﻿/*******************************************************************************
 * You may amend and distribute as you like, but don't remove this header!
 *
 * EPPlus provides server-side generation of Excel 2007/2010 spreadsheets.
 * See http://www.codeplex.com/EPPlus for details.
 *
 * 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       		        2011-01-08
 * Jan Källman		    License changed GPL-->LGPL  2011-12-27
 *******************************************************************************/
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using OfficeOpenXml.DataValidation.Formulas.Contracts;
using System.Globalization;

namespace OfficeOpenXml.DataValidation.Formulas
{
    internal class ExcelDataValidationFormulaDateTime : ExcelDataValidationFormulaValue<DateTime?>, IExcelDataValidationFormulaDateTime
    {
        public ExcelDataValidationFormulaDateTime(XmlNamespaceManager namespaceManager, XmlNode topNode, string formulaPath)
            : base(namespaceManager, topNode, formulaPath)
        {
            var value = GetXmlNodeString(formulaPath);
            if (!string.IsNullOrEmpty(value))
            {
                double oADate = default(double);
                if (double.TryParse(value, NumberStyles.Any, CultureInfo.InvariantCulture, out oADate))
                {
                    Value = DateTime.FromOADate(oADate);
                }
                else
                {
                    ExcelFormula = value;
                }
            }
        }

        protected override string GetValueAsString()
        {
            return Value.HasValue ? Value.Value.ToOADate().ToString(CultureInfo.InvariantCulture) : string.Empty;
        }

    }
}