#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.Collections.Generic;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;
using System.ServiceModel;
using HeuristicLab.Common;
using HeuristicLab.Hive.Contracts;
using HeuristicLab.Hive.Contracts.BusinessObjects;
using HeuristicLab.Hive.Contracts.ResponseObjects;
using HeuristicLab.Hive.Slave.Common;
using HeuristicLab.Hive.Slave.Communication.SlaveFacade;
using HeuristicLab.PluginInfrastructure;
using HeuristicLab.Tracing;

namespace HeuristicLab.Hive.Slave.Communication {

  /// <summary>
  /// WcfService class is implemented as a Singleton and works as a communication Layer with the Server
  /// </summary>
  public class WcfService {
    private static WcfService instance;
    /// <summary>
    /// Getter for the Instance of the WcfService
    /// </summary>
    /// <returns>the Instance of the WcfService class</returns>
    public static WcfService Instance {
      get {
        if (instance == null) {
          Logger.Debug("New WcfService Instance created");
          instance = new WcfService();
        }
        return instance;
      }
    }

    public DateTime ConnectedSince { get; private set; }
    public NetworkEnum.WcfConnState ConnState { get; private set; }

    private string serverIp;
    public string ServerIp {
      get { return serverIp; }
      set {
        if (serverIp != value) {
          serverIp = value;
        }
      }
    }

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

    /// <summary>
    /// Constructor
    /// </summary>
    private WcfService() {
      ConnState = NetworkEnum.WcfConnState.Disconnected;
    }

    /// <summary>
    /// Connects with the Server, registers the events and fires the Connected (and quiet possibly the ConnectionRestored) Event.
    /// </summary>
    public void Connect(SlaveDto slaveInfo) {
      ServiceLocator.Instance.HostAddress = ServerIp;
      RegisterServiceEvents();
      using (Disposable<SlaveFacade.ISlaveFacade> service = ServiceLocator.Instance.StreamedSlaveFacadePool.GetService()) {
        try {
          Logger.Debug("Starting the Connection Process");
          if (String.Empty.Equals(ServerIp)) {
            Logger.Info("No Server IP set!");
            return;
          }
          ConnState = NetworkEnum.WcfConnState.Connected;
          ConnectedSince = DateTime.Now;
          service.Obj.Login(slaveInfo);
          OnConnected();
        }
        catch (Exception ex) {
          HandleNetworkError(ex);
        }
      }
    }

    private void RegisterServiceEvents() {
      ServiceLocator.Instance.SlaveFacadePool.ExceptionOccured += new EventHandler<HeuristicLab.Common.EventArgs<Exception>>(ClientFacadePool_ExceptionOccured);
      ServiceLocator.Instance.StreamedSlaveFacadePool.ExceptionOccured += new EventHandler<HeuristicLab.Common.EventArgs<Exception>>(ClientFacadePool_ExceptionOccured);
    }

    private void DeregisterServiceEvents() {
      ServiceLocator.Instance.SlaveFacadePool.ExceptionOccured -= new EventHandler<HeuristicLab.Common.EventArgs<Exception>>(ClientFacadePool_ExceptionOccured);
      ServiceLocator.Instance.StreamedSlaveFacadePool.ExceptionOccured -= new EventHandler<HeuristicLab.Common.EventArgs<Exception>>(ClientFacadePool_ExceptionOccured);
    }

    void ClientFacadePool_ExceptionOccured(object sender, EventArgs<Exception> e) {
      HandleNetworkError(e.Value);
      Logger.Error("An exception occured in the WCF-Communication: " + e.Value.ToString());
    }

    ///// <summary>
    ///// Disconnects the Slave from the Server
    ///// </summary>
    public void Disconnect() {
      ConnState = NetworkEnum.WcfConnState.Disconnected;
      DeregisterServiceEvents();
    }

    /// <summary>
    /// Network communication Error Handler - Every network error gets logged and the connection switches to faulted state
    /// </summary>
    /// <param name="e">The Exception</param>
    private void HandleNetworkError(Exception e) {
      ConnState = NetworkEnum.WcfConnState.Failed;
      DeregisterServiceEvents();
      Logger.Error("Network exception occurred: " + e);
    }

    /// <summary>
    /// Methods for the Server Login
    /// </summary>
    //public void Login(SlaveDto slaveInfo) {
    //  try {
    //    using (Disposable<SlaveFacade.ISlaveFacade> service = ServiceLocator.Instance.SlaveFacadePool.GetService()) {
    //      if (ConnState == NetworkEnum.WcfConnState.Connected) {
    //        Logger.Debug("STARTED: Login Sync");
    //        Response res = service.Obj.Login(slaveInfo);
    //        if (res.StatusMessage != ResponseStatus.Ok) {
    //          Logger.Error("FAILED: Login Failed! " + res.StatusMessage);
    //          throw new Exception(res.StatusMessage.ToString());
    //        } else {
    //          Logger.Info("ENDED: Login succeeded" + res.StatusMessage);
    //        }
    //      }
    //    }
    //  }
    //  catch (Exception e) {
    //    OnExceptionOccured(e);
    //  }
    //}

