#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2015 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 HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HeuristicLab.Operators;
using HeuristicLab.Optimization;
using HeuristicLab.Optimization.Operators;
using HeuristicLab.Parameters;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
using HeuristicLab.PluginInfrastructure;
using HeuristicLab.Random;
using HeuristicLab.Selection;

namespace HeuristicLab.Algorithms.ALPS {
  [Item("ALPS Genetic Algorithm", "A genetic algorithm with an age-layered population structure.")]
  [Creatable("Algorithms")]
  [StorableClass]
  public sealed class AlpsGeneticAlgorithm : Alps {
    #region Parameter Properties
    private IValueParameter<IntArray> PopulationSizeParameter {
      get { return (IValueParameter<IntArray>)Parameters["PopulationSize"]; }
    }
    public IConstrainedValueParameter<ISelector> SelectorParameter {
      get { return (IConstrainedValueParameter<ISelector>)Parameters["Selector"]; }
    }
    public IConstrainedValueParameter<ICrossover> CrossoverParameter {
      get { return (IConstrainedValueParameter<ICrossover>)Parameters["Crossover"]; }
    }
    private IValueParameter<PercentValue> MutationProbabilityParameter {
      get { return (IValueParameter<PercentValue>)Parameters["MutationProbability"]; }
    }
    public IConstrainedValueParameter<IManipulator> MutatorParameter {
      get { return (IConstrainedValueParameter<IManipulator>)Parameters["Mutator"]; }
    }
    private IValueParameter<IntValue> ElitesParameter {
      get { return (IValueParameter<IntValue>)Parameters["Elites"]; }
    }
    private IFixedValueParameter<BoolValue> ReevaluateElitesParameter {
      get { return (IFixedValueParameter<BoolValue>)Parameters["ReevaluateElites"]; }
    }
    private IValueParameter<BoolValue> PlusSelectionParameter {
      get { return (IValueParameter<BoolValue>)Parameters["PlusSelection"]; }
    }
    #endregion

    #region Properties
    public IntArray PopulationSize {
      get { return PopulationSizeParameter.Value; }
      set { PopulationSizeParameter.Value = value; }
    }
    public int MaximumGenerations {
      get { return generationsTerminator.Threshold.Value; }
      set { generationsTerminator.Threshold.Value = value; }
    }
    public ISelector Selector {
      get { return SelectorParameter.Value; }
      set { SelectorParameter.Value = value; }
    }
    public ICrossover Crossover {
      get { return CrossoverParameter.Value; }
      set { CrossoverParameter.Value = value; }
    }
    public PercentValue MutationProbability {
      get { return MutationProbabilityParameter.Value; }
      set { MutationProbabilityParameter.Value = value; }
    }
    public IManipulator Mutator {
      get { return MutatorParameter.Value; }
      set { MutatorParameter.Value = value; }
    }
    public IntValue Elites {
      get { return ElitesParameter.Value; }
      set { ElitesParameter.Value = value; }
    }
    public bool ReevaluteElites {
      get { return ReevaluateElitesParameter.Value.Value; }
      set { ReevaluateElitesParameter.Value.Value = value; }
    }
    public bool PlusSelection {
      get { return PlusSelectionParameter.Value.Value; }
      set { PlusSelectionParameter.Value.Value = value; }
    }

    private AlpsGeneticAlgorithmMainLoop MainLoop {
      get { return OperatorGraph.Iterate().OfType<AlpsGeneticAlgorithmMainLoop>().First(); }
    }
    #endregion

    [Storable]
    private ComparisonTerminator<IntValue> generationsTerminator;

