lmxopcua/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Tests/ModbusArrayWriteSupportParityTests.cs

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

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

/// <summary>
///     Gitea #610 — pins <see cref="DriverArrayWriteSupport"/>'s Modbus row against the REAL write path. For every
///     region × element type, the server advertises an array node writable exactly when the driver accepts a
///     whole-array write for it. A driver change that gains or loses an array