/*
    * 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.shared.util;
  
  import java.lang.reflect.Array;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Iterator;
  import java.util.Map;
  import java.util.NoSuchElementException;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  import javax.el.ValueExpression;
  import javax.faces.application.ProjectStage;
  import javax.faces.component.UIComponent;
  import javax.faces.component.UISelectItem;
  import javax.faces.component.UISelectItems;
  import javax.faces.context.FacesContext;
  import javax.faces.model.SelectItem;
  
  import org.apache.myfaces.shared.util.renderkit.JsfProperties;
  
  // ATTENTION
  // This class is associated with javax.faces.component._SelectItemsIterator.
  // Changes here should also be applied to this class.
  
  public class SelectItemsIterator implements Iterator<SelectItem>
  {
      private static final Logger log = Logger.getLogger(SelectItemsIterator.class.getName());
      
      private static final String VAR_PROP = JsfProperties.VAR_PROP;
      private static final String ITEM_VALUE_PROP = JsfProperties.ITEM_VALUE_PROP;
      private static final String ITEM_LABEL_PROP = JsfProperties.ITEM_LABEL_PROP;
      private static final String ITEM_DESCRIPTION_PROP = JsfProperties.ITEM_DESCRIPTION_PROP;
      private static final String ITEM_DISABLED_PROP = JsfProperties.ITEM_DISABLED_PROP;
      private static final String ITEM_LABEL_ESCAPED_PROP = JsfProperties.ITEM_LABEL_ESCAPED_PROP;
      private static final String NO_SELECTION_VALUE_PROP = JsfProperties.NO_SELECTION_VALUE_PROP;
      
      private static final Iterator<UIComponent> _EMPTY_UICOMPONENT_ITERATOR = new _EmptyIterator<UIComponent>();
      
      private final Iterator<UIComponent> _children;
      private Iterator<? extends Object> _nestedItems;
      private SelectItem _nextItem;
      private UIComponent _currentComponent;
      private UISelectItems _currentUISelectItems;
      private Object _currentValue;
      private FacesContext _facesContext;
  
      public SelectItemsIterator(UIComponent selectItemsParent, FacesContext facesContext)
      {
          _children = selectItemsParent.getChildCount() > 0
                  ? selectItemsParent.getChildren().iterator()
                  : _EMPTY_UICOMPONENT_ITERATOR;
          _facesContext = facesContext;
      }
  
      @SuppressWarnings("unchecked")
      public boolean hasNext()
      {
          if (_nextItem != null)
          {
              return true;
          }
          if (_nestedItems != null)
          {
              if (_nestedItems.hasNext())
              {
                  return true;
              }
              _nestedItems = null;
              _currentComponent = null;
              _currentValue = null;
          }
          if (_children.hasNext())
          {
              UIComponent child = _children.next();
              // When there is other components nested that does
              // not extends from UISelectItem or UISelectItems
              // the behavior for this iterator is just skip this
              // element(s) until an element that extends from these
              // classes are found. If there is no more elements
              // that conform this condition, just return false.
             while (!(child instanceof UISelectItem) && !(child instanceof UISelectItems))
             {
                 // Try to skip it
                 if (_children.hasNext())
                 {
                     // Skip and do the same check
                     child = _children.next();
                 }
                 else
                 {
                     // End loop, so the final result is return false,
                     // since there are no more components to iterate.
                     return false;
                 }
             }
             if (child instanceof UISelectItem)
             {
                 UISelectItem uiSelectItem = (UISelectItem) child;
                 Object item = uiSelectItem.getValue();
                 if (item == null)
                 {
                     // no value attribute --> create the SelectItem out of the other attributes
                     Object itemValue = uiSelectItem.getItemValue();
                     String label = uiSelectItem.getItemLabel();
                     String description = uiSelectItem.getItemDescription();
                     boolean disabled = uiSelectItem.isItemDisabled();
                     boolean escape = uiSelectItem.isItemEscaped();
                     boolean noSelectionOption = uiSelectItem.isNoSelectionOption();
                     if (label == null && itemValue != null)
                     {
                         label = itemValue.toString();
                     }
                     item = new SelectItem(itemValue, label, description, disabled, escape, noSelectionOption);
                 }
                 else if (!(item instanceof SelectItem))
                 {
                     ValueExpression expression = uiSelectItem.getValueExpression("value");
                     throw new IllegalArgumentException("ValueExpression '"
                             + (expression == null ? null : expression.getExpressionString()) + "' of UISelectItem : "
                             + DebugUtils.getPathToComponent(child)
                             + " does not reference an Object of type SelectItem");
                 }
                 _nextItem = (SelectItem) item;
                 _currentComponent = child;
                 _currentValue = item;
                 return true;
             }
             else if (child instanceof UISelectItems)
             {
                 _currentUISelectItems = ((UISelectItems) child);
                 Object value = _currentUISelectItems.getValue();
                 _currentComponent = child;
 
                 if (value instanceof SelectItem)
                 {
                     _nextItem = (SelectItem) value;
                     return true;
                 }
                 else if (value != null && value.getClass().isArray())
                 {
                     // value is any kind of array (primitive or non-primitive)
                     // --> we have to use class Array to get the values
                     final int length = Array.getLength(value);
                     Collection<Object> items = new ArrayList<Object>(length);
                     for (int i = 0; i < length; i++)
                     {
                         items.add(Array.get(value, i));
                     }
                     _nestedItems = items.iterator();
                     return hasNext();
                 }
                 else if (value instanceof Iterable)
                 {
                     // value is Iterable --> Collection, DataModel,...
                     _nestedItems = ((Iterable<?>) value).iterator();
                     return hasNext();
                 }
                 else if (value instanceof Map)
                 {
                     Map<Object, Object> map = ((Map<Object, Object>) value);
                     Collection<SelectItem> items = new ArrayList<SelectItem>(map.size());
                     for (Map.Entry<Object, Object> entry : map.entrySet())
                     {
                         items.add(new SelectItem(entry.getValue(), entry.getKey().toString()));
                     }
                     
