#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2010 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab 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.
 *
 * HeuristicLab 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 HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using System.Threading;
using HeuristicLab.Common;
using HeuristicLab.Hive.Contracts;
using HeuristicLab.Hive.Contracts.BusinessObjects;
using HeuristicLab.Hive.Contracts.Interfaces;
using HeuristicLab.Hive.Contracts.ResponseObjects;
using HeuristicLab.Clients.Common;

namespace HeuristicLab.Hive.ExperimentManager {
  internal class JobResultPoller {
    private bool stopRequested { get; set; }
    private AutoResetEvent waitHandle;
    private Thread thread;

    private HiveJob hiveJob;
    public HiveJob HiveJob {
      get { return hiveJob; }
      set { hiveJob = value; }
    }

    private TimeSpan interval;
    public TimeSpan Interval {
      get { return interval; }
      set { interval = value; }
    }

    private bool isPolling;
    public bool IsPolling {
      get { return isPolling; }
      set {
        if (isPolling != value) {
          isPolling = value;
          OnIsPollingChanged();
        }
      }
    }

    public JobResultPoller(HiveJob hiveJob, TimeSpan interval) {
      this.isPolling = false;
      this.hiveJob = hiveJob;
      this.interval = interval;
    }

    public void Start() {
      stopRequested = false;
      thread = new Thread(RunPolling);
      thread.Start();
      IsPolling = true;
    }

    public void Stop() {
      // use AutoResetEvent.Set instead if Thread.Interrupt because its much cleaner
      stopRequested = true;
      waitHandle.Set();
      IsPolling = false;
      thread = null;
    }

    public void RunPolling() {
      try {
        waitHandle = new AutoResetEvent(false);
        while (!stopRequested) {
          OnPollingStarted();
          FetchJobResults();
          OnPollingFinished();
          waitHandle.WaitOne(Interval);
        }
        waitHandle.Close();
      }
      catch (Exception e) {
        OnExceptionOccured(e);
        IsPolling = false;
      }
    }

    private void FetchJobResults() {
      int repetitions = 5;
      ResponseObject<JobResultList> response = null;
      while (response == null && repetitions > 0) {
        repetitions--;
        try {
          using (Disposable<IClientFacade> service = ServiceLocator.Instance.StreamedClientFacadePool.GetService()) {
            response = service.Obj.GetChildJobResults(hiveJob.JobDto.Id, true, true);
          }
        }
        catch (Exception e) {
          if (repetitions == 0)
            throw e;
        }
      }
      if (response.StatusMessage == ResponseStatus.Ok) {
        OnJobResultsReceived(response.Obj);
      } else {
        throw new JobResultPollingException(response.StatusMessage.ToString());
      }
    }

    public event EventHandler<EventArgs<JobResultList>> JobResultsReceived;
    private void OnJobResultsReceived(JobResultList jobResults) {
      var handler = JobResultsReceived;
      if (handler != null) handler(this, new EventArgs<JobResultList>(jobResults));
    }

    public event EventHandler<EventArgs<Exception>> ExceptionOccured;
    private void OnExceptionOccured(Exception e) {
      var handler = ExceptionOccured;
      if (handler != null) handler(this, new EventArgs<Exception>(e));
    }

    public event EventHandler IsPollingChanged;
    private void OnIsPollingChanged() {
      var handler = IsPollingChanged;
      if (handler != null) handler(this, EventArgs.Empty);
    }
    public event EventHandler PollingStarted;
    private void OnPollingStarted() {
      var handler = PollingStarted;
      if (handler != null) handler(this, EventArgs.Empty);
    }
    public event EventHandler PollingFinished;
    private void OnPollingFinished() {
      var handler = PollingFinished;
      if (handler != null) handler(this, EventArgs.Empty);
    }
  }
}