AppsheetEpplus/FormulaParsing/Excel/Functions/RefAndLookup/Lookup.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 Lookup : LookupFunction {
  public override CompileResult Execute(
      IEnumerable<FunctionArgument> arguments,
      ParsingContext context) {
    ValidateArguments(arguments, 2);
    if (HaveTwoRanges(arguments)) {
      return HandleTwoRanges(arguments, context);
    }
    return HandleSingleRange(arguments, context);
  }

  private bool HaveTwoRanges(IEnumerable<FunctionArgument> arguments) {
    if (arguments.Count() == 2) {
      return false;
    }
    return (ExcelAddressUtil.IsValidAddress(arguments.ElementAt(2).Value.ToString()));
  }

  private CompileResult HandleSingleRange(
      IEnumerable<FunctionArgument> arguments,
      ParsingContext context) {
    var searchedValue = arguments.ElementAt(0).Value;
    Require.That(arguments.ElementAt(1).Value).Named("firstAddress").IsNotNull();
    var firstAddress = ArgToString(arguments, 1);
    var rangeAddressFactory = new RangeAddressFactory(context.ExcelDataProvider);
    var address = rangeAddressFactory.Create(firstAddress);
    var nRows = address.ToRow - address.FromRow;
    var nCols = address.ToCol - address.FromCol;
    var lookupIndex = nCols + 1;
    var lookupDirection = LookupDirection.Vertical;
    if (nCols > nRows) {
      lookupIndex = nRows + 1;
      lookupDirection = LookupDirection.Horizontal;
    }
    var lookupArgs = new LookupArguments(searchedValue, firstAddress, lookupIndex, 0, true);
    var navigator = LookupNavigatorFactory.Create(lookupDirection, lookupArgs, context);
    return Lookup(navigator, lookupArgs);
  }

  private CompileResult HandleTwoRanges(
      IEnumerable<FunctionArgument> arguments,
      ParsingContext context) {
    var searchedValue = arguments.ElementAt(0).Value;
    Require.That(arguments.ElementAt(1).Value).Named("firstAddress").IsNotNull();
    Require.That(arguments.ElementAt(2).Value).Named("secondAddress").IsNotNull();
    var firstAddress = ArgToString(arguments, 1);
    var secondAddress = ArgToString(arguments, 2);
    var rangeAddressFactory = new RangeAddressFactory(context.ExcelDataProvider);
    var address1 = rangeAddressFactory.Create(firstAddress);
    var address2 = rangeAddressFactory.Create(secondAddress);
    var lookupIndex = (address2.FromCol - address1.FromCol) + 1;
    var lookupOffset = address2.FromRow - address1.FromRow;
    var lookupDirection = GetLookupDirection(address1);
    if (lookupDirection == LookupDirection.Horizontal) {
      lookupIndex = (address2.FromRow - address1.FromRow) + 1;
      lookupOffset = address2.FromCol - address1.FromCol;
    }
    var lookupArgs = new LookupArguments(
        searchedValue,
        firstAddress,
        lookupIndex,
        lookupOffset,
        true);
    var navigator = LookupNavigatorFactory.Create(lookupDirection, lookupArgs, context);
    return Lookup(navigator, lookupArgs);
  }
}