#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2013 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.Collections.Generic;
using System.Linq;
using HeuristicLab.DataImporter.Data;
using HeuristicLab.DataImporter.Data.CommandBase;
using HeuristicLab.DataImporter.Data.Model;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;

namespace HeuristicLab.DataImporter.Command {
  [StorableClass]
  [ViewableCommandInfoAttribute("Percental Change", 1, ColumnGroupState.DoubleColumnSelected, "Change Values", Position = 3)]
  public class PercentalChangeCommand : ColumnGroupCommandWithAffectedColumnsBase {
    private Dictionary<int, DoubleColumn> oldColumns;
    private ICollection<int> oldSortedColumnIndices;

    [StorableConstructor]
    protected PercentalChangeCommand(bool deserializing)
      : base(deserializing) {
      oldColumns = new Dictionary<int, DoubleColumn>();
    }

    public PercentalChangeCommand(DataSet dataSet, string columnGroupName, int[] affectedColumns)
      : base(dataSet, columnGroupName, affectedColumns) {
      oldColumns = new Dictionary<int, DoubleColumn>();
    }

    public override string Description {
      get { return "Calculate the percental change from last to the current value"; }
    }

    public override void Execute() {
      base.Execute();
      foreach (int col in AffectedColumns) {
        DoubleColumn doubleCol = ColumnGroup.GetColumn(col) as DoubleColumn;
        if (doubleCol == null) throw new CommandExecutionException("Filtering is only supported for double columns.", this);
      }
      DoubleColumn column;
      oldSortedColumnIndices = new List<int>(ColumnGroup.SortedColumnIndexes);
      foreach (int col in AffectedColumns) {
        if (ColumnGroup.GetColumn(col) is DoubleColumn) {
          column = (DoubleColumn)ColumnGroup.GetColumn(col);
          oldColumns.Add(col, column);
          ColumnGroup.ReplaceColumn(col, CalcNewColumn(column));
        }
      }
      ColumnGroup.SortedColumnIndexes = oldSortedColumnIndices;
      ColumnGroup.FireChanged();
      ColumnGroup = null;
    }

    public override void UndoExecute() {
      base.UndoExecute();
      foreach (KeyValuePair<int, DoubleColumn> pair in oldColumns)
        ColumnGroup.ReplaceColumn(pair.Key, pair.Value);

      ColumnGroup.SortedColumnIndexes = oldSortedColumnIndices;
      oldSortedColumnIndices = null;
      oldColumns.Clear();
      ColumnGroup.FireChanged();
      ColumnGroup = null;
    }

    private DoubleColumn CalcNewColumn(DoubleColumn oldColumn) {
      DoubleColumn newCol = (DoubleColumn)oldColumn.CreateCopyOfColumnWithoutValues();
      var data = oldColumn.ValuesEnumerable.Cast<double?>();

      var ans = new double?[] { null } // insert an empty value at the beginning
      .Concat(data)
      .Zip(data, (prev, cur) => (cur.HasValue && prev.HasValue) ? (cur - prev) / prev : null)
      .ToArray();

      foreach (var e in ans) newCol.AddValue(e);

      newCol.SortOrder = oldColumn.SortOrder;
      return newCol;
    }
  }
}