/*
    * #%L
    * Bitrepository Audit Trail Service
    * %%
    * Copyright (C) 2010 - 2012 The State and University Library, The Royal Library and The State Archives, Denmark
    * %%
    * This program is free software: you can redistribute it and/or modify
    * it under the terms of the GNU Lesser General Public License as 
    * published by the Free Software Foundation, either version 2.1 of the 
   * License, or (at your option) any later version.
   * 
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Lesser Public License for more details.
   * 
   * You should have received a copy of the GNU General Lesser Public 
   * License along with this program.  If not, see
   * <http://www.gnu.org/licenses/lgpl-2.1.html>.
   * #L%
   */
  package org.bitrepository.audittrails.store;
  
  import static org.bitrepository.audittrails.store.AuditDatabaseConstants.AUDITTRAIL_CONTRIBUTOR_KEY;
  import static org.bitrepository.audittrails.store.AuditDatabaseConstants.AUDITTRAIL_FILE_KEY;
  import static org.bitrepository.audittrails.store.AuditDatabaseConstants.AUDITTRAIL_SEQUENCE_NUMBER;
  import static org.bitrepository.audittrails.store.AuditDatabaseConstants.AUDITTRAIL_TABLE;
  import static org.bitrepository.audittrails.store.AuditDatabaseConstants.COLLECTION_ID;
  import static org.bitrepository.audittrails.store.AuditDatabaseConstants.COLLECTION_KEY;
  import static org.bitrepository.audittrails.store.AuditDatabaseConstants.COLLECTION_TABLE;
  import static org.bitrepository.audittrails.store.AuditDatabaseConstants.CONTRIBUTOR_ID;
  import static org.bitrepository.audittrails.store.AuditDatabaseConstants.CONTRIBUTOR_KEY;
  import static org.bitrepository.audittrails.store.AuditDatabaseConstants.CONTRIBUTOR_TABLE;
  import static org.bitrepository.audittrails.store.AuditDatabaseConstants.FILE_COLLECTION_KEY;
  import static org.bitrepository.audittrails.store.AuditDatabaseConstants.FILE_KEY;
  import static org.bitrepository.audittrails.store.AuditDatabaseConstants.FILE_TABLE;
  import static org.bitrepository.audittrails.store.AuditDatabaseConstants.PRESERVATION_COLLECTION_KEY;
  import static org.bitrepository.audittrails.store.AuditDatabaseConstants.PRESERVATION_CONTRIBUTOR_KEY;
  import static org.bitrepository.audittrails.store.AuditDatabaseConstants.PRESERVATION_KEY;
  import static org.bitrepository.audittrails.store.AuditDatabaseConstants.PRESERVATION_SEQ;
  import static org.bitrepository.audittrails.store.AuditDatabaseConstants.PRESERVATION_TABLE;
  
  import java.sql.SQLException;
  import java.util.Date;
  
  import org.bitrepository.bitrepositoryelements.AuditTrailEvent;
  import org.bitrepository.bitrepositoryelements.AuditTrailEvents;
  import org.bitrepository.bitrepositoryelements.FileAction;
  import org.bitrepository.common.ArgumentValidator;
  import org.bitrepository.service.database.DBConnector;
  import org.bitrepository.service.database.DatabaseManager;
  import org.bitrepository.service.database.DatabaseUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Audit trail storages backed by a database for preserving
   */
  public class AuditTrailServiceDAO implements AuditTrailStore {
      /** The log.*/
      private Logger log = LoggerFactory.getLogger(getClass());
      /** The connection to the database.*/
      private DBConnector dbConnector;
      
      /** 
       * Constructor.
       * @param databaseManager The database manager
       */
      public AuditTrailServiceDAO(DatabaseManager databaseManager) {
          dbConnector = databaseManager.getConnector();
      }
      
