#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.ConditionActionEncoding {
  [Item("XCSModel", "Represents a model of XCS")]
  [StorableClass]
  public class XCSModel : ReadOnlyItemCollection<XCSClassifier>, IXCSModel {

    public int ClassifierCount { get { return Count; } }

    [Storable]
    private IClassifierComparer comparer;
    public IClassifierComparer ClassifierComparer {
      get { return comparer; }
      set { comparer = value; }
    }

    [StorableConstructor]
    protected XCSModel(bool deserializing) : base(deserializing) { }
    protected XCSModel(XCSModel original, Cloner cloner)
      : base(original, cloner) {
      name = (string)original.name.Clone();
      description = (string)original.description.Clone();
      if (original.comparer != null) {
        comparer = (IClassifierComparer)original.comparer.Clone();
      }
    }
    public override IDeepCloneable Clone(Cloner cloner) {
      return new XCSModel(this, cloner);
    }
    public XCSModel() : base(new ItemCollection<XCSClassifier>()) { }
    public XCSModel(IItemCollection<XCSClassifier> collection)
      : base(collection) {
      this.name = ItemName;
      this.description = ItemDescription;
    }

    public IEnumerable<IAction> GetAction(IEnumerable<IInput> classifiers) {
      foreach (var classifier in classifiers) {
        yield return GetAction(classifier);
      }
    }

    public IAction GetAction(IInput classifier) {
      var matchedClassifiers = new ItemCollection<XCSClassifier>();
      foreach (var xcsClassifier in this) {
        if (xcsClassifier.Classifier.MatchInput(classifier)) {
          matchedClassifiers.Add(xcsClassifier);
        }
      }

      if (matchedClassifiers.Count == 0) {
        return null;
      }

      IDictionary<IAction, double> predictionArray = CreatePredictionArray(matchedClassifiers);
      return predictionArray.OrderByDescending(x => x.Value).First().Key;
    }

    private IDictionary<IAction, double> CreatePredictionArray(ItemCollection<XCSClassifier> matchedClassifiers) {
      if (ClassifierComparer == null) {
        throw new ArgumentException("No classifier comparer specified!");
      }
      var predictionArray = new Dictionary<IAction, double>(ClassifierComparer);
      var fitnessSumPerAction = new Dictionary<IAction, double>(ClassifierComparer);

      foreach (var xcsClassifier in matchedClassifiers) {
        var action = xcsClassifier.Classifier.Action;
        if (predictionArray.ContainsKey(action)) {
          predictionArray[action] += xcsClassifier.Prediction.Value * xcsClassifier.Fitness.Value;
          fitnessSumPerAction[action] += xcsClassifier.Fitness.Value;
        } else {
          predictionArray[action] = xcsClassifier.Prediction.Value * xcsClassifier.Fitness.Value;
          fitnessSumPerAction[action] = xcsClassifier.Fitness.Value;
        }
      }

      var actions = new List<IAction>(predictionArray.Keys);
      foreach (var action in actions) {
        if (fitnessSumPerAction[action] != 0) {
          predictionArray[action] = predictionArray[action] / fitnessSumPerAction[action];
        }
      }
      return predictionArray;
    }

    public IXCSSolution CreateConditionActionSolution(IConditionActionProblemData problemData) {
      return new XCSSolution(this, problemData);
    }

    IConditionActionSolution IConditionActionModel.CreateConditionActionSolution(IConditionActionProblemData problemData) {
      return CreateConditionActionSolution(problemData);
    }

    #region INamedItem Members
    [Storable]
    protected string name;
    public string Name {
      get { return name; }
      set {
        if (!CanChangeName) throw new NotSupportedException("Name cannot be changed.");
        if (!(name.Equals(value) || (value == null) && (name == string.Empty))) {
          CancelEventArgs<string> e = value == null ? new CancelEventArgs<string>(string.Empty) : new CancelEventArgs<string>(value);
          OnNameChanging(e);
          if (!e.Cancel) {
            name = value == null ? string.Empty : value;
            OnNameChanged();
          }
        }
      }
    }
    public virtual bool CanChangeName {
      get { return true; }
    }
    [Storable]
    protected string description;
    public string Description {
      get { return description; }
      set {
        if (!CanChangeDescription) throw new NotSupportedException("Description cannot be changed.");
        if (!(description.Equals(value) || (value == null) && (description == string.Empty))) {
          description = value == null ? string.Empty : value;
          OnDescriptionChanged();
        }
      }
    }
    public virtual bool CanChangeDescription {
      get { return true; }
    }

    public override string ToString() {
      return Name;
    }

    public event EventHandler<CancelEventArgs<string>> NameChanging;
    protected virtual void OnNameChanging(CancelEventArgs<string> e) {
      var handler = NameChanging;
      if (handler != null) handler(this, e);
    }

    public event EventHandler NameChanged;
    protected virtual void OnNameChanged() {
      var handler = NameChanged;
      if (handler != null) handler(this, EventArgs.Empty);
      OnToStringChanged();
    }

    public event EventHandler DescriptionChanged;
    protected virtual void OnDescriptionChanged() {
      var handler = DescriptionChanged;
      if (handler != null) handler(this, EventArgs.Empty);
    }
    #endregion
  }
}