BuildingBlocks.Time

public interface IClock
{
    DateTime UtcNow { get; }
}

// Program.cs / Infrastructure DI
services.AddSingleton<IClock>(SystemClock.Instance);

// Kullanım — zamana bağlı mantık
public sealed class OtpChallenge(IClock clock)
{
    private readonly DateTime _expiresAt;
    public OtpChallenge(IClock clock, int expireMinutes)
        => _expiresAt = clock.UtcNow.AddMinutes(expireMinutes);

    public bool IsExpired(IClock clock) => clock.UtcNow >= _expiresAt;
}

[Fact]
public void Otp_Tam_3_Dakika_Sonra_Suresi_Dolar()
{
    var t0 = new DateTime(2026, 6, 3, 10, 0, 0, DateTimeKind.Utc);
    IClock atStart = new FakeClock(t0);

    var challenge = new OtpChallenge(atStart, expireMinutes: 3);

    // 2 dk 59 sn → hâlâ geçerli
    Assert.False(challenge.IsExpired(new FakeClock(t0.AddSeconds(179))));
    // 3 dk 00 sn → süresi doldu
    Assert.True(challenge.IsExpired(new FakeClock(t0.AddMinutes(3))));
}

using (Time.Override(new FakeClock(new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc))))
{
    // bu blok içinde Time.UtcNow sabit; dispose'da gerçek saate döner
    var result = ServiceUsingStaticTime.DoWork();
    Assert.Equal(2026, result.Year);
}