#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.Linq;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
using HeuristicLab.Optimization;
using System.Drawing;
using HeuristicLab.Collections;
using System.Collections.Generic;
using HeuristicLab.Hive.Contracts.BusinessObjects;
using System.IO;
using HeuristicLab.Persistence.Default.Xml;
using HeuristicLab.PluginInfrastructure;
using System.Reflection;
using HeuristicLab.Hive.Contracts.Interfaces;
using HeuristicLab.Hive.Contracts;
using System.Threading;
using HeuristicLab.Tracing;
using HeuristicLab.Hive.JobBase;
using System.Diagnostics;
using System.Collections;

namespace HeuristicLab.Hive.Experiment {
  /// <summary>
  /// An experiment which contains multiple batch runs of algorithms.
  /// </summary>
  [Item(itemName, itemDescription)]
  [Creatable("Testing & Analysis")]
  [StorableClass]
  public class HiveExperiment : NamedItem, IExecutable {
    private const string itemName = "Hive Experiment";
    private const string itemDescription = "An experiment which contains multiple batch runs of algorithms which are executed in the Hive.";
    private const int resultPollingIntervalMs = 15000;

    private object locker = new object();
    private const int maxSnapshotRetries = 20;
    private System.Timers.Timer timer;
    private bool pausePending, stopPending;
    private DateTime lastUpdateTime;

    [Storable]
    private IDictionary<Guid, IOptimizer> pendingOptimizers = new Dictionary<Guid, IOptimizer>();

    [Storable]
    private JobItemList jobItems;
    public JobItemList JobItems {
      get { return jobItems; }
    }
    

    [Storable]
    private string serverUrl;
    public string ServerUrl {
      get { return serverUrl; }
      set {
        if (serverUrl != value) {
          serverUrl = value; 
          OnServerUrlChanged();
        }
      }
    }

    [Storable]
    private string resourceIds;
    public string ResourceIds {
      get { return resourceIds; }
      set {
        if (resourceIds != value) {
          resourceIds = value; 
          OnResourceIdsChanged();
        }
      }
    }

    [Storable]
    private HeuristicLab.Optimization.Experiment experiment;
    public HeuristicLab.Optimization.Experiment Experiment {
      get { return experiment; }
      set {
        if (experiment != value) {
          experiment = value;
          OnExperimentChanged();
        }
      }
    }

    [Storable]
    private ILog log;
    public ILog Log {
      get { return log; }
    }

    [StorableConstructor]
    public HiveExperiment(bool deserializing)
      : base(deserializing) {
    }

    public HiveExperiment()
      : base(itemName, itemDescription) {
      this.ServerUrl = HeuristicLab.Hive.Experiment.Properties.Settings.Default.HiveServerUrl;
      this.ResourceIds = HeuristicLab.Hive.Experiment.Properties.Settings.Default.ResourceIds;
      this.log = new Log();
      pausePending = stopPending = false;
      jobItems = new JobItemList();
      InitTimer();
    }

    public override IDeepCloneable Clone(Cloner cloner) {
      LogMessage("I am beeing cloned");
      HiveExperiment clone = (HiveExperiment)base.Clone(cloner);
      clone.resourceIds = this.resourceIds;
      clone.serverUrl = this.serverUrl;
      clone.experiment = (HeuristicLab.Optimization.Experiment)cloner.Clone(experiment);
      clone.executionState = this.executionState;
      clone.executionTime = this.executionTime;
      clone.pendingOptimizers = new Dictionary<Guid, IOptimizer>();
      foreach (var pair in this.pendingOptimizers)
        clone.pendingOptimizers[pair.Key] = (IOptimizer)cloner.Clone(pair.Value);
      clone.log = (ILog)cloner.Clone(log);
      clone.stopPending = this.stopPending;
      clone.pausePending = this.pausePending;
      clone.jobItems = (JobItemList)cloner.Clone(jobItems);
      return clone;
    }

