#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2012 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.Collections.Generic;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
using HeuristicLab.Operators;
using HeuristicLab.Optimization;
using HeuristicLab.Parameters;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;

namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
  [Item("ReplaceBranchMoveSoftTabuCriterion", @"")]
  [StorableClass]
  public class ReplaceBranchMoveSoftTabuCriterion : SingleSuccessorOperator, ISymbolicExpressionTreeMoveOperator, ITabuChecker {
    public override bool CanChangeName {
      get { return false; }
    }
    public ILookupParameter<ReplaceBranchMove> ReplaceBranchMoveParameter {
      get { return (LookupParameter<ReplaceBranchMove>)Parameters["ReplaceBranchMove"]; }
    }
    public ILookupParameter<ISymbolicExpressionTree> SymbolicExpressionTreeParameter {
      get { return (LookupParameter<ISymbolicExpressionTree>)Parameters["SymbolicExpressionTree"]; }
    }
    public ILookupParameter<ItemList<IItem>> TabuListParameter {
      get { return (ILookupParameter<ItemList<IItem>>)Parameters["TabuList"]; }
    }
    public ILookupParameter<BoolValue> MoveTabuParameter {
      get { return (ILookupParameter<BoolValue>)Parameters["MoveTabu"]; }
    }
    public IValueLookupParameter<BoolValue> MaximizationParameter {
      get { return (IValueLookupParameter<BoolValue>)Parameters["Maximization"]; }
    }
    public ILookupParameter<DoubleValue> MoveQualityParameter {
      get { return (ILookupParameter<DoubleValue>)Parameters["MoveQuality"]; }
    }
    public ValueParameter<BoolValue> UseQualityAspirationCriterionParameter {
      get { return (ValueParameter<BoolValue>)Parameters["UseQualityAspirationCriterion"]; }
    }
    public ValueParameter<BoolValue> UseSemanticAspirationCriterionParameter {
      get { return (ValueParameter<BoolValue>)Parameters["UseSemanticAspirationCriterion"]; }
    }
    public ILookupParameter<DoubleValue> SemanticAspirationParameter {
      get { return (ILookupParameter<DoubleValue>)Parameters["SemanticAspirations"]; }
    }
    public ILookupParameter<DoubleValue> QualityAspirationParameter {
      get { return (ILookupParameter<DoubleValue>)Parameters["QualityAspirations"]; }
    }

    public BoolValue UseQualityAspirationCriterion {
      get { return UseQualityAspirationCriterionParameter.Value; }
      set { UseQualityAspirationCriterionParameter.Value = value; }
    }
    public BoolValue UseSemanticAspirationCriterion {
      get { return UseSemanticAspirationCriterionParameter.Value; }
      set { UseSemanticAspirationCriterionParameter.Value = value; }
    }

    [StorableConstructor]
    protected ReplaceBranchMoveSoftTabuCriterion(bool deserializing) : base(deserializing) { }
    protected ReplaceBranchMoveSoftTabuCriterion(ReplaceBranchMoveSoftTabuCriterion original, Cloner cloner) : base(original, cloner) { }
    public ReplaceBranchMoveSoftTabuCriterion()
      : base() {
      Parameters.Add(new LookupParameter<ReplaceBranchMove>("ReplaceBranchMove", "The move to evaluate."));
      Parameters.Add(new LookupParameter<BoolValue>("MoveTabu", "The variable to store if a move was tabu."));
      Parameters.Add(new LookupParameter<ISymbolicExpressionTree>("SymbolicExpressionTree", "The solution as symbolic expression tree."));
      Parameters.Add(new LookupParameter<ItemList<IItem>>("TabuList", "The tabu list."));
      Parameters.Add(new ValueParameter<BoolValue>("UseQualityAspirationCriterion", "Whether to use the aspiration criterion or not.", new BoolValue(true)));
      Parameters.Add(new ValueParameter<BoolValue>("UseSemanticAspirationCriterion", "Whether to use the aspiration criterion or not.", new BoolValue(true)));
      Parameters.Add(new ValueLookupParameter<BoolValue>("Maximization", "True if the problem is a maximization problem, else if it is a minimization problem."));
      Parameters.Add(new LookupParameter<DoubleValue>("MoveQuality", "The quality of the current move."));
      Parameters.Add(new LookupParameter<DoubleValue>("SemanticAspirations"));
      Parameters.Add(new LookupParameter<DoubleValue>("QualityAspirations"));
    }

