#region License Information
/* HeuristicLab
 * Copyright (C) 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.Linq;
using HeuristicLab.Analysis;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HeuristicLab.Operators;
using HeuristicLab.Optimization;
using HeuristicLab.Parameters;
using HEAL.Attic;

namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding {
  /// <summary>
  /// An operator that tracks tree lengths of Symbolic Expression Trees
  /// </summary>
  [Item("SymbolicExpressionTreeLengthAnalyzer", "An operator that tracks tree lengths of Symbolic Expression Trees")]
  [StorableType("8A9F09AC-40E4-4AA2-9270-9204C9460E66")]
  public sealed class SymbolicExpressionTreeLengthAnalyzer : SingleSuccessorOperator, ISymbolicExpressionTreeAnalyzer {
    private const string SymbolicExpressionTreeParameterName = "SymbolicExpressionTree";
    private const string MaximumSymbolicExpressionTreeLengthParameterName = "MaximumSymbolicExpressionTreeLength";
    private const string SymbolicExpressionTreeLengthsParameterName = "SymbolicExpressionTreeLengthsTable";
    private const string SymbolicExpressionTreeLengthsHistoryParameterName = "SymbolicExpressionTreeLengthsHistoryTable";
    private const string ResultsParameterName = "Results";
    private const string StoreHistoryParameterName = "StoreHistory";
    private const string UpdateIntervalParameterName = "UpdateInterval";
    private const string UpdateCounterParameterName = "UpdateCounter";

    #region Parameter properties
    public IScopeTreeLookupParameter<ISymbolicExpressionTree> SymbolicExpressionTreeParameter {
      get { return (IScopeTreeLookupParameter<ISymbolicExpressionTree>)Parameters[SymbolicExpressionTreeParameterName]; }
    }

    public IValueLookupParameter<IntValue> MaximumSymbolicExpressionTreeLengthParameter {
      get { return (IValueLookupParameter<IntValue>)Parameters[MaximumSymbolicExpressionTreeLengthParameterName]; }
    }
    public ValueLookupParameter<DataTable> SymbolicExpressionTreeLengthsParameter {
      get { return (ValueLookupParameter<DataTable>)Parameters[SymbolicExpressionTreeLengthsParameterName]; }
    }
    public ValueLookupParameter<DataTableHistory> SymbolicExpressionTreeLengthsHistoryParameter {
      get { return (ValueLookupParameter<DataTableHistory>)Parameters[SymbolicExpressionTreeLengthsHistoryParameterName]; }
    }
    public ValueLookupParameter<ResultCollection> ResultsParameter {
      get { return (ValueLookupParameter<ResultCollection>)Parameters[ResultsParameterName]; }
    }
    // history
    public ValueParameter<BoolValue> StoreHistoryParameter {
      get { return (ValueParameter<BoolValue>)Parameters[StoreHistoryParameterName]; }
    }
    public ValueParameter<IntValue> UpdateIntervalParameter {
      get { return (ValueParameter<IntValue>)Parameters[UpdateIntervalParameterName]; }
    }
    public ValueParameter<IntValue> UpdateCounterParameter {
      get { return (ValueParameter<IntValue>)Parameters[UpdateCounterParameterName]; }
    }
    #endregion

    #region Properties
    public bool EnabledByDefault {
      get { return true; }
    }
    public IntValue UpdateInterval {
      get { return UpdateIntervalParameter.Value; }
    }
    public IntValue UpdateCounter {
      get { return UpdateCounterParameter.Value; }
    }
    public BoolValue StoreHistory {
      get { return StoreHistoryParameter.Value; }
    }
    #endregion

    [StorableConstructor]
    private SymbolicExpressionTreeLengthAnalyzer(StorableConstructorFlag _) : base(_) { }
    private SymbolicExpressionTreeLengthAnalyzer(SymbolicExpressionTreeLengthAnalyzer original, Cloner cloner)
      : base(original, cloner) {
    }
    public override IDeepCloneable Clone(Cloner cloner) {
      return new SymbolicExpressionTreeLengthAnalyzer(this, cloner);
    }
    public SymbolicExpressionTreeLengthAnalyzer()
      : base() {
      Parameters.Add(new ScopeTreeLookupParameter<ISymbolicExpressionTree>(SymbolicExpressionTreeParameterName, "The symbolic expression tree whose length should be calculated."));
      Parameters.Add(new ValueLookupParameter<IntValue>(MaximumSymbolicExpressionTreeLengthParameterName, "The maximum allowed symbolic expression tree length"));
      Parameters.Add(new ValueLookupParameter<DataTable>(SymbolicExpressionTreeLengthsParameterName, "The data table to store the symbolic expression tree lengths."));
      Parameters.Add(new ValueLookupParameter<DataTableHistory>(SymbolicExpressionTreeLengthsHistoryParameterName, "The data table to store the symbolic expression tree lengths history."));
      Parameters.Add(new ValueLookupParameter<ResultCollection>(ResultsParameterName, "The results collection where the analysis values should be stored."));
      Parameters.Add(new ValueParameter<BoolValue>(StoreHistoryParameterName, "True if the tree lengths history of the population should be stored.", new BoolValue(false)));
      Parameters.Add(new ValueParameter<IntValue>(UpdateIntervalParameterName, "The interval in which the tree length analysis should be applied.", new IntValue(1)));
      Parameters.Add(new ValueParameter<IntValue>(UpdateCounterParameterName, "The value which counts how many times the operator was called since the last update", new IntValue(0)));