    [StorableHook(HookType.AfterDeserialization)]
    private void AfterDeserialization() {
      InitTimer();
      LogMessage("I was deserialized.");
    }

    private void InitTimer() {
      timer = new System.Timers.Timer(100);
      timer.AutoReset = true;
      timer.Elapsed += new System.Timers.ElapsedEventHandler(timer_Elapsed);
    }

    private void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e) {
      DateTime now = DateTime.Now;
      ExecutionTime += now - lastUpdateTime;
      lastUpdateTime = now;
    }

    public IEnumerable<string> ResourceGroups {
      get {
        if (!string.IsNullOrEmpty(resourceIds)) {
          return resourceIds.Split(';');
        } else {
          return new List<string>();
        }
      }
    }
    #region IExecutable Members

    [Storable]
    private Core.ExecutionState executionState;
    public ExecutionState ExecutionState {
      get { return executionState; }
      private set {
        if (executionState != value) {
          executionState = value;
          OnExecutionStateChanged();
        }
      }
    }

    [Storable]
    private TimeSpan executionTime;
    public TimeSpan ExecutionTime {
      get { return executionTime; }
      private set {
        if (executionTime != value) {
          executionTime = value;
          OnExecutionTimeChanged();
        }
      }
    }

    public void Pause() {
      throw new NotSupportedException();
    }

    public void Prepare() {
      if (experiment != null) {
        experiment.Prepare();
        this.ExecutionState = Core.ExecutionState.Prepared;
        OnPrepared();
      }
    }

    public void Start() {
      OnStarted();
      lastUpdateTime = DateTime.Now;
      this.ExecutionState = Core.ExecutionState.Started;
      Thread t = new Thread(() => {
        IExecutionEngineFacade executionEngineFacade = ServiceLocator.CreateExecutionEngineFacade(ServerUrl);

        pendingOptimizers = new Dictionary<Guid, IOptimizer>();
        IEnumerable<string> groups = ResourceGroups;

        foreach (IOptimizer optimizer in GetOptimizers(false)) {
          SerializedJob serializedJob = CreateSerializedJob(optimizer);
          ResponseObject<JobDto> response = executionEngineFacade.AddJobWithGroupStrings(serializedJob, groups);
          pendingOptimizers.Add(response.Obj.Id, optimizer);

          JobItem jobItem = new JobItem() {
            JobDto = response.Obj,
            LatestSnapshot = new ResponseObject<SerializedJob>() {
              Obj = serializedJob,
              StatusMessage = "Initial Snapshot",
              Success = true
            }
          };
          jobItems.Add(jobItem);

          LogMessage("Sent job to server (jobId: " + response.Obj.Id + ")");
        }

        // start results polling after sending sending the jobs to the server (to avoid race conflicts at the optimizers-collection)
        foreach (JobItem jobItem in jobItems) {
          StartResultPollingThread(jobItem.JobDto);
        }
      });
      t.Start();
    }

    /// <summary>
    /// Returns all optimizers in the current Experiment
    /// </summary>
    /// <param name="flatout">if false only top level optimizers are returned, if true the optimizer-tree is flatted</param>
    /// <returns></returns>
    private IEnumerable<IOptimizer> GetOptimizers(bool flatout) {
      if (!flatout) {
        return experiment.Optimizers;
      } else {
        throw new NotImplementedException();
      }
    }

    private void ReplaceOptimizer(IOptimizer originalOptimizer, IOptimizer newOptimizer) {
      lock (locker) {
        int originalOptimizerIndex = experiment.Optimizers.IndexOf(originalOptimizer);
        experiment.Optimizers[originalOptimizerIndex] = newOptimizer;
      }
    }

    public void Stop() {
      // todo
    }
    
    #endregion

    private SerializedJob CreateSerializedJob(IOptimizer optimizer) {
      IJob job = new OptimizerJob() {
        Optimizer = optimizer
      };

      // serialize job
      MemoryStream memStream = new MemoryStream();
      XmlGenerator.Serialize(job, memStream);
      byte[] jobByteArray = memStream.ToArray();
      memStream.Dispose();

