using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Operators;
using HeuristicLab.Optimization;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;

namespace HeuristicLab.Algorithms.IslandALPS {

  /// <summary>
  /// <pre> 
  ///          __ scope __                    __ scope __         
  ///         /           \                  /           \        
  ///       Island1      Island2     =>    Island1      Island2   
  ///       /    \         / \             /    \         / \     
  ///     L1     L2      L1     L2       L1     L2      L1     L2 
  ///     / \    / \     / \    / \      / \    / \     / \    / \
  ///    R  S   R  S    R  S   R  S     R  S   R  S    R  S   R  S
  ///   /|\ |  /|\ |   /|\ |  /|\ |    /|\ |  /|\ |   /|\ |  /|\ |
  ///   ABC A  DEF D   GHI G  JKL J    ABC J  DEF A   GHI D  JKL G                        
  /// 
  /// </pre>
  /// </summary>
  [Item("LayerMigrator", "Migrates the selected scopes of each layer to the correspondant layer of the next island (clockwise).")]
  [StorableClass]
  public class LayerMigrator : SingleSuccessorOperator, IMigrator {

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

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

    public override IOperation Apply() {
      var globalScope = ExecutionContext.Scope;
      var openLayer = globalScope.SubScopes[0].SubScopes.Count;

      for (int layerIndex = 0; layerIndex < openLayer; layerIndex++) {
        IScope emigrants = null;
        for (int islandIndex = 0; islandIndex < globalScope.SubScopes.Count; islandIndex++) {
          var currentLayer = globalScope.SubScopes[islandIndex].SubScopes[layerIndex];
          if (emigrants != null) {
            currentLayer.SubScopes.Add(emigrants);              
          }
          emigrants = currentLayer.SubScopes[1];
          currentLayer.SubScopes.Remove(emigrants);
        }
        //first island gets the individuals from the last island
        globalScope.SubScopes[0].SubScopes[layerIndex].SubScopes.Add(emigrants);
      }

      return base.Apply();
    }
  }
}