﻿/* 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 OfficeOpenXml.FormulaParsing.ExpressionGraph;

namespace OfficeOpenXml.FormulaParsing.Excel.Functions.Math;

public class Count : HiddenValuesHandlingFunction {
  private enum ItemContext {
    InRange,
    InArray,
    SingleArg,
  }

  public override CompileResult Execute(
      IEnumerable<FunctionArgument> arguments,
      ParsingContext context) {
    ValidateArguments(arguments, 1);
    var nItems = 0d;
    Calculate(arguments, ref nItems, context, ItemContext.SingleArg);
    return CreateResult(nItems, DataType.Integer);
  }

  private void Calculate(
      IEnumerable<FunctionArgument> items,
      ref double nItems,
      ParsingContext context,
      ItemContext itemContext) {
    foreach (var item in items) {
      var cs = item.Value as ExcelDataProvider.IRangeInfo;
      if (cs != null) {
        foreach (var c in cs) {
          _CheckForAndHandleExcelError(c, context);
          if (ShouldIgnore(c, context) == false && ShouldCount(c.Value, ItemContext.InRange)) {
            nItems++;
          }
        }
      } else {
        var value = item.Value as IEnumerable<FunctionArgument>;
        if (value != null) {
          Calculate(value, ref nItems, context, ItemContext.InArray);
        } else {
          _CheckForAndHandleExcelError(item, context);
          if (ShouldIgnore(item) == false && ShouldCount(item.Value, itemContext)) {
            nItems++;
          }
        }
      }
    }
  }

  private void _CheckForAndHandleExcelError(FunctionArgument arg, ParsingContext context) {
    //if (context.Scopes.Current.IsSubtotal)
    //{
    //    CheckForAndHandleExcelError(arg);
    //}
  }

  private void _CheckForAndHandleExcelError(
      ExcelDataProvider.ICellInfo cell,
      ParsingContext context) {
    //if (context.Scopes.Current.IsSubtotal)
    //{
    //    CheckForAndHandleExcelError(cell);
    //}
  }

  private bool ShouldCount(object value, ItemContext context) {
    switch (context) {
      case ItemContext.SingleArg:
        return IsNumeric(value) || IsNumericString(value);
      case ItemContext.InRange:
        return IsNumeric(value);
      case ItemContext.InArray:
        return IsNumeric(value) || IsNumericString(value);
      default:
        throw new ArgumentException("Unknown ItemContext:" + context);
    }
  }
}