// Copyright (c) 2017 schick Informatik
// Description: Converter für die Darstellung von Databinding Values aus der DB in Local Time in der Anwendung
//

using System;
using System.Globalization;
using System.Windows.Data;
using System.Windows.Markup;

namespace ENI2.Util
{
    public class UtcToLocalDateTimeConverter : MarkupExtension, IValueConverter
    {
        private static UtcToLocalDateTimeConverter _converter = null;
        public override object ProvideValue(IServiceProvider serviceProvider)
        {
            if (_converter == null)
            {
                _converter = new UtcToLocalDateTimeConverter();
            }
            return _converter;
        }

        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            DateTime? sourceVal = (DateTime?) value;
            if (sourceVal.HasValue)
            {
                //if(sourceVal.Value.)
                return DateTime.SpecifyKind(sourceVal.Value, DateTimeKind.Utc).ToLocalTime();
            }
            else
                return null;
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if(value is string dateString)
            {
                if(DateTime.TryParse(dateString, out DateTime theValue))
                {
                    return DateTime.SpecifyKind(theValue, DateTimeKind.Local).ToUniversalTime();
                } 
                else
                {
                    return null;
                }
            } 
            else  if(value is DateTime?)
            {
                DateTime? sourceVal = (DateTime?)value;
                if (sourceVal.HasValue)
                    return DateTime.SpecifyKind(sourceVal.Value, DateTimeKind.Local).ToUniversalTime();
                else
                    return null;
            }
            else
            {
                return null;
            }
        }
    }
}