#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2010 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 HeuristicLab.Core;
using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
using HeuristicLab.Optimization;
using HeuristicLab.Parameters;
using HeuristicLab.Problems.DataAnalysis.Symbolic.Symbols;
using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.Symbols;

namespace HeuristicLab.Problems.DataAnalysis.Regression.Symbolic.Analyzers {

  public class GeneticInformationItem {

    private Type myAncestorDefinition;
    public Type AncestorDefinition {
      get { return myAncestorDefinition; }
    }

    private int myAncestorIndex;
    public int AncestorIndex {
      get { return myAncestorIndex; }
    }

    private Type myDescendantDefinition;
    public Type DescendantDefinition {
      get { return myDescendantDefinition; }
    }

    private int myAncestorLevel;
    public int AncestorLevel {
      get { return myAncestorLevel; }
    }

    private double myDescendantCoefficient;
    public double DescendantCoefficient {
      get { return myDescendantCoefficient; }
    }

    private double myDescendantVariableIndex;
    public double DescendantVariableIndex {
      get { return myDescendantVariableIndex; }
    }

    private int myDescendantTimeOffset;
    public int DescendantTimeOffset {
      get { return myDescendantTimeOffset; }
    }

    private SymbolicExpressionTreeNode myDescendantTreeNode;
    public SymbolicExpressionTreeNode DescendantTreeNode {
      get { return myDescendantTreeNode; }
    }

    private int myDescendantLevel;
    public int DescendantLevel {
      get { return myDescendantLevel; }
    }

    public int LevelDelta {
      get { return (myDescendantLevel - myAncestorLevel); }
    }

    public GeneticInformationItem(SymbolicExpressionTreeNode parentNode, GeneticInformationItem descendantGeneticInformationItem,
        int ancestorIndex, int parentNodeLevel) {
      myAncestorIndex = ancestorIndex;
      myAncestorLevel = parentNodeLevel;
      myAncestorDefinition = parentNode.Symbol.GetType();
      myDescendantCoefficient = descendantGeneticInformationItem.DescendantCoefficient;
      myDescendantDefinition = descendantGeneticInformationItem.DescendantDefinition;
      myDescendantTimeOffset = descendantGeneticInformationItem.DescendantTimeOffset;
      myDescendantVariableIndex = descendantGeneticInformationItem.DescendantVariableIndex;
      myDescendantLevel = descendantGeneticInformationItem.DescendantLevel;
      myDescendantTreeNode = descendantGeneticInformationItem.DescendantTreeNode;
    }

    public static IList<GeneticInformationItem> CopyList(IList<GeneticInformationItem> geneticInformationItemsList) {
      List<GeneticInformationItem> list = new List<GeneticInformationItem>(geneticInformationItemsList.Count);
      list.AddRange(geneticInformationItemsList);
      return list;
    }

    public static string GetKey(GeneticInformationItem item) {
      return item.AncestorDefinition.Name.ToString() + "," + item.DescendantDefinition.Name.ToString();
    }

    public static IDictionary<string, IList<GeneticInformationItem>> GetDictionary(IList<GeneticInformationItem> geneticInformationItemsList) {
      IDictionary<string, IList<GeneticInformationItem>> dictionary = new Dictionary<string, IList<GeneticInformationItem>>();
      foreach (GeneticInformationItem item in geneticInformationItemsList) {
        string key = GetKey(item);
        if (!dictionary.ContainsKey(key))
          dictionary.Add(key, new List<GeneticInformationItem>());
        dictionary[key].Add(item);
      }
      return dictionary;
    }

    public static IDictionary<string, IList<GeneticInformationItem>> CopyDictionary(IDictionary<string, IList<GeneticInformationItem>> dictionary) {
      IDictionary<string, IList<GeneticInformationItem>> copy = new Dictionary<string, IList<GeneticInformationItem>>();
      foreach (KeyValuePair<string, IList<GeneticInformationItem>> pair in dictionary) {
        copy.Add(pair.Key, CopyList(pair.Value));
      }
      return copy;
    }