    /// <summary>
    /// Pull a Job from the Server
    /// </summary>
    #region PullJob
    public event System.EventHandler<GetJobCompletedEventArgs> GetJobCompleted;
    public void GetJobAsync(Guid guid) {
      Disposable<SlaveFacade.ISlaveFacade> service = ServiceLocator.Instance.StreamedSlaveFacadePool.GetService();
      Logger.Debug("STARTED: Fetching of Jobs from Server for Slave");
      service.Obj.BeginGetStreamedJob(guid, (ar => {
        Stream stream = null;
        MemoryStream memStream = null;
        try {
          if (ar.IsCompleted) {
            Logger.Debug("ENDED: Fetching of Jobs from Server for Slave");
            stream = service.Obj.EndGetStreamedJob(ar);

            //first deserialize the response
            BinaryFormatter formatter = new BinaryFormatter();
            ResponseObject<JobDto> response = (ResponseObject<JobDto>)formatter.Deserialize(stream);

            //second deserialize the BLOB
            memStream = new MemoryStream();

            byte[] buffer = new byte[3024];
            int read = 0;
            while ((read = stream.Read(buffer, 0, buffer.Length)) > 0) {
              memStream.Write(buffer, 0, read);
            }

            memStream.Close();

            GetJobCompletedEventArgs completedEventArgs = new GetJobCompletedEventArgs(new object[] { response, memStream.GetBuffer() }, null, !ar.IsCompleted, ar.AsyncState);
            GetJobCompleted(this, completedEventArgs);

          } else {
            HandleNetworkError(new FaultException("GetJobAsync did not complete"));
          }
        }
        catch (Exception e) {
          OnExceptionOccured(e);
        }
        finally {
          if (stream != null)
            stream.Dispose();

          if (memStream != null)
            memStream.Dispose();

          try { service.Dispose(); }
          catch (Exception e) { OnExceptionOccured(e); }
        }
      }), null);
    }

    #endregion

    /// <summary>
    /// Send back finished Job Results
    /// </summary>
    #region SendJobResults
    public event System.EventHandler<StoreFinishedJobResultCompletedEventArgs> GetFinishedJobResultCompleted;
    public void GetFinishedJobResultAsync(Guid clientId, Guid jobId, byte[] result, TimeSpan executionTime, string exception, bool finished) {
      Disposable<SlaveFacade.ISlaveFacade> service = ServiceLocator.Instance.StreamedSlaveFacadePool.GetService();
      Logger.Debug("STARTED: Sending back the finished job results");
      Logger.Debug("Building stream");
      Stream stream = GetStreamedJobResult(clientId, jobId, result, executionTime, exception);
      Logger.Debug("Builded stream");
      Logger.Debug("Making the call");

      service.Obj.BeginStoreFinishedJobResultStreamed(stream, (ar => {
        try {
          Logger.Debug("Finished storing the job");
          if (stream != null)
            stream.Dispose();

          if (ar.IsCompleted) {
            var res = service.Obj.EndStoreFinishedJobResultStreamed(ar);
            StoreFinishedJobResultCompletedEventArgs args = new StoreFinishedJobResultCompletedEventArgs(new object[] { res }, null, false, null);
            Logger.Debug("calling the Finished Job Event");
            GetFinishedJobResultCompleted(this, args);
            Logger.Debug("ENDED: Sending back the finished job results");
          } else {
            HandleNetworkError(new FaultException("GetFinishedJobResultAsync did not complete"));
          }
        }
        catch (Exception e) {
          OnExceptionOccured(e);
        }
        finally {
          try { service.Dispose(); }
          catch (Exception e) { OnExceptionOccured(e); }
        }
      }), null);
    }

    #endregion

    #region Processsnapshots
    public event System.EventHandler<ProcessSnapshotCompletedEventArgs> ProcessSnapshotCompleted;
    public void ProcessSnapshotAsync(Guid clientId, Guid jobId, byte[] result, TimeSpan executionTime, string exception, bool finished) {
      Disposable<SlaveFacade.ISlaveFacade> service = ServiceLocator.Instance.StreamedSlaveFacadePool.GetService();

