/* Copyright 2009, Sebastian Prehn
    *
    * This file is part of JCR Blog
    *
    * JCR Blog is free software: you can redistribute it and/or modify
    * it under the terms of the GNU General Public License as published by
    * the Free Software Foundation, either version 3 of the License, or
    * (at your option) any later version.
    *
   * JCR Blog 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 Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with JCR Blog.  If not, see <http://www.gnu.org/licenses/>.
   *
   *  Versioning:
   *  $LastChangedDate: 2010-08-02 21:55:43 +0200 (Mo, 02 Aug 2010) $
   *  $LastChangedRevision: 210 $
   */
  package org.jcr_blog.persistence;
  
  import java.io.*;
  import java.util.Arrays;
  import java.util.Properties;
  import javax.annotation.PostConstruct;
  import javax.enterprise.context.ApplicationScoped;
  import javax.enterprise.context.RequestScoped;
  import javax.enterprise.inject.Disposes;
  import javax.enterprise.inject.Produces;
  import javax.inject.Inject;
  import javax.inject.Named;
  import javax.jcr.Credentials;
  import javax.jcr.NamespaceRegistry;
  import javax.jcr.Repository;
  import javax.jcr.RepositoryException;
  import javax.jcr.Session;
  import javax.jcr.SimpleCredentials;
  import org.slf4j.Logger;
  import static org.jcr_blog.persistence.JcrBlogNamespace.*;
  
  /**
   * Provider of JcrSession.
   * @author Sebastian Prehn <sebastian.prehn@planetswebdesign.de>
   */
  @Named
  @ApplicationScoped
  public class SessionProvider {
  
      @Inject
      private Logger logger;
      @Inject
      private Repository repository;
      
      private Credentials credentials;
  
      @PostConstruct
      void init() throws Exception {
          final Properties p = new Properties();
          try {
              InputStream in = this.getClass().getClassLoader().getResourceAsStream("jcr.properties");
              if (in == null) {
                  this.logger.warn("jcr.properties file not found => using defaults");
              } else {
                  p.load(in);
              }
              this.credentials = new SimpleCredentials(
                      p.getProperty("username", "anonymous"),
                      p.getProperty("password", "").toCharArray());
  
          } catch (IOException ex) {
              this.logger.error("unable to open required configuration file jcr.properties", ex);
              this.credentials = null;
          }
  
      }
  
      private void initNamespaceRegistry(final Session session) throws RepositoryException {
          try {
              final NamespaceRegistry namespaceRegistry = session.getWorkspace().getNamespaceRegistry();
              if (!Arrays.asList(namespaceRegistry.getURIs()).contains(JCRBLOG_NAMESPACE_URI)) {
                  this.logger.info("adding missing namespace binding for: {}", JCRBLOG_NAMESPACE_URI);
                  namespaceRegistry.registerNamespace(JCRBLOG_NAMESPACE_PREFIX, JCRBLOG_NAMESPACE_URI);
              } else if (!namespaceRegistry.getPrefix(JCRBLOG_NAMESPACE_URI).equals(JCRBLOG_NAMESPACE_PREFIX)) {
                  throw new AssertionError(String.format("namespace %s bound to wrong prefix! expected %s but was %s", JCRBLOG_NAMESPACE_URI, JCRBLOG_NAMESPACE_PREFIX, namespaceRegistry.getPrefix(JCRBLOG_NAMESPACE_URI)));
              }
  
          } catch (RepositoryException ex) {
              this.logger.error("problem initializing namespace registry", ex);
              throw ex;
          }
      }
  
      /**
       * Producer method for a JCRSession.
       *
       */
      @Produces
     @Named
     @RequestScoped // maybe this provider should not make assumption that it will be called within a web request
     @JcrSession
     public Session getSession() throws RepositoryException {
         this.logger.debug("creating jcr session");
         final Session session = this.repository.login(credentials);
         initNamespaceRegistry(session);
         return session;
     }
 
     /**
      * Disposer method for a JCRSession.
      *
      * @param session that will be disposed
      */
     public void closeSession(@Disposes @JcrSession final Session session) {
         this.logger.debug("disposing jcr session");
         session.logout();
     }
 
 }