      SymbolicExpressionTreeLengthsParameter.Hidden = true;
      SymbolicExpressionTreeLengthsHistoryParameter.Hidden = true;
      ResultsParameter.Hidden = true;
      UpdateCounterParameter.Hidden = true;
    }

    [StorableHook(HookType.AfterDeserialization)]
    private void AfterDeserialization() {
      // reset MaximumSymbolicExpressionTreeLengthParameterName to ValueLookupParameter
      if (Parameters.TryGetValue(MaximumSymbolicExpressionTreeLengthParameterName, out IParameter treeLengthParam) && !(treeLengthParam is ValueLookupParameter<IntValue>))
        Parameters.Remove(MaximumSymbolicExpressionTreeLengthParameterName);
      if(!Parameters.ContainsKey(MaximumSymbolicExpressionTreeLengthParameterName))
        Parameters.Add(new ValueLookupParameter<IntValue>(MaximumSymbolicExpressionTreeLengthParameterName, "The maximum allowed symbolic expression tree length"));

      // check if all the parameters are present and accounted for 
      if (!Parameters.ContainsKey(StoreHistoryParameterName))
        Parameters.Add(new ValueParameter<BoolValue>(StoreHistoryParameterName, "True if the tree lengths history of the population should be stored.", new BoolValue(false)));
      
      if (!Parameters.ContainsKey(UpdateIntervalParameterName))
        Parameters.Add(new ValueParameter<IntValue>(UpdateIntervalParameterName, "The interval in which the tree length analysis should be applied.", new IntValue(1)));

      //necessary code to correct UpdateCounterParameter - type was changed from LookupParameter to ValueParameter
      if (Parameters.TryGetValue(UpdateCounterParameterName, out IParameter updateCounterParam) && updateCounterParam is LookupParameter<IntValue>)
        Parameters.Remove(UpdateCounterParameterName);
      if (!Parameters.ContainsKey(UpdateCounterParameterName)) {
        Parameters.Add(new ValueParameter<IntValue>(UpdateCounterParameterName, "The value which counts how many times the operator was called since the last update", new IntValue(0)));
        UpdateCounterParameter.Hidden = true;
      }
    }

    #region IStatefulItem members
    public override void InitializeState() {
      base.InitializeState();
      UpdateCounter.Value = 0;
    }
    public override void ClearState() {
      base.ClearState();
      UpdateCounter.Value = 0;
    }
    #endregion

    public override IOperation Apply() {
      UpdateCounter.Value++;
      // the analyzer runs periodically, every 'updateInterval' times
      if (UpdateCounter.Value == UpdateInterval.Value) {
        UpdateCounter.Value = 0; // reset counter

        // compute all tree lengths and store them in the lengthsTable
        var solutions = SymbolicExpressionTreeParameter.ActualValue;

        var treeLengthsTable = SymbolicExpressionTreeLengthsParameter.ActualValue;
        // if the table was not created yet, we create it here
        if (treeLengthsTable == null) {
          treeLengthsTable = new DataTable("Tree Length Histogram");
          SymbolicExpressionTreeLengthsParameter.ActualValue = treeLengthsTable;
        }

