/*
    * Copyright (c) 2002-2014, Mairie de 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.service.datastore;
  
  import fr.paris.lutece.portal.business.datastore.DataEntity;
  import fr.paris.lutece.portal.business.datastore.DataEntityHome;
  import fr.paris.lutece.portal.service.cache.AbstractCacheableService;
  import fr.paris.lutece.portal.service.template.FreeMarkerTemplateService;
  import fr.paris.lutece.portal.service.util.AppLogService;
  import fr.paris.lutece.portal.service.util.AppPathService;
  import fr.paris.lutece.portal.service.util.NoDatabaseException;
  import fr.paris.lutece.util.ReferenceList;
  
  import java.util.List;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  
  /**
   * Datastore Service
   */
  public final class DatastoreService
  {
      public static final String VALUE_TRUE = "true";
      public static final String VALUE_FALSE = "false";
      private static final String DATASTORE_KEY = "dskey";
      private static final Pattern PATTERN_DATASTORE_KEY = Pattern.compile( "#" + DATASTORE_KEY + "\\{(.*?)\\}" );
      static final String VALUE_MISSING = "DS Value Missing";
      private static AbstractCacheableService _cache;
      private static boolean _bDatabase = true;
  
      /**
       * Private constructor
       */
      private DatastoreService(  )
      {
      }
  
      /**
       * initialize the service
       */
      public static void init(  )
      {
          FreeMarkerTemplateService.getInstance(  ).setSharedVariable( DATASTORE_KEY, new DatastoreTemplateMethod(  ) );
      }
  
      /**
       * Get entity
       *
       * @param strKey The entity's key
       * @param strDefault The default value
       * @return The value
       */
      public static String getDataValue( String strKey, String strDefault )
      {
          try
          {
              if ( _bDatabase )
              {
                  DataEntity entity = null;
  
                  if ( _cache != null )
                  {
                      entity = (DataEntity) _cache.getFromCache( strKey );
                  }
  
                  if ( entity == null )
                  {
                     entity = DataEntityHome.findByPrimaryKey( strKey );
 
                     if ( entity == null )
                     {
                         return strDefault;
                     }
 
                     if ( _cache != null )
                     {
                         _cache.putInCache( strKey, entity );
                     }
                 }
 
                 return entity.getValue(  );
             }
         }
         catch ( NoDatabaseException e )
         {
             disableDatastore( e );
         }
 
         return strDefault;
     }
 
     /**
      * Get entity depending the current web app instance
      *
      * @param strKey The entity's key
      * @param strDefault The default value
      * @return The value
      */
     public static String getInstanceDataValue( String strKey, String strDefault )
     {
         String strInstanceKey = getInstanceKey( strKey );
 
         return getDataValue( strInstanceKey, strDefault );
     }
 
     /**
      * Set entity
      *
      * @param strKey The entity's key
      * @param strValue The value
      */
     public static void setDataValue( String strKey, String strValue )
     {
         try
         {
             if ( _bDatabase )
             {
                 DataEntity p = new DataEntity( strKey, strValue );
                 DataEntity entity = DataEntityHome.findByPrimaryKey( strKey );
 
                 if ( entity != null )
                 {
                     DataEntityHome.update( p );
 
                     if ( _cache != null )
                     {
                         _cache.removeKey( strKey );
                     }
                 }
                 else
                 {
                     DataEntityHome.create( p );
                 }
             }
         }
         catch ( NoDatabaseException e )
         {
             disableDatastore( e );
         }
     }
 
     /**
      * Set entity depending the current web app instance
      *
      * @param strKey The entity's key
      * @param strValue The value
      */
     public static void setInstanceDataValue( String strKey, String strValue )
     {
         String strInstanceKey = getInstanceKey( strKey );
         setDataValue( strInstanceKey, strValue );
     }
 
     /**
      * Remove a give key
      *
      * @param strKey The key
      */
     public static void removeData( String strKey )
     {
         try
         {
             if ( _bDatabase )
             {
                 DataEntityHome.remove( strKey );
 
                 if ( _cache != null )
                 {
                     _cache.removeKey( strKey );
                 }
             }
         }
         catch ( NoDatabaseException e )
         {
             disableDatastore( e );
         }
     }
 
     /**
      * Remove a give key depending the current web app instance
      *
      * @param strKey The key
      */
     public static void removeInstanceData( String strKey )
     {
         String strInstanceKey = getInstanceKey( strKey );
         removeData( strInstanceKey );
     }
 
     /**
      * Remove all data where keys begin with a given prefix
      *
      * @param strPrefix The prefix
      */
     public static void removeDataByPrefix( String strPrefix )
     {
         try
         {
             if ( _bDatabase )
             {
                 List<DataEntity> listEntities = DataEntityHome.findAll(  );
 
                 for ( DataEntity entity : listEntities )
                 {
                     if ( entity.getKey(  ).startsWith( strPrefix ) )
                     {
                         removeData( entity.getKey(  ) );
                     }
                 }
             }
         }
         catch ( NoDatabaseException e )
         {
             disableDatastore( e );
         }
     }
 
