using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
using ZB.MOM.WW.OtOpcUa.Driver.Historian.Conformance;
using ZB.MOM.WW.OtOpcUa.Driver.Historian.Sql.Common;

namespace ZB.MOM.WW.OtOpcUa.Driver.Historian.QuestDb.IntegrationTests;

/// <summary>
///     QuestDB AtTime regressions found in the T5 review (M1, M3), and the data source's reported timestamp
///     resolution (the HistoryRead paging step, C1).
/// </summary>
[Collection(QuestDbCollection.Name)]
public sealed class AtTimeRegressionTests(QuestDbFixture fx) : IAsyncLifetime
{
    private static readonly CancellationToken Ct = CancellationToken.None;
    private const uint GoodInterpolated = 0x00000402u;

    private QuestDbConformanceBackend _b = null!;

    private static DateTime At(double s) => ConformanceData.At(s);

    public async ValueTask InitializeAsync() => _b = await QuestDbConformanceBackend.CreateConcreteAsync(fx);

    public async ValueTask DisposeAsync()
    {
        if (_b is not null) await _b.DisposeAsync();
    }

    /// <summary>
    ///     M3: a request time with a sub-microsecond remainder is answered stamped with THAT time (as SQL Server does),
    ///     not with the rounded time the seek used. The value is still the one at the rounded time.
    /// </summary>
    [Fact]
    public async Task AtTime_result_is_stamped_with_the_original_sub_microsecond_request_time()
    {
        await ConformanceData.SeedAAsync(_b);                    // +0=10, +10=20, ...
        var requested = _b.Round(At(5)).AddTicks(3);             // 0.3 µs past a microsecond (T0 itself is not µs-aligned)
        var unspecified = DateTime.SpecifyKind(_b.Round(At(7)).AddTicks(7), DateTimeKind.Unspecified);

        var s = (await _b.CreateDataSource().ReadAtTimeAsync("A", [requested, unspecified], Ct)).Samples;

        s[0].SourceTimestampUtc.ShouldBe(requested);
        s[0].SourceTimestampUtc!.Value.Kind.ShouldBe(DateTimeKind.Utc);
        s[0].Value.ShouldBe(15d);                                // evaluated at the rounded time Round(At(5))
        s[0].StatusCode.ShouldBe(GoodInterpolated);
        s[1].SourceTimestampUtc.ShouldBe(DateTime.SpecifyKind(unspecified, DateTimeKind.Utc));
        s[1].SourceTimestampUtc!.Value.Ticks.ShouldBe(unspecified.Ticks);
    }

    /// <summary>M3 on the unknown-tag path: every BadNoData entry carries its own requested time.</summary>
    [Fact]
    public async Task AtTime_unknown_tag_entries_are_stamped_with_the_original_request_time()
    {
        var requested = _b.Round(At(5)).AddTicks(3);
        var s = (await _b.CreateDataSource().ReadAtTimeAsync("nope", [requested], Ct)).Samples;
        s.Single().StatusCode.ShouldBe(HistorianStatusCodes.BadNoData);
        s.Single().SourceTimestampUtc.ShouldBe(requested);
    }

    /// <summary>
    ///     M1: the NEXT seek skips a tombstone and finds the next live row. With +10 deleted, At(5) lies between the
    ///     live +0 (10) and the live +20 (30), so it interpolates to 15, Good. Seeing the tombstone as "next" would
    ///     instead hold 10 as Uncertain (an Empty BadNoData neighbour is not usable).
    /// </summary>
    [Fact]
    public async Task AtTime_next_seek_skips_a_tombstone_and_finds_the_next_live_row()
    {
        await _b.SeedAsync("M",
            (At(0), HistorianValue.FromDouble(10), ConformanceData.Good),
            (At(10), HistorianValue.FromDouble(20), ConformanceData.Good),
            (At(20), HistorianValue.FromDouble(30), ConformanceData.Good));
        await _b.InsertRowsAsync("M", [(At(10), HistorianValue.Empty, HistorianStatusCodes.BadNoData, true)]);

        var s = (await _b.CreateDataSource().ReadAtTimeAsync("M", [At(5)], Ct)).Samples.Single();

        s.Value.ShouldBe(15d);                                   // 10 + (30 - 10) * 5/20
        s.StatusCode.ShouldBe(GoodInterpolated);
    }

    /// <summary>C1: the data source reports QuestDB's microsecond storage resolution to the paging code.</summary>
    [Fact]
    public void Data_source_reports_a_ten_tick_timestamp_resolution() =>
        ((IHistorianDataSource)_b.CreateDataSource()).TimestampResolutionTicks.ShouldBe(10);
}