      Stream stream = GetStreamedJobResult(clientId, jobId, result, executionTime, exception);
      service.Obj.BeginProcessSnapshotStreamed(stream, (ar => {
        try {
          if (stream != null)
            stream.Dispose();

          if (ar.IsCompleted) {
            var res = service.Obj.EndStoreFinishedJobResultStreamed(ar);
            ProcessSnapshotCompletedEventArgs args = new ProcessSnapshotCompletedEventArgs(new object[] { res }, null, false, null);
            ProcessSnapshotCompleted(this, args);
          } else {
            HandleNetworkError(new FaultException("ProcessSnapshotAsync did not complete"));
          }
        }
        catch (Exception e) {
          OnExceptionOccured(e);
        }
        finally {
          try { service.Dispose(); }
          catch (Exception e) { OnExceptionOccured(e); }
        }
      }), null);
    }

    #endregion

    /// <summary>
    /// Methods for sending the periodically Heartbeat
    /// </summary>
    #region Heartbeat

    public event EventHandler<ProcessHeartBeatCompletedEventArgs> ProcessHeartBeatCompleted;
    public void ProcessHeartBeatSync(HeartBeatData hbd) {
      using (Disposable<SlaveFacade.ISlaveFacade> service = ServiceLocator.Instance.StreamedSlaveFacadePool.GetService()) {
        Logger.Debug("STARTING: sending heartbeat");
        var res = service.Obj.ProcessHeartBeat(hbd);

        if (res.StatusMessage == ResponseStatus.Ok) {
          ProcessHeartBeatCompleted(this, new ProcessHeartBeatCompletedEventArgs(new object[] { res }, null, false, null));
          Logger.Debug("ENDED: sending heartbeats");
        } else {
          Logger.Error("FAILED: sending heartbeats: " + res.StatusMessage.ToString());
        }
      }
    }

    #endregion

    /// <summary>
    /// Send back finished and Stored Job Results
    /// </summary>
    private Stream GetStreamedJobResult(Guid clientId, Guid jobId, byte[] result, TimeSpan executionTime, string exception) {
      JobResult jobResult = new JobResult();
      jobResult.SlaveId = clientId;
      jobResult.Id = jobId;
      jobResult.ExecutionTime = executionTime;
      jobResult.Exception = exception;

      MultiStream stream = new MultiStream();

      //first send result
      stream.AddStream(new StreamedObject<JobResult>(jobResult));

      //second stream the job binary data
      MemoryStream memStream = new MemoryStream(result, false);
      stream.AddStream(memStream);

      return stream;
    }

    public ResponseResultReceived StoreFinishedJobResultsSync(Guid clientId, Guid jobId, byte[] result, TimeSpan executionTime, string exception, bool finished) {
      using (Disposable<SlaveFacade.ISlaveFacade> service = ServiceLocator.Instance.StreamedSlaveFacadePool.GetService()) {
        ResponseResultReceived res = service.Obj.StoreFinishedJobResultStreamed(GetStreamedJobResult(clientId, jobId, result, executionTime, exception));
        return res;
      }
    }

    public Response IsJobStillNeeded(Guid jobId) {
      try {
        Logger.Debug("STARTING: Sync call: IsJobStillNeeded");
        using (Disposable<SlaveFacade.ISlaveFacade> service = ServiceLocator.Instance.StreamedSlaveFacadePool.GetService()) {
          Response res = service.Obj.IsJobStillNeeded(jobId);
          Logger.Debug("ENDED: Sync call: IsJobStillNeeded");
          return res;
        }
      }
      catch (Exception e) {
        OnExceptionOccured(e);
        return null;
      }
    }

    public ResponseResultReceived ProcessSnapshotSync(Guid clientId, Guid jobId, byte[] result, TimeSpan executionTime, string exception) {
      try {
        using (Disposable<SlaveFacade.ISlaveFacade> service = ServiceLocator.Instance.StreamedSlaveFacadePool.GetService()) {
          return service.Obj.ProcessSnapshotStreamed(GetStreamedJobResult(clientId, jobId, result, executionTime, exception));
        }
      }
      catch (Exception e) {
        OnExceptionOccured(e);
        return null;
      }
    }

    public IEnumerable<CachedHivePluginInfoDto> RequestPlugins(List<HivePluginInfoDto> requestedPlugins) {
      try {
        using (Disposable<SlaveFacade.ISlaveFacade> service = ServiceLocator.Instance.StreamedSlaveFacadePool.GetService()) {
          Logger.Debug("STARTED: Requesting Plugins for Job");
          Logger.Debug("STARTED: Getting the stream");
          Stream stream = service.Obj.GetStreamedPlugins(requestedPlugins.ToArray());
          Logger.Debug("ENDED: Getting the stream");
          BinaryFormatter formatter = new BinaryFormatter();
          Logger.Debug("STARTED: Deserializing the stream");
          ResponseList<CachedHivePluginInfoDto> response = (ResponseList<CachedHivePluginInfoDto>)formatter.Deserialize(stream);
          Logger.Debug("ENDED: Deserializing the stream");
          if (stream != null)
            stream.Dispose();
          return response.List;
        }
      }
      catch (Exception e) {
        OnExceptionOccured(e);
        return null;
      }
    }