     /**
      * Remove all data where keys begin with a given prefix depending the current web app instance
      *
      * @param strPrefix The prefix
      */
     public static void removeInstanceDataByPrefix( String strPrefix )
     {
         String strInstancePrefix = getInstanceKey( strPrefix );
         removeDataByPrefix( strInstancePrefix );
     }
 
     /**
      * Gets a list of key/value where keys are matching a given prefix
      *
      * @param strPrefix The prefix
      * @return The list
      */
     public static ReferenceList getDataByPrefix( String strPrefix )
     {
         ReferenceList list = new ReferenceList(  );
 
         try
         {
             if ( _bDatabase )
             {
                 List<DataEntity> listEntities = DataEntityHome.findAll(  );
 
                 for ( DataEntity entity : listEntities )
                 {
                     if ( entity.getKey(  ).startsWith( strPrefix ) )
                     {
                         list.addItem( entity.getKey(  ), entity.getValue(  ) );
                     }
                 }
             }
         }
         catch ( NoDatabaseException e )
         {
             disableDatastore( e );
         }
 
         return list;
     }
 
     /**
      * Gets a list of key/value where keys are matching a given prefix depending the current web app instance
      *
      * @param strPrefix The prefix
      * @return The list
      */
     public static ReferenceList getInstanceDataByPrefix( String strPrefix )
     {
         String strInstancePrefix = getInstanceKey( strPrefix );
 
         return getDataByPrefix( strInstancePrefix );
     }
 
     /**
      * This method replace keys by their value into a given content
      *
      * @param strSource The string that contains datastore keys
      * @return The string with keys replaced
      */
     public static String replaceKeys( String strSource )
     {
         String result = strSource;
 
         if ( strSource != null )
         {
             Matcher matcher = PATTERN_DATASTORE_KEY.matcher( strSource );
 
             if ( matcher.find(  ) )
             {
                 StringBuffer sb = new StringBuffer(  );
 
                 do
                 {
                     String strKey = matcher.group( 1 );
                     String strValue = DatastoreService.getDataValue( strKey, VALUE_MISSING );
 
                     if ( VALUE_MISSING.equals( strValue ) )
                     {
                         AppLogService.error( "Datastore Key missing : " + strKey +
                             " - Please fix to avoid performance issues." );
                     }
 
                     matcher.appendReplacement( sb, strValue );
                 }
                 while ( matcher.find(  ) );
 
                 matcher.appendTail( sb );
                 result = sb.toString(  );
             }
         }
 
         return result;
     }
 
     /**
      * Check if a key is available in the datastore
      *
      * @param strKey The key
      * @return True if the key is found otherwise false
      */
     public static boolean existsKey( String strKey )
     {
         try
         {
             if ( _bDatabase )
             {
                 DataEntity entity = null;
 
                 if ( _cache != null )
                 {
                     entity = (DataEntity) _cache.getFromCache( strKey );
                 }
 
                 if ( entity == null )
                 {
                     entity = DataEntityHome.findByPrimaryKey( strKey );
 
                     if ( entity == null )
                     {
                         return false;
                     }
                 }
 
                 return true;
             }
         }
         catch ( NoDatabaseException e )
         {
             disableDatastore( e );
         }
 
         return false;
     }
 
     /**
      * Check if a key is available in the datastore depending the current web app instance
      *
      * @param strKey The key
      * @return True if the key is found otherwise false
      */
     public static boolean existsInstanceKey( String strKey )
     {
         String strInstanceKey = getInstanceKey( strKey );
 
         return existsKey( strInstanceKey );
     }
 
     /**
      * Start cache. NB : Cache can't be created at DataStore creation because
      * CacheService uses DatastoreService (Circular reference)
      */
     public static void startCache(  )
     {
         _cache = new DatastoreCacheService(  );
         AppLogService.info( "Datastore's cache started." );
     }
 
     /**
      * Disable the Datastore if a NoDatabaseException is catched
      * @param e The NoDatabaseException
      */
     private static void disableDatastore( NoDatabaseException e )
     {
         _bDatabase = false;
         AppLogService.error( "##### CRITICAL ERROR ##### : Datastore has been disabled due to a NoDatabaseException catched",
             e );
     }
 
     /**
      * Return a datastore key for the current webapp instance
      * @param strKey The key
      * @return The key for the current instance
      */
     private static String getInstanceKey( String strKey )
     {
         if ( !AppPathService.isDefaultWebappInstance(  ) )
         {
             StringBuilder sbInstanceKey = new StringBuilder(  );
             sbInstanceKey.append( AppPathService.getWebappInstance(  ) ).append( "." ).append( strKey );
 
             return sbInstanceKey.toString(  );
         }
 
         return strKey;
     }
 }