    public static GeneticInformationItem FindBestPendant(GeneticInformationItem item, IList<GeneticInformationItem> comparisonItems,
        double constantMinimum, double constantMaximum, double variableWeightSigma,
        int maximumTreeHeight, int minimumTimeOffset, int maximumTimeOffset,
        double levelDifferenceCoefficient, double ancestorIndexCoefficient,
        double constantValueCoefficient, double variableWeightCoefficient, double timeOffsetCoefficient, double variableIndexCoefficient,
        bool additiveSimilarityCalculation,
        out double bestPendantSimilarity) {
      int maxSimilarityIndex = -1;
      double similarity, maxSimilarity = -double.MaxValue;
      for (int i = 0; i < comparisonItems.Count; i++) {
        similarity = Similarity(item, comparisonItems[i], constantMinimum, constantMaximum, variableWeightSigma, maximumTreeHeight, minimumTimeOffset, maximumTimeOffset,
          levelDifferenceCoefficient, ancestorIndexCoefficient, constantValueCoefficient, variableWeightSigma, timeOffsetCoefficient,
          variableWeightCoefficient, additiveSimilarityCalculation);
        if (!double.IsNaN(similarity) && similarity > maxSimilarity) {
          maxSimilarity = similarity;
          maxSimilarityIndex = i;
        }
      }
      bestPendantSimilarity = maxSimilarity;
      if (maxSimilarityIndex >= 0)
        return comparisonItems[maxSimilarityIndex];
      else
        return null;
    }

    public static double Similarity(GeneticInformationItem item1, GeneticInformationItem item2,
        double constantMinimum, double constantMaximum, double variableWeightSigma,
        int maximumTreeHeight, int minimumTimeOffset, int maximumTimeOffset,
        double levelDifferenceCoefficient, double ancestorIndexCoefficient,
        double constantValueCoefficient, double variableWeightCoefficient, double timeOffsetCoefficient, double variableIndexCoefficient,
        bool additiveSimilarityCalculation) {

      if (item1.AncestorDefinition != item2.AncestorDefinition || item1.DescendantDefinition != item2.DescendantDefinition)
        return double.NaN;

      // the two items for sure have the same behavior definitions

      #region initialize punishments

      double punishmentContributionSum = 0;
      double punishmentCoefficientsProduct = 1;

      double ancestorIndexDifferencePunishment = 0;
      double levelDifferencePunishment = 0;

      double descendantConstantValueDifferencePunishment = 0;
      double descendantVariableWeightDifferencePunishment = 0;
      double descendantTimeOffsetDifferencePunishment = 0;
      double descendantVariableIndexDifferencePunishment = 0;

      #endregion

      if (levelDifferenceCoefficient > 0) {
        levelDifferencePunishment = item1.LevelDelta - item2.LevelDelta;
        if (levelDifferencePunishment < 0)
          levelDifferencePunishment = -levelDifferencePunishment;
        levelDifferencePunishment /= maximumTreeHeight;
        if (levelDifferencePunishment > 1)
          levelDifferencePunishment = 1;
        levelDifferencePunishment *= levelDifferenceCoefficient;
        punishmentContributionSum += levelDifferenceCoefficient;
        punishmentCoefficientsProduct *= (1 - levelDifferenceCoefficient);
      }
      if (ancestorIndexCoefficient > 0) {
        if (item1.AncestorIndex != item2.AncestorIndex)
          ancestorIndexDifferencePunishment = 1;
        else
          ancestorIndexDifferencePunishment = 0;
        ancestorIndexDifferencePunishment *= ancestorIndexCoefficient;
        punishmentContributionSum += ancestorIndexCoefficient;
        punishmentCoefficientsProduct *= (1 - ancestorIndexCoefficient);
      }

