/*
    * Licensed to The Apereo Foundation under one or more contributor license
    * agreements. See the NOTICE file distributed with this work for additional
    * information regarding copyright ownership.
    *
    *
    * The Apereo Foundation licenses this file to you under the Educational
    * Community License, Version 2.0 (the "License"); you may not use this file
    * except in compliance with the License. You may obtain a copy of the License
   * at:
   *
   *   http://opensource.org/licenses/ecl2.txt
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
   * License for the specific language governing permissions and limitations under
   * the License.
   *
   */
  
  package org.opencastproject.kernel.bundleinfo;
  
  import static org.opencastproject.kernel.bundleinfo.BundleInfoImpl.bundleInfo;
  import static org.opencastproject.kernel.bundleinfo.BundleInfos.getBuildNumber;
  import static org.opencastproject.util.OsgiUtil.getContextProperty;
  import static org.opencastproject.util.data.Option.none;
  import static org.opencastproject.util.data.Option.option;
  import static org.opencastproject.util.data.Option.some;
  
  import org.opencastproject.systems.OpencastConstants;
  import org.opencastproject.util.UrlSupport;
  import org.opencastproject.util.data.Option;
  import org.opencastproject.util.data.functions.Strings;
  
  import org.osgi.framework.Bundle;
  import org.osgi.framework.BundleEvent;
  import org.osgi.framework.BundleListener;
  import org.osgi.service.component.ComponentContext;
  import org.osgi.service.component.annotations.Activate;
  import org.osgi.service.component.annotations.Component;
  import org.osgi.service.component.annotations.Deactivate;
  import org.osgi.service.component.annotations.Reference;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Log information about bundle build versions. The bundle needs to have the manifest header "Build-Number" set.
   */
  @Component(
      immediate = true
  )
  public class BundleInfoLogger implements BundleListener {
  
    private static final Logger logger = LoggerFactory.getLogger(BundleInfoLogger.class);
  
    // Wrap db into an option.
    // This strategy prevents potential exceptions caused by an already closed connection pool or
    // entity manager in deactivate(). This happens when the logger is deactivated because of a db shutdown.
    //
    // However in a concurrent situation there may still occur exceptions when db methods are called _after_
    // the pool has been closed but _before_ BundleInfoLogger's deactivate method has been called.
    private Option<BundleInfoDb> db;
    private String host;
  
    /** OSGi DI */
    @Reference(unbind = "unsetDb")
    public void setDb(BundleInfoDb db) {
      this.db = some(db);
    }
  
    /** OSGi DI */
    public void unsetDb(BundleInfoDb db) {
      this.db = none();
    }
  
    /** OSGi callback */
    @Activate
    public void activate(ComponentContext cc) {
      host = option(getContextProperty(cc, OpencastConstants.SERVER_URL_PROPERTY)).bind(Strings.trimToNone).getOrElse(
              UrlSupport.DEFAULT_BASE_URL);
      for (BundleInfoDb a : db)
        a.clear(host);
      cc.getBundleContext().addBundleListener(this);
      for (Bundle b : cc.getBundleContext().getBundles()) {
        logBundle(b);
      }
    }
  
    /** OSGi callback */
    @Deactivate
    public void deactivate() {
      for (BundleInfoDb a : db) {
        logger.info("Clearing versions");
        a.clear(host);
      }
    }
  
    @Override
   public void bundleChanged(BundleEvent event) {
     switch (event.getType()) {
       case BundleEvent.INSTALLED:
         logBundle(event.getBundle());
         break;
       case BundleEvent.STOPPED:
       case BundleEvent.UNINSTALLED:
         for (BundleInfoDb a : db)
           a.delete(host, event.getBundle().getBundleId());
         break;
       default:
         // do nothing
     }
   }
 
   private void logBundle(final Bundle bundle) {
     final BundleInfo info = bundleInfo(host, bundle.getSymbolicName(), bundle.getBundleId(), bundle.getVersion()
             .toString(), getBuildNumber(bundle));
     final String log = String.format("Bundle %s, id %d, version %s, build number %s", info.getBundleSymbolicName(),
             info.getBundleId(), info.getBundleVersion(), info.getBuildNumber().getOrElse("n/a"));
     logger.info(log);
     for (BundleInfoDb a : db)
       a.store(info);
   }
 }