    [StorableConstructor]
    private AlpsGeneticAlgorithm(bool deserializing)
      : base(deserializing) { }
    private AlpsGeneticAlgorithm(AlpsGeneticAlgorithm original, Cloner cloner)
      : base(original, cloner) {
      generationsTerminator = cloner.Clone(original.generationsTerminator);
      Initialize();
    }
    public override IDeepCloneable Clone(Cloner cloner) {
      return new AlpsGeneticAlgorithm(this, cloner);
    }
    public AlpsGeneticAlgorithm()
      : base() {
      Parameters.Add(new ValueParameter<IntArray>("PopulationSize", "The size of the population of solutions each layer.", new IntArray(new[] { 100 })));
      Parameters.Add(new ConstrainedValueParameter<ISelector>("Selector", "The operator used to select solutions for reproduction."));
      Parameters.Add(new ConstrainedValueParameter<ICrossover>("Crossover", "The operator used to cross solutions."));
      Parameters.Add(new ValueParameter<PercentValue>("MutationProbability", "The probability that the mutation operator is applied on a solution.", new PercentValue(0.05)));
      Parameters.Add(new OptionalConstrainedValueParameter<IManipulator>("Mutator", "The operator used to mutate solutions."));
      Parameters.Add(new ValueParameter<IntValue>("Elites", "The numer of elite solutions which are kept in each generation.", new IntValue(1)));
      Parameters.Add(new FixedValueParameter<BoolValue>("ReevaluateElites", "Flag to determine if elite individuals should be reevaluated (i.e., if stochastic fitness functions are used.)", new BoolValue(false)) { Hidden = true });
      Parameters.Add(new ValueParameter<BoolValue>("PlusSelection", "Include the parents in the selection of the invividuals for the next generation.", new BoolValue(false)) { Hidden = true });

      var globalRandomCreator = new RandomCreator();
      var layer0Creator = new SubScopesCreator() { Name = "Create Layer Zero" };
      var layer0Processor = new LayerUniformSubScopesProcessor();
      var localRandomCreator = new LocalRandomCreator();
      var layerVariableCreator = new VariableCreator();
      var layerSolutionsCreator = new SolutionsCreator();
      var initializeAgeProcessor = new UniformSubScopesProcessor();
      var initializeAge = new VariableCreator() { Name = "Initialize Age" };
      var initializeLayerPopulationSize = new SubScopesCounter() { Name = "Init LayerPopulationCounter" };
      var initializeLocalEvaluatedSolutions = new Assigner() { Name = "Initialize LayerEvaluatedSolutions" };
      var initializeGlobalEvaluatedSolutions = new DataReducer() { Name = "Initialize EvaluatedSolutions" };
      var resultsCollector = new ResultsCollector();
      var mainLoop = new AlpsGeneticAlgorithmMainLoop();

      OperatorGraph.InitialOperator = globalRandomCreator;

      globalRandomCreator.RandomParameter.ActualName = "GlobalRandom";
      globalRandomCreator.SeedParameter.Value = null;
      globalRandomCreator.SetSeedRandomlyParameter.Value = null;
      globalRandomCreator.Successor = layer0Creator;

      layer0Creator.NumberOfSubScopesParameter.Value = new IntValue(1);
      layer0Creator.Successor = layer0Processor;

      layer0Processor.Operator = localRandomCreator;
      layer0Processor.Successor = initializeGlobalEvaluatedSolutions;

      localRandomCreator.Successor = layerVariableCreator;

      layerVariableCreator.CollectedValues.Add(new ValueParameter<IntValue>("Layer", new IntValue(0)));
      layerVariableCreator.Successor = layerSolutionsCreator;

      layerSolutionsCreator.NumberOfSolutionsParameter.ActualName = PopulationSizeParameter.Name;
      layerSolutionsCreator.Successor = initializeAgeProcessor;

      initializeAgeProcessor.Operator = initializeAge;
      initializeAgeProcessor.Successor = initializeLayerPopulationSize;

      initializeLayerPopulationSize.ValueParameter.ActualName = "LayerPopulationSize";
      initializeLayerPopulationSize.Successor = initializeLocalEvaluatedSolutions;

      initializeAge.CollectedValues.Add(new ValueParameter<IntValue>("Age", new IntValue(0)));
      initializeAge.Successor = null;

      initializeLocalEvaluatedSolutions.LeftSideParameter.ActualName = "LayerEvaluatedSolutions";
      initializeLocalEvaluatedSolutions.RightSideParameter.ActualName = "LayerPopulationSize";
      initializeLocalEvaluatedSolutions.Successor = null;

