/*
    * 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.rest;
  
  import org.opencastproject.job.api.Job;
  import org.opencastproject.job.api.JobProducer;
  import org.opencastproject.serviceregistry.api.ServiceRegistry;
  import org.opencastproject.serviceregistry.api.ServiceRegistryException;
  import org.opencastproject.serviceregistry.api.UndispatchableJobException;
  import org.opencastproject.util.NotFoundException;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import javax.ws.rs.FormParam;
  import javax.ws.rs.HEAD;
  import javax.ws.rs.POST;
  import javax.ws.rs.Path;
  import javax.ws.rs.WebApplicationException;
  import javax.ws.rs.core.Response;
  import javax.ws.rs.core.Response.Status;
  
  /**
   * Base implementation for job producer REST endpoints.
   */
  public abstract class AbstractJobProducerEndpoint {
  
    /** The logger */
    private static final Logger logger = LoggerFactory.getLogger(AbstractJobProducerEndpoint.class);
  
    /**
     * @see org.opencastproject.job.api.JobProducer#acceptJob(org.opencastproject.job.api.Job)
     */
    @POST
    @Path("/dispatch")
    public Response dispatchJob(@FormParam("id") long jobId, @FormParam("operation") String jobOperation)
            throws ServiceRegistryException {
      final JobProducer service = getService();
      if (service == null)
        throw new WebApplicationException(Status.SERVICE_UNAVAILABLE);
  
      // See if the service is ready to accept anything
      if (!service.isReadyToAcceptJobs(jobOperation)) {
        logger.debug("Service {} is not ready to accept jobs with operation {}", service, jobOperation);
        return Response.status(Status.SERVICE_UNAVAILABLE).build();
      }
  
      Job job;
      try {
        job = getServiceRegistry().getJob(jobId);
      } catch (NotFoundException e) {
        logger.warn("Unable to find dispatched job {}", jobId);
        return Response.status(Status.NOT_FOUND).build();
      }
  
      // See if the service has strong feelings about this particular job
      try {
        if (!service.isReadyToAccept(job)) {
          logger.debug("Service {} temporarily refused to accept job {}", service, jobId);
          return Response.status(Status.SERVICE_UNAVAILABLE).build();
        }
      } catch (UndispatchableJobException e) {
        logger.warn("Service {} permanently refused to accept job {}", service, jobId);
        return Response.status(Status.PRECONDITION_FAILED).build();
      }
  
      service.acceptJob(job);
      return Response.noContent().build();
  
    }
  
    @HEAD
    @Path("/dispatch")
    public Response checkHeartbeat() {
      return Response.ok().build();
    }
  
    /**
     * Returns the job producer that is backing this REST endpoint.
     *
    * @return the job producer
    */
   public abstract JobProducer getService();
 
   /**
    * Return the service registry.
    */
   public abstract ServiceRegistry getServiceRegistry();
 
 }