/*
    * 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.plugins.helpdesk.modules.solr.search;
  
  import java.io.ByteArrayInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.Reader;
  import java.io.StringReader;
  import java.nio.charset.StandardCharsets;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.tika.exception.TikaException;
  import org.apache.tika.metadata.Metadata;
  import org.apache.tika.parser.ParseContext;
  import org.apache.tika.parser.html.HtmlParser;
  import org.apache.tika.sax.BodyContentHandler;
  import org.xml.sax.ContentHandler;
  import org.xml.sax.SAXException;
  
  import fr.paris.lutece.plugins.helpdesk.business.Faq;
  import fr.paris.lutece.plugins.helpdesk.business.FaqHome;
  import fr.paris.lutece.plugins.helpdesk.business.QuestionAnswer;
  import fr.paris.lutece.plugins.helpdesk.business.Subject;
  import fr.paris.lutece.plugins.helpdesk.business.SubjectHome;
  import fr.paris.lutece.plugins.helpdesk.service.HelpdeskPlugin;
  import fr.paris.lutece.plugins.helpdesk.service.helpdesksearch.HelpdeskSearchItem;
  import fr.paris.lutece.plugins.helpdesk.utils.HelpdeskIndexerUtils;
  import fr.paris.lutece.plugins.helpdesk.web.HelpdeskApp;
  import fr.paris.lutece.plugins.search.solr.business.field.Field;
  import fr.paris.lutece.plugins.search.solr.indexer.SolrIndexer;
  import fr.paris.lutece.plugins.search.solr.indexer.SolrIndexerService;
  import fr.paris.lutece.plugins.search.solr.indexer.SolrItem;
  import fr.paris.lutece.plugins.search.solr.util.SolrConstants;
  import fr.paris.lutece.portal.service.content.XPageAppService;
  import fr.paris.lutece.portal.service.plugin.Plugin;
  import fr.paris.lutece.portal.service.plugin.PluginService;
  import fr.paris.lutece.portal.service.util.AppLogService;
  import fr.paris.lutece.portal.service.util.AppPropertiesService;
  import fr.paris.lutece.util.url.UrlItem;
  
  
  /**
   * The Helpdesk indexer for Solr search platform
   *
   */
  public class SolrHelpdeskIndexer implements SolrIndexer
  {
      private static final String PROPERTY_DESCRIPTION = "helpdesk-solr.indexer.description";
      private static final String PROPERTY_NAME = "helpdesk-solr.indexer.name";
      private static final String PROPERTY_VERSION = "helpdesk-solr.indexer.version";
      private static final String PROPERTY_INDEXER_ENABLE = "helpdesk-solr.indexer.enable";
      public static final String SHORT_NAME_SUBJECT = "hds";
      public static final String SHORT_NAME_QUESTION_ANSWER = "hdq";
      private static final String BLANK = " ";
      private static final String PROPERTY_PAGE_PATH_LABEL = "helpdesk.pagePathLabel";
      private static final String PROPERTY_FAQ_ID_LABEL = "helpdesk-solr.indexer.faq_id.label";
      private static final String PROPERTY_FAQ_ID_DESCRIPTION = "helpdesk-solr.indexer.faq_id.description";
      private static final String PROPERTY_SUBJECT_LABEL = "helpdesk-solr.indexer.subject.label";
      private static final String PROPERTY_SUBJECT_DESCRIPTION = "helpdesk-solr.indexer.subject.description";
  
      // Site name
      private static final List<String> LIST_RESSOURCES_NAME = new ArrayList<String>(  );
      private static final String SUBJECT_INDEXATION_ERROR = "An error occured during the indexation of the subject number ";
      
     public SolrHelpdeskIndexer(  )
     {
         super(  );
         LIST_RESSOURCES_NAME.add( HelpdeskIndexerUtils.CONSTANT_QUESTION_ANSWER_TYPE_RESOURCE );
         LIST_RESSOURCES_NAME.add( HelpdeskIndexerUtils.CONSTANT_SUBJECT_TYPE_RESOURCE );
     }
 
     /**
      * {@inheritDoc}
      */
     public String getDescription(  )
     {
         return AppPropertiesService.getProperty( PROPERTY_DESCRIPTION );
     }
 
     /**
      * {@inheritDoc}
      */
     public String getName(  )
     {
         return AppPropertiesService.getProperty( PROPERTY_NAME );
     }
 
     /**
      * {@inheritDoc}
      */
     public String getVersion(  )
     {
         return AppPropertiesService.getProperty( PROPERTY_VERSION );
     }
 
     /**
      * {@inheritDoc}
      */
     public List<String> indexDocuments(  )
     {
         Plugin plugin = PluginService.getPlugin( HelpdeskPlugin.PLUGIN_NAME );
         List<String> lstErrors = new ArrayList<String>(  );
         