      initializeGlobalEvaluatedSolutions.ReductionOperation.Value.Value = ReductionOperations.Sum;
      initializeGlobalEvaluatedSolutions.TargetOperation.Value.Value = ReductionOperations.Assign;
      initializeGlobalEvaluatedSolutions.ParameterToReduce.ActualName = "LayerEvaluatedSolutions";
      initializeGlobalEvaluatedSolutions.TargetParameter.ActualName = "EvaluatedSolutions";
      initializeGlobalEvaluatedSolutions.Successor = resultsCollector;

      resultsCollector.CollectedValues.Add(new LookupParameter<IntValue>("Evaluated Solutions", null, "EvaluatedSolutions"));
      resultsCollector.Successor = mainLoop;

      foreach (var selector in ApplicationManager.Manager.GetInstances<ISelector>().Where(s => !(s is IMultiObjectiveSelector)).OrderBy(s => Name))
        SelectorParameter.ValidValues.Add(selector);
      var tournamentSelector = SelectorParameter.ValidValues.OfType<TournamentSelector>().FirstOrDefault();
      if (tournamentSelector != null) {
        tournamentSelector.GroupSizeParameter.Value = new IntValue(4);
        SelectorParameter.Value = tournamentSelector;
      }

      ParameterizeSelectors();
      Initialize();
    }

    #region Events
    protected override void OnProblemChanged() {
      base.OnProblemChanged();
      ParameterizeSolutionsCreator();
      ParameterizeMainLoop();
      ParameterizeSelectors();
      ParameterizeIterationBasedOperators();
      UpdateCrossovers();
      UpdateMutators();
    }
    protected override void Problem_SolutionCreatorChanged(object sender, EventArgs e) {
      base.Problem_SolutionCreatorChanged(sender, e);
      ParameterizeSolutionsCreator();
    }
    protected override void Problem_EvaluatorChanged(object sender, EventArgs e) {
      base.Problem_EvaluatorChanged(sender, e);
      ParameterizeSolutionsCreator();
      ParameterizeMainLoop();
      ParameterizeSelectors();
    }
    protected override void Problem_OperatorsChanged(object sender, EventArgs e) {
      base.Problem_OperatorsChanged(sender, e);
      ParameterizeIterationBasedOperators();
      UpdateCrossovers();
      UpdateMutators();
    }
    protected override void Evaluator_QualityParameter_ActualNameChanged(object sender, EventArgs e) {
      base.Evaluator_QualityParameter_ActualNameChanged(sender, e);
      ParameterizeMainLoop();
      ParameterizeSelectors();
    }
    #endregion

    #region Parameterization
    private void Initialize() {
    }
    private void ParameterizeSolutionsCreator() {
      MainLoop.LayerUpdator.SolutionsCreator.EvaluatorParameter.ActualName = Problem.EvaluatorParameter.Name;
      MainLoop.LayerUpdator.SolutionsCreator.SolutionCreatorParameter.ActualName = Problem.SolutionCreatorParameter.Name;
    }
    private void ParameterizeMainLoop() {
      MainLoop.MaximizationParameter.ActualName = Problem.MaximizationParameter.Name;
      MainLoop.QualityParameter.ActualName = Problem.Evaluator.QualityParameter.ActualName;
      MainLoop.MainOperator.EvaluatorParameter.ActualName = Problem.EvaluatorParameter.Name;
      MainLoop.MainOperator.MaximizationParameter.ActualName = Problem.MaximizationParameter.Name;
      MainLoop.MainOperator.QualityParameter.ActualName = Problem.Evaluator.QualityParameter.ActualName;
      MainLoop.LayerUpdator.SolutionsCreator.NumberOfSolutionsParameter.ActualName = PopulationSizeParameter.Name;
    }
    private void ParameterizeSelectors() {
      foreach (var selector in SelectorParameter.ValidValues) {
        selector.CopySelected = new BoolValue(true);
        // Explicit setting of NumberOfSelectedSubScopesParameter is not required anymore because the NumberOfSelectedSubScopesCalculator calculates it itself
        //selector.NumberOfSelectedSubScopesParameter.Value = new IntValue(2 * (PopulationSize - Elites.Value)); 
        selector.NumberOfSelectedSubScopesParameter.Hidden = true;
        ParameterizeStochasticOperatorForLayer(selector);
      }
      if (Problem != null) {
        foreach (var selector in SelectorParameter.ValidValues.OfType<ISingleObjectiveSelector>()) {
          selector.MaximizationParameter.ActualName = Problem.MaximizationParameter.Name;
          selector.MaximizationParameter.Hidden = true;
          selector.QualityParameter.ActualName = Problem.Evaluator.QualityParameter.ActualName;
          selector.QualityParameter.Hidden = true;
        }
      }
    }
    private void ParameterizeIterationBasedOperators() {
      if (Problem != null) {
        foreach (var @operator in Problem.Operators.OfType<IIterationBasedOperator>()) {
          @operator.IterationsParameter.ActualName = "Generations";
          @operator.IterationsParameter.Hidden = true;
          @operator.MaximumIterationsParameter.ActualName = generationsTerminator.ThresholdParameter.Name;
          @operator.MaximumIterationsParameter.Hidden = true;
        }
      }
    }

