/*
    * Copyright (c) 2002-2022, City of Paris
    * All rights reserved.
    *
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions
    * are met:
    *
    *  1. Redistributions of source code must retain the above copyright notice
   *     and the following disclaimer.
   *
   *  2. Redistributions in binary form must reproduce the above copyright notice
   *     and the following disclaimer in the documentation and/or other materials
   *     provided with the distribution.
   *
   *  3. Neither the name of 'Mairie de Paris' nor 'Lutece' nor the names of its
   *     contributors may be used to endorse or promote products derived from
   *     this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   * License 1.0
   */
  package fr.paris.lutece.portal.web.l10n;
  
  import fr.paris.lutece.portal.service.datastore.DatastoreService;
  import fr.paris.lutece.portal.service.util.AppLogService;
  import fr.paris.lutece.portal.service.util.AppPropertiesService;
  import java.util.ArrayList;
  import java.util.List;
  
  import java.util.Locale;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpSession;
  
  /**
   * LocaleService
   */
  public final class LocaleService
  {
      private static final String ATTRIBUTE_SELECTED_LOCALE = "LUTECE_ATTRIBUTE_USER_SELECTED_LOCALE";
      private static final String DSKEY_LANGUAGE_DEFAULT = "portal.site.site_property.locale.default";
      private static final String PROPERTY_LANG_LIST = "lutece.i18n.availableLocales";
      private static final String PROPERTY_LANG_DEFAULT = "lutece.i18n.defaultLocale";
      private static Locale _locale;
      private static List<Locale> _supportedLocales;
  
      /**
       * Private constructor
       */
      private LocaleService( )
      {
      }
  
      /**
       * Set the locale selected by the user in the front office. The user may select a language without been authenticated.
       * 
       * @param request
       *            The request
       * @param locale
       *            The locale
       */
      public static void setUserSelectedLocale( HttpServletRequest request, Locale locale )
      {
          HttpSession session = request.getSession( true );
          session.setAttribute( ATTRIBUTE_SELECTED_LOCALE, locale );
      }
  
      /**
       * Get a Locale selected by the user in front office
       * 
       * @param request
       *            The HTTP request
       * @return The locale selected, or the default jvm locale if no locale has been selected
       */
      public static Locale getUserSelectedLocale( HttpServletRequest request )
      {
          Locale locale = LocaleService.getDefault( );
          HttpSession session = request.getSession( );
  
          if ( session != null )
          {
              Locale localeSession = (Locale) session.getAttribute( ATTRIBUTE_SELECTED_LOCALE );
  
              if ( localeSession != null )
              {
                  locale = localeSession;
              }
         }
 
         return locale;
     }
 
     /**
      * Return a Lutece defined default Locale
      * 
      * @return The locale
      */
     public static synchronized Locale getDefault( )
     {
         if ( _locale != null )
         {
             return _locale;
         }
         else
         {
             String dsLang = DatastoreService.getInstanceDataValue( DSKEY_LANGUAGE_DEFAULT, null );
 
             if ( dsLang != null )
             {
                 for ( String strISOLang : Locale.getISOLanguages( ) )
                 {
                     if ( strISOLang.equals( dsLang ) )
                     {
                         _locale = new Locale( dsLang );
                         AppLogService.info( "LocaleService : default locale set to : {}", dsLang );
 
                         return _locale;
                     }
                 }
             }
 
             // otherwise, get the default locale from properties
             _locale = new Locale( AppPropertiesService.getProperty( PROPERTY_LANG_DEFAULT ) );
             AppLogService.error( "LocaleService : invalid defined locale {} - default set to {}", dsLang, _locale.getLanguage( ) );
 
             return _locale;
         }
     }
 
     /**
      * Retrieve the best supported locale for the user's session Priority order : 1- selected locale session attribute 2- browser locale (if supported) 3-
      * default server locale
      * 
      * @param request
      *            The HTTP request
      * @return The locale
      */
     public static Locale getContextUserLocale( HttpServletRequest request )
     {
         // consider the current session locale
         if ( request != null )
         {
             HttpSession session = request.getSession( false );
             if ( session != null )
             {
                 Locale userSessionLocale = (Locale) session.getAttribute( ATTRIBUTE_SELECTED_LOCALE );
                 if ( userSessionLocale != null )
                 {
                     if ( isSupported( userSessionLocale ) )
                     {
                         return userSessionLocale;
                     }
                 }
             }
         }
 
         // consider the browser language
         Locale locale = new Locale( request.getLocale( ).getLanguage( ).substring( 0, 2 ) );
         if ( isSupported( locale ) )
         {
             return locale;
         }
 
         // otherwise consider the server default
         return getDefault( );
     }
 
     /**
      * check if Locale is supported according to locale list in lutece properties
      * 
      * @param locale
      * @return true if supported
      */
     public static boolean isSupported( Locale locale )
     {
         if ( _supportedLocales == null )
         {
             getSupportedLangList( );
         }
 
         // check if the mandatory language is supported
         for ( Locale supportedLocale : _supportedLocales )
         {
             if ( supportedLocale.equals( locale ) )
             {
                 return true;
             }
         }
 
         return false;
     }
 
     /**
      * get Supported Lang List
      * 
      * @return the Supported Lang List
      */
     public static synchronized List<Locale> getSupportedLangList( )
     {
         if ( _supportedLocales == null )
         {
             String [ ] strLangList = AppPropertiesService.getProperty( PROPERTY_LANG_LIST ).split( "," );
             _supportedLocales = new ArrayList<>( );
             for ( String lang : strLangList )
             {
                 _supportedLocales.add( new Locale( lang ) );
             }
         }
 
         return _supportedLocales;
     }
 }