/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache 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.apache.org/licenses/LICENSE-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.apache.myfaces.trinidad.model;
  
  import java.beans.IntrospectionException;
  
  import java.util.HashMap;
  import java.util.Map;
  
  import javax.faces.context.FacesContext;
  import javax.faces.el.PropertyResolver;
  
  import org.apache.myfaces.trinidad.logging.TrinidadLogger;
  
  
  /**
   * Creates a MenuModel from a TreeModel where nodes in the treeModel contain
   * viewId information.
   * <p>
   * Each node must have either a bean getter method or a Map property
   * that returns a viewId. There are several restrictions on the data:
   * <ul>
   * <li>The nodes in the tree must either be all beans or all maps,
   * but not a mix of beans and maps.
   * <li>The viewId of a node can be null, but if set it must be unique.
   * <li>The tree cannot be mutable.
   * </ul>
   * The getFocusPath method
   * <ul>
   * <li>gets the current viewId by calling
   * FacesContext.getCurrentInstance().getViewRoot().getViewId()
   * <li> compares the current viewId with the viewId's in
   * the nodes of the tree
   * <li>returns the path to the node with the current viewId or null if the current viewId can't be found
   * </ul>
   * <p>
   * Assuming that NavigationTree is a tree of beans with a vieId getter, an
   * example of creating a MenuModel with this class might look like:
   * <pre><code>
   *     CollectionModel collectionModel = ModelUtils.toCollectionModel(new NavigationTree());
   *     TreeModel treeModel = new ChildPropertyTreeModel(collectionModel, "children");
   *     MenuModel menuModel = new ViewIdPropertyMenuModel(treeModel, "viewId");
   * </code></pre>
   */
  // TODO - support for mutable trees?
  public class ViewIdPropertyMenuModel extends BaseMenuModel
  {
    /**
     * No-arg constructor for use with managed-beans.
     * Must call the {@link #setViewIdProperty} and
     * {@link #setWrappedData} methods after constructing this instance.
     */
    public ViewIdPropertyMenuModel()
    {
      super();
      _focusPathMap = new HashMap<Object, Object>();
    }
    /**
     *
     * @param instance a treeModel. This object will be passed to
     * {@link ModelUtils#toTreeModel}
     * @param viewIdProperty the property to use to retrieve a viewId
     * from a node in the tree
     * @throws IntrospectionException
     */
    public ViewIdPropertyMenuModel(Object instance, String viewIdProperty)
      throws IntrospectionException
    {
      super(instance);
      _focusPathMap = new HashMap<Object, Object>();
      setViewIdProperty(viewIdProperty);
      setWrappedData(instance);
    }
  
    @Override
    public void setWrappedData(Object data)
    {
      super.setWrappedData(data);
      Object oldPath = getRowKey();
  
      //set the focus path map
      _focusPathMap.clear();
      setRowKey(null);
     FacesContext context = FacesContext.getCurrentInstance();
     _addToMap(context, this, _focusPathMap, getViewIdProperty());
     setRowKey(oldPath);
   }
 
   /**
    * Returns the rowKey to the current viewId.
    * <p>
    *
    * The getFocusRowKey method
    * <ul>
    * <li>gets the current viewId by calling
    * FacesContext.getCurrentInstance().getViewRoot().getViewId()
    * <li> compares the current viewId with the viewId's in
    * the nodes of the tree
    * <li>returns the rowKey to the node with the current viewId or null
    * if the current viewId can't be found
    * </ul>
    *
    * @return  the rowKey to the node with the current viewId or null if the current viewId can't be found
    */
   @Override
   public Object getFocusRowKey()
   {
     String currentViewId = getCurrentViewId();
     Object focusPath = _focusPathMap.get(currentViewId);
     return focusPath;
   }
 
   /**
    * Maps the focusPath returned when the viewId is newViewId
    * to the focusPath returned when the viewId is aliasedViewId.
    * This allows view id's not in the treeModel to be mapped
    * to a focusPath.
    * @param newViewId the view id to add a focus path for
    * @param aliasedViewId the view id to use to get the focusPath to use for newViewId
    */
   public void addViewId(
     String newViewId,
     String aliasedViewId
   )
   {
     Object focusPath = _focusPathMap.get(aliasedViewId);
     if (focusPath != null)
     {
       _focusPathMap.put(newViewId, focusPath);
     }
   }
 
   /**
    * Gets the property to use to retrieve a viewId
    * from a node in the tree
    */
   public String getViewIdProperty()
   {
     return _viewIdProperty;
   }
 
   /**
    * Sets the property to use to retrieve a viewId
    * from a node in the tree
    */
   public void setViewIdProperty(String viewIdProperty)
   {
     _viewIdProperty = viewIdProperty;
   }
 
   /**
    * Returns the current viewId.
    * <p>
    *
    *
    * @return  the current viewId or null if the current viewId can't be found
    */
 
   protected String getCurrentViewId()
   {
     String currentViewId =
                    FacesContext.getCurrentInstance().getViewRoot().getViewId();
 
     return currentViewId;
   }
 
 
   private static void _addToMap(
     FacesContext context,
     TreeModel tree,
     Map<Object, Object> focusPathMap,
     String viewIdProperty
     )
   {
     for ( int i = 0; i < tree.getRowCount(); i++)
     {
       tree.setRowIndex(i);
       if (viewIdProperty != null)
       {
         Object focusPath = tree.getRowKey();
         Object data = tree.getRowData();
         PropertyResolver resolver =
           context.getApplication().getPropertyResolver();
         Object viewIdObject = resolver.getValue(data, viewIdProperty);
         focusPathMap.put(viewIdObject, focusPath);
       }
       else
       {
         _LOG.warning("NULL_VIEWID");
       }
 
       if (tree.isContainer() && !tree.isContainerEmpty())
       {
         tree.enterContainer();
         _addToMap(context, tree, focusPathMap, viewIdProperty);
         tree.exitContainer();
       }
 
     }
   }
 
 
   private final Map<Object, Object> _focusPathMap;
   private String _viewIdProperty = null;
 
 
 
   static private final TrinidadLogger _LOG = TrinidadLogger.createTrinidadLogger(ViewIdPropertyMenuModel.class);
 }