#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.Linq;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HeuristicLab.Operators;
using HeuristicLab.Optimization;
using HeuristicLab.Parameters;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;

namespace HeuristicLab.Encodings.ConditionActionEncoding {
  [Item("ActionSelector", "")]
  [StorableClass]
  public class ActionSelector : SingleSuccessorOperator, IStochasticOperator {

    public ILookupParameter<IRandom> RandomParameter {
      get { return (ILookupParameter<IRandom>)Parameters["Random"]; }
    }
    public IValueLookupParameter<IAction> SelectedActionParameter {
      get { return (IValueLookupParameter<IAction>)Parameters["SelectedAction"]; }
    }
    public ILookupParameter<IItemDictionary<IAction, DoubleValue>> PredictionArrayParameter {
      get { return (ILookupParameter<IItemDictionary<IAction, DoubleValue>>)Parameters["PredictionArray"]; }
    }
    public ILookupParameter<PercentValue> ExplorationProbabilityParameter {
      get { return (ILookupParameter<PercentValue>)Parameters["ExplorationProbability"]; }
    }

    [StorableConstructor]
    protected ActionSelector(bool deserializing) : base(deserializing) { }
    protected ActionSelector(ActionSelector original, Cloner cloner)
      : base(original, cloner) {
    }
    public ActionSelector()
      : base() {
      Parameters.Add(new LookupParameter<IRandom>("Random"));
      Parameters.Add(new ValueLookupParameter<IAction>("SelectedAction", "Action, which has been selected."));
      Parameters.Add(new LookupParameter<IItemDictionary<IAction, DoubleValue>>("PredictionArray"));
      Parameters.Add(new LookupParameter<PercentValue>("ExplorationProbability"));
    }

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

    public override IOperation Apply() {
      if (RandomParameter.ActualValue.NextDouble() > ExplorationProbabilityParameter.ActualValue.Value) {
        double maxValue = PredictionArrayParameter.ActualValue.Max(x => x.Value.Value);
        SelectedActionParameter.ActualValue = PredictionArrayParameter.ActualValue.Where(x => x.Value.Value.IsAlmost(maxValue))
                                                                                  .Select(x => x.Key)
                                                                                  .First();
      } else {
        int actionIndex = RandomParameter.ActualValue.Next(0, PredictionArrayParameter.ActualValue.Count);
        SelectedActionParameter.ActualValue = PredictionArrayParameter.ActualValue.ElementAt(actionIndex).Key;
      }
      return base.Apply();
    }
  }
}