/*
    * #%L
    * Bitrepository Audit Trail Service
    * 
    * $Id$
    * $HeadURL$
    * %%
    * 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;
  
  import java.io.BufferedReader;
  import java.io.File;
  import java.io.FileReader;
  import java.io.IOException;
  import java.util.Properties;
  
  import access.AccessComponentFactory;
  import access.getaudittrails.AuditTrailClient;
  import org.bitrepository.audittrails.collector.AuditTrailCollector;
  import org.bitrepository.audittrails.preserver.AuditTrailPreserver;
  import org.bitrepository.audittrails.preserver.LocalAuditTrailPreserver;
  import org.bitrepository.audittrails.store.AuditTrailDatabaseManager;
  import org.bitrepository.audittrails.store.AuditTrailServiceDAO;
  import org.bitrepository.audittrails.store.AuditTrailStore;
  import org.bitrepository.common.settings.Settings;
  import org.bitrepository.common.settings.XMLFileSettingsLoader;
  import org.bitrepository.modify.ModifyComponentFactory;
  import org.bitrepository.modify.putfile.PutFileClient;
  import org.bitrepository.protocol.ProtocolComponentFactory;
  import org.bitrepository.protocol.security.BasicMessageAuthenticator;
  import org.bitrepository.protocol.security.BasicMessageSigner;
  import org.bitrepository.protocol.security.BasicOperationAuthorizor;
  import org.bitrepository.protocol.security.BasicSecurityManager;
  import org.bitrepository.protocol.security.MessageAuthenticator;
  import org.bitrepository.protocol.security.MessageSigner;
  import org.bitrepository.protocol.security.OperationAuthorizor;
  import org.bitrepository.protocol.security.PermissionStore;
  import org.bitrepository.protocol.security.SecurityManager;
  import org.bitrepository.service.ServiceSettingsProvider;
  import org.bitrepository.service.contributor.ContributorMediator;
  import org.bitrepository.service.contributor.SimpleContributorMediator;
  import org.bitrepository.service.database.DatabaseManager;
  import org.bitrepository.settings.referencesettings.ServiceType;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Factory class for accessing the AuditTrailService 
   */
  public final class AuditTrailServiceFactory {
  
      private static Logger log = LoggerFactory.getLogger(AuditTrailServiceFactory.class);
      /** The audit trail service. 
       * @see #getAuditTrailService().*/
      private static AuditTrailService auditTrailService;
      /** The path to the directory containing the configuration files.*/
      private static String configurationDir;
      /** The path to the private key file.*/
      private static String privateKeyFile;
      
      /** The properties file holding implementation specifics for the alarm service. */
      private static final String CONFIGFILE = "audittrails.properties";
      /** Property key to tell where to locate the path and filename to the private key file. */
      private static final String PRIVATE_KEY_FILE = "org.bitrepository.audit-trail-service.privateKeyFile";
          
      /**
       * Private constructor as the class is meant to be used in a static way.
       */
      private AuditTrailServiceFactory() { }
      
      /**
       * Initialize the factory with configuration. 
       * @param confDir String containing the path to the AuditTrailService's configuration directory
       */
      public static synchronized void init(String confDir) {
          configurationDir = confDir;
      }
      
      /**
       * Factory method to retrieve AuditTrailService  
       * @return The AuditTrailService.
       */
      public static synchronized AuditTrailService getAuditTrailService() {
         if(auditTrailService == null) {
             MessageAuthenticator authenticator;
             MessageSigner signer;
             OperationAuthorizor authorizer;
             PermissionStore permissionStore;
             SecurityManager securityManager;
             ServiceSettingsProvider settingsLoader =
                     new ServiceSettingsProvider(
                             new XMLFileSettingsLoader(configurationDir), ServiceType.AUDIT_TRAIL_SERVICE);
 
             Settings settings = settingsLoader.getSettings();
             try {
                 loadProperties();
                 permissionStore = new PermissionStore();
                 authenticator = new BasicMessageAuthenticator(permissionStore);
                 signer = new BasicMessageSigner();
                 authorizer = new BasicOperationAuthorizor(permissionStore);
                 securityManager = new BasicSecurityManager(settings.getRepositorySettings(), privateKeyFile,
                         authenticator, signer, authorizer, permissionStore, 
                         settings.getReferenceSettings().getAuditTrailServiceSettings().getID());
                 
                 ContributorMediator mediator = new SimpleContributorMediator(
                         ProtocolComponentFactory.getInstance().getMessageBus(settings, securityManager), 
                         settings, null);
                 
                 PutFileClient putClient = ModifyComponentFactory.getInstance().retrievePutClient(settings, 
                         securityManager, "audit-trail-preserver");
                 
                 DatabaseManager auditTrailServiceDatabaseManager = new AuditTrailDatabaseManager(
                         settings.getReferenceSettings().getAuditTrailServiceSettings().getAuditTrailServiceDatabase());
                 AuditTrailStore store = new AuditTrailServiceDAO(auditTrailServiceDatabaseManager);
                 AuditTrailClient client = AccessComponentFactory.getInstance().createAuditTrailClient(settings, 
                         securityManager, settings.getReferenceSettings().getAuditTrailServiceSettings().getID());
 
                 AuditTrailCollector collector = new AuditTrailCollector(settings, client, store);
                 AuditTrailPreserver preserver;
                 if (settings.getReferenceSettings().getAuditTrailServiceSettings().isSetAuditTrailPreservation()) {
                     preserver = new LocalAuditTrailPreserver(
                             settings, store, putClient, ProtocolComponentFactory.getInstance().getFileExchange(settings));
                     preserver.start();
                 } else {
                     log.info("Audit trail preservation disabled, no configuration defined.");
                 }
                 
                 auditTrailService = new AuditTrailService(store, collector, mediator, settings);
             } catch (IOException e) {
                 throw new RuntimeException(e);
             }
         }
         
         return auditTrailService;
     }
     
     /**
      * Loads the properties.
      * @throws IOException If any input/output issues occurs.
      */
     private static void loadProperties() throws IOException {
         Properties properties = new Properties();
         File propertiesFile = new File(configurationDir, CONFIGFILE);
         BufferedReader propertiesReader = new BufferedReader(new FileReader(propertiesFile));
         properties.load(propertiesReader);
         privateKeyFile = properties.getProperty(PRIVATE_KEY_FILE);
     }
 }