    protected override ReductionOperations GetAgeInheritanceReduction(AgeInheritance ageInheritance) {
      switch (ageInheritance) {
        case ALPS.AgeInheritance.Older: return ReductionOperations.Max;
        case ALPS.AgeInheritance.Agerage: return ReductionOperations.Avg;
        case ALPS.AgeInheritance.Younger: return ReductionOperations.Min;
        default: throw new NotSupportedException("AgeInheritance " + ageInheritance + " is not supported.");
      }
    }
    #endregion

    #region Updates
    protected override void UpdateTerminators() {
      var newTerminators = new Dictionary<ITerminator, bool> {
        {generationsTerminator, !Terminators.Operators.Contains(generationsTerminator) || Terminators.Operators.ItemChecked(generationsTerminator)},
      };

      base.UpdateTerminators();

      foreach (var newTerminator in newTerminators)
        Terminators.Operators.Insert(0, newTerminator.Key, newTerminator.Value);
    }
    protected override void CreateTerminators() {
      generationsTerminator = new ComparisonTerminator<IntValue>("Generations", ComparisonType.Less, new IntValue(1000)) { Name = "Generations" };
      base.CreateTerminators();
    }
    private void UpdateCrossovers() {
      var oldCrossover = CrossoverParameter.Value;
      var defaultCrossover = Problem.Operators.OfType<ICrossover>().FirstOrDefault();
      CrossoverParameter.ValidValues.Clear();
      foreach (var crossover in Problem.Operators.OfType<ICrossover>().OrderBy(c => c.Name)) {
        ParameterizeStochasticOperatorForLayer(crossover);
        CrossoverParameter.ValidValues.Add(crossover);
      }
      if (oldCrossover != null) {
        var crossover = CrossoverParameter.ValidValues.FirstOrDefault(c => c.GetType() == oldCrossover.GetType());
        if (crossover != null)
          CrossoverParameter.Value = crossover;
        else
          oldCrossover = null;
      }
      if (oldCrossover == null && defaultCrossover != null)
        CrossoverParameter.Value = defaultCrossover;
    }
    private void UpdateMutators() {
      var oldMutator = MutatorParameter.Value;
      MutatorParameter.ValidValues.Clear();
      foreach (var mutator in Problem.Operators.OfType<IManipulator>().OrderBy(m => m.Name)) {
        ParameterizeStochasticOperatorForLayer(mutator);
        MutatorParameter.ValidValues.Add(mutator);
      }
      if (oldMutator != null) {
        var mutator = MutatorParameter.ValidValues.FirstOrDefault(m => m.GetType() == oldMutator.GetType());
        if (mutator != null)
          MutatorParameter.Value = mutator;
      }
    }
    #endregion
  }
}