnailService;
  
     public LazyThumbnailLayoutWidget() {
 
         addStyleName("thumbnail-layout");
 
         thumbnailStyle.setProperty("margin", "3px");
 
         scroller.setWidget(imageContainer);
         scroller.addStyleName("thumbnail-scroller");
         scroller.getElement().getStyle().setPosition(Position.ABSOLUTE);
 
         add(thumbnailSizeSlider);
         add(scroller);
 
         bindHandlers();
         reset();
     }
 
     protected void bindHandlers() {
 
         scroller.addScrollHandler(new ScrollHandler() {
             @Override
             public void onScroll(ScrollEvent event) {
                 createStubsAndQueryThumbnails();
             }
         });
 
         final TouchDelegate touchDelegate = new TouchDelegate(this);
         touchDelegate.addTouchHandler(new MagnoliaPinchRecognizer(touchDelegate, new UIObjectToOffsetProvider(scroller)));
         MultiTapRecognizer multitapRecognizer = new MultiTapRecognizer(touchDelegate, 1, 2);
         touchDelegate.addTouchHandler(multitapRecognizer);
 
         addHandler(new MagnoliaPinchMoveEvent.Handler() {
             @Override
             public void onPinchMove(MagnoliaPinchMoveEvent event) {
                 double scaleFactor = 1 / event.getScaleFactor();
                 int width = Math.max((int) (ComputedStyle.parseInt(thumbnailStyle.getProperty("width")) * scaleFactor), 25);
                 int height = Math.max((int) (ComputedStyle.parseInt(thumbnailStyle.getProperty("height")) * scaleFactor), 25);
                 scroller.setVerticalScrollPosition((int) (scroller.getVerticalScrollPosition() * scaleFactor));
                 setThumbnailSize(width, height);
 
             }
         }, MagnoliaPinchMoveEvent.TYPE);
 
         thumbnailSizeSlider.addValueChangeHandler(new ValueChangeHandler<Integer>() {
             @Override
             public void onValueChange(ValueChangeEvent<Integer> event) {
 
                 double scaleFactor = (double) event.getValue() / 100.0;
                 int widthRequest = (int) (MIN_WIDTH + (MAX_WIDTH - MIN_WIDTH) * scaleFactor);
                 int width = Math.max(widthRequest, 10);
                 setThumbnailSize(width, width);
             }
         });
 
         DOM.sinkEvents(getElement(), Event.MOUSEEVENTS | Event.ONSCROLL);
     }
 
     private void createStubsAndQueryThumbnails() {
         int thumbnailsNeeded = calculateThumbnailsNeeded();
         addStubs(thumbnailsNeeded);
         queryTimer.schedule(QUERY_TIMER_DELAY);
     }
 
     private void addStubs(int thumbnailsNeeded) {
         for (int i = 0; i < thumbnailsNeeded; ++i) {
             addStub();
         }
     }
 
     private void addStub() {
         final ThumbnailWidget thumbnailStub = new ThumbnailWidget();
         thumbnailStubs.add(thumbnailStub);
         imageContainer.add(thumbnailStub);
     }
 
     public void setThumbnailSize(int width, int height) {
         Logger.getLogger(getClass().getName()).log(Level.INFO, "Thumbnails: setThumbnailSize: " + width + " h:" + height);
         if (this.thumbnailHeight != height || this.thumbnailWidth != width) {
             this.thumbnailHeight = height;
             this.thumbnailWidth = width;
 
             // Scale the thumbnail divs.
             thumbnailStyle.setProperty("width", width + "px");
             thumbnailStyle.setProperty("height", width + "px");
             String fontSize = String.valueOf((int) (width * 0.75));
             thumbnailStyle.setProperty("fontSize", fontSize + "px");
 
             // Scale the size of the image in the thumbnails.
             thumbnailImageStyle.setProperty("maxWidth", width + "px");
             thumbnailImageStyle.setProperty("maxHeight", width + "px");
 
             createStubsAndQueryThumbnails();
         }
     }
 
     private final Timer queryTimer = new Timer() {
         @Override
         public void run() {
             doQueryThumbnails(thumbnailStubs.size());
         }
 