    public void Logout(Guid guid) {
      try {
        Logger.Debug("STARTED: Logout");
        using (Disposable<SlaveFacade.ISlaveFacade> service = ServiceLocator.Instance.StreamedSlaveFacadePool.GetService()) {
          service.Obj.Logout(guid);
        }
        Logger.Debug("ENDED: Logout");
      }
      catch (Exception e) {
        OnExceptionOccured(e);
      }
    }

    public ResponseCalendar GetCalendarSync(Guid clientId) {
      try {
        Logger.Debug("STARTED: Syncing Calendars");
        using (Disposable<SlaveFacade.ISlaveFacade> service = ServiceLocator.Instance.StreamedSlaveFacadePool.GetService()) {
          ResponseCalendar cal = service.Obj.GetCalendar(clientId);
          Logger.Debug("ENDED: Syncing Calendars");
          return cal;
        }
      }
      catch (Exception e) {
        OnExceptionOccured(e);
        return null;
      }
    }

    public Response SetCalendarStatus(Guid clientId, CalendarState state) {
      try {
        Logger.Debug("STARTED: Setting Calendar status to: " + state);
        using (Disposable<SlaveFacade.ISlaveFacade> service = ServiceLocator.Instance.StreamedSlaveFacadePool.GetService()) {
          Response resp = service.Obj.SetCalendarStatus(clientId, state);
          Logger.Debug("ENDED: Setting Calendar status to: " + state);
          return resp;
        }
      }
      catch (Exception e) {
        OnExceptionOccured(e);
        return null;
      }
    }

    public ResponseObject<JobDto> AddChildJob(Guid parentJobId, SerializedJob serializedJob) {
      try {
        Logger.Debug("STARTED: Add Child Job for parent: " + parentJobId);
        using (Disposable<SlaveFacade.ISlaveFacade> service = ServiceLocator.Instance.StreamedSlaveFacadePool.GetService()) {
          ResponseObject<JobDto> response = service.Obj.AddChildJob(parentJobId, serializedJob);
          Logger.Debug("ENDED: Add Child Job for parent: " + parentJobId);
          return response;
        }
      }
      catch (Exception e) {
        OnExceptionOccured(e);
        return null;
      }
    }

    public ResponseObject<JobDto> PauseJob(SerializedJob serializedJob) {
      try {
        Logger.Debug("STARTED: Pausing job: " + serializedJob.JobInfo.Id);
        using (Disposable<SlaveFacade.ISlaveFacade> service = ServiceLocator.Instance.StreamedSlaveFacadePool.GetService()) {
          ResponseObject<JobDto> response = service.Obj.PauseJob(serializedJob);
          Logger.Debug("ENDED: Pausing job: " + serializedJob.JobInfo.Id);
          return response;
        }
      }
      catch (Exception e) {
        OnExceptionOccured(e);
        return null;
      }
    }

    public ResponseObject<SerializedJobList> GetChildJobs(Guid parentJob) {
      try {
        Logger.Debug("STARTED: GetChildJobs job: " + parentJob);
        using (Disposable<SlaveFacade.ISlaveFacade> service = ServiceLocator.Instance.StreamedSlaveFacadePool.GetService()) {
          SerializedJobList serializedJobs = new SerializedJobList();
          JobResult[] results = service.Obj.GetChildJobResults(new Guid?(parentJob), false, false);
          foreach (JobResult result in results) {
            serializedJobs.Add(service.Obj.GetLastSerializedResult(result.Id));
          }

          Logger.Debug("ENDED: GetChildJobs job: " + parentJob);
          return new ResponseObject<SerializedJobList>() {
            Obj = serializedJobs
          };
        }
      }
      catch (Exception e) {
        OnExceptionOccured(e);
        return null;
      }
    }

    public void DeleteChildJobs(Guid jobId) {
      try {
        using (Disposable<SlaveFacade.ISlaveFacade> service = ServiceLocator.Instance.StreamedSlaveFacadePool.GetService()) {
          service.Obj.DeleteChildJobs(jobId);
        }
      }
      catch (Exception e) {
        OnExceptionOccured(e);
      }
    }

    public event EventHandler<EventArgs<Exception>> ExceptionOccured;
    private void OnExceptionOccured(Exception e) {
      Logger.Error("Error: " + e.ToString());
      var handler = ExceptionOccured;
      if (handler != null) handler(this, new EventArgs<Exception>(e));
    }
  }
}