/*
    * 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 javax.faces.component;
  
  import java.lang.reflect.Array;
  import java.util.Arrays;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
  
  import javax.faces.application.FacesMessage;
  import javax.faces.context.FacesContext;
  import javax.faces.convert.ConverterException;
  import javax.faces.el.ValueBinding;
  import javax.faces.render.Renderer;
  
  /**
   * Base class for the various component classes that allow a user to select zero or
   * more options from a set.
   * <p>
   * This is not an abstract class; java code can create an instance of this, configure
   * its rendererType appropriately, and add it to a view. However there is no tag class
   * for this component, ie it cannot be added directly to a page when using JSP (and
   * other presentation technologies are expected to behave similarly). Instead, there
   * is a family of subclasses that extend this base functionality, and they do have
   * tag classes. 
   * <p>
   * See Javadoc of <a href="http://java.sun.com/j2ee/javaserverfaces/1.1_01/docs/api/index.html">JSF Specification</a>
   *
   * @JSFComponent
   *   type = "javax.faces.SelectMany"
   *   family = "javax.faces.SelectMany"
   *   desc = "UISelectMany"
   *
   * @author Manfred Geiler (latest modification by $Author: skitching $)
   * @version $Revision: 685669 $ $Date: 2008-08-13 15:25:49 -0500 (Wed, 13 Aug 2008) $
   */
  public class UISelectMany extends UIInput
  {
      public static final String COMPONENT_TYPE = "javax.faces.SelectMany";
      public static final String COMPONENT_FAMILY = "javax.faces.SelectMany";
      public static final String INVALID_MESSAGE_ID = "javax.faces.component.UISelectMany.INVALID";
  
      private static final String DEFAULT_RENDERER_TYPE = "javax.faces.Listbox";
  
      public UISelectMany()
      {
          setRendererType(DEFAULT_RENDERER_TYPE);
      }
  
      public String getFamily()
      {
          return COMPONENT_FAMILY;
      }
  
      public Object[] getSelectedValues()
      {
          return (Object[]) getValue();
      }
  
      public void setSelectedValues(Object[] selectedValues)
      {
          setValue(selectedValues);
      }
  
      public ValueBinding getValueBinding(String name)
      {
          if (name == null)
              throw new NullPointerException("name");
          if (name.equals("selectedValues"))
          {
              return super.getValueBinding("value");
          }
          else
          {
              return super.getValueBinding(name);
          }
      }
  
      public void setValueBinding(String name, ValueBinding binding)
      {
         if (name == null)
             throw new NullPointerException("name");
         if (name.equals("selectedValues"))
         {
             super.setValueBinding("value", binding);
         }
         else
         {
             super.setValueBinding(name, binding);
         }
     }
 
     /**
      * @return true if Objects are different (!)
      */
     protected boolean compareValues(Object previous, Object value)
     {
         if (previous == null)
         {
             // one is null, the other not
             return value != null;
         }
         else if (value == null)
         {
             // one is null, the other not
             return previous != null;
         }
         else
         {
             if (previous instanceof Object[] && value instanceof Object[])
             {
                 return compareObjectArrays((Object[]) previous,
                                 (Object[]) value);
             }
             else if (previous instanceof List && value instanceof List)
             {
                 return compareLists((List) previous, (List) value);
             }
             else if (previous.getClass().isArray()
                             && value.getClass().isArray())
             {
                 return comparePrimitiveArrays(previous, value);
             }
             else
             {
                 //Objects have different classes
                 return true;
             }
         }
     }
 
     private boolean compareObjectArrays(Object[] previous, Object[] value)
     {
         int length = value.length;
         if (previous.length != length)
         {
             //different length
             return true;
         }
 
         boolean[] scoreBoard = new boolean[length];
         for (int i = 0; i < length; i++)
         {
             Object p = previous[i];
             boolean found = false;
             for (int j = 0; j < length; j++)
             {
                 if (scoreBoard[j] == false)
                 {
                     Object v = value[j];
                     if ((p == null && v == null)
                                     || (p != null && v != null && p.equals(v)))
                     {
                         scoreBoard[j] = true;
                         found = true;
                         break;
                     }
                 }
             }
             if (!found)
             {
                 return true; //current element of previous array not found in new array
             }
         }
 
         return false; // arrays are identical
     }
 
     private boolean compareLists(List previous, List value)
     {
         int length = value.size();
         if (previous.size() != length)
         {
             //different length
             return true;
         }
 
         boolean[] scoreBoard = new boolean[length];
         for (int i = 0; i < length; i++)
         {
             Object p = previous.get(i);
             boolean found = false;
             for (int j = 0; j < length; j++)
             {
                 if (scoreBoard[j] == false)
                 {
                     Object v = value.get(j);
                     if ((p == null && v == null)
                                     || (p != null && v != null && p.equals(v)))
                     {
                         scoreBoard[j] = true;
                         found = true;
                         break;
                     }
                 }
             }
             if (!found)
             {
                 return true; //current element of previous List not found in new List
             }
         }
 
