#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2018 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 System.Threading.Tasks;
using HeuristicLab.Data;
using HeuristicLab.MainForm;
using HeuristicLab.Problems.DataAnalysis.Symbolic.Regression;

namespace HeuristicLab.Problems.DataAnalysis.Views {
  [View("Variable Impacts")]
  [Content(typeof(IRegressionSolution))]
  public partial class RegressionSolutionVariableImpactsView : DataAnalysisSolutionEvaluationView {

    private const int ORDER_BY_VARIABLE = 0;
    private const int ORDER_BY_IMPACT = 1;

    private Dictionary<string, double> rawVariableImpacts = new Dictionary<string, double>();

    public new IRegressionSolution Content {
      get { return (IRegressionSolution)base.Content; }
      set {
        base.Content = value;
      }
    }

    public RegressionSolutionVariableImpactsView()
      : base() {
      InitializeComponent();
      this.dataPartitionComboBox.SelectedIndex = 0;
      this.replacementComboBox.SelectedIndex = 0;
      this.factorVarReplComboBox.SelectedIndex = 0;
    }

    #region events
    protected override void RegisterContentEvents() {
      base.RegisterContentEvents();
      Content.ModelChanged += new EventHandler(Content_ModelChanged);
      Content.ProblemDataChanged += new EventHandler(Content_ProblemDataChanged);
    }

    protected override void DeregisterContentEvents() {
      base.DeregisterContentEvents();
      Content.ModelChanged -= new EventHandler(Content_ModelChanged);
      Content.ProblemDataChanged -= new EventHandler(Content_ProblemDataChanged);
    }

    protected virtual void Content_ProblemDataChanged(object sender, EventArgs e) {
      OnContentChanged();
    }

    protected virtual void Content_ModelChanged(object sender, EventArgs e) {
      OnContentChanged();
    }

    protected override void OnContentChanged() {
      base.OnContentChanged();
      if (Content == null) {
        variableImactsArrayView.Content = null;
      } else {
        UpdateVariableImpacts();
      }
    }

    private void UpdateVariableImpacts() {
      if (Content == null || replacementComboBox.SelectedIndex < 0
        || factorVarReplComboBox.SelectedIndex < 0
        || dataPartitionComboBox.SelectedIndex < 0) return;
      var mainForm = (MainForm.WindowsForms.MainForm)MainFormManager.MainForm;
      variableImactsArrayView.Caption = Content.Name + " Variable Impacts";
      var replMethod =
         (RegressionSolutionVariableImpactsCalculator.ReplacementMethodEnum)
           replacementComboBox.Items[replacementComboBox.SelectedIndex];
      var factorReplMethod =
        (RegressionSolutionVariableImpactsCalculator.FactorReplacementMethodEnum)
          factorVarReplComboBox.Items[factorVarReplComboBox.SelectedIndex];
      var dataPartition =
        (RegressionSolutionVariableImpactsCalculator.DataPartitionEnum)dataPartitionComboBox.SelectedItem;

      Task.Factory.StartNew(() => {
        try {
          mainForm.AddOperationProgressToView(this, "Calculating variable impacts for " + Content.Name);

          var impacts = RegressionSolutionVariableImpactsCalculator.CalculateImpacts(Content, dataPartition, replMethod, factorReplMethod);
          var impactArray = new DoubleArray(impacts.Select(i => i.Item2).ToArray());
          impactArray.ElementNames = impacts.Select(i => i.Item1);
          variableImactsArrayView.Content = (DoubleArray)impactArray.AsReadOnly();

          //Remember the original ordering of the variables
          var problemData = Content.ProblemData;
          var inputvariables = new HashSet<string>(problemData.AllowedInputVariables.Union(Content.Model.VariablesUsedForPrediction));
          var originalVariableOrdering = problemData.Dataset.VariableNames.Where(v => inputvariables.Contains(v)).Where(problemData.Dataset.VariableHasType<double>).ToList();
          rawVariableImpacts.Clear();
          originalVariableOrdering.ForEach(v => rawVariableImpacts.Add(v, impacts.First(vv => vv.Item1 == v).Item2));

        } finally {
          mainForm.RemoveOperationProgressFromView(this);
        }
      });
    }

    private void dataPartitionComboBox_SelectedIndexChanged(object sender, EventArgs e) {
      ResetOrdering();
      UpdateVariableImpacts();
    }

    private void replacementComboBox_SelectedIndexChanged(object sender, EventArgs e) {
      ResetOrdering();
      UpdateVariableImpacts();
    }

    private void sortByComboBox_SelectedIndexChanged(object sender, EventArgs e) {
      UpdateDataOrdering();
    }

    private void ascendingCheckBox_CheckedChanged(object sender, EventArgs e) {
      UpdateDataOrdering();
    }
    #endregion

    #region Helper Methods
    /// <summary>
    /// Updates the <see cref="variableImactsArrayView"/> according to the selected ordering <see cref="ascendingCheckBox"/> of the selected Column <see cref="sortByComboBox"/>
    /// The default is "Descending" by "VariableImpact" (as in previous versions)
    /// </summary>
    private void UpdateDataOrdering() {
      int orderIdx = sortByComboBox.SelectedIndex;
      bool ascending = ascendingCheckBox.Checked;

      //Check if valid ordering is selected AND at if any VariableImpact exists
      if (orderIdx > -1 && rawVariableImpacts != null && rawVariableImpacts.Any()) {
        IEnumerable<KeyValuePair<string, double>> orderedEntries = null;

        //Sort accordingly
        if (orderIdx == ORDER_BY_VARIABLE) {
          orderedEntries = ascending ? rawVariableImpacts : rawVariableImpacts.Reverse();
        } else if (orderIdx == ORDER_BY_IMPACT) {
          orderedEntries = ascending ? rawVariableImpacts.OrderBy(v => v.Value) : rawVariableImpacts.OrderByDescending(v => v.Value);
        }

        //Write the data back
        var impactArray = new DoubleArray(orderedEntries.Select(i => i.Value).ToArray());
        impactArray.ElementNames = orderedEntries.Select(i => i.Key);
        variableImactsArrayView.Content = (DoubleArray)impactArray.AsReadOnly();
      }
    }

    /// <summary>
    /// Resets the ordering to the default behaviour (descending by variableImpact), meaning <see cref="ascendingCheckBox"/> and <see cref="sortByComboBox"/> will be updated
    /// Note: this will NOT update the UI
    /// </summary>
    private void ResetOrdering() {
      //The events shouldn't fire everytime we reset the data
      ascendingCheckBox.CheckedChanged -= ascendingCheckBox_CheckedChanged;
      sortByComboBox.SelectedIndexChanged -= sortByComboBox_SelectedIndexChanged;

      ascendingCheckBox.Checked = false;
      sortByComboBox.SelectedIndex = ORDER_BY_IMPACT;

      ascendingCheckBox.CheckedChanged += ascendingCheckBox_CheckedChanged;
      sortByComboBox.SelectedIndexChanged += sortByComboBox_SelectedIndexChanged;
    }
    #endregion
  }
}