#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;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;

namespace HeuristicLab.Problems.DataAnalysis.Symbolic {
  [Item("Excel String Formatter", "String formatter for string representations of symbolic data analysis expressions in Excel syntax.")]
  [StorableClass]
  public sealed class SymbolicDataAnalysisExpressionExcelFormatter : NamedItem, ISymbolicExpressionTreeStringFormatter {
    [StorableConstructor]
    private SymbolicDataAnalysisExpressionExcelFormatter(bool deserializing) : base(deserializing) { }
    private SymbolicDataAnalysisExpressionExcelFormatter(SymbolicDataAnalysisExpressionExcelFormatter original, Cloner cloner) : base(original, cloner) { }
    public SymbolicDataAnalysisExpressionExcelFormatter()
      : base() {
      Name = ItemName;
      Description = ItemDescription;
    }
    public override IDeepCloneable Clone(Cloner cloner) {
      return new SymbolicDataAnalysisExpressionExcelFormatter(this, cloner);
    }
    private string GetExcelColumnName(int columnNumber) {
      int dividend = columnNumber;
      string columnName = String.Empty;

      while (dividend > 0) {
        int modulo = (dividend - 1) % 26;
        columnName = Convert.ToChar(65 + modulo).ToString() + columnName;
        dividend = (int)((dividend - modulo) / 26);
      }

      return columnName;
    }

    private readonly Dictionary<string, string> variableNameMapping = new Dictionary<string, string>();
    private int currentVariableIndex = 0;
    private string GetColumnToVariableName(string variabelName) {
      if (!variableNameMapping.ContainsKey(variabelName)) {
        currentVariableIndex++;
        variableNameMapping.Add(variabelName, GetExcelColumnName(currentVariableIndex));
      }
      return string.Format("${0}1", variableNameMapping[variabelName]);
    }
    public string Format(ISymbolicExpressionTree symbolicExpressionTree) {
      return Format(symbolicExpressionTree, null);
    }

    public string Format(ISymbolicExpressionTree symbolicExpressionTree, Dataset dataset) {
      var stringBuilder = new StringBuilder();
      if (dataset != null) CalculateVariableMapping(symbolicExpressionTree, dataset);

      stringBuilder.Append("=");
      stringBuilder.Append(FormatRecursively(symbolicExpressionTree.Root));

      foreach (var variable in variableNameMapping) {
        stringBuilder.AppendLine();
        stringBuilder.Append(variable.Key + " = " + variable.Value);
      }
      return stringBuilder.ToString();
    }

    private void CalculateVariableMapping(ISymbolicExpressionTree tree, Dataset dataset) {
      int columnIndex = 0;
      int inputIndex = 0;
      var usedVariables = tree.IterateNodesPrefix().OfType<VariableTreeNode>().Select(v => v.VariableName).Distinct();
      foreach (var variable in dataset.VariableNames) {
        columnIndex++;
        if (!usedVariables.Contains(variable)) continue;
        inputIndex++;
        variableNameMapping[variable] = GetExcelColumnName(inputIndex);
      }
    }

    private string FormatRecursively(ISymbolicExpressionTreeNode node) {
      ISymbol symbol = node.Symbol;
      StringBuilder stringBuilder = new StringBuilder();

      if (symbol is ProgramRootSymbol) {
        stringBuilder.AppendLine(FormatRecursively(node.GetSubtree(0)));
      } else if (symbol is StartSymbol)
        return FormatRecursively(node.GetSubtree(0));
      else if (symbol is Addition) {
        stringBuilder.Append("(");
        for (int i = 0; i < node.SubtreeCount; i++) {
          if (i > 0) stringBuilder.Append("+");
          stringBuilder.Append(FormatRecursively(node.GetSubtree(i)));
        }
        stringBuilder.Append(")");
      } else if (symbol is Average) {
        stringBuilder.Append("(1/");
        stringBuilder.Append(node.SubtreeCount);
        stringBuilder.Append(")*(");
        for (int i = 0; i < node.SubtreeCount; i++) {
          if (i > 0) stringBuilder.Append("+");
          stringBuilder.Append("(");
          stringBuilder.Append(FormatRecursively(node.GetSubtree(i)));
          stringBuilder.Append(")");
        }
        stringBuilder.Append(")");
      } else if (symbol is Constant) {
        ConstantTreeNode constantTreeNode = node as ConstantTreeNode;
        stringBuilder.Append(constantTreeNode.Value.ToString(CultureInfo.InvariantCulture));
      } else if (symbol is Cosine) {
        stringBuilder.Append("COS(");
        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
        stringBuilder.Append(")");
      } else if (symbol is Division) {
        if (node.SubtreeCount == 1) {
          stringBuilder.Append("1/");
          stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
        } else {
          stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
          stringBuilder.Append("/(");
          for (int i = 1; i < node.SubtreeCount; i++) {
            if (i > 1) stringBuilder.Append("*");
            stringBuilder.Append(FormatRecursively(node.GetSubtree(i)));
          }
          stringBuilder.Append(")");
        }
      } else if (symbol is Exponential) {
        stringBuilder.Append("EXP(");
        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
        stringBuilder.Append(")");
      } else if (symbol is Square) {
        stringBuilder.Append("POWER(");
        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
        stringBuilder.Append(",2)");
      } else if (symbol is SquareRoot) {
        stringBuilder.Append("SQRT(");
        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
        stringBuilder.Append(")");
      } else if (symbol is Logarithm) {
        stringBuilder.Append("LN(");
        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
        stringBuilder.Append(")");
      } else if (symbol is Multiplication) {
        for (int i = 0; i < node.SubtreeCount; i++) {
          if (i > 0) stringBuilder.Append("*");
          stringBuilder.Append(FormatRecursively(node.GetSubtree(i)));
        }
      } else if (symbol is Sine) {
        stringBuilder.Append("SIN(");
        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
        stringBuilder.Append(")");
      } else if (symbol is Subtraction) {
        stringBuilder.Append("(");
        if (node.SubtreeCount == 1) {
          stringBuilder.Append("-");
          stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
        } else {
          stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
          for (int i = 1; i < node.SubtreeCount; i++) {
            stringBuilder.Append("-");
            stringBuilder.Append(FormatRecursively(node.GetSubtree(i)));
          }
        }
        stringBuilder.Append(")");
      } else if (symbol is Tangent) {
        stringBuilder.Append("TAN(");
        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
        stringBuilder.Append(")");

      } else if (symbol is Variable) {
        VariableTreeNode variableTreeNode = node as VariableTreeNode;
        stringBuilder.Append(variableTreeNode.Weight.ToString(CultureInfo.InvariantCulture));
        stringBuilder.Append("*");
        stringBuilder.Append(GetColumnToVariableName(variableTreeNode.VariableName));// + LagToString(currentLag));
      } else if (symbol is Power) {
        stringBuilder.Append("POWER(");
        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
        stringBuilder.Append(",ROUND(");
        stringBuilder.Append(FormatRecursively(node.GetSubtree(1)));
        stringBuilder.Append(",0))");
      } else if (symbol is Root) {
        stringBuilder.Append("(");
        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
        stringBuilder.Append(")^(1 / ROUND(");
        stringBuilder.Append(FormatRecursively(node.GetSubtree(1)));
        stringBuilder.Append(",0))");
      } else {
        throw new NotImplementedException("Excel export of " + node.Symbol + " is not implemented.");
      }
      return stringBuilder.ToString();
    }
  }
}