/*
    * Copyright (c) 2002-2021, 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.plugins.asynchronousupload.service;
  
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpSession;
  
  import org.apache.commons.fileupload.FileItem;
  import org.apache.commons.lang3.StringUtils;
  
  import fr.paris.lutece.portal.service.i18n.I18nService;
  import fr.paris.lutece.portal.service.spring.SpringContextService;
  import fr.paris.lutece.portal.service.util.AppException;
  import fr.paris.lutece.util.filesystem.UploadUtil;
  
  public class AsynchronousUploadHandler extends AbstractAsynchronousUploadHandler
  {
  
      private static final String BEAN_NAME = "asynchronous-upload.asynchronousUploadHandler";
      private static final String HANDLER_NAME = "asynchronousUploadHandler";
  
      // Error messages
      private static final String ERROR_MESSAGE_UNKNOWN_ERROR = "asynchronousupload.message.unknownError";
  
      /** contains uploaded file items */
      private static Map<String, Map<String, List<FileItem>>> _mapAsynchronousUpload = new ConcurrentHashMap<>( );
  
      /**
       * Get the handler
       * 
       * @return the handler
       */
      public static AsynchronousUploadHandler getHandler( )
      {
          return SpringContextService.getBean( BEAN_NAME );
      }
  
      @Override
      public String canUploadFiles( HttpServletRequest request, String strFieldName, List<FileItem> listFileItemsToUpload, Locale locale )
      {
          if ( StringUtils.isNotBlank( strFieldName ) )
          {
              String sessionId = getCustomSessionId( request.getSession( ) );
              initMap( sessionId, strFieldName );
  
              return null;
          }
          return I18nService.getLocalizedString( ERROR_MESSAGE_UNKNOWN_ERROR, locale );
      }
  
      @Override
      public List<FileItem> getListUploadedFiles( String strFieldName, HttpSession session )
      {
          if ( StringUtils.isBlank( strFieldName ) )
          {
              throw new AppException( "id field name is not provided for the current file upload" );
          }
  
          String sessionId = getCustomSessionId( session );
  
          initMap( sessionId, strFieldName );
 
         // find session-related files in the map
         Map<String, List<FileItem>> mapFileItemsSession = _mapAsynchronousUpload.get( sessionId );
 
         return mapFileItemsSession.get( strFieldName );
     }
 
     @Override
     public void addFileItemToUploadedFilesList( FileItem fileItem, String strFieldName, HttpServletRequest request )
     {
         // This is the name that will be displayed in the form. We keep
         // the original name, but clean it to make it cross-platform.
         String strFileName = UploadUtil.cleanFileName( fileItem.getName( ).trim( ) );
 
         String sessionId = getCustomSessionId( request.getSession( ) );
         initMap( sessionId, strFieldName );
 
         // Check if this file has not already been uploaded
         List<FileItem> uploadedFiles = getListUploadedFiles( strFieldName, request.getSession( ) );
 
         if ( uploadedFiles != null )
         {
             boolean bNew = true;
 
             if ( !uploadedFiles.isEmpty( ) )
             {
                 Iterator<FileItem> iterUploadedFiles = uploadedFiles.iterator( );
 
                 while ( bNew && iterUploadedFiles.hasNext( ) )
                 {
                     FileItem uploadedFile = iterUploadedFiles.next( );
                     String strUploadedFileName = UploadUtil.cleanFileName( uploadedFile.getName( ).trim( ) );
                     // If we find a file with the same name and the same
                     // length, we consider that the current file has
                     // already been uploaded
                     bNew = !( StringUtils.equals( strUploadedFileName, strFileName ) && ( uploadedFile.getSize( ) == fileItem.getSize( ) ) );
                 }
             }
 
             if ( bNew )
             {
                 uploadedFiles.add( fileItem );
             }
         }
     }
 
     @Override
     public String getHandlerName( )
     {
         return HANDLER_NAME;
     }
 
     private void initMap( String strSessionId, String strFieldName )
     {
         // find session-related files in the map
         Map<String, List<FileItem>> mapFileItemsSession = _mapAsynchronousUpload.get( strSessionId );
 
         // create map if not exists
         if ( mapFileItemsSession == null )
         {
             synchronized( this )
             {
                 // Ignore double check locking error : assignation and instanciation of objects are separated.
                 mapFileItemsSession = _mapAsynchronousUpload.computeIfAbsent( strSessionId, s -> new ConcurrentHashMap<>( ) );
             }
         }
 
         mapFileItemsSession.computeIfAbsent( strFieldName, s -> new ArrayList<>( ) );
     }
 
     @Override
     public void removeSessionFiles( HttpSession session )
     {
         String sessionId = (String) session.getAttribute( PARAM_CUSTOM_SESSION_ID );
         if ( sessionId != null )
         {
             _mapAsynchronousUpload.remove( sessionId );
         }
 
     }
 }