      // find out which which plugins are needed for the given object
      List<HivePluginInfoDto> pluginsNeeded = (
        from p in GetDeclaringPlugins(optimizer.GetType())
        select new HivePluginInfoDto() {
          Name = p.Name,
          Version = p.Version
        }).ToList();

      JobDto jobDto = new JobDto() {
        CoresNeeded = 1, // [chn] how to determine real cores needed?
        PluginsNeeded = pluginsNeeded,
        State = State.Offline,
        MemoryNeeded = 0,
        UserId = Guid.Empty // [chn] set real userid here!
      };

      SerializedJob serializedJob = new SerializedJob() {
        JobInfo = jobDto,
        SerializedJobData = jobByteArray
      };

      return serializedJob;
    }

    private void StartResultPollingThread(JobDto job) {
      Thread t = new Thread(() => {
        IExecutionEngineFacade executionEngineFacade = ServiceLocator.CreateExecutionEngineFacade(ServerUrl);
        IJob restoredObject = null;

        do {
          Thread.Sleep(resultPollingIntervalMs);
          //lock (locker) { [chn] try without locking for better performance
            if (stopPending) return;

            ResponseObject<JobDto> response = executionEngineFacade.GetJobById(job.Id);
            LogMessage("Response: " + response.StatusMessage + " (jobId: " + job.Id + ")");

            if (response.Obj != null) {
              UpdateJobItem(response.Obj);
            }
            
            // loop while 
            // 1. the user doesn't request an abort 
            // 2. there is a problem with server communication (success==false)
            // 3. no result for the job is available yet (response.Obj==null)
            // 4. the result that we get from the server is a snapshot and not the final result
            if (response.Success && response.Obj != null && response.Obj.State == State.Finished) {
              ResponseObject<SerializedJob> jobResponse = executionEngineFacade.GetLastSerializedResult(job.Id, false, false);
              restoredObject = XmlParser.Deserialize<IJob>(new MemoryStream(jobResponse.Obj.SerializedJobData));
              UpdateSnapshot(jobResponse);
            }
          //}
        } while (restoredObject == null || restoredObject.ExecutionState != Core.ExecutionState.Stopped);

        LogMessage("Job finished (jobId: " + job.Id + ")");
        // job retrieved... replace the existing optimizers with the finished one
        IOptimizer originalOptimizer = pendingOptimizers[job.Id];
        IOptimizer restoredOptimizer = ((OptimizerJob)restoredObject).Optimizer;

        ReplaceOptimizer(originalOptimizer, restoredOptimizer);
        pendingOptimizers.Remove(job.Id);

        if (pendingOptimizers.Count == 0) {
          // finished
          this.ExecutionState = Core.ExecutionState.Stopped;
          OnStopped();
        }
      });
      t.Start();
    }

    private void UpdateJobItem(JobDto jobDto) {
      JobItem jobItem = jobItems.Single(x => x.JobDto.Id == jobDto.Id);
      jobItem.JobDto = jobDto;
    }

    private void UpdateSnapshot(ResponseObject<SerializedJob> response) {
      JobItem jobItem = jobItems.Single(x => x.JobDto.Id == response.Obj.JobInfo.Id);
      jobItem.LatestSnapshot = response;
    }

    private void LogMessage(string message) {
      // HeuristicLab.Log is not Thread-Safe, so lock every call
      lock (locker) {
        log.LogMessage(message);
      }
    }
    
    #region Required Plugin Search
    /// <summary>
    /// Returns a list of plugins in which the type itself and all members 
    /// of the type are declared. Objectgraph is searched recursively.
    /// </summary>
    private IEnumerable<IPluginDescription> GetDeclaringPlugins(Type type) {
      HashSet<Type> types = new HashSet<Type>();
      FindTypes(type, types, "HeuristicLab.");
      return GetDeclaringPlugins(types);
    }

    /// <summary>
    /// Returns the plugins (including dependencies) in which the given types are declared
    /// </summary>
    private IEnumerable<IPluginDescription> GetDeclaringPlugins(IEnumerable<Type> types) {
      HashSet<IPluginDescription> plugins = new HashSet<IPluginDescription>();
      foreach (Type t in types) {
        FindDeclaringPlugins(ApplicationManager.Manager.GetDeclaringPlugin(t), plugins);
      }
      return plugins;
    }

