#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2017 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.Encodings.IntegerVectorEncoding;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;

namespace HeuristicLab.Problems.GeneralizedQuadraticAssignment {

  [Item("SwapLocationManipluator", "Swaps two locations by exchanging all equipments between the locations.")]
  [StorableClass]
  public class SwapLocationManipluator : GQAPManipulator {
    
    [StorableConstructor]
    protected SwapLocationManipluator(bool deserializing) : base(deserializing) { }
    protected SwapLocationManipluator(SwapLocationManipluator original, Cloner cloner) : base(original, cloner) { }
    public SwapLocationManipluator()
      : base() {
    }

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

    public static void Apply(IRandom random, IntegerVector assignment, int locations) {
      if (assignment.Length < 2) throw new InvalidOperationException("Vector is too small for swap operation.");
      var groupedLocations = assignment
        .Select((value, index) => new { Index = index, Value = value })
        .GroupBy(x => x.Value)
        .ToDictionary(x => x.Key, y => y.AsEnumerable());
      if (locations < 2) throw new InvalidOperationException("There doesn't exist more than one location.");

      int location1 = random.Next(locations), location2 = random.Next(locations);
      while (location1 == location2) location2 = random.Next(locations);

      if (groupedLocations.ContainsKey(location1)) {
        foreach (var index in groupedLocations[location1])
          assignment[index.Index] = location2;
      }
      if (groupedLocations.ContainsKey(location2)) {
        foreach (var index in groupedLocations[location2])
          assignment[index.Index] = location1;
      }
    }

    protected override void Manipulate(IRandom random, IntegerVector vector, GQAPInstance problemInstance) {
      Apply(random, vector, problemInstance.Capacities.Length);
    }
  }
}