/*
    * Copyright 2005 The Apache Software Foundation.
    *
    * Licensed 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.util;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.Iterator;
  import java.util.Map;
  import java.util.NoSuchElementException;
  
  import javax.faces.component.UIComponent;
  import javax.faces.component.UISelectItem;
  import javax.faces.component.UISelectItems;
  import javax.faces.el.ValueBinding;
  import javax.faces.model.SelectItem;
  
  import org.apache.myfaces.renderkit.RendererUtils;
  
  /***
   * @author Mathias Broekelmann (latest modification by $Author$)
   * @version $Revision$ $Date$
   */
  public class SelectItemsIterator implements Iterator
  {
      private final Iterator _childs;
      private Iterator _nestedItems;
      private Object _nextItem;
      private String _collectionLabel;
      private UISelectItems _currentUISelectItems;
  
      public SelectItemsIterator(UIComponent selectItemsParent)
      {
          _childs = selectItemsParent.getChildren().iterator();
      }
  
      public boolean hasNext()
      {
          if(_nextItem != null)
          {
              return true;
          }
          if(_nestedItems != null)
          {
              if(_nestedItems.hasNext())
              {
                  return true;
              }
              _nestedItems = null;
          }            
          if (_childs.hasNext())
          {
              UIComponent child = (UIComponent) _childs.next();
              if (child instanceof UISelectItem)
              {
                  UISelectItem uiSelectItem = (UISelectItem) child;
                  Object item = uiSelectItem.getValue();
                  if (item == null)
                  {
                      Object itemValue = ((UISelectItem) child).getItemValue();
                      String label = ((UISelectItem) child).getItemLabel();
                      String description = ((UISelectItem) child)
                                      .getItemDescription();
                      boolean disabled = ((UISelectItem) child).isItemDisabled();
                      if (label == null)
                      {
                          label = itemValue.toString();
                      }
                      item = new SelectItem(itemValue, label, description,
                                      disabled);
                  }
                  else if (!(item instanceof SelectItem))
                  {
                      ValueBinding binding = ((UISelectItem) child)
                                      .getValueBinding("value");
                      throw new IllegalArgumentException(
                                      "Value binding '"
                                      + (binding == null ? null : binding.getExpressionString())
                                      + "' of UISelectItem : "
                                      + RendererUtils.getPathToComponent(child)
                                      + " does not reference an Object of type SelectItem");
                  }
                  _nextItem = item;
                  return true;
              }
              else if (child instanceof UISelectItems)
             {
                 _currentUISelectItems = ((UISelectItems) child);
                 Object value = _currentUISelectItems.getValue();
 
                 if (value instanceof SelectItem)
                 {
                     _nextItem = value;
                     return true;
                 }
                 else if (value instanceof SelectItem[])
                 {
                     _nestedItems = Arrays.asList((SelectItem[]) value)
                                     .iterator();
                     _collectionLabel = "Array";
                     return hasNext();
                 }
                 else if (value instanceof Collection)
                 {
                     _nestedItems = ((Collection)value).iterator();
                     _collectionLabel = "Collection";
                     return hasNext();
                 }
                 else if (value instanceof Map)
                 {
                     Map map = ((Map) value);
                     Collection items = new ArrayList(map.size()); 
                     for (Iterator it = map.entrySet().iterator(); it
                                     .hasNext();)
                     {
                         Map.Entry entry = (Map.Entry) it.next();
                         items.add(new SelectItem(entry.getValue(), entry
                                         .getKey().toString()));
                     }
                     _nestedItems = items.iterator();
                     _collectionLabel = "Map";
                     return hasNext();
                 }
                 else
                 {
                     ValueBinding binding = _currentUISelectItems.getValueBinding("value");
 
                     throw new IllegalArgumentException(
                         "Value binding '"
                         + (binding == null ? null : binding
                                         .getExpressionString())
                         + "'of UISelectItems with component-path "
                         + RendererUtils.getPathToComponent(child)
                         + " does not reference an Object of type SelectItem, SelectItem[], Collection or Map but of type : "
                         + ((value == null) ? null : value
                                         .getClass()
                                         .getName()));
                 }
             }
             else
             {
                 //todo: may other objects than selectItems be nested or not?
                 //log.error("Invalid component : " + getPathToComponent(child) + " : must be UISelectItem or UISelectItems, is of type : "+((child==null)?"null":child.getClass().getName()));
             }
         }
         return false;
     }
 
     public Object next()
     {
         if (!hasNext())
         {
             throw new NoSuchElementException();
         }
         if(_nextItem != null)
         {
             Object value = _nextItem;
             _nextItem = null;
             return value;
         }        
         if (_nestedItems != null)
         {
             Object item = _nestedItems.next();
             if (!(item instanceof SelectItem))
             {
                 ValueBinding binding = _currentUISelectItems
                                 .getValueBinding("value");
                 throw new IllegalArgumentException(
                 _collectionLabel + " referenced by UISelectItems with binding '"
                 + binding.getExpressionString()
                 + "' and Component-Path : " + RendererUtils.getPathToComponent(_currentUISelectItems)
                 + " does not contain Objects of type SelectItem");
             }
             return item;
         }
         throw new NoSuchElementException();
     }
 
     public void remove()
     {
         throw new UnsupportedOperationException();
     }
 }