/*
    * $Id: LocaleUtil.java 667964 2008-06-15 15:00:54Z apetrelli $
    *
    * 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.tiles.util;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Locale;
  
  /***
   * Utilities for locale manipulation.
   *
   * @version $Rev: 667964 $ $Date: 2008-06-15 17:00:54 +0200 (dom, 15 giu 2008) $
   * @since 2.1.0
   */
  public final class LocaleUtil {
  
      /***
       * The "null" Locale, i.e. a Locale that points to no real locale.
       *
       * @since 2.1.0
       */
      public static final Locale NULL_LOCALE = new Locale("");
  
      /***
       * Private constructor to avoid instantiation.
       */
      private LocaleUtil() {
      }
  
      /***
       * Calculate the postfixes along the search path from the base bundle to the
       * bundle specified by baseName and locale. Method copied from
       * java.util.ResourceBundle
       *
       * @param locale The locale.
       * @return a list of postfixes to add to filenames.
       * @since 2.1.0
       */
      public static List<String> calculatePostfixes(Locale locale) {
          final List<String> result = new ArrayList<String>();
          // The default configuration file must be loaded to allow correct
          // definition inheritance.
          result.add("");
  
          if (locale == null) {
              return result;
          }
  
          final String language = locale.getLanguage();
          final int languageLength = language.length();
          final String country = locale.getCountry();
          final int countryLength = country.length();
          final String variant = locale.getVariant();
          final int variantLength = variant.length();
  
          if (languageLength + countryLength + variantLength == 0) {
              // The locale is "", "", "".
              return result;
          }
  
          final StringBuffer temp = new StringBuffer();
          temp.append('_');
          temp.append(language);
  
          if (languageLength > 0) {
              result.add(temp.toString());
          }
  
          if (countryLength + variantLength == 0) {
              return result;
          }
  
          temp.append('_');
          temp.append(country);
  
          if (countryLength > 0) {
              result.add(temp.toString());
          }
  
          if (variantLength == 0) {
              return result;
         } else {
             temp.append('_');
             temp.append(variant);
             result.add(temp.toString());
             return result;
         }
     }
 
     /***
      * Calculate the postfix to append to a filename to load the correct single
      * filename for that Locale.
      *
      * @param locale The locale.
      * @return The postfix to append to the filename.
      * @since 2.1.0
      */
     public static String calculatePostfix(Locale locale) {
         if (locale == null) {
             return "";
         }
 
         StringBuilder builder = new StringBuilder();
         String language = locale.getLanguage();
         String country = locale.getCountry();
         String variant = locale.getVariant();
         if (!"".equals(language)) {
             builder.append("_");
             builder.append(language);
             if (!"".equals(country)) {
                 builder.append("_");
                 builder.append(country);
                 if (!"".equals(variant)) {
                     builder.append("_");
                     builder.append(variant);
                 }
             }
         }
         return builder.toString();
     }
 
     /***
      * Concat postfix to the name. Take care of existing filename extension.
      * Transform the given name "name.ext" to have "name" + "postfix" + "ext".
      * If there is no ext, return "name" + "postfix".
      *
      * @param name Filename.
      * @param postfix Postfix to add.
      * @return Concatenated filename.
      * @since 2.1.0
      */
     public static String concatPostfix(String name, String postfix) {
         if (postfix == null || "".equals(postfix)) {
             return name;
         }
 
         // Search file name extension.
         // take care of Unix files starting with .
         int dotIndex = name.lastIndexOf(".");
         int lastNameStart = name.lastIndexOf(java.io.File.pathSeparator);
         if (dotIndex < 1 || dotIndex < lastNameStart) {
             return name + postfix;
         }
 
         String ext = name.substring(dotIndex);
         name = name.substring(0, dotIndex);
         return name + postfix + ext;
     }
 
     /***
      * <p>
      * Returns the "parent" locale of a given locale.
      * </p>
      * <p>
      * If the original locale is only language-based, the {@link #NULL_LOCALE}
      * object is returned.
      * </p>
      * <p>
      * If the original locale is {@link #NULL_LOCALE}, then <code>null</code>
      * is returned.
      * </p>
      *
      * @param locale The original locale.
      * @return The parent locale.
      */
     public static Locale getParentLocale(Locale locale) {
         Locale retValue = null;
         String language = locale.getLanguage();
         String country = locale.getCountry();
         String variant = locale.getVariant();
         if (!"".equals(variant)) {
             retValue = new Locale(language, country);
         } else if (!"".equals(country)) {
             retValue = new Locale(language);
         } else if (!"".equals(language)) {
             retValue = NULL_LOCALE;
         }
 
         return retValue;
     }
 }