      if (item1.DescendantTreeNode is ConstantTreeNode) {
        if (constantValueCoefficient > 0) {
          double constantValueCoefficientDifference = Math.Abs(item1.DescendantCoefficient - item2.DescendantCoefficient);
          // assume uniform distribution within given minimum and maximum
          descendantConstantValueDifferencePunishment = (constantValueCoefficientDifference / (constantMaximum - constantMinimum));
          if (descendantConstantValueDifferencePunishment > 1)
            descendantConstantValueDifferencePunishment = 1;
          descendantConstantValueDifferencePunishment *= constantValueCoefficient;
          punishmentContributionSum += constantValueCoefficient;
          punishmentCoefficientsProduct *= (1 - constantValueCoefficient);
        }
      }
      if (item1.DescendantTreeNode is VariableTreeNode) {
        if (variableWeightCoefficient > 0) {
          double variableWeightDifference = Math.Abs(item1.DescendantCoefficient - item2.DescendantCoefficient);
          // assume normal distribution within given sigma
          descendantVariableWeightDifferencePunishment = variableWeightDifference / (variableWeightSigma * 4);
          if (descendantVariableWeightDifferencePunishment > 1)
            descendantVariableWeightDifferencePunishment = 1;
          descendantVariableWeightDifferencePunishment *= variableWeightCoefficient;
          punishmentContributionSum += variableWeightCoefficient;
          punishmentCoefficientsProduct *= (1 - variableWeightCoefficient);
        }
        if (timeOffsetCoefficient > 0) {
          double timeOffsetDifference = Math.Abs(item1.DescendantTimeOffset - item2.DescendantTimeOffset);
          if (maximumTimeOffset > 0)
            descendantTimeOffsetDifferencePunishment = timeOffsetDifference / (maximumTimeOffset - minimumTimeOffset);
          descendantTimeOffsetDifferencePunishment *= timeOffsetCoefficient;
          punishmentContributionSum += timeOffsetCoefficient;
          punishmentCoefficientsProduct *= (1 - timeOffsetCoefficient);
        }
        if (variableIndexCoefficient > 0) {
          if (item1.DescendantVariableIndex != item2.DescendantVariableIndex)
            descendantVariableIndexDifferencePunishment = 1;
          else
            descendantVariableIndexDifferencePunishment = 0;
          descendantVariableIndexDifferencePunishment *= variableIndexCoefficient;
          punishmentContributionSum += variableIndexCoefficient;
          punishmentCoefficientsProduct *= (1 - variableIndexCoefficient);
        }
      }

      double result;

      if (additiveSimilarityCalculation) {
        double punishmentsSum = ancestorIndexDifferencePunishment + levelDifferencePunishment +
          descendantConstantValueDifferencePunishment + descendantVariableWeightDifferencePunishment +
          descendantTimeOffsetDifferencePunishment + descendantVariableIndexDifferencePunishment;
        result = (1 - punishmentsSum / punishmentContributionSum);
      } else {
        result =
          (1 - ancestorIndexDifferencePunishment) *
          (1 - levelDifferencePunishment) *
          (1 - descendantConstantValueDifferencePunishment) *
          (1 - descendantVariableWeightDifferencePunishment) *
          (1 - descendantTimeOffsetDifferencePunishment) *
          (1 - descendantVariableIndexDifferencePunishment);
        // worst possible result is (1-punishmentCoefficientsProduct), so scale linearly to [0;1]:
        result = (result - punishmentCoefficientsProduct) / (1 - punishmentCoefficientsProduct);
      }

      if (result < 0 || result > 1)
        throw new InvalidOperationException("ERROR in GeneticInformationItem.Similarity: An invalid similarity value (" + result.ToString() + ") has been calculated.");

      return result;

