#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2016 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 HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HeuristicLab.Encodings.PermutationEncoding;
using HeuristicLab.Parameters;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;

namespace HeuristicLab.Problems.TravelingSalesman {
  /// <summary>
  /// A base class for operators which evaluate TSP solutions.
  /// </summary>
  [Item("TSPMoveEvaluator", "A base class for operators which evaluate TSP moves.")]
  [StorableClass]
  public abstract class TSPPathMoveEvaluator : TSPMoveEvaluator, ITSPPathMoveEvaluator {
    public ILookupParameter<Permutation> PermutationParameter {
      get { return (ILookupParameter<Permutation>)Parameters["Permutation"]; }
    }
    public ILookupParameter<DoubleMatrix> CoordinatesParameter {
      get { return (ILookupParameter<DoubleMatrix>)Parameters["Coordinates"]; }
    }
    public ILookupParameter<DistanceMatrix> DistanceMatrixParameter {
      get { return (ILookupParameter<DistanceMatrix>)Parameters["DistanceMatrix"]; }
    }
    public ILookupParameter<BoolValue> UseDistanceMatrixParameter {
      get { return (ILookupParameter<BoolValue>)Parameters["UseDistanceMatrix"]; }
    }

    [StorableConstructor]
    protected TSPPathMoveEvaluator(bool deserializing) : base(deserializing) { }
    protected TSPPathMoveEvaluator(TSPPathMoveEvaluator original, Cloner cloner) : base(original, cloner) { }
    protected TSPPathMoveEvaluator()
      : base() {
      Parameters.Add(new LookupParameter<Permutation>("Permutation", "The solution as permutation."));
      Parameters.Add(new LookupParameter<DoubleMatrix>("Coordinates", "The city's coordinates."));
      Parameters.Add(new LookupParameter<DistanceMatrix>("DistanceMatrix", "The matrix which contains the distances between the cities."));
      Parameters.Add(new LookupParameter<BoolValue>("UseDistanceMatrix", "True if a distance matrix should be calculated (if it does not exist already) and used for evaluation, otherwise false."));
    }

    [StorableHook(HookType.AfterDeserialization)]
    private void AfterDeserialization() {
      // BackwardsCompatibility3.3
      #region Backwards compatible code (remove with 3.4)
      LookupParameter<DoubleMatrix> oldDistanceMatrixParameter = Parameters["DistanceMatrix"] as LookupParameter<DoubleMatrix>;
      if (oldDistanceMatrixParameter != null) {
        Parameters.Remove(oldDistanceMatrixParameter);
        Parameters.Add(new LookupParameter<DistanceMatrix>("DistanceMatrix", "The matrix which contains the distances between the cities."));
        DistanceMatrixParameter.ActualName = oldDistanceMatrixParameter.ActualName;
      }
      #endregion
    }

    public override IOperation Apply() {
      Permutation permutation = PermutationParameter.ActualValue;
      DoubleMatrix coordinates = CoordinatesParameter.ActualValue;
      double relativeQualityDifference = 0;
      if (UseDistanceMatrixParameter.ActualValue.Value) {
        DistanceMatrix distanceMatrix = DistanceMatrixParameter.ActualValue;
        if (distanceMatrix == null) {
          if (coordinates == null) throw new InvalidOperationException("Neither a distance matrix nor coordinates were given.");
          distanceMatrix = CalculateDistanceMatrix(coordinates);
          DistanceMatrixParameter.ActualValue = distanceMatrix;
        }
        relativeQualityDifference = EvaluateByDistanceMatrix(permutation, distanceMatrix);
      } else {
        if (coordinates == null) throw new InvalidOperationException("No coordinates were given.");
        relativeQualityDifference = EvaluateByCoordinates(permutation, coordinates);
      }
      DoubleValue moveQuality = MoveQualityParameter.ActualValue;
      if (moveQuality == null) MoveQualityParameter.ActualValue = new DoubleValue(QualityParameter.ActualValue.Value + relativeQualityDifference);
      else moveQuality.Value = QualityParameter.ActualValue.Value + relativeQualityDifference;
      return base.Apply();
    }

    protected abstract double CalculateDistance(double x1, double y1, double x2, double y2);
    protected abstract double EvaluateByDistanceMatrix(Permutation permutation, DistanceMatrix distanceMatrix);
    protected abstract double EvaluateByCoordinates(Permutation permutation, DoubleMatrix coordinates);

    private DistanceMatrix CalculateDistanceMatrix(DoubleMatrix c) {
      DistanceMatrix distanceMatrix = new DistanceMatrix(c.Rows, c.Rows);
      for (int i = 0; i < distanceMatrix.Rows; i++) {
        for (int j = 0; j < distanceMatrix.Columns; j++)
          distanceMatrix[i, j] = CalculateDistance(c[i, 0], c[i, 1], c[j, 0], c[j, 1]);
      }
      return (DistanceMatrix)distanceMatrix.AsReadOnly();
    }
  }
}