using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Driver.TwinCAT;

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

[Trait("Category", "Unit")]
public sealed class TwinCATBitWriteTests
{
    // ---- Helper unit tests ----

    [Theory]
    [InlineData("Flags.3", "Flags")]
    [InlineData("MAIN.Status.7", "MAIN.Status")]
    [InlineData("GVL.Motors[0].Status.5", "GVL.Motors[0].Status")]
    public void TryGetParentSymbolPath_strips_trailing_bit_selector(string input, string expected)
    {
        AdsTwinCATClient.TryGetParentSymbolPath(input).ShouldBe(expected);
    }

    [Theory]
    [InlineData("Counter")]      // single segment — no parent
    [InlineData(".Bad")]         // leading dot
    public void TryGetParentSymbolPath_returns_null_for_pathless(string input)
    {
        AdsTwinCATClient.TryGetParentSymbolPath(input).ShouldBeNull();
    }

    [Theory]
    [InlineData(0u, 0, true, 0x0000_0001u)]
    [InlineData(0u, 31, true, 0x8000_0000u)]
    [InlineData(0xFFFF_FFFFu, 0, false, 0xFFFF_FFFEu)]
    [InlineData(0xFFFF_FFFFu, 31, false, 0x7FFF_FFFFu)]
    [InlineData(0x0000_0008u, 3, true, 0x0000_0008u)] // already set — idempotent
    [InlineData(0x0000_0000u, 3, false, 0x0000_0000u)] // already clear — idempotent
    public void ApplyBit_sets_or_clears_bit(uint word, int bit, bool setBit, uint expected)
    {
        AdsTwinCATClient.ApplyBit(word, bit, setBit).ShouldBe(expected);
    }

    // ---- Driver-level round-trip ----

    private static (TwinCATDriver drv, FakeTwinCATClientFactory factory) NewDriver(params TwinCATTagDefinition[] tags)
    {
        var factory = new FakeTwinCATClientFactory();
        var drv = new TwinCATDriver(new TwinCATDriverOptions
        {
            Devices = [new TwinCATDeviceOptions("ads://5.23.91.23.1.1:851")],
            Tags = tags,
            Probe = new TwinCATProbeOptions { Enabled = false },
        }, "drv-1", factory);
        return (drv, factory);
    }

    [Fact]
    public async Task Bit_write_sets_bit_in_parent_word()
    {
        var (drv, factory) = NewDriver(
            new TwinCATTagDefinition("FlagBit3", "ads://5.23.91.23.1.1:851", "Flags.3", TwinCATDataType.Bool));
        await drv.InitializeAsync("{}", CancellationToken.None);
        // Parent word starts at 0.
        factory.Customise = () => new FakeTwinCATClient { Values = { ["Flags"] = 0u } };

        var results = await drv.WriteAsync(
            [new Core.Abstractions.WriteRequest("FlagBit3", true)], CancellationToken.None);

        results.Single().StatusCode.ShouldBe(TwinCATStatusMapper.Good);
        // Parent should now have bit 3 set.
        Convert.ToUInt32(factory.Clients[0].Values["Flags"]!).ShouldBe(0x0000_0008u);
    }

    [Fact]
    public async Task Bit_write_clears_bit_without_disturbing_neighbours()
    {
        var (drv, factory) = NewDriver(
            new TwinCATTagDefinition("FlagBit3", "ads://5.23.91.23.1.1:851", "Flags.3", TwinCATDataType.Bool));
        await drv.InitializeAsync("{}", CancellationToken.None);
        // Parent word has bits 0, 3, 7 set initially.
        factory.Customise = () => new FakeTwinCATClient { Values = { ["Flags"] = 0x0000_0089u } };

        var results = await drv.WriteAsync(
            [new Core.Abstractions.WriteRequest("FlagBit3", false)], CancellationToken.None);

        results.Single().StatusCode.ShouldBe(TwinCATStatusMapper.Good);
        // Bit 3 cleared; bits 0 and 7 untouched.
        Convert.ToUInt32(factory.Clients[0].Values["Flags"]!).ShouldBe(0x0000_0081u);
    }

    [Fact]
    public async Task Bit_write_does_not_throw_NotSupported()
    {
        // Regression: AdsTwinCATClient previously threw NotSupportedException for bit writes.
        var (drv, factory) = NewDriver(
            new TwinCATTagDefinition("Bit", "ads://5.23.91.23.1.1:851", "GVL.Word.0", TwinCATDataType.Bool));
        await drv.InitializeAsync("{}", CancellationToken.None);
        factory.Customise = () => new FakeTwinCATClient { Values = { ["GVL.Word"] = 0u } };

        var results = await drv.WriteAsync(
            [new Core.Abstractions.WriteRequest("Bit", true)], CancellationToken.None);

        results.Single().StatusCode.ShouldBe(TwinCATStatusMapper.Good);
        // Status should be Good, not BadNotSupported (which is what the catch block produced).
        results.Single().StatusCode.ShouldNotBe(TwinCATStatusMapper.BadNotSupported);
    }
}