                     _nestedItems = items.iterator();
                     return hasNext();
                 }
                 else
                 {
                     Level level = Level.FINE;
                     if (!_facesContext.isProjectStage(ProjectStage.Production))
                     {
                         level = Level.WARNING;
                     }
 
                     if (log.isLoggable(level))
                     {
                         ValueExpression expression = _currentUISelectItems.getValueExpression("value");
                         log.log(level, "ValueExpression {0} of UISelectItems with component-path {1}"
                                 + " does not reference an Object of type SelectItem,"
                                 + " array, Iterable or Map, but of type: {2}",
                                 new Object[] {
                                     (expression == null ? null : expression.getExpressionString()),
                                     DebugUtils.getPathToComponent(child),
                                     (value == null ? null : value.getClass().getName()) 
                                 });
                     }
                 }
             }
             else
             {
                 _currentComponent = null;
                 _currentValue = null;
             }
         }
         return false;
     }
 
     public SelectItem next()
     {
         if (!hasNext())
         {
             throw new NoSuchElementException();
         }
         if (_nextItem != null)
         {
             SelectItem value = _nextItem;
             _nextItem = null;
             return value;
         }
         if (_nestedItems != null)
         {
             Object item = _nestedItems.next();
             
             if (!(item instanceof SelectItem))
             {
                 // check new params of SelectItems (since 2.0): itemValue, itemLabel, itemDescription,...
                 // Note that according to the spec UISelectItems does not provide Getter and Setter 
                 // methods for this values, so we have to use the attribute map
                 Map<String, Object> attributeMap = _currentUISelectItems.getAttributes();
                 _currentValue = item;
                 
                 // write the current item into the request map under the key listed in var, if available
                 boolean wroteRequestMapVarValue = false;
                 Object oldRequestMapVarValue = null;
                 final String var = (String) attributeMap.get(VAR_PROP);
                 if(var != null && !"".equals(var))
                 {
                     // save the current value of the key listed in var from the request map
                     oldRequestMapVarValue = _facesContext.getExternalContext().getRequestMap().put(var, item);
                     wroteRequestMapVarValue = true;
                 }
                 
                 // check the itemValue attribute
                 Object itemValue = attributeMap.get(ITEM_VALUE_PROP);
                 if (itemValue == null)
                 {
                     // the itemValue attribute was not provided
                     // --> use the current item as the itemValue
                     itemValue = item;
                 }
                 
                 // Spec: When iterating over the select items, toString() 
                 // must be called on the string rendered attribute values
                 Object itemLabel = attributeMap.get(ITEM_LABEL_PROP);
                 if (itemLabel == null)
                 {
                     if (itemValue != null)
                     {
                         itemLabel = itemValue.toString();
                     }
                 }
                 else
                 {
                     itemLabel = itemLabel.toString();
                 }
                 Object itemDescription = attributeMap.get(ITEM_DESCRIPTION_PROP);
                 if (itemDescription != null)
                 {
                     itemDescription = itemDescription.toString();
                 }
                 Boolean itemDisabled = getBooleanAttribute(_currentUISelectItems, ITEM_DISABLED_PROP, false);
                 Boolean itemLabelEscaped = getBooleanAttribute(_currentUISelectItems, ITEM_LABEL_ESCAPED_PROP, true);
                 Object noSelectionValue = attributeMap.get(NO_SELECTION_VALUE_PROP);
                 item = new SelectItem(itemValue,
                         (String) itemLabel,
                         (String) itemDescription,
                         itemDisabled,
                         itemLabelEscaped,
                         itemValue.equals(noSelectionValue)); 
                     
                 // remove the value with the key from var from the request map, if previously written
                 if(wroteRequestMapVarValue)
                 {
                     // If there was a previous value stored with the key from var in the request map, restore it
                     if (oldRequestMapVarValue != null)
                     {
                         _facesContext.getExternalContext()
                                 .getRequestMap().put(var, oldRequestMapVarValue);
                     }
                     else
                     {
                         _facesContext.getExternalContext()
                                 .getRequestMap().remove(var);
                     }
                 } 
             }
             return (SelectItem) item;
         }
         throw new NoSuchElementException();
     }
 
     public void remove()
     {
         throw new UnsupportedOperationException();
     }
     
     public UIComponent getCurrentComponent()
     {
         return _currentComponent;
     }
     
     public Object getCurrentValue()
     {
         return _currentValue;
     }
 
     private boolean getBooleanAttribute(UIComponent component, String attrName, boolean defaultValue)
     {
         Object value = component.getAttributes().get(attrName);
         if (value == null)
         {
             return defaultValue;
         }
         else if (value instanceof Boolean)
         {
             return (Boolean) value;
         }
         else
         {
             // If the value is a String, parse the boolean.
             // This makes the following code work: <tag attribute="true" />,
             // otherwise you would have to write <tag attribute="#{true}" />.
             return Boolean.valueOf(value.toString());
         }
     }
 
 }