#region License Information
/* HeuristicLab
 * Copyright (C) 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.Drawing;
using System.Linq;
using System.Threading;
using Google.ProtocolBuffers;
using HEAL.Attic;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HeuristicLab.Optimization;
using HeuristicLab.Parameters;

namespace HeuristicLab.Problems.ExternalEvaluation {
  [Item("External Evaluation Problem (multi-objective)", "A multi-objective problem that is evaluated in a different process.")]
  [Creatable(CreatableAttribute.Categories.ExternalEvaluationProblems, Priority = 200)]
  [StorableType("CCA50199-A6AB-4C84-B4FA-0262CAF416EC")]
  public class MultiObjectiveExternalEvaluationProblem<TEncoding, TEncodedSolution> : MultiObjectiveProblem<TEncoding, TEncodedSolution>, IExternalEvaluationProblem
    where TEncoding : class, IEncoding
    where TEncodedSolution : class, IEncodedSolution {

    public static new Image StaticItemImage {
      get { return HeuristicLab.Common.Resources.VSImageLibrary.Type; }
    }

    #region Parameters
    public OptionalValueParameter<EvaluationCache> CacheParameter {
      get { return (OptionalValueParameter<EvaluationCache>)Parameters["Cache"]; }
    }
    public IValueParameter<CheckedItemCollection<IEvaluationServiceClient>> ClientsParameter {
      get { return (IValueParameter<CheckedItemCollection<IEvaluationServiceClient>>)Parameters["Clients"]; }
    }
    public IValueParameter<SolutionMessageBuilder> MessageBuilderParameter {
      get { return (IValueParameter<SolutionMessageBuilder>)Parameters["MessageBuilder"]; }
    }
    public IFixedValueParameter<MultiObjectiveOptimizationSupportScript<TEncodedSolution>> SupportScriptParameter {
      get { return (IFixedValueParameter<MultiObjectiveOptimizationSupportScript<TEncodedSolution>>)Parameters["SupportScript"]; }
    }
    #endregion

    #region Properties
    public new TEncoding Encoding {
      get { return base.Encoding; }
      set { base.Encoding = value; }
    }
    public EvaluationCache Cache {
      get { return CacheParameter.Value; }
    }
    public CheckedItemCollection<IEvaluationServiceClient> Clients {
      get { return ClientsParameter.Value; }
    }
    public SolutionMessageBuilder MessageBuilder {
      get { return MessageBuilderParameter.Value; }
    }
    public MultiObjectiveOptimizationSupportScript<TEncodedSolution> OptimizationSupportScript {
      get { return SupportScriptParameter.Value; }
    }
    private IMultiObjectiveOptimizationSupport<TEncodedSolution> OptimizationSupport {
      get { return SupportScriptParameter.Value; }
    }
    #endregion

    [StorableConstructor]
    protected MultiObjectiveExternalEvaluationProblem(StorableConstructorFlag _) : base(_) { }
    protected MultiObjectiveExternalEvaluationProblem(MultiObjectiveExternalEvaluationProblem<TEncoding, TEncodedSolution> original, Cloner cloner) : base(original, cloner) { }
    public override IDeepCloneable Clone(Cloner cloner) {
      return new MultiObjectiveExternalEvaluationProblem<TEncoding, TEncodedSolution>(this, cloner);
    }
    public MultiObjectiveExternalEvaluationProblem(TEncoding encoding)
      : base(encoding) {
      MaximizationParameter.ReadOnly = false;
      MaximizationParameter.Value = new BoolArray();
      Parameters.Add(new OptionalValueParameter<EvaluationCache>("Cache", "Cache of previously evaluated solutions."));
      Parameters.Add(new ValueParameter<CheckedItemCollection<IEvaluationServiceClient>>("Clients", "The clients that are used to communicate with the external application.", new CheckedItemCollection<IEvaluationServiceClient>() { new EvaluationServiceClient() }));
      Parameters.Add(new ValueParameter<SolutionMessageBuilder>("MessageBuilder", "The message builder that converts from HeuristicLab objects to SolutionMessage representation.", new SolutionMessageBuilder()) { Hidden = true });
      Parameters.Add(new FixedValueParameter<MultiObjectiveOptimizationSupportScript<TEncodedSolution>>("SupportScript", "A script that can analyze the results of the optimization.", new MultiObjectiveOptimizationSupportScript<TEncodedSolution>()));
    }