      @Override
      public AuditEventIterator getAuditTrailsByIterator(String fileId, String collectionID, String contributorId, 
              Long minSeqNumber, Long maxSeqNumber, String actorName, FileAction operation, Date startDate, 
              Date endDate, String fingerprint, String operationID) {
          ExtractModel model = new ExtractModel();
          model.setFileId(fileId);
          model.setCollectionId(collectionID);
          model.setContributorId(contributorId);
          model.setMinSeqNumber(minSeqNumber);
          model.setMaxSeqNumber(maxSeqNumber);
          model.setActorName(actorName);
          model.setOperation(operation);
          model.setStartDate(startDate);
          model.setEndDate(endDate);
          model.setFingerprint(fingerprint);
          model.setOperationID(operationID);
  
          AuditDatabaseExtractor extractor = new AuditDatabaseExtractor(model, dbConnector);
          return extractor.extractAuditEventsByIterator();
      }
      
      
      
      @Override
      public void addAuditTrails(AuditTrailEvents newAuditTrails, String collectionId) {
          ArgumentValidator.checkNotNull(newAuditTrails, "AuditTrailEvents newAuditTrails");
          ArgumentValidator.checkNotNullOrEmpty(collectionId, "String collectionId");
         
         AuditDatabaseIngestor ingestor = new AuditDatabaseIngestor(dbConnector);
         for(AuditTrailEvent event : newAuditTrails.getAuditTrailEvent()) {
             ingestor.ingestAuditEvents(event, collectionId);
         }
     }
     
     @Override
     public int largestSequenceNumber(String contributorId, String collectionId) {
         ArgumentValidator.checkNotNullOrEmpty(contributorId, "String contributorId");
         ArgumentValidator.checkNotNullOrEmpty(collectionId, "String collectionId");
         
         // Indirectly extracts contributor and collection keys, and joins with the file table where the query can be
         // limited by collection
         String sql = "SELECT " + AUDITTRAIL_SEQUENCE_NUMBER + " FROM " + AUDITTRAIL_TABLE 
                 + " JOIN " + FILE_TABLE 
                 + " ON " + AUDITTRAIL_TABLE + "." + AUDITTRAIL_FILE_KEY + " = " + FILE_TABLE + "." + FILE_KEY
                 + " WHERE "  + AUDITTRAIL_TABLE + "." + AUDITTRAIL_CONTRIBUTOR_KEY + " = ("
                     + " SELECT " + CONTRIBUTOR_KEY + " FROM " + CONTRIBUTOR_TABLE 
                     + " WHERE " + CONTRIBUTOR_ID + " = ? )"
                 + " AND " + FILE_TABLE + "." + FILE_COLLECTION_KEY + " = (" 
                     + " SELECT " + COLLECTION_KEY + " FROM " + COLLECTION_TABLE 
                     + " WHERE " + COLLECTION_ID + " = ? )"
                 + " ORDER BY " + AUDITTRAIL_TABLE + "." + AUDITTRAIL_SEQUENCE_NUMBER + " DESC";
         
         Long seq = DatabaseUtils.selectFirstLongValue(dbConnector, sql, contributorId, collectionId);
         if(seq != null) {
             return seq.intValue();
         }
         return 0;
     }    
 
     @Override
     public long getPreservationSequenceNumber(String contributorId, String collectionId) {
         ArgumentValidator.checkNotNullOrEmpty(contributorId, "String contributorId");
         ArgumentValidator.checkNotNullOrEmpty(collectionId, "String collectionId");
         
         String sql = "SELECT " + PRESERVATION_SEQ + " FROM " + PRESERVATION_TABLE 
                 + " WHERE " + PRESERVATION_CONTRIBUTOR_KEY + " = (" 
                     + " SELECT " + CONTRIBUTOR_KEY + " FROM " + CONTRIBUTOR_TABLE 
                     + " WHERE " + CONTRIBUTOR_ID + " = ? )"
                 + "AND " + PRESERVATION_COLLECTION_KEY + " = (" 
                     + " SELECT " + COLLECTION_KEY + " FROM " + COLLECTION_TABLE 
                     + " WHERE " + COLLECTION_ID + " = ? )";
         
         Long seq = DatabaseUtils.selectLongValue(dbConnector, sql, contributorId, collectionId);
         if(seq != null) {
             return seq.intValue();
         }
         return 0;
     }
 
