using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;

namespace ZB.MOM.WW.OtOpcUa.Driver.Modbus.Tests;

/// <summary>
///     Review 07 H2: the deadband baseline is keyed on (value, status). A Good-after-Bad recovery carrying
///     the IDENTICAL value must publish — the value-only dedup left the node Bad until the value drifted.
/// </summary>
[Trait("Category", "Unit")]
public sealed class ModbusDeadbandRecoveryTests
{
    private const uint Good = 0u;
    private const uint Uncertain = 0x40000000u;
    private const uint BadComm = 0x80050000u;

    private static async Task<ModbusDriver> NewDriverAsync()
    {
        var tag = new ModbusTagDefinition("Temp", ModbusRegion.HoldingRegisters, 0, ModbusDataType.Int16, Deadband: 5.0);
        var opts = new ModbusDriverOptions
        {
            Host = "f", RawTags = ModbusRawTags.Entries([tag]), Probe = new ModbusProbeOptions { Enabled = false },
        };
        var drv = new ModbusDriver(opts, "m1", _ => new ModbusDriverTests.FakeTransport());
        await drv.InitializeAsync("{}", TestContext.Current.CancellationToken);
        return drv;
    }

    private static DataValueSnapshot Snap(object? v, uint status) => new(v, status, DateTime.UtcNow, DateTime.UtcNow);

    [Fact]
    public async Task Good_after_Bad_with_the_same_value_publishes()
    {
        await using var drv = await NewDriverAsync();
        drv.ShouldPublish("Temp", Snap((short)10, Good)).ShouldBeTrue();      // baseline
        drv.ShouldPublish("Temp", Snap(null, BadComm)).ShouldBeTrue();        // comms drop
        drv.ShouldPublish("Temp", Snap((short)10, Good)).ShouldBeTrue("the recovery publish must not be swallowed");
        // Positive control: the deadband is still active after the recovery re-seeded the baseline.
        drv.ShouldPublish("Temp", Snap((short)11, Good)).ShouldBeFalse();
        drv.ShouldPublish("Temp", Snap((short)16, Good)).ShouldBeTrue();
    }

    [Fact]
    public async Task A_status_change_with_the_same_value_publishes()
    {
        await using var drv = await NewDriverAsync();
        drv.ShouldPublish("Temp", Snap((short)10, Good)).ShouldBeTrue();
        drv.ShouldPublish("Temp", Snap((short)10, Uncertain)).ShouldBeTrue("a quality change must publish");
        drv.ShouldPublish("Temp", Snap((short)12, Uncertain)).ShouldBeFalse("within deadband at the same quality");
        drv.ShouldPublish("Temp", Snap((short)10, Good)).ShouldBeTrue("back to Good must publish");
    }
}