         ;
     };
 
     public void addImages(List<ThumbnailData> thumbnailsData, ServerConnector connector) {
         final Iterator<ThumbnailData> it = thumbnailsData.iterator();
         while (it.hasNext() && !thumbnailStubs.isEmpty()) {
             final ThumbnailWidget thumbnail = thumbnailStubs.remove(0);
             thumbnail.setData(it.next(), connector);
             thumbnails.add(thumbnail);
         }
     }
 
     public void setThumbnailAmount(int thumbnailAmount) {
         if (this.thumbnailAmount != thumbnailAmount) {
             this.thumbnailAmount = thumbnailAmount;
             int width = getOffsetWidth();
             int totalThumbnailWidth = (thumbnailWidth + getHorizontalMargin());
             if (totalThumbnailWidth != 0) {
                 int thumbnailsInRow = (int) (width / totalThumbnailWidth * 1d);
                 if (thumbnailsInRow != 0) {
                     int pixelHeight = (int) Math.ceil(thumbnailAmount / thumbnailsInRow * 1d) * (thumbnailHeight + getVerticalMargin());
                     imageContainer.getElement().getStyle().setHeight(pixelHeight, Unit.PX);
                     createStubsAndQueryThumbnails();
                 }
             }
         }
     }
 
     private void doQueryThumbnails(int amount) {
         if (amount > 0) {
             thumbnailService.loadThumbnails(amount);
         }
     }
 
     public void reset() {
         thumbnails.clear();
         thumbnailStubs.clear();
         imageContainer.clear();
         selectedThumbnail = null;
         thumbnailAmount = 0;
         int thumbnailsNeeded = calculateThumbnailsNeeded();
         addStubs(thumbnailsNeeded);
         doQueryThumbnails(thumbnailsNeeded);
     }
 
     private int calculateThumbnailsNeeded() {
         int totalHeight = scroller.getVerticalScrollPosition() + getOffsetHeight();
         int width = getOffsetWidth();
         int thumbnailsInRow = (int) (width / (thumbnailWidth + getHorizontalMargin()) * 1d);
         int rows = (int) Math.ceil(1d * totalHeight / (thumbnailHeight + getVerticalMargin()));
         int totalThumbnailsPossible = Math.min(thumbnailAmount, thumbnailsInRow * rows);
         return Math.max(totalThumbnailsPossible - thumbnailStubs.size() - thumbnails.size(), 0);
     }
 
     public void generateStubs() {
         addStubs(calculateThumbnailsNeeded());
         queryTimer.schedule(QUERY_TIMER_DELAY);
     }
 
     private int getHorizontalMargin() {
         return ComputedStyle.parseInt(thumbnailStyle.getProperty("marginTop")) * 2;
     }
 
     private int getVerticalMargin() {
         return ComputedStyle.parseInt(thumbnailStyle.getProperty("marginLeft")) * 2;
     }
 
     public void setSelectedThumbnail(String thumbnailId) {
         if (thumbnailId != null) {
             for (ThumbnailWidget thumbnail : thumbnails) {
                 if (thumbnail.getId().equals(thumbnailId)) {
                     setSelectedThumbnail(thumbnail);
                     return;
                 }
             }
         }
         // Either we we're passed null or there was no thumbnail with this id, so we make nothing selected
         setSelectedThumbnail((ThumbnailWidget)null);
     }
 
     public void setSelectedThumbnail(ThumbnailWidget thumbnail) {
         if (selectedThumbnail != null) {
             selectedThumbnail.setSelected(false);
         }
         if (thumbnail != null) {
             thumbnail.setSelected(true);
         }
         selectedThumbnail = thumbnail;
     }
 
     @Override
     public void clear() {
         thumbnailStubs.addAll(thumbnails);
         thumbnails.clear();
     }
 
     public void setThumbnailService(ThumbnailService thumbnailService) {
         this.thumbnailService = thumbnailService;
     }
 }