         //FAQ
         for ( Faq faq : FaqHome.findAll( plugin ) )
         {
         	for ( Subject subject : (Collection<Subject>) SubjectHome.getInstance(  ).findByIdFaq( faq.getId(  ), plugin ) )
         	{
         		try
         		{
         			indexSubject( faq, subject );
         		}
         		catch ( IOException e )
         		{
         			lstErrors.add( SolrIndexerService.buildErrorMessage( e ) );
         			AppLogService.error( SUBJECT_INDEXATION_ERROR + subject.getId(  ), e );
         		}
         	}
         }
         
         return lstErrors;
     }
 
     /**
      * Get the subject document
      * @param strDocument id of the subject to index
      * @return The list of Solr items
      */
     public List<SolrItem> getDocuments( String strDocument )
     {
         List<SolrItem> listDocs = new ArrayList<SolrItem>(  );
         String strPortalUrl = SolrIndexerService.getBaseUrl(  );
         Plugin plugin = PluginService.getPlugin( HelpdeskPlugin.PLUGIN_NAME );
 
         Subject subject = (Subject) SubjectHome.getInstance(  ).findByPrimaryKey( Integer.parseInt( strDocument ),
                 plugin );
 
         if ( subject != null )
         {
             UrlItem urlSubject = new UrlItem( strPortalUrl );
             urlSubject.addParameter( XPageAppService.PARAM_XPAGE_APP,
                 AppPropertiesService.getProperty( PROPERTY_PAGE_PATH_LABEL ) ); //FIXME
 
             //if it's a sub-subject, we need to get the first parent to have the faq
             int nIdParent = subject.getIdParent(  );
             Subject parentSubject = subject;
 
             while ( nIdParent != SubjectHome.FIRST_ORDER )
             {
                 parentSubject = (Subject) SubjectHome.getInstance(  ).findByPrimaryKey( nIdParent, plugin );
                 nIdParent = parentSubject.getIdParent(  );
             }
 
             Faq faq = FaqHome.findBySubjectId( parentSubject.getId(  ), plugin );
 
             if ( faq != null )
             {
                 urlSubject.addParameter( HelpdeskApp.PARAMETER_FAQ_ID, faq.getId(  ) );
                 urlSubject.setAnchor( HelpdeskApp.ANCHOR_SUBJECT + subject.getId(  ) );
 
                 SolrItem docSubject;
 
                 try
                 {
                     docSubject = getDocument( subject, faq.getRoleKey(  ), urlSubject.getUrl(  ), plugin );
 
                     listDocs.add( docSubject );
 
                     for ( QuestionAnswer questionAnswer : (List<QuestionAnswer>) subject.getQuestions(  ) )
                     {
                         if ( questionAnswer.isEnabled(  ) )
                         {
                             UrlItem urlQuestionAnswer = new UrlItem( strPortalUrl );
                             urlQuestionAnswer.addParameter( XPageAppService.PARAM_XPAGE_APP,
                                 AppPropertiesService.getProperty( PROPERTY_PAGE_PATH_LABEL ) ); //FIXME
                             urlQuestionAnswer.addParameter( HelpdeskApp.PARAMETER_FAQ_ID, faq.getId(  ) );
                             urlQuestionAnswer.setAnchor( HelpdeskApp.ANCHOR_QUESTION_ANSWER +
                                 questionAnswer.getIdQuestionAnswer(  ) );
 
                             SolrItem docQuestionAnswer = getDocument( faq.getId(  ), questionAnswer,
                                     urlQuestionAnswer.getUrl(  ), faq.getRoleKey(  ), plugin );
                             listDocs.add( docQuestionAnswer );
                         }
                     }
                 }
                 catch ( IOException e )
                 {
                     throw new RuntimeException( e );
                 }
             }
         }
 
         return listDocs;
     }
 
     /**
      * {@inheritDoc}
      */
     public boolean isEnable(  )
     {
         return "true".equalsIgnoreCase( AppPropertiesService.getProperty( PROPERTY_INDEXER_ENABLE ) );
     }
 
     /**
      * {@inheritDoc}
      */
     public List<Field> getAdditionalFields(  )
     {
         List<Field> fields = new ArrayList<Field>(  );
         Field fieldFaqId = new Field(  );
         fieldFaqId.setEnableFacet( false );
         fieldFaqId.setName( HelpdeskSearchItem.FIELD_FAQ_ID );
         fieldFaqId.setLabel( AppPropertiesService.getProperty( PROPERTY_FAQ_ID_LABEL ) );
         fieldFaqId.setDescription( AppPropertiesService.getProperty( PROPERTY_FAQ_ID_DESCRIPTION ) );
         fields.add( fieldFaqId );
 
