/*
    * 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.context;
  
  import java.io.Serializable;
  
  /**
   * Specifies a set of accessibility-related properties that are applied
   * to the current request.
   *
   * AccessibilityProfile instances are obtained by the getInstance()
   * factory method.
   *
   * AccessibilityProfile instances are immutable.
   */
  public class AccessibilityProfile 
  {
    /**
     * Color contrast values
     */
    public enum ColorContrast
    {
      /**
       * Color contrast value for users who prefer styles/content optimized
       * for high contrast settings.
       */
      HIGH,
      
      /**
       * Color contrast value for users who prefer the default
       * (non-high contrast-optimized) styles/content.
       */
      STANDARD
    }
  
    /**
     * Font size values.
     * 
     * Note that the font size property is not used to define a specific
     * (eg. pixel-based) font size, but rather to provide a hint that the
     * use may prefer larger fonts.  The physical font size to use is specified
     * by the skin.
     */
    public enum FontSize
    {
      /**
       * Font size value for users who prefer larger font sizes.
       */
      LARGE,
      
      /**
       * Font size value for users who prefer the default (medium) font sizes.
       */
      MEDIUM
    }
    
    /**
     * Returns an AccessibilityProfile instance with the specified properties.
     * @param colorContrast Specifies the user's color contrast preference.  If 
     *   null, defaults to ColorContrast.STANDARD.
     * @param fontSize Specifies the user's font size preference.  If null, 
     *   defaults to FontSize.MEDIUM.
     */
    public static AccessibilityProfile getInstance(
      ColorContrast colorContrast,
      FontSize      fontSize
      )
    {    
      // Note: we could cache and share AccessibilityProfile instances
      // here if that seems useful.
      return new SerializableAccessibilityProfile(colorContrast, fontSize);
    }
  
    /**
     * Returns an AccessiblityProfile instance with the default preferences.
     */
    public static AccessibilityProfile getDefaultInstance()
    {
      return _sDefaultInstance;
    }
  
    /**
     * Returns the user's preferred color contrast setting.
    */
   public ColorContrast getColorContrast()
   {
     return _colorContrast;
   }
   
   /**
    * Returns the user's preferred font size setting.
    */
   public FontSize getFontSize()
   {
     return _fontSize;    
   }
 
   /**
    * Convenience method for testing whether high contrast content is required.
    */
   public final boolean isHighContrast()
   {
     return (_colorContrast == ColorContrast.HIGH);
   }
     
   /**
    * Convenience method for testing whether large fonts are required.
    */
   public final boolean isLargeFonts()
   {
     return (_fontSize == FontSize.LARGE);
   }
   
   @Override
   public final int hashCode()
   {
     return _hashCode;
   }
   
   @Override
   public boolean equals(Object o)
   {
     if (this == o)
       return true;
     else if (o instanceof AccessibilityProfile)
     {
       AccessibilityProfile otherProfile = (AccessibilityProfile)o;
       
       return (_hashCode == otherProfile._hashCode) &&
               _colorContrast.equals(otherProfile._colorContrast) &&
               _fontSize.equals(otherProfile._fontSize);
     }
     else
     {
       return false;
     }
   }
   
   // No need to support subclassing yet, so keep the constructor private.
   // Clients should use the getInstance() factory method.
   private AccessibilityProfile(
     ColorContrast colorContrast,
     FontSize      fontSize
     )
   {
     _colorContrast = (colorContrast == null) ? ColorContrast.STANDARD : colorContrast;
     _fontSize = (fontSize == null) ? FontSize.MEDIUM : fontSize;
     _hashCode = _colorContrast.hashCode() * 37 + _fontSize.hashCode();
   }
 
   //Serialization for SerializableAccessibilityProfile internal subclass requires no-arg constructor
   //access of at least package security level.
   AccessibilityProfile()
   {
     this(ColorContrast.STANDARD, FontSize.MEDIUM);
   }
 
   private final ColorContrast _colorContrast;
   private final FontSize      _fontSize;
   
   // hashCode could be transient, but then we would have to recalculate it when deserializing
   // and it couldn't be final
   private final int           _hashCode;
 
   // Default instance
   private static final AccessibilityProfile _sDefaultInstance =
     AccessibilityProfile.getInstance(ColorContrast.STANDARD, FontSize.MEDIUM);
 
   /**
    * We maintain a private internal serializable class for our singleton instance.
    */
   private static final class SerializableAccessibilityProfile extends AccessibilityProfile implements Serializable
   {
     public SerializableAccessibilityProfile(
       ColorContrast colorContrast,
       FontSize      fontSize
       )
     {
       super(colorContrast, fontSize);
     }
 
     private static final long serialVersionUID = 1L;
   }
 }