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

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

/// <summary>
///     Driver-level publish of self-describing <c>cnc_rddynamic2</c> positions. Each block's own
///     <c>base^exponent</c> wins over the configured <c>PositionDecimalPlaces</c> (which is now only
///     the fallback for a scale-less block), and a block describing no usable position Bads its own
///     node without disturbing its siblings. Replaces the <c>cnc_getfigure</c> (0x00D3) auto-scale
///     tests — that command is not a FOCAS wire command; the real 31i-B refuses it with <c>rc=1</c>.
/// </summary>
[Trait("Category", "Unit")]
public sealed class FocasPositionBlockScaleTests
{
    private const string Host = "focas://10.0.0.5:8193";

    private static FocasDynamicSnapshot Snap(int axisIndex, FocasPosition abs, FocasPosition mach) =>
        new(AxisIndex: axisIndex, AlarmFlags: 0, ProgramNumber: 0, MainProgramNumber: 0,
            SequenceNumber: 0, ActualFeedRate: 0, ActualSpindleSpeed: 0,
            AbsolutePosition: abs, MachinePosition: mach, RelativePosition: 0, DistanceToGo: 0);

    private static FocasDriver NewDriver(int positionDecimalPlaces, FakeFocasClient client) =>
        new(new FocasDriverOptions
        {
            Devices = [new FocasDeviceOptions(Host, PositionDecimalPlaces: positionDecimalPlaces)],
            Probe = new FocasProbeOptions { Enabled = false },
            FixedTree = new FocasFixedTreeOptions { Enabled = true, PollInterval = TimeSpan.FromMilliseconds(10) },
        }, "drv-1", new FakeFocasClientFactory { Customise = () => client });

    private static async Task<DataValueSnapshot> ReadWhenPolledAsync(FocasDriver drv, string reference)
    {
        var deadline = DateTime.UtcNow + TimeSpan.FromSeconds(5);
        DataValueSnapshot last;
        do
        {
            // Until the first poll lands the reference resolves to nothing; once it has, the node
            // reads either Good or (for an undescribable block) BadNoData.
            last = (await drv.ReadAsync([reference], CancellationToken.None)).Single();
            if (last.StatusCode is FocasStatusMapper.Good or FocasStatusMapper.BadNoData) return last;
            await Task.Delay(15);
        } while (DateTime.UtcNow < deadline);
        return last;
    }

    private static FakeFocasClient XAxisClient(FocasDynamicSnapshot snap)
    {
        var c = new FakeFocasClient();
        c.AxisNames.Clear();
        c.AxisNames.Add(new("X", ""));
        c.DynamicByAxis[1] = snap;
        return c;
    }

    [Fact]
    public async Task The_blocks_own_scale_wins_over_PositionDecimalPlaces()
    {
        // The live 31i-B shape: raw 2801574, base 10, exponent 4 → 280.1574 mm.
        var client = XAxisClient(Snap(1, new FocasPosition(2_801_574, 10, 4, HasScale: true), 0));
        var drv = NewDriver(positionDecimalPlaces: 1, client);
        await drv.InitializeAsync("{}", CancellationToken.None);

        var abs = await ReadWhenPolledAsync(drv, $"{Host}/Axes/X/AbsolutePosition");

        abs.StatusCode.ShouldBe(FocasStatusMapper.Good);
        ((double)abs.Value!).ShouldBe(280.1574, 1e-9); // NOT 280157.4 (the ÷10 fallback)
        await drv.ShutdownAsync(CancellationToken.None);
    }

    [Fact]
    public async Task A_scale_less_block_falls_back_to_PositionDecimalPlaces()
    {
        var client = XAxisClient(Snap(1, 12345, 0));
        var drv = NewDriver(positionDecimalPlaces: 2, client);
        await drv.InitializeAsync("{}", CancellationToken.None);

        var abs = await ReadWhenPolledAsync(drv, $"{Host}/Axes/X/AbsolutePosition");

        abs.StatusCode.ShouldBe(FocasStatusMapper.Good);
        abs.Value.ShouldBe(123.45);
        await drv.ShutdownAsync(CancellationToken.None);
    }

    [Fact]
    public async Task A_vacant_block_bads_its_own_node_and_not_its_sibling()
    {
        var client = XAxisClient(Snap(
            1,
            abs: new FocasPosition(0, 10, 0xFFFF, HasScale: true),   // vacant-slot marker
            mach: new FocasPosition(-22000, 10, 3, HasScale: true)));
        var drv = NewDriver(positionDecimalPlaces: 0, client);
        await drv.InitializeAsync("{}", CancellationToken.None);

        var mach = await ReadWhenPolledAsync(drv, $"{Host}/Axes/X/MachinePosition");
        var abs = await ReadWhenPolledAsync(drv, $"{Host}/Axes/X/AbsolutePosition");

        mach.StatusCode.ShouldBe(FocasStatusMapper.Good);
        mach.Value.ShouldBe(-22.0);
        abs.StatusCode.ShouldBe(FocasStatusMapper.BadNoData);
        abs.Value.ShouldBeNull("an undescribable block is not a Good 0.0 at the origin");
        await drv.ShutdownAsync(CancellationToken.None);
    }
}