/*
    * 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.workspace.impl;
  
  import org.opencastproject.workspace.api.Workspace;
  
  import org.quartz.Job;
  import org.quartz.JobDetail;
  import org.quartz.JobExecutionContext;
  import org.quartz.JobExecutionException;
  import org.quartz.Trigger;
  import org.quartz.TriggerUtils;
  import org.quartz.impl.StdSchedulerFactory;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.util.Date;
  
  /** Clear outdated workspace files {@link Workspace}. */
  public class WorkspaceCleaner {
  
    /** Log facility */
    private static final Logger logger = LoggerFactory.getLogger(WorkspaceCleaner.class);
  
    private static final String JOB_NAME = "mh-workspace-cleaner-job";
    private static final String JOB_GROUP = "mh-workspace-cleaner-job-group";
    private static final String TRIGGER_NAME = "mh-workspace-cleaner-trigger";
    private static final String TRIGGER_GROUP = "mh-workspace-cleaner-trigger-group";
    private static final String JOB_PARAM_PARENT = "parent";
  
    private final org.quartz.Scheduler quartz;
  
    private final Workspace workspace;
    private final int maxAge;
    private int schedulerPeriod;
  
    protected WorkspaceCleaner(Workspace workspace, int schedulerPeriod, int maxAge) {
      this.workspace = workspace;
      this.maxAge = maxAge;
      this.schedulerPeriod = schedulerPeriod;
  
      // Continue only if we have a sensible period value
      if (schedulerPeriod <= 0) {
        logger.debug("No scheduler initialized due to invalid scheduling period ({})", schedulerPeriod);
        quartz = null;
        return;
      }
  
      try {
        quartz = new StdSchedulerFactory().getScheduler();
        quartz.start();
        // create and set the job. To actually run it call schedule(..)
        final JobDetail job = new JobDetail(JOB_NAME, JOB_GROUP, Runner.class);
        job.setDurability(false);
        job.setVolatility(true);
        job.getJobDataMap().put(JOB_PARAM_PARENT, this);
        quartz.addJob(job, true);
      } catch (org.quartz.SchedulerException e) {
        throw new RuntimeException(e);
      }
    }
  
    public Workspace getWorkspace() {
      return workspace;
    }
  
    public int getMaxAge() {
      return maxAge;
    }
  
    /**
     * Set the schedule and start or restart the scheduler.
     */
    public void schedule() {
      if (quartz == null || schedulerPeriod <= 0) {
        logger.debug("Cancel scheduling of workspace cleaner due to invalid scheduling period");
        return;
      }
      logger.debug("Scheduling workspace cleaner to run every {} seconds.", schedulerPeriod);
      try {
       final Trigger trigger = TriggerUtils.makeSecondlyTrigger(schedulerPeriod);
       trigger.setStartTime(new Date());
       trigger.setName(TRIGGER_NAME);
       trigger.setGroup(TRIGGER_GROUP);
       trigger.setJobName(JOB_NAME);
       trigger.setJobGroup(JOB_GROUP);
       if (quartz.getTriggersOfJob(JOB_NAME, JOB_GROUP).length == 0) {
         quartz.scheduleJob(trigger);
       } else {
         quartz.rescheduleJob(TRIGGER_NAME, TRIGGER_GROUP, trigger);
       }
     } catch (Exception e) {
       logger.error("Error scheduling Quartz job", e);
     }
   }
 
   /** Shutdown the scheduler. */
   public void shutdown() {
     try {
       quartz.shutdown();
     } catch (org.quartz.SchedulerException ignore) {
     }
   }
 
   // just to make sure Quartz is being shut down...
   @Override
   protected void finalize() throws Throwable {
     super.finalize();
     shutdown();
   }
 
   // --
 
   /** Quartz work horse. */
   public static class Runner implements Job {
 
     @Override
     public void execute(JobExecutionContext jobExecutionContext) throws JobExecutionException {
       logger.debug("Start workspace cleaner");
       try {
         execute((WorkspaceCleaner) jobExecutionContext.getJobDetail().getJobDataMap().get(JOB_PARAM_PARENT));
       } catch (Exception e) {
         throw new JobExecutionException("An error occurred while cleaning workspace", e);
       }
       logger.debug("Finished workspace cleaner");
     }
 
     private void execute(WorkspaceCleaner workspaceCleaner) {
       workspaceCleaner.getWorkspace().cleanup(workspaceCleaner.getMaxAge());
     }
 
   }
 
 }