         return false; // Lists are identical
     }
 
     private boolean comparePrimitiveArrays(Object previous, Object value)
     {
         int length = Array.getLength(value);
         if (Array.getLength(previous) != length)
         {
             //different length
             return true;
         }
 
         boolean[] scoreBoard = new boolean[length];
         for (int i = 0; i < length; i++)
         {
             Object p = Array.get(previous, i);
             boolean found = false;
             for (int j = 0; j < length; j++)
             {
                 if (scoreBoard[j] == false)
                 {
                     Object v = Array.get(value, j);
                     if ((p == null && v == null)
                                     || (p != null && v != null && p.equals(v)))
                     {
                         scoreBoard[j] = true;
                         found = true;
                         break;
                     }
                 }
             }
             if (!found)
             {
                 return true; //current element of previous array not found in new array
             }
         }
 
         return false; // arrays are identical
     }
 
     protected void validateValue(FacesContext context, Object convertedValue)
     {
         Iterator itemValues = _createItemValuesIterator(convertedValue);
 
         // verify that iterator was successfully created for convertedValue type
         if (itemValues == null)
         {
             _MessageUtils.addErrorMessage(context, this,
                                           INVALID_MESSAGE_ID,
                                           new Object[] {getId()});
             setValid(false);
             return;
         }
 
         boolean hasValues = itemValues.hasNext();
 
         // if UISelectMany is required, then there must be some selected values
         if (isRequired() && !hasValues)
         {
             _MessageUtils.addErrorMessage(context, this, REQUIRED_MESSAGE_ID,
                             new Object[] {getId()});
             setValid(false);
             return;
         }
 
         // run the validators only if there are item values to validate
         if (hasValues)
         {
             _ComponentUtils.callValidators(context, this, convertedValue);
         }
 
         if (isValid() && hasValues)
         {
             Collection items = new ArrayList();
             for (Iterator iter = new _SelectItemsIterator(this); iter.hasNext();)
             {
                 items.add( iter.next() );
             }
             while (itemValues.hasNext())
             {
                 Object itemValue = itemValues.next();
 
                 if (!_SelectItemsUtil.matchValue(itemValue, items.iterator()))
                 {
                     _MessageUtils.addErrorMessage(context, this,
                                     INVALID_MESSAGE_ID,
                                     new Object[] {getId()});
                     setValid(false);
                     return;
                 }
             }
         }
     }
 
     /**
      * First part is identical to super.validate except the empty condition.
      * Second part: iterate through UISelectItem and UISelectItems and check
      *              current values against these items
      */
     public void validate(FacesContext context)
     {
         // TODO : Setting the submitted value to null in the super class causes a bug, if set to null, you'll get the following error :
         // java.lang.NullPointerException at org.apache.myfaces.renderkit._SharedRendererUtils.getConvertedUISelectManyValue(_SharedRendererUtils.java:118)
         super.validate(context);
     }
 
     protected Object getConvertedValue(FacesContext context,
                     Object submittedValue)
     {
         try
         {
             Renderer renderer = getRenderer(context);
             if (renderer != null)
             {
                 return renderer
                                 .getConvertedValue(context, this,
                                                 submittedValue);
             }
             else if (submittedValue == null)
             {
                 return null;
             }
             else if (submittedValue instanceof String[])
             {
                 return _SharedRendererUtils.getConvertedUISelectManyValue(
                                 context, this, (String[]) submittedValue);
             }
         }
         catch (ConverterException e)
         {
             FacesMessage facesMessage = e.getFacesMessage();
             if (facesMessage != null)
             {
                 context.addMessage(getClientId(context), facesMessage);
             }
             else
             {
                 _MessageUtils.addErrorMessage(context, this,
                                 CONVERSION_MESSAGE_ID, new Object[] {getId()});
             }
             setValid(false);
         }
         return submittedValue;
     }
 
     private Iterator _createItemValuesIterator(Object convertedValue)
     {
         if (convertedValue == null)
         {
             return Collections.EMPTY_LIST.iterator();
         }
         else
         {
             Class valueClass = convertedValue.getClass();
             if (valueClass.isArray())
             {
                 return new _PrimitiveArrayIterator(convertedValue);
             }
             else if (convertedValue instanceof Object[])
             {
                 Object[] values = (Object[]) convertedValue;
                 return Arrays.asList(values).iterator();
             }
             else if (convertedValue instanceof List)
             {
                 List values = (List) convertedValue;
                 return values.iterator();
             }
             else
             {
                 // unsupported type for iteration
                 return null;
             }
         }
     }
 }