/*
    * Copyright (c) 2002-2017, 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.plugins.googleapi.service;
  
  import fr.paris.lutece.plugins.googleapi.business.FeedProvider;
  import fr.paris.lutece.plugins.googleapi.business.Item;
  import fr.paris.lutece.portal.service.spring.SpringContextService;
  import fr.paris.lutece.portal.service.util.AppLogService;
  import fr.paris.lutece.portal.service.util.AppPropertiesService;
  import fr.paris.lutece.util.ReferenceList;
  import fr.paris.lutece.util.url.UrlItem;
  
  import org.xml.sax.SAXException;
  
  import java.io.IOException;
  import java.io.InputStream;
  
  import java.net.HttpURLConnection;
  import java.net.URL;
  import java.net.URLEncoder;
  
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import javax.xml.parsers.ParserConfigurationException;
  import javax.xml.parsers.SAXParser;
  import javax.xml.parsers.SAXParserFactory;
  
  
  /**
   * This service provides an access to all feeds defined in the Spring context file : googleapi_context.xml
   */
  public class FeedsService
  {
      private static final String PLUGIN_NAME = "googleapi";
      private static final String BEAN_FEEDS = "googleapi.feeds";
      private static final String PROPERTY_API_KEY = "googleapi.api.key";
      private static Map<String, FeedProvider> _mapProviders = new HashMap<String, FeedProvider>(  );
      private static FeedsService _singleton;
  
      /** Creates a new instance of FeedsService */
      private FeedsService(  )
      {
      }
  
      /**
       * Returns the unique instance of the service
       * @return The instance
       */
      public static FeedsService getInstance(  )
      {
          if ( _singleton == null )
          {
              _singleton = (FeedsService) SpringContextService.getPluginBean( PLUGIN_NAME, BEAN_FEEDS );
          }
  
          return _singleton;
      }
  
      /**
       * Sets the feeds map (used for spring injection)
       * @param map The feeds map
       */
      public void setFeedsMap( Map<String, FeedProvider> map )
      {
          _mapProviders = map;
      }
 
     /**
      * Returns a provider from its key
      * @param strKey The provider's key
      * @return The provider
      */
     public FeedProvider getProvider( String strKey )
     {
         return _mapProviders.get( strKey );
     }
 
     /**
      * Returns the providers list
      * @return the providers list
      */
     public ReferenceList getProviders(  )
     {
         ReferenceList listProviders = new ReferenceList(  );
 
         for ( FeedProvider fp : _mapProviders.values(  ) )
         {
             listProviders.addItem( fp.getKey(  ), fp.getName(  ) );
         }
 
         return listProviders;
     }
 
     /**
      * Returns the providers list
      * @return the providers list
      */
     public ReferenceList getProviders( Class classProvider )
     {
         ReferenceList listProviders = new ReferenceList(  );
 
         for ( FeedProvider fp : _mapProviders.values(  ) )
         {
             if ( classProvider.isInstance( fp ) )
             {
                 listProviders.addItem( fp.getKey(  ), fp.getName(  ) );
             }
         }
 
         return listProviders;
     }
 
     /**
     * Connect to the Google Base data API server, retrieve the items
     *
     * @param strQuery The query
     * @param listItems A list of item to feed
     * @param provider The feed provider
     * @throws java.io.IOException if an error occured during the process
     * @throws org.xml.sax.SAXException if an error occured during the process
     * @throws javax.xml.parsers.ParserConfigurationException if an error occured during the process
     */
     public void getItems( String strQuery, List<Item> listItems, FeedProvider provider )
         throws IOException, SAXException, ParserConfigurationException
     {
         /*
          * Create a URL object, open an Http connection on it and get the input
          * stream that reads the Http response.
          */
         String strApiKey = AppPropertiesService.getProperty( PROPERTY_API_KEY );
 
         UrlItem url = new UrlItem( provider.getFeedsUrl(  ) );
         url.addParameter( provider.getQueryParameter(  ), URLEncoder.encode( strQuery, "UTF-8" ) );
 
         if ( ( strApiKey != null ) && ( !strApiKey.equals( "" ) ) )
         {
             url.addParameter( "key", strApiKey );
         }
 
         URL urlFeed = new URL( url.getUrl(  ) );
         HttpURLConnection httpConnection = (HttpURLConnection) urlFeed.openConnection(  );
         InputStream inputStream = httpConnection.getInputStream(  );
 
         AppLogService.info( "Retrieving items URL : " + url.getUrl(  ) );
 
         //        AppLogService.info( "Feed : " + getFeedAsString( inputStream ) );
 
         /*
          * Create a SAX XML parser and pass in the input stream to the parser to extract
          * fields from the stream.
          */
         SAXParserFactory factory = SAXParserFactory.newInstance(  );
         SAXParser parser = factory.newSAXParser(  );
         FeedHandler handler = provider.getFeedHandler(  );
         handler.setItemList( listItems );
         parser.parse( inputStream, handler );
     }
 }