    /// <summary>
    /// Finds the dependencies of the given plugin and adds it to the plugins hashset.
    /// Also searches the dependencies recursively.
    /// </summary>
    private void FindDeclaringPlugins(IPluginDescription plugin, HashSet<IPluginDescription> plugins) {
      if (!plugins.Contains(plugin)) {
        plugins.Add(plugin);
        foreach (IPluginDescription dependency in plugin.Dependencies) {
          FindDeclaringPlugins(dependency, plugins);
        }
      }
    }

    /// <summary>
    /// Recursively finds all types used in type which are in a namespace which starts with namespaceStart
    /// Be aware that search is not performed on attributes
    /// </summary>
    /// <param name="type">the type to be searched</param>
    /// <param name="types">found types will be stored there, needed in order to avoid duplicates</param>
    /// <param name="namespaceStart">only types from namespaces which start with this will be searched and added</param>
    private void FindTypes(Type type, HashSet<Type> types, string namespaceStart) {
      if (!types.Contains(type) && type.Namespace.StartsWith(namespaceStart)) {
        types.Add(type);

        // constructors
        foreach (ConstructorInfo info in type.GetConstructors()) {
          foreach (ParameterInfo paramInfo in info.GetParameters()) {
            FindTypes(paramInfo.ParameterType, types, namespaceStart);
          }
        }

        // interfaces
        foreach (Type t in type.GetInterfaces()) {
          FindTypes(t, types, namespaceStart);
        }

        // events
        foreach (EventInfo info in type.GetEvents()) {
          FindTypes(info.EventHandlerType, types, namespaceStart);
          FindTypes(info.DeclaringType, types, namespaceStart);
        }

        // properties
        foreach (PropertyInfo info in type.GetProperties()) {
          FindTypes(info.PropertyType, types, namespaceStart);
        }

        // fields
        foreach (FieldInfo info in type.GetFields()) {
          FindTypes(info.FieldType, types, namespaceStart);
        }

        // methods
        foreach (MethodInfo info in type.GetMethods()) {
          foreach (ParameterInfo paramInfo in info.GetParameters()) {
            FindTypes(paramInfo.ParameterType, types, namespaceStart);
          }
          FindTypes(info.ReturnType, types, namespaceStart);
        }
      }
    }
    #endregion

    #region Eventhandler

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

    public event EventHandler ExecutionStateChanged;
    private void OnExecutionStateChanged() {
      LogMessage("ExecutionState changed to " + executionState.ToString());
      EventHandler handler = ExecutionStateChanged;
      if (handler != null) handler(this, EventArgs.Empty);
    }

    public event EventHandler<EventArgs<Exception>> ExceptionOccurred;

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

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

    public event EventHandler Paused;
    private void OnPaused() {
      timer.Stop();
      LogMessage("Paused");
      EventHandler handler = Paused;
      if (handler != null) handler(this, EventArgs.Empty);
    }

    public event EventHandler Prepared;
    protected virtual void OnPrepared() {
      LogMessage("Prepared");
      EventHandler handler = Prepared;
      if (handler != null) handler(this, EventArgs.Empty);
    }

    public event EventHandler ResourceIdsChanged;
    protected virtual void OnResourceIdsChanged() {
      EventHandler handler = ResourceIdsChanged;
      if (handler != null) handler(this, EventArgs.Empty);
    }

    public event EventHandler ExperimentChanged;
    protected virtual void OnExperimentChanged() {
      LogMessage("Experiment changed");
      EventHandler handler = ExperimentChanged;
      if (handler != null) handler(this, EventArgs.Empty);
    }

    public event EventHandler ServerUrlChanged;
    protected virtual void OnServerUrlChanged() {
      EventHandler handler = ServerUrlChanged;
      if (handler != null) handler(this, EventArgs.Empty);
    }

    #endregion
  }
}