    #region Multi Objective Problem Overrides
    public virtual void SetMaximization(bool[] maximization) {
      ((IStringConvertibleArray)MaximizationParameter.Value).Length = maximization.Length;
      var array = MaximizationParameter.Value;
      for (var i = 0; i < maximization.Length; i++)
        array[i] = maximization[i];
    }

    public override double[] Evaluate(TEncodedSolution individual, IRandom random, CancellationToken cancellationToken) {
      var qualityMessage = Evaluate(BuildSolutionMessage(individual), cancellationToken);
      if (!qualityMessage.HasExtension(MultiObjectiveQualityMessage.QualityMessage_))
        throw new InvalidOperationException("The received message is not a MultiObjectiveQualityMessage.");
      return qualityMessage.GetExtension(MultiObjectiveQualityMessage.QualityMessage_).QualitiesList.ToArray();
    }
    public virtual QualityMessage Evaluate(SolutionMessage solutionMessage, CancellationToken cancellationToken) {
      return Cache == null
        ? EvaluateOnNextAvailableClient(solutionMessage, cancellationToken)
        : Cache.GetValue(solutionMessage, EvaluateOnNextAvailableClient, GetQualityMessageExtensions(), cancellationToken);
    }

    public override void Analyze(TEncodedSolution[] individuals, double[][] qualities, ResultCollection results, IRandom random) {
      OptimizationSupport.Analyze(individuals, qualities, results, random);
    }

    #endregion

    public virtual ExtensionRegistry GetQualityMessageExtensions() {
      var extensions = ExtensionRegistry.CreateInstance();
      extensions.Add(MultiObjectiveQualityMessage.QualityMessage_);
      return extensions;
    }

    #region Evaluation
    private HashSet<IEvaluationServiceClient> activeClients = new HashSet<IEvaluationServiceClient>();
    private readonly object clientLock = new object();

    private QualityMessage EvaluateOnNextAvailableClient(SolutionMessage message, CancellationToken cancellationToken) {
      IEvaluationServiceClient client = null;
      lock (clientLock) {
        client = Clients.CheckedItems.FirstOrDefault(c => !activeClients.Contains(c));
        while (client == null && Clients.CheckedItems.Any()) {
          Monitor.Wait(clientLock);
          client = Clients.CheckedItems.FirstOrDefault(c => !activeClients.Contains(c));
        }
        if (client != null)
          activeClients.Add(client);
      }
      try {
        return client.Evaluate(message, GetQualityMessageExtensions());
      } finally {
        lock (clientLock) {
          activeClients.Remove(client);
          Monitor.PulseAll(clientLock);
        }
      }
    }

    private SolutionMessage BuildSolutionMessage(TEncodedSolution solution, int solutionId = 0) {
      lock (clientLock) {
        SolutionMessage.Builder protobufBuilder = SolutionMessage.CreateBuilder();
        protobufBuilder.SolutionId = solutionId;
        var scope = new Scope();
        ScopeUtil.CopyEncodedSolutionToScope(scope, Encoding, solution);
        foreach (var variable in scope.Variables) {
          try {
            MessageBuilder.AddToMessage(variable.Value, variable.Name, protobufBuilder);
          } catch (ArgumentException ex) {
            throw new InvalidOperationException(string.Format("ERROR while building solution message: Parameter {0} cannot be added to the message", Name), ex);
          }
        }
        return protobufBuilder.Build();
      }
    }
    #endregion
  }
}