     @Override
     public void setPreservationSequenceNumber(String contributorId, String collectionId, long seqNumber) {
         ArgumentValidator.checkNotNullOrEmpty(contributorId, "String contributorId");
         ArgumentValidator.checkNotNegative(seqNumber, "int seqNumber");
         long preservationKey = retrievePreservationKey(contributorId, collectionId);
         log.debug("Updating preservation sequence number for contributor: " + contributorId 
                 + " in collection: " + collectionId + " to seq: " + seqNumber);
         String sqlUpdate = "UPDATE " + PRESERVATION_TABLE + " SET " + PRESERVATION_SEQ + " = ?"
                 + " WHERE " + PRESERVATION_KEY + " = ? ";
         DatabaseUtils.executeStatement(dbConnector, sqlUpdate, seqNumber, preservationKey);
     }
     
     @Override
     public boolean havePreservationKey(String contributorID, String collectionID) {
         String sql = "SELECT " + PRESERVATION_KEY + " FROM " + PRESERVATION_TABLE 
                 + " WHERE " + PRESERVATION_CONTRIBUTOR_KEY + " = (" 
                     + " SELECT " + CONTRIBUTOR_KEY + " FROM " + CONTRIBUTOR_TABLE 
                     + " WHERE " + CONTRIBUTOR_ID + " = ? ) "
                 + "AND " + PRESERVATION_COLLECTION_KEY + " = ("
                     + " SELECT " + COLLECTION_KEY + " FROM " + COLLECTION_TABLE
                     + " WHERE " + COLLECTION_ID + " = ? )";
         
         Long preservationKey = DatabaseUtils.selectLongValue(dbConnector, sql, contributorID, collectionID);
         if(preservationKey == null) {
             return false;    
         } else {
             return true;
         }
         
     }
     
     /**
      * Retrieves the key of the preservation table entry for the given collection and contributor.
      * 
      * @param contributorId The contributor of the preservation table entry.
      * @param collectionId The collection of the preservation table entry.
      * @return The key of the entry in the preservation table.
      */
     private Long retrievePreservationKey(String contributorId, String collectionId) {
         String sqlRetrieve = "SELECT " + PRESERVATION_KEY + " FROM " + PRESERVATION_TABLE 
                 + " WHERE " + PRESERVATION_CONTRIBUTOR_KEY + " = (" 
                     + " SELECT " + CONTRIBUTOR_KEY + " FROM " + CONTRIBUTOR_TABLE 
                     + " WHERE " + CONTRIBUTOR_ID + " = ? ) "
                 + "AND " + PRESERVATION_COLLECTION_KEY + " = ("
                     + " SELECT " + COLLECTION_KEY + " FROM " + COLLECTION_TABLE
                     + " WHERE " + COLLECTION_ID + " = ? )";
         Long guid = DatabaseUtils.selectLongValue(dbConnector, sqlRetrieve, contributorId, collectionId);
         
         if(guid == null) {
             log.debug("Inserting preservation entry for contributor '" + contributorId + "' and collection '" 
                     + collectionId + "' into the preservation table.");
             String sqlInsert = "INSERT INTO " + PRESERVATION_TABLE + " ( " + PRESERVATION_CONTRIBUTOR_KEY + " , " 
                     + PRESERVATION_COLLECTION_KEY + ") VALUES ( "
                         + "(SELECT " + CONTRIBUTOR_KEY + " FROM " + CONTRIBUTOR_TABLE + " WHERE " 
                         + CONTRIBUTOR_ID + " = ?)"
                     + ", "
                         + "( SELECT " + COLLECTION_KEY + " FROM " + COLLECTION_TABLE + " WHERE " 
                         + COLLECTION_ID + " = ? )"
                     + ")";
             DatabaseUtils.executeStatement(dbConnector, sqlInsert, contributorId, collectionId);
             
             guid = DatabaseUtils.selectLongValue(dbConnector, sqlRetrieve, contributorId, collectionId);
         }
         
         if(guid == null) {
             throw new IllegalStateException("PreservationKey cannot be obtained for contributor: " + contributorId +
                     " in collection: " + collectionId);
         }
         
         return guid;
     }
 
     @Override
     public void close() {
         try {
             dbConnector.getConnection().close();
         } catch (SQLException e) {
             log.warn("Cannot close the database properly.", e);
         }
     }
 
 }