         Field fieldSubjectId = new Field(  );
         fieldSubjectId.setEnableFacet( true );
         fieldSubjectId.setName( HelpdeskSearchItem.FIELD_SUBJECT );
         fieldSubjectId.setLabel( AppPropertiesService.getProperty( PROPERTY_SUBJECT_LABEL ) );
         fieldSubjectId.setDescription( AppPropertiesService.getProperty( PROPERTY_SUBJECT_DESCRIPTION ) );
         fields.add( fieldSubjectId );
 
         return fields;
     }
 
     /**
      * Recursive method for indexing a subject and his children
      *
      * @param faq the faq linked to the subject
      * @param subject the subject
      * @throws IOException I/O Exception
      * @throws InterruptedException interruptedException
      */
     private void indexSubject( Faq faq, Subject subject )
         throws IOException
     {
         Plugin plugin = PluginService.getPlugin( HelpdeskPlugin.PLUGIN_NAME );
 
         String strWebappName = SolrIndexerService.getBaseUrl(  );
         UrlItem urlSubject = new UrlItem( strWebappName );
         urlSubject.addParameter( XPageAppService.PARAM_XPAGE_APP,
             AppPropertiesService.getProperty( PROPERTY_PAGE_PATH_LABEL ) ); //FIXME
         urlSubject.addParameter( HelpdeskApp.PARAMETER_FAQ_ID, faq.getId(  ) );
         urlSubject.setAnchor( HelpdeskApp.ANCHOR_SUBJECT + subject.getId(  ) );
 
         // Indexing the subject
         SolrItem itemSubject = getDocument( subject, faq.getRoleKey(  ), urlSubject.getUrl(  ), plugin );
         SolrIndexerService.write( itemSubject );
 
         for ( QuestionAnswer questionAnswer : (List<QuestionAnswer>) subject.getQuestions(  ) )
         {
             if ( questionAnswer.isEnabled(  ) )
             {
                 UrlItem urlQuestionAnswer = new UrlItem( strWebappName );
                 urlQuestionAnswer.addParameter( XPageAppService.PARAM_XPAGE_APP,
                     AppPropertiesService.getProperty( PROPERTY_PAGE_PATH_LABEL ) ); //FIXME
                 urlQuestionAnswer.addParameter( HelpdeskApp.PARAMETER_FAQ_ID, faq.getId(  ) );
                 urlQuestionAnswer.setAnchor( HelpdeskApp.ANCHOR_QUESTION_ANSWER +
                     questionAnswer.getIdQuestionAnswer(  ) );
 
                 // Indexing the questionAnswer
                 SolrItem itemQuestionAnswer = getDocument( faq.getId(  ), questionAnswer, urlQuestionAnswer.getUrl(  ),
                         faq.getRoleKey(  ), plugin );
                 SolrIndexerService.write( itemQuestionAnswer );
             }
         }
 
         Collection<Subject> children = subject.getChilds( plugin );
 
         for ( Subject childSubject : children )
         {
             indexSubject( faq, childSubject );
         }
     }
 
     /**
      * Builds a {@link SolrItem} which will be used by Solr during the indexing of the question/answer list
      *
      * @param nIdFaq The {@link Faq} Id
      * @param questionAnswer the {@link QuestionAnswer} to index
      * @param strUrl the url of the subject
      * @param strRoleKey The role key
      * @param plugin The {@link Plugin}
      * @return A Solr {@link SolrItem} containing QuestionAnswer Data
      * @throws IOException The IO Exception
      */
     private SolrItem getDocument( int nIdFaq, QuestionAnswer questionAnswer, String strUrl, String strRoleKey,
         Plugin plugin ) throws IOException
     {
         // make a new, empty document
         SolrItem item = new SolrItem(  );
 
         // Setting the Id faq field
         item.addDynamicField( HelpdeskSearchItem.FIELD_FAQ_ID, String.valueOf( nIdFaq ) );
 
         // Setting the Role field
         item.setRole( strRoleKey );
 
         // Setting the URL field
         item.setUrl( strUrl );
 
         // Setting the subject field
         item.addDynamicField( HelpdeskSearchItem.FIELD_SUBJECT, String.valueOf( questionAnswer.getIdSubject(  ) ) );
 
         // Setting the Uid field
         String strIdQuestionAnswer = String.valueOf( questionAnswer.getIdQuestionAnswer(  ) );
         item.setUid( getResourceUid( strIdQuestionAnswer, HelpdeskIndexerUtils.CONSTANT_QUESTION_ANSWER_TYPE_RESOURCE ) );
 
