namespace Marathon.Domain.ValueObjects;

/// <summary>
/// Single source of truth for the Moscow timezone offset.
/// </summary>
/// <remarks>
/// <para>
/// marathonbet.by serves all timestamps in Moscow time (UTC+3) and the domain
/// invariant on <see cref="Marathon.Domain.Entities.Event.ScheduledAt"/>
/// rejects any other offset. Code that constructs <see cref="DateTimeOffset"/>
/// values for events, results, snapshots, or test fixtures MUST use this
/// constant rather than re-deriving <c>TimeSpan.FromHours(3)</c>.
/// </para>
/// </remarks>
public static class MoscowTime
{
    /// <summary>The Moscow time offset (UTC+3).</summary>
    public static readonly TimeSpan Offset = TimeSpan.FromHours(3);

    /// <summary>Current Moscow time.</summary>
    public static DateTimeOffset Now => DateTimeOffset.UtcNow.ToOffset(Offset);

    /// <summary>
    /// Returns the inclusive end-of-day for the given Moscow date — i.e.,
    /// the moment one second before the next day starts. Used by date-range
    /// filters where the user picks "to: 2026-05-09" meaning "through the
    /// rest of that day."
    /// </summary>
    public static DateTimeOffset EndOfMoscowDay(DateOnly date) =>
        new DateTimeOffset(date.ToDateTime(TimeOnly.MinValue), Offset)
            .AddDays(1).AddSeconds(-1);
}