using System;
using Microsoft.EntityFrameworkCore.Storage.ValueConversion;

namespace AMWD.Common.EntityFrameworkCore.Converters
{
	/// <summary>
	/// Defines the conversion from a nullable <see cref="TimeOnly"/> object to a nullable <see cref="TimeSpan"/> which can be handled by the database engine.
	/// </summary>
	/// <remarks>
	/// As of 2022-06-04 only required for Microsoft SQL server on .NET 6.0.
	/// </remarks>
	public class NullableTimeOnlyConverter : ValueConverter<TimeOnly?, TimeSpan?>
	{
		/// <summary>
		/// Initializes a new instance of the <see cref="NullableTimeOnlyConverter"/> class.
		/// </summary>
		public NullableTimeOnlyConverter()
			: base(
				d => d == null ? null : new TimeSpan?(d.Value.ToTimeSpan()),
				d => d == null ? null : new TimeOnly?(TimeOnly.FromTimeSpan(d.Value))
			)
		{ }
	}
}