         // Setting the Date field
         // Add the last modified date of the file a field named "modified".
         item.setDate( questionAnswer.getCreationDate(  ) );
 
         //Setting the Content field
         String strContentToIndex = getContentToIndex( questionAnswer, plugin );
 
         HtmlParser parser = new HtmlParser(  );
         ContentHandler handler = new BodyContentHandler();
         Metadata metadata = new Metadata();
         InputStream stream = new ByteArrayInputStream(strContentToIndex.getBytes(StandardCharsets.UTF_8));
         try {
 			parser.parse(stream,  handler, metadata, new ParseContext());
 		} catch (SAXException e) {
 			e.printStackTrace();
 		} catch (TikaException e) {
 			e.printStackTrace();
 		}
         
         item.setContent( handler.toString(  ) );
 
         // Setting the Title field
         item.setTitle( questionAnswer.getQuestion(  ) );
 
         // Setting the Site field
         item.setSite( SolrIndexerService.getWebAppName(  ) );
 
         // Setting the Type field
         item.setType( HelpdeskPlugin.PLUGIN_NAME );
 
         // return the document
         return item;
     }
 
     /**
      * Builds a {@link SolrItem} element which will be used by Solr during the indexing of the subject list
      *
      * @param subject the {@link Subject} to index
      * @param strUrl the url of the subject
      * @param strRoleKey The role key
      * @param plugin The {@link Plugin}
      * @return The Solr {@link SolrItem} containing Subject data
      * @throws IOException The IO Exception
      */
     private SolrItem getDocument( Subject subject, String strRoleKey, String strUrl, Plugin plugin )
         throws IOException
     {
         // make a new, empty document
         SolrItem item = new SolrItem(  );
 
         // Setting the URL field
         item.setUrl( strUrl );
 
         // Setting the Uid field
         String strIdSubject = String.valueOf( subject.getId(  ) );
         item.setUid( getResourceUid( strIdSubject, HelpdeskIndexerUtils.CONSTANT_SUBJECT_TYPE_RESOURCE ) );
 
         //Setting the Content field
         String strContentToIndex = subject.getText(  );
         
         HtmlParser parser = new HtmlParser(  );
         ContentHandler handler = new BodyContentHandler();
         Metadata metadata = new Metadata();
         InputStream stream = new ByteArrayInputStream(strContentToIndex.getBytes(StandardCharsets.UTF_8));
         try {
 			parser.parse(stream,  handler, metadata, new ParseContext());
 		} catch (SAXException e) {
 			e.printStackTrace();
 		} catch (TikaException e) {
 			e.printStackTrace();
 		}
         
         item.setContent( strContentToIndex.toString(  ) );
 
         // Setting the Title field
         item.setTitle( subject.getText(  ) );
 
         // Setting the Site field
         item.setSite( SolrIndexerService.getWebAppName(  ) );
 
         // Setting the Type field
         item.setType( HelpdeskPlugin.PLUGIN_NAME );
 
         // Setting the Role field
         item.setRole( strRoleKey );
 
         // return the document
         return item;
     }
 
     /**
      * Set the Content to index (Question and Answer)
      * @param questionAnswer The {@link QuestionAnswer} to index
      * @param plugin The {@link Plugin}
      * @return The content to index
      */
     private static String getContentToIndex( QuestionAnswer questionAnswer, Plugin plugin )
     {
         StringBuffer sbContentToIndex = new StringBuffer(  );
         //Do not index question here
         sbContentToIndex.append( questionAnswer.getQuestion(  ) );
         sbContentToIndex.append( BLANK );
         sbContentToIndex.append( questionAnswer.getAnswer(  ) );
 
         return sbContentToIndex.toString(  );
     }
 
     /**
          * {@inheritDoc}
          */
     public List<String> getResourcesName(  )
     {
         return LIST_RESSOURCES_NAME;
     }
 
     /**
      * {@inheritDoc}
      */
     public String getResourceUid( String strResourceId, String strResourceType )
     {
         StringBuffer sb = new StringBuffer(  );
 
         if ( HelpdeskIndexerUtils.CONSTANT_QUESTION_ANSWER_TYPE_RESOURCE.equals( strResourceType ) )
         {
             sb.append( strResourceId ).append( SolrConstants.CONSTANT_UNDERSCORE ).append( SHORT_NAME_QUESTION_ANSWER );
         }
         else if ( HelpdeskIndexerUtils.CONSTANT_SUBJECT_TYPE_RESOURCE.equals( strResourceType ) )
         {
             sb.append( strResourceId ).append( SolrConstants.CONSTANT_UNDERSCORE ).append( SHORT_NAME_SUBJECT );
         }
 
         return StringUtils.isNotBlank( sb.toString(  ) ) ? sb.toString(  ) : null;
     }
 }