using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
using static ZB.MOM.WW.OtOpcUa.Driver.Historian.Sql.Common.Tests.Fixture;

namespace ZB.MOM.WW.OtOpcUa.Driver.Historian.Sql.Common.Tests;

public sealed class BucketPlanTests
{
    [Fact]
    public void BucketPlan_rejects_more_than_100k_buckets()
    {
        var ex = Should.Throw<ArgumentOutOfRangeException>(() =>
            BucketPlan.Create(DateTime.UnixEpoch, DateTime.UnixEpoch.AddSeconds(100_001), TimeSpan.FromSeconds(1)));
        ex.ParamName.ShouldBe("interval");
    }

    [Fact]
    public void Exactly_100k_one_tick_buckets_are_allowed()
    {
        var p = BucketPlan.Create(At(0), At(0).AddTicks(100_000), TimeSpan.FromTicks(1));
        p.BucketCount.ShouldBe(100_000);
        p.IntervalTicks.ShouldBe(1);
    }

    [Fact]
    public void A_partial_last_interval_is_its_own_bucket()
    {
        var p = BucketPlan.Create(At(0), At(50), TimeSpan.FromSeconds(20));
        p.BucketCount.ShouldBe(3);
        p.BucketStart(2).ShouldBe(At(40));
        p.BucketStart(2).Kind.ShouldBe(DateTimeKind.Utc);
    }

    [Fact]
    public void Zero_or_oversized_interval_is_one_bucket_and_an_empty_window_none()
    {
        BucketPlan.Create(At(0), At(80), TimeSpan.Zero).BucketCount.ShouldBe(1);
        var wide = BucketPlan.Create(At(0), At(80), TimeSpan.FromDays(1));
        wide.BucketCount.ShouldBe(1);
        wide.IntervalTicks.ShouldBe(80 * TimeSpan.TicksPerSecond);
        BucketPlan.Create(At(0), At(0), TimeSpan.FromSeconds(1)).BucketCount.ShouldBe(0);
    }

    [Fact]
    public void A_reverse_window_is_planned_forward_and_assembled_descending()
    {
        var p = BucketPlan.Create(At(80), At(0), TimeSpan.FromSeconds(20));
        p.Reversed.ShouldBeTrue();
        p.StartUtc.ShouldBe(At(0));
        p.EndUtc.ShouldBe(At(80));
        var s = p.Assemble(new Dictionary<long, DataValueSnapshot>(), t => new DataValueSnapshot(null, 0, t, t));
        s.Select(x => x.SourceTimestampUtc).ShouldBe([At(60), At(40), At(20), At(0)]);
    }

    [Fact]
    public void Assemble_fills_missing_buckets_with_the_empty_factory()
    {
        var p = BucketPlan.Create(At(0), At(60), TimeSpan.FromSeconds(20));
        var hit = new DataValueSnapshot(7d, 0, At(20), At(20));
        var s = p.Assemble(new Dictionary<long, DataValueSnapshot> { [1] = hit }, t => new DataValueSnapshot(null, 1u, t, t));
        s.Select(x => x.Value).ShouldBe([null, (object?)7d, null]);
        s[0].SourceTimestampUtc.ShouldBe(At(0));
        s[2].SourceTimestampUtc.ShouldBe(At(40));
    }

    [Fact]
    public void StartUnixTicks_is_ticks_since_the_unix_epoch()
        => BucketPlan.Create(DateTime.UnixEpoch.AddTicks(1234567), DateTime.UnixEpoch.AddSeconds(10), TimeSpan.Zero)
            .StartUnixTicks.ShouldBe(1234567L);
}