#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2011 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.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.Net.Sockets;
using System.ServiceModel;
using System.ServiceModel.Description;
using HeuristicLab.Operators.MPISupport;
using HeuristicLab.Optimization;
using HeuristicLab.Core;
using System.Threading;
using System.Xml;
using System.IO;
using HeuristicLab.Persistence.Default.Xml;
                     
namespace HeuristicLab.MPIAlgorithmRunner {
  public class StreamingHelper {
    public static IItem StreamItem(Stream stream) {
      using (MemoryStream memoryStream = new MemoryStream()) {
        byte[] buffer = new byte[256];
        int read;
        while ((read = stream.Read(buffer, 0, buffer.Length)) != 0)
          memoryStream.Write(buffer, 0, read);

        using (MemoryStream itemStream = new MemoryStream(memoryStream.GetBuffer())) {
          IItem result = XmlParser.Deserialize(itemStream) as IItem;
          return result;
        }
      }
    }
  }

  [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single)]
  class AlgorithmBroker: IAlgorithmBroker {
    private static int FindFreeTcpPort() {
      TcpListener l = new TcpListener(IPAddress.Parse("127.0.0.1"), 0);
      l.Start();
      int port = ((IPEndPoint)l.LocalEndpoint).Port;
      l.Stop();
      return port;
    }

    private static ServiceHost CreateService(MPI.Communicator communicator) {
      AlgorithmBroker broker = new AlgorithmBroker(communicator);
      ServiceHost service = new ServiceHost(broker);

      ContractDescription contract = ContractDescription.GetContract(typeof(IAlgorithmBroker));
      contract.ContractType = typeof(IAlgorithmBroker);
      ServiceEndpoint endpoint = new ServiceEndpoint(contract);
      endpoint.Name = "AlgorithmBrokerEndpoint";
      NetTcpBinding netTCPBinding = new NetTcpBinding(SecurityMode.None);
      netTCPBinding.TransferMode = TransferMode.Streamed;
      netTCPBinding.MaxReceivedMessageSize = int.MaxValue;
      endpoint.Binding = netTCPBinding;
      int port = FindFreeTcpPort();
      endpoint.Address = new EndpointAddress("net.tcp://localhost:" + port + "/AlgorithmBroker");
      service.AddServiceEndpoint(endpoint);
      ServiceDebugBehavior debug = service.Description.Behaviors.Find<ServiceDebugBehavior>();
      debug.IncludeExceptionDetailInFaults = true;

      return service;
    }

    public static ServiceHost StartService(MPI.Communicator communicator) {
      try {
        ServiceHost service = CreateService(communicator);

        service.Open();

        return service;
      }
      catch (AddressAlreadyInUseException) {
        return StartService(communicator);
      }
    }

    private MPI.Communicator communicator;

    public AlgorithmBroker(MPI.Communicator communicator) {
      this.communicator = communicator;
      ExitWaitHandle = new EventWaitHandle(false, EventResetMode.ManualReset);
    }

    #region IAlgorithmBroker Members

    public void SetUpdateInterval(int updateInterval) {
      Console.WriteLine("Set update interval...");

      int clients = MPI.Communicator.world.Group.Size - 1;
      for (int i = 0; i < clients; i++) {
        int client = i + 1;
        communicator.Send<int>(updateInterval, client, 1);
      }
    }

    public void TransmitAlgorithm(Stream stream) {
      Console.WriteLine("Transmitting Algorithm...");

      IAlgorithm alg = StreamingHelper.StreamItem(stream) as IAlgorithm;
      MPITransportWrapper<IAlgorithm> algorithm = new MPITransportWrapper<IAlgorithm>(alg);

      int clients = MPI.Communicator.world.Group.Size - 1;
      for(int i = 0; i < clients; i++) {
        int client = i + 1;
        communicator.Send<MPITransportWrapper<IAlgorithm>>(algorithm, client, 0);
      }
    }

    public object resultLocker = new object();
    public ItemList<ResultCollection> Results { get; set; }

    public Stream GetResults() {
      Console.WriteLine("Transmitting Results...");
      MemoryStream stream = new MemoryStream();
      lock (resultLocker) {
        XmlGenerator.Serialize(Results, stream);
      }
      stream = new MemoryStream((stream as MemoryStream).GetBuffer());

      return stream;
    }

    public EventWaitHandle ExitWaitHandle { get; private set; }

    public bool Terminated { get; set; }

    public bool IsAlgorithmTerminated() {
      lock (ExitWaitHandle) {
        if (Terminated)
          ExitWaitHandle.Set();
        return Terminated;
      }
    }
    #endregion
  }
}