AppsheetEpplus/FormulaParsing/Excel/Functions/RefAndLookup/ExcelMatch.cs

/* Copyright (C) 2011  Jan Källman
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.

 * This library 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 Lesser General Public License for more details.
 *
 * The GNU Lesser General Public License can be viewed at http://www.opensource.org/licenses/lgpl-license.php
 * If you unfamiliar with this license or have questions about it, here is an http://www.gnu.org/licenses/gpl-faq.html
 *
 * All code and executables are provided "as is" with no warranty either express or implied.
 * The author accepts no liability for any damage or loss of business that this product may cause.
 *
 * Code change notes:
 *
 * Author							Change						Date
 *******************************************************************************
 * Mats Alm   		                Added		                2013-12-03
 *******************************************************************************/

using System.Collections.Generic;
using System.Linq;

namespace AppsheetEpplus;

public class ExcelMatch : LookupFunction {
  private enum MatchType {
    ClosestAbove = -1,
    ExactMatch = 0,
    ClosestBelow = 1,
  }

  public ExcelMatch()
      : base(new WildCardValueMatcher(), new()) {}

  public override CompileResult Execute(
      IEnumerable<FunctionArgument> arguments,
      ParsingContext context) {
    ValidateArguments(arguments, 2);

    var searchedValue = arguments.ElementAt(0).Value;
    var address = ArgToString(arguments, 1);
    var rangeAddressFactory = new RangeAddressFactory(context.ExcelDataProvider);
    var rangeAddress = rangeAddressFactory.Create(address);
    var matchType = GetMatchType(arguments);
    var args = new LookupArguments(searchedValue, address, 0, 0, false);
    var lookupDirection = GetLookupDirection(rangeAddress);
    var navigator = LookupNavigatorFactory.Create(lookupDirection, args, context);
    int? lastMatchResult = default(int?);
    do {
      var matchResult = IsMatch(navigator.CurrentValue, searchedValue);
      if (matchType == MatchType.ClosestBelow && matchResult >= 0) {
        if (!lastMatchResult.HasValue && matchResult > 0) {
          // TODO: error handling. This happens only if the first item is
          // below the searched value.
        }
        var index = matchResult == 0 ? navigator.Index + 1 : navigator.Index;
        return CreateResult(index, DataType.Integer);
      }
      if (matchType == MatchType.ClosestAbove && matchResult <= 0) {
        if (!lastMatchResult.HasValue && matchResult < 0) {
          // TODO: error handling. This happens only if the first item is
          // above the searched value
        }
        var index = matchResult == 0 ? navigator.Index + 1 : navigator.Index;
        return CreateResult(index, DataType.Integer);
      }
      if (matchType == MatchType.ExactMatch && matchResult == 0) {
        return CreateResult(navigator.Index + 1, DataType.Integer);
      }
      lastMatchResult = matchResult;
    } while (navigator.MoveNext());
    return CreateResult(null, DataType.Integer);
  }

  private MatchType GetMatchType(IEnumerable<FunctionArgument> arguments) {
    var matchType = MatchType.ClosestBelow;
    if (arguments.Count() > 2) {
      matchType = (MatchType)ArgToInt(arguments, 2);
    }
    return matchType;
  }
}