using MeterVault.Infrastructure.Options;

namespace MeterVault.Integration.Tests;

/// <summary>
/// The configured zone id reaches .NET and PostgreSQL alike. Pure, so no Docker.
/// </summary>
public sealed class InstanceTimeZoneTests
{
    [Fact]
    public void A_windows_zone_id_is_turned_into_the_iana_id_postgres_understands()
    {
        if (!TimeZoneInfo.TryFindSystemTimeZoneById("W. Europe Standard Time", out _))
        {
            return; // No Windows-id support on this host (no ICU): nothing to translate.
        }

        Assert.Equal("Europe/Berlin", InstanceTimeZone.Canonical("W. Europe Standard Time"));
    }

    [Theory]
    [InlineData("Europe/Berlin")]
    [InlineData("America/New_York")]
    [InlineData("Not/AZone")]
    public void Iana_and_unknown_ids_are_left_as_they_are(string id) =>
        Assert.Equal(id, InstanceTimeZone.Canonical(id));

    [Fact]
    public void A_local_date_starts_at_its_local_midnight()
    {
        var berlin = InstanceTimeZone.Resolve("Europe/Berlin");

        Assert.Equal(new DateTimeOffset(2026, 7, 31, 22, 0, 0, TimeSpan.Zero), InstanceTimeZone.StartOf(new DateOnly(2026, 8, 1), berlin));
        Assert.Equal(TimeZoneInfo.Utc, InstanceTimeZone.Resolve("Not/AZone"));
    }
}