#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;
using System.Collections.Generic;
using System.Linq;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;

namespace HeuristicLab.Encodings.VariableVector {
  [Item("SinglePointCrossover", "Description missing")]
  [StorableClass]
  public class SinglePointCrossover : VariableVectorCrossover {

    #region Parameter Properties
    #endregion

    [StorableConstructor]
    protected SinglePointCrossover(bool deserializing) : base(deserializing) { }
    protected SinglePointCrossover(SinglePointCrossover original, Cloner cloner)
      : base(original, cloner) {
    }
    public SinglePointCrossover() : base() { }

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

    public static VariableVector Apply(IRandom random, VariableVector parent1, VariableVector parent2) {
      var parent1Condition = parent1.Condition;
      var parent2Condition = parent2.Condition;

      var parent1Action = parent1.Action;
      var parent2Action = parent2.Action;

      if (parent1.Count != parent2.Count && parent1.VirtualLength != parent2.VirtualLength
        && parent1Condition.VariableDictionary.Count != parent2Condition.VariableDictionary.Count && parent1Condition.VirtualLength != parent2Condition.VirtualLength
        && parent1Action.VariableDictionary.Count != parent2Action.VariableDictionary.Count && parent1Action.VirtualLength != parent2Action.VirtualLength)
        throw new ArgumentException("SinglePointCrossover: The parents are of different length.");

      int conditionLength = parent1Condition.VirtualLength;
      int breakPoint = random.Next(1, conditionLength);
      IList<IVariable> newCondition = new List<IVariable>(parent1Condition.VariableDictionary.Count);

      var keyEnumerator = parent1Condition.VariableDictionary.Keys.GetEnumerator();

      int index = 0;
      IVariable curVariable = null;
      while (index < breakPoint) {
        if (!keyEnumerator.MoveNext()) { throw new IndexOutOfRangeException("Enumerator has no next element!"); }
        curVariable = parent1Condition.VariableDictionary[keyEnumerator.Current];
        if (index + curVariable.VirtualLength <= breakPoint) {
          newCondition.Add(curVariable.GetSetCopy());
        }
        index += curVariable.VirtualLength;
      }

      // breakpoint is in between a variable
      if (index != breakPoint) {
        newCondition.Add(parent1Condition.VariableDictionary[keyEnumerator.Current].CrossParentsAtPosition(parent2Condition.VariableDictionary[keyEnumerator.Current], breakPoint - (index - curVariable.VirtualLength)));
      }

      while (index < conditionLength) {
        keyEnumerator.MoveNext();
        curVariable = parent2Condition.VariableDictionary[keyEnumerator.Current];
        newCondition.Add(curVariable.GetSetCopy());
        index += curVariable.VirtualLength;
      }

      var action = random.Next(2) == 1 ? parent1Action.VariableDictionary.Values.Select(x => x.GetSetCopy()) : parent2Action.VariableDictionary.Values.Select(x => x.GetSetCopy());

      return new VariableVector(newCondition, action);
    }

    protected override VariableVector Cross(IRandom random, ItemArray<VariableVector> parents) {
      if (parents.Length != 2) throw new ArgumentException("ERROR in SinglePointCrossover: The number of parents is not equal to 2");
      return Apply(random, parents[0], parents[1]);
    }
  }
}