#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2018 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.Data;
using HeuristicLab.Encodings.IntegerVectorEncoding;
using HeuristicLab.Operators;
using HeuristicLab.Parameters;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;

namespace HeuristicLab.Problems.GeneralizedQuadraticAssignment {
  [Item("N-Move Evaluator", "Evaluates an N-Move.")]
  [StorableClass]
  public class GQAPNMoveEvaluator : SingleSuccessorOperator, IGQAPNMoveEvaluator,
    IQualityAwareGQAPOperator, IProblemInstanceAwareGQAPOperator, IAssignmentAwareGQAPOperator {

    #region Parameter Descriptions
    public static readonly string MoveQualityDescription = "The quality of the move if it would be applied.";
    public static readonly string MoveEvaluationDescription = "The results of evaluating the move.";
    #endregion

    #region Parameter Properties
    public ILookupParameter<DoubleValue> MoveQualityParameter {
      get { return (ILookupParameter<DoubleValue>)Parameters["MoveQuality"]; }
    }
    public ILookupParameter<Evaluation> MoveEvaluationParameter {
      get { return (ILookupParameter<Evaluation>)Parameters["MoveEvaluation"]; }
    }
    public ILookupParameter<NMove> MoveParameter {
      get { return (ILookupParameter<NMove>)Parameters["Move"]; }
    }
    public ILookupParameter<IntegerVector> AssignmentParameter {
      get { return (ILookupParameter<IntegerVector>)Parameters["Assignment"]; }
    }
    public ILookupParameter<DoubleValue> QualityParameter {
      get { return (ILookupParameter<DoubleValue>)Parameters["Quality"]; }
    }
    public ILookupParameter<Evaluation> EvaluationParameter {
      get { return (ILookupParameter<Evaluation>)Parameters["Evaluation"]; }
    }
    public ILookupParameter<GQAPInstance> ProblemInstanceParameter {
      get { return (ILookupParameter<GQAPInstance>)Parameters["ProblemInstance"]; }
    }
    #endregion

    [StorableConstructor]
    protected GQAPNMoveEvaluator(bool deserializing) : base(deserializing) { }
    protected GQAPNMoveEvaluator(GQAPNMoveEvaluator original, Cloner cloner) : base(original, cloner) { }
    public GQAPNMoveEvaluator()
      : base() {
      Parameters.Add(new LookupParameter<IntegerVector>("Assignment", GQAPSolutionCreator.AssignmentDescription));
      Parameters.Add(new LookupParameter<NMove>("Move", GQAPNMoveGenerator.MoveDescription));
      Parameters.Add(new LookupParameter<DoubleValue>("Quality", ""));
      Parameters.Add(new LookupParameter<Evaluation>("Evaluation", GQAP.EvaluationDescription));
      Parameters.Add(new LookupParameter<DoubleValue>("MoveQuality", MoveQualityDescription));
      Parameters.Add(new LookupParameter<Evaluation>("MoveEvaluation", MoveEvaluationDescription));
      Parameters.Add(new LookupParameter<GQAPInstance>("ProblemInstance", GQAP.ProblemInstanceDescription));
    }

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

    public static Evaluation Evaluate(NMove move, IntegerVector assignment, Evaluation evaluation, GQAPInstance problemInstance) {
      int moves = move.N;
      var excessDemand = evaluation.ExcessDemand;
      var flowCosts = evaluation.FlowCosts;
      var installationCosts = evaluation.InstallationCosts;
      var slack = evaluation.Slack.ToArray();

      foreach (var equip in move.Indices) {
        int newLoc = move.Reassignments[equip] - 1; // locations are given 1-based
        int oldLoc = assignment[equip];
        var equipDemand = problemInstance.Demands[equip];
        installationCosts -= problemInstance.InstallationCosts[equip, oldLoc];
        installationCosts += problemInstance.InstallationCosts[equip, newLoc];
        for (int j = 0; j < assignment.Length; j++) {
          var reassignedLoc = move.Reassignments[j] - 1; // 0 indicates that this equipment is not reassigned
          if (reassignedLoc < 0) {
            flowCosts += problemInstance.Weights[equip, j] * problemInstance.Distances[newLoc, assignment[j]];
            flowCosts -= problemInstance.Weights[equip, j] * problemInstance.Distances[oldLoc, assignment[j]];
            flowCosts += problemInstance.Weights[j, equip] * problemInstance.Distances[assignment[j], newLoc];
            flowCosts -= problemInstance.Weights[j, equip] * problemInstance.Distances[assignment[j], oldLoc];
          } else {
            flowCosts += problemInstance.Weights[equip, j] * problemInstance.Distances[newLoc, reassignedLoc];
            flowCosts -= problemInstance.Weights[equip, j] * problemInstance.Distances[oldLoc, assignment[j]];
          }
        }
        slack[oldLoc] += equipDemand;
        if (slack[oldLoc] < equipDemand)
          excessDemand -= Math.Min(equipDemand, equipDemand - slack[oldLoc]);
        slack[newLoc] -= equipDemand;
        if (slack[newLoc] < 0)
          excessDemand += Math.Min(equipDemand, -slack[newLoc]);
      }

      return new Evaluation(flowCosts, installationCosts, excessDemand, slack);
    }

    public override IOperation Apply() {
      var problemInstance = ProblemInstanceParameter.ActualValue;
      var evaluation = EvaluationParameter.ActualValue;

      var moveEvaluation = Evaluate(MoveParameter.ActualValue,
               AssignmentParameter.ActualValue,
               evaluation,
               problemInstance);

      MoveEvaluationParameter.ActualValue = moveEvaluation;
      MoveQualityParameter.ActualValue = new DoubleValue(problemInstance.ToSingleObjective(moveEvaluation));
      return base.Apply();
    }
  }
}