EPPlus/FormulaParsing/Excel/Functions/Math/Product.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;
using System.Collections.Generic;
using System.Linq;
using OfficeOpenXml.FormulaParsing.ExpressionGraph;

namespace OfficeOpenXml.FormulaParsing.Excel.Functions.Math;

public class Product : HiddenValuesHandlingFunction {
  public override CompileResult Execute(
      IEnumerable<FunctionArgument> arguments,
      ParsingContext context) {
    ValidateArguments(arguments, 1);
    var result = 0d;
    var index = 0;
    while (AreEqual(result, 0d) && index < arguments.Count()) {
      result = CalculateFirstItem(arguments, index++, context);
    }
    result = CalculateCollection(
        arguments.Skip(index),
        result,
        (arg, current) => {
          if (ShouldIgnore(arg)) {
            return current;
          }
          if (arg.ValueIsExcelError) {
            ThrowExcelErrorValueException(arg.ValueAsExcelErrorValue.Type);
          }
          if (arg.IsExcelRange) {
            foreach (var cell in arg.ValueAsRangeInfo) {
              if (ShouldIgnore(cell, context)) {
                return current;
              }
              current *= cell.ValueDouble;
            }
            return current;
          }
          var obj = arg.Value;
          if (obj != null && IsNumeric(obj)) {
            var val = Convert.ToDouble(obj);
            current *= val;
          }
          return current;
        });
    return CreateResult(result, DataType.Decimal);
  }

  private double CalculateFirstItem(
      IEnumerable<FunctionArgument> arguments,
      int index,
      ParsingContext context) {
    var element = arguments.ElementAt(index);
    var argList = new List<FunctionArgument> { element };
    var valueList = ArgsToDoubleEnumerable(false, false, argList, context);
    var result = 0d;
    foreach (var value in valueList) {
      if (result == 0d && value > 0d) {
        result = value;
      } else {
        result *= value;
      }
    }
    return result;
  }
}