        // data table which stores tree length values
        DataRow treeLengthsTableRow;

        const string treeLengthsTableRowName = "Symbolic expression tree lengths";
        const string treeLengthsTableRowDesc = "The distribution of symbolic expression tree lengths";
        const string xAxisTitle = "Symbolic expression tree lengths";
        const string yAxisTitle = "Frequency / Number of tree individuals";

        var treeLengths = solutions.Select(s => (int)s.Length).ToList();

        int maxLength = treeLengths.Max(t => t);
        int minLength = treeLengths.Min(t => t);

        if (!treeLengthsTable.Rows.ContainsKey(treeLengthsTableRowName)) {
          treeLengthsTableRow = new DataRow(treeLengthsTableRowName, treeLengthsTableRowDesc, treeLengths.Select(x => (double)x));
          treeLengthsTable.Rows.Add(treeLengthsTableRow);
        } else {
          treeLengthsTableRow = treeLengthsTable.Rows[treeLengthsTableRowName];
          treeLengthsTableRow.Values.Replace(treeLengths.Select(x => (double)x));
        }

        double maximumAllowedTreeLength = MaximumSymbolicExpressionTreeLengthParameter.ActualValue.Value;

        treeLengthsTableRow.VisualProperties.ChartType = DataRowVisualProperties.DataRowChartType.Histogram;
        treeLengthsTable.VisualProperties.HistogramExactBins = false;

        int range = maxLength - minLength;
        if (range == 0) range = 1;
        // the following trick should result in an integer intervalWidth of 1,2,4,...
        treeLengthsTable.VisualProperties.HistogramBins = range;

        if (maxLength <= 25) // [0,25]
          treeLengthsTableRow.VisualProperties.ScaleFactor = 1.0;
        else if (maxLength <= 100) // [26,100]
          treeLengthsTableRow.VisualProperties.ScaleFactor = 1.0 / 2.0;
        else if (maxLength <= 250) // [101,250]
          treeLengthsTableRow.VisualProperties.ScaleFactor = 1.0 / 5.0;
        else if (maxLength <= 500) // [251,500]
          treeLengthsTableRow.VisualProperties.ScaleFactor = 1.0 / 10.0;
        else
          treeLengthsTableRow.VisualProperties.ScaleFactor = 1.0 / 20.0; // [501,inf]

        treeLengthsTableRow.VisualProperties.IsVisibleInLegend = false;

        // visual properties for the X-axis
        treeLengthsTable.VisualProperties.XAxisMinimumAuto = false;
        treeLengthsTable.VisualProperties.XAxisMaximumAuto = false;
        treeLengthsTable.VisualProperties.XAxisMinimumFixedValue = 0.0;
        if (maxLength > maximumAllowedTreeLength + 1)
          treeLengthsTable.VisualProperties.XAxisMaximumFixedValue = maxLength + 1; // +1 so the histogram column for the maximum length won't get trimmed
        else
          treeLengthsTable.VisualProperties.XAxisMaximumFixedValue = maximumAllowedTreeLength + 1;
        treeLengthsTable.VisualProperties.XAxisTitle = xAxisTitle;
        //visual properties for the Y-axis
        treeLengthsTable.VisualProperties.YAxisMinimumAuto = false;
        treeLengthsTable.VisualProperties.YAxisMaximumAuto = false;
        treeLengthsTable.VisualProperties.YAxisMinimumFixedValue = 0.0;
        int maxFreq = (int)Math.Round(solutions.GroupBy(s => s.Length).Max(g => g.Count()) / treeLengthsTableRow.VisualProperties.ScaleFactor);
        if (maxFreq % 5 != 0)
          maxFreq += (5 - maxFreq % 5);
        double yAxisMaximumFixedValue = maxFreq;

        treeLengthsTable.VisualProperties.YAxisMaximumFixedValue = yAxisMaximumFixedValue;
        treeLengthsTable.VisualProperties.YAxisTitle = yAxisTitle;

        var results = ResultsParameter.ActualValue;

        if (!results.ContainsKey(treeLengthsTableRowName)) {
          results.Add(new Result(treeLengthsTableRowName, treeLengthsTable));
        } else {
          results[treeLengthsTableRowName].Value = treeLengthsTable;
        }

        bool storeHistory = StoreHistoryParameter.Value.Value;
        const string treeLengthHistoryTableName = "Tree lengths history";

        if (storeHistory) {
          var treeLengthsHistory = SymbolicExpressionTreeLengthsHistoryParameter.ActualValue;
          if (treeLengthsHistory == null) {
            treeLengthsHistory = new DataTableHistory();
            SymbolicExpressionTreeLengthsHistoryParameter.ActualValue = treeLengthsHistory;
          }
          treeLengthsHistory.Add((DataTable)treeLengthsTable.Clone());

          if (!results.ContainsKey(treeLengthHistoryTableName)) {
            results.Add(new Result(treeLengthHistoryTableName, treeLengthsHistory));
          } else {
            results[treeLengthHistoryTableName].Value = treeLengthsHistory;
          }
        }
      }
      return base.Apply();
    }
  }
}