    public override IDeepCloneable Clone(Cloner cloner) {
      return new ReplaceBranchMoveSoftTabuCriterion(this, cloner);
    }

    public override IOperation Apply() {
      ItemList<IItem> tabuList = TabuListParameter.ActualValue;
      var move = ReplaceBranchMoveParameter.ActualValue;
      bool isTabu = true;
      bool useQualityAspiration = UseQualityAspirationCriterion.Value;
      bool useSemanticAspiration = UseSemanticAspirationCriterion.Value;
      bool maximization = MaximizationParameter.ActualValue.Value;
      double moveQuality = MoveQualityParameter.ActualValue.Value;

      List<int> path = new List<int>();
      path.Add(move.SubtreeIndex);
      var parent = move.Parent.Parent;
      var child = move.Parent;
      while (parent != null) {
        path.Add(parent.IndexOfSubtree(child));
        child = parent;
        parent = parent.Parent;
      }
      path.Reverse();

      isTabu = false;
      int semanticAspirations = 0;
      int qualityAspirations = 0;
      // run through the tabu list backwards so that we can break at the most recent relevant change
      for (int i = tabuList.Count - 1; i >= 0 && isTabu == false; i--) {
        var tabuAttribute = tabuList[i];
        var absTabuAttribute = tabuAttribute as ChangeNodeTypeMoveAbsoluteAttribute;
        // three aspiration criteria
        if (useQualityAspiration && IsBetter(maximization, moveQuality, absTabuAttribute.MoveQuality)) {
          qualityAspirations++;
          continue;
        }
        if (BeginsWith(path, absTabuAttribute.Path))
          break; // not necessary to check the remainder of the tabu list

        isTabu = IsSamePath(path, absTabuAttribute.Path);
        // check semantic aspiration criterion only afterwards because it is expansive to evaluate
        if (isTabu && useSemanticAspiration && IsLessSimilar(absTabuAttribute, move)) {
          isTabu = false;
          semanticAspirations++;
        }
      }

      MoveTabuParameter.ActualValue = new BoolValue(isTabu);
      var semAsp = SemanticAspirationParameter.ActualValue ?? new DoubleValue();
      var qualAsp = QualityAspirationParameter.ActualValue ?? new DoubleValue();
      semAsp.Value += semanticAspirations;
      qualAsp.Value += qualityAspirations;
      SemanticAspirationParameter.ActualValue = semAsp;
      QualityAspirationParameter.ActualValue = qualAsp;
      return base.Apply();
    }

    // checks wether the path to the node is the same or the tabu path is a parent
    private bool IsSamePath(List<int> path, int[] tabuPath) {
      if (tabuPath.Length != path.Count) return false;
      for (int j = 0; j < tabuPath.Length; j++) {
        if (tabuPath[j] != path[j]) {
          return false;
        }
      }
      return true;
    }

    private bool IsLessSimilar(ChangeNodeTypeMoveAbsoluteAttribute tabuAttribute, ReplaceBranchMove move) {
      // check correlations
      // R(prev, next)
      // R(current, next)
      // tabu = R(prev,next) > R(current,next)
      // == the new move would be closer to the original than the previous move
      OnlineCalculatorError error;
      double rPrevNext = OnlinePearsonsRSquaredCalculator.Calculate(tabuAttribute.PreviousOutput, move.NewOutput, out error);
      if (error != OnlineCalculatorError.None) rPrevNext = 0.0;
      double rPrevCurrent = OnlinePearsonsRSquaredCalculator.Calculate(tabuAttribute.PreviousOutput, move.OriginalOutput,
                                                                       out error);
      if (error != OnlineCalculatorError.None) rPrevCurrent = 0.0;
      return rPrevNext < rPrevCurrent;
    }

    private bool BeginsWith(List<int> path, int[] prefix) {
      if (path.Count <= prefix.Length) return false;
      for (int j = 0; j < prefix.Length; j++)
        if (prefix[j] != path[j]) return false;
      return true;
    }

    private bool IsBetter(bool maximization, double lhs, double rhs) {
      return maximization ? lhs > rhs : lhs < rhs;
    }
  }
}