#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.Hive.Contracts.Interfaces;
using HeuristicLab.Hive.Tracing;
using System.Collections.Generic;
using HeuristicLab.PluginInfrastructure.Manager;
using System.IO;

namespace HeuristicLab.Hive.Server.Core {
  public class LifecycleManager : ILifecycleManager {
    private readonly string pluginDir = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "App_Data\\Plugins");
    private AutoResetEvent waitHandle;
    private Thread thread;
    private bool shutdownRequested;
    private PluginManager pm;

    private TimeSpan interval = new TimeSpan(0, 0, 10);
    public TimeSpan Interval {
      get { return interval; }
      set { interval = value; }
    }

    private int jobsCurrentlyTransfering = 0;
    public int JobsCurrentlyTransferring {
      get { return jobsCurrentlyTransfering; }
      set {
        if (jobsCurrentlyTransfering != value) {
          jobsCurrentlyTransfering = value;
          Logger.Info("JobsCurrentlyTransfering: " + jobsCurrentlyTransfering);
        }
      }
    }

    private IEnumerable<PluginDescription> plugins;
    public IEnumerable<PluginDescription> Plugins {
      get { return pm.Plugins; }
    }

    private byte[] configurationFile;
    public byte[] ConfigurationFile {
      get {
        if (configurationFile == null) {
          configurationFile = File.ReadAllBytes(Path.Combine(pluginDir, "HeuristicLab 3.3.exe.config"));
        }
        return configurationFile;
      }
    }

    #region ILifecycleManager Members

    public void Start() {
      LoadPlugins();
      Thread thread = new Thread(RunHeartbeatThread);
      thread.Start();
      using (ServiceLocator.GetContextFactory().GetContext()) {
        OnStarted();
      }
    }

    private void LoadPlugins() {
      pm = new PluginManager(pluginDir);
      pm.DiscoverAndCheckPlugins();
      pm.InitializeLifetimeService();
    }

    private void RunHeartbeatThread() {
      waitHandle = new AutoResetEvent(false);
      shutdownRequested = false;
      while (!shutdownRequested) {
        using (ServiceLocator.GetContextFactory().GetContext(false)) {
          OnServerHeartbeat();
        }
        waitHandle.WaitOne(this.Interval);
      }
      waitHandle.Close();
      using (ServiceLocator.GetContextFactory().GetContext()) {
        OnStopped();
      }
    }

    public void Stop() {
      shutdownRequested = true;
      if (waitHandle != null) waitHandle.Set();
      if (thread != null) thread.Join();
      thread = null;
    }

    public event EventHandler ServerHeartbeat;
    private void OnServerHeartbeat() {
      var handler = ServerHeartbeat;
      if (handler != null) handler(this, EventArgs.Empty);
    }

    public event EventHandler Started;
    private void OnStarted() {
      var handler = Started;
      if (handler != null) handler(this, EventArgs.Empty);
    }

    public event EventHandler Stopped;
    private void OnStopped() {
      var handler = Stopped;
      if (handler != null) handler(this, EventArgs.Empty);
    }

    #endregion
  }
}