    }

    public static IList<GeneticInformationItem> GetGeneticInformationItems(SymbolicExpressionTreeNode node, List<string> variableNames,
        int MinimumLevelDelta, int MaximumLevelDelta) {
      // first we have to collect all items, then we filter; it is not possible to filter while collecting because the items are
      // collected recursively and used for collecting the parents' items.
      if (MinimumLevelDelta > MaximumLevelDelta)
        return new List<GeneticInformationItem>();
      IList<GeneticInformationItem> list = GetGeneticInformationItems(node, variableNames, 0);
      List<GeneticInformationItem> resultList = new List<GeneticInformationItem>();
      foreach (GeneticInformationItem item in list)
        if (item.LevelDelta >= MinimumLevelDelta && item.LevelDelta <= MaximumLevelDelta)
          resultList.Add(item);
      return resultList;
    }

    private static IList<GeneticInformationItem> GetGeneticInformationItems(SymbolicExpressionTreeNode node, List<string> variableNames, int level) {
      // Idea: collect all descendants' lists and then add new items using the retrieved ones.
      // This should save lots of time and reduce complexity of the items retrieval process.
      // Program roots are not considered, neither are start symbol nodes
      if (node.Symbol is ProgramRootSymbol)
        return GetGeneticInformationItems(node.SubTrees[0], variableNames, level + 1);
      List<GeneticInformationItem> list = new List<GeneticInformationItem>();
      // add item for this node:
      if (!(node.Symbol is StartSymbol)) {
        list.Add(new GeneticInformationItem(node, variableNames, level));
      }
      // add items for the descendants, but prevent multiple references to descendant nodes:
      List<SymbolicExpressionTreeNode> descendantNodes = new List<SymbolicExpressionTreeNode>();
      for (int i = 0; i < node.SubTrees.Count; i++) {
        IList<GeneticInformationItem> descendantItems = GetGeneticInformationItems(node.SubTrees[i], variableNames, level + 1);
        list.AddRange(descendantItems);
        if (!(node.Symbol is StartSymbol))
          foreach (GeneticInformationItem item in descendantItems) {
            if (!descendantNodes.Contains(item.DescendantTreeNode)) {
              list.Add(new GeneticInformationItem(node, item, i, level));
              descendantNodes.Add(item.DescendantTreeNode);
            }
          }
      }
      return list;
    }

    private GeneticInformationItem(SymbolicExpressionTreeNode node, List<string> variableNames, int level) {
      myAncestorIndex = -1;
      VariableTreeNode variableTreeNode = node as VariableTreeNode;
      LaggedVariableTreeNode laggedVariableTreeNode = node as LaggedVariableTreeNode;
      ConstantTreeNode constantTreeNode = node as ConstantTreeNode;
      myAncestorDefinition = node.Symbol.GetType();
      myDescendantDefinition = myAncestorDefinition;
      if (variableTreeNode != null)
        myDescendantCoefficient = variableTreeNode.Weight;
      else if (constantTreeNode != null)
        myDescendantCoefficient = constantTreeNode.Value;
      else
        myDescendantCoefficient = double.NaN;
      if (laggedVariableTreeNode != null)
        myDescendantTimeOffset = laggedVariableTreeNode.Lag;
      else
        myDescendantTimeOffset = 0;
      if (variableTreeNode != null)
        myDescendantVariableIndex = variableNames.IndexOf(variableTreeNode.VariableName);
      else
        myDescendantVariableIndex = -1;
      myAncestorLevel = level;
      myDescendantLevel = level;
      myDescendantTreeNode = node;
    }

    public override string ToString() {
      return "ancestor: " + AncestorDefinition.Name.ToString() + ", [" + AncestorIndex + "]; "
        + "descendant: " + DescendantDefinition.Name.ToString() + " (varIndex " + DescendantVariableIndex + ", "
        + DescendantCoefficient + ", t-" + DescendantTimeOffset + ");"
        + " level delta = " + DescendantLevel + "-" + AncestorLevel + " = " + LevelDelta;
    }

  }

}