namespace HeuristicLab.Problems.ProgramSynthesis.Push.Analyzer {
  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 HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
  using HeuristicLab.Problems.ProgramSynthesis.Push.Problem;

  /// <summary>
  /// An operater that tracks the count of individuals with zero error on the cases
  /// </summary>
  [Item("IndividualZeroErrorDistributionAnalyzer", "An operater that tracks the distribution of individuals with zero error on the cases")]
  [StorableClass]
  public class IndividualZeroErrorDistributionAnalyzer : SingleSuccessorOperator, IIndividualZeroErrorDistributionAnalyzer {
    private const string RESULTS_PARAMETER_NAME = "Results";
    private const string INDIVIDUAL_ZERO_ERROR_PARAMETER_NAME = "ZeroErrorIndividualsPerCaseDistribution";

    private const string RESULT_PARAMETER_NAME = "Zero Error Individual Per Case Distribution";
    private const string RESULT_PARAMETER_DESCRIPTION = "Relative frequency of instructions aggregated over the whole population.";
    private const string Y_AXIS_TITLE = "Number of zero error cases";
    private const string X_AXIS_TITLE = "Number of individuals";
    private const string ROW_NAME = "Cases";

    public IndividualZeroErrorDistributionAnalyzer() {
      Parameters.Add(new LookupParameter<DataTable>(
        INDIVIDUAL_ZERO_ERROR_PARAMETER_NAME,
        "The data table to store the count of individuals with zero error."));

      Parameters.Add(new LookupParameter<ResultCollection>(
        RESULTS_PARAMETER_NAME,
        "The result collection where the symbol frequencies should be stored."));

      Parameters.Add(new ScopeTreeLookupParameter<DoubleArray>(
       IntegerVectorPushProblem.CaseQualitiesScopeParameterName,
       "The quality of every single training case for each individual."));
    }

    [StorableConstructorAttribute]
    public IndividualZeroErrorDistributionAnalyzer(bool deserializing) : base(deserializing) { }

    public IndividualZeroErrorDistributionAnalyzer(IndividualZeroErrorDistributionAnalyzer origin, Cloner cloner) : base(origin, cloner) { }

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

    public bool EnabledByDefault { get { return true; } }

    public ILookupParameter<DataTable> IndividualZeroErrorDistributionParameter
    {
      get { return (ILookupParameter<DataTable>)Parameters[INDIVIDUAL_ZERO_ERROR_PARAMETER_NAME]; }
    }

    public ILookupParameter<ResultCollection> ResultsParameter
    {
      get { return (ILookupParameter<ResultCollection>)Parameters[RESULTS_PARAMETER_NAME]; }
    }

    public ILookupParameter<ItemArray<DoubleArray>> CaseQualitiesParameter
    {
      get { return (ILookupParameter<ItemArray<DoubleArray>>)Parameters[IntegerVectorPushProblem.CaseQualitiesScopeParameterName]; }
    }

    public override IOperation Apply() {
      var caseQualitiesPerIndividual = CaseQualitiesParameter.ActualValue;
      var individualCount = caseQualitiesPerIndividual.Length;
      var caseCount = caseQualitiesPerIndividual[0].Length;

      var results = ResultsParameter.ActualValue;
      var individualZeroErrorDistribution = IndividualZeroErrorDistributionParameter.ActualValue;

      if (individualZeroErrorDistribution == null) {
        individualZeroErrorDistribution = new DataTable(
         RESULT_PARAMETER_NAME,
         RESULT_PARAMETER_DESCRIPTION) {
          VisualProperties = {
            YAxisTitle = Y_AXIS_TITLE,
            XAxisTitle = X_AXIS_TITLE,
            XAxisMinimumFixedValue = 0,
            XAxisMaximumAuto = true,
            XAxisMinimumAuto = false,
          }
        };

        IndividualZeroErrorDistributionParameter.ActualValue = individualZeroErrorDistribution;
      }

      if (!results.ContainsKey(RESULT_PARAMETER_NAME)) {
        results.Add(new Result(RESULT_PARAMETER_NAME, individualZeroErrorDistribution));
      }

      DataRow row;
      if (!individualZeroErrorDistribution.Rows.TryGetValue(ROW_NAME, out row)) {
        row = new DataRow(ROW_NAME) {
          VisualProperties = {
              StartIndexZero = true,
              IsVisibleInLegend = false,
              ChartType = DataRowVisualProperties.DataRowChartType.Histogram,
            }
        };

        individualZeroErrorDistribution.Rows.Add(row);
      }

      var caseCountChanged = row.Values.Count != caseCount;

      if (caseCountChanged) {
        row.Values.Clear();
      }

      // key represents the number of cases with zero error
      // value represents the number of individuals with key cases with zero error
      var distribution = caseQualitiesPerIndividual
              .Select(individual => individual.Count(x => x == 0.0))
              .GroupBy(x => x)
              .ToDictionary(x => x.Key, x => x.Count());

      for (var i = 0; i < caseCount; i++) {
        int count;
        distribution.TryGetValue(i, out count);
        var x = count / (double)individualCount;

        if (caseCountChanged)
          row.Values.Add(x);
        else
          row.Values[i] = x;
      }

      return base.Apply();
    }
  }
}