/*

  * 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.ClassPathContext;

 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 --------------------------------------------------------

 }