/*
    * Copyright 2012-2013 smartics, Kronseder & Reiner GmbH
    *
    * 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 de.smartics.properties.spi.core.context;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.Comparator;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Locale;
  import java.util.Set;
  
  import org.apache.commons.io.FilenameUtils;
  import org.apache.commons.lang.LocaleUtils;
  
  import de.smartics.properties.api.core.domain.ConfigException;
  import de.smartics.properties.api.core.domain.PropertiesContext;
  import de.smartics.util.lang.classpath.ClassPathContext;
  import de.smartics.util.lang.classpath.ClassPathListing;
  import de.smartics.util.lang.classpath.JarAndFileClassPathListing;
  import de.smartics.util.util.GenericServiceFactory;
  
  /**
   * Finds all supported locales.
   */
  final class LocaleFinder
  {
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    /**
     * Helper to get listing of a folder on the class path.
     */
    private static final ClassPathListing CLASS_PATH_LISTING;
  
    // --- members --------------------------------------------------------------
  
    /**
     * Locale comparator.
     */
    private static final Comparator<Locale> COMPARATOR = new Comparator<Locale>()
    {
      @Override
      public int compare(final Locale o1, final Locale o2)
      {
        return o1.toString().compareTo(o2.toString());
      }
    };
  
    // ****************************** Initializer *******************************
  
    static
    {
      ClassPathListing service = null;
      try
      {
        service =
            new GenericServiceFactory<ClassPathListing>(ClassPathListing.class)
                .create();
      }
      catch (final IllegalStateException e)
      {
        service = new JarAndFileClassPathListing();
      }
  
      CLASS_PATH_LISTING = service;
    }
  
    // ****************************** Constructors ******************************
  
    /**
     * Default constructor.
     */
    LocaleFinder()
    {
    }
  
    // ****************************** Inner Classes *****************************
  
    // ********************************* Methods ********************************
  
    // --- init -----------------------------------------------------------------
  
    // --- get&set --------------------------------------------------------------
  
   // --- business -------------------------------------------------------------
 
   List<Locale> find(final String systemId, final ClassPathContext context)
     throws ConfigException
   {
     final Set<Locale> locales = new HashSet<Locale>();
     locales.add(new Locale(""));
 
     final List<String> listing =
         CLASS_PATH_LISTING.list(context,
             PropertiesContext.META_INF_PROPERTY_SET_REPORT);
 
     for (final String path : listing)
     {
       final Locale locale = calcLocale(path);
       if (locale != null)
       {
         locales.add(locale);
       }
     }
 
     final List<Locale> list = new ArrayList<Locale>(locales);
     Collections.sort(list, COMPARATOR);
     return list;
   }
 
   Locale calcLocale(final String urlString)
   {
     final String fileName = FilenameUtils.getBaseName(urlString);
     final int urlStringLength = urlString.length();
     int separatorIndex = fileName.indexOf('_');
     Locale locale = null;
 
     while (separatorIndex != -1)
     {
       final String localeString = fileName.substring(separatorIndex + 1);
       locale = constructLocale(localeString);
       separatorIndex =
           locale != null || separatorIndex + 1 >= urlStringLength ? -1
               : fileName.indexOf('_', separatorIndex + 1);
     }
     return locale;
   }
 
   private Locale constructLocale(final String localeString)
   {
     try
     {
       final Locale locale = LocaleUtils.toLocale(localeString);
       return locale;
     }
     catch (final IllegalArgumentException e)
     {
       return null;
     }
   }
 
   // --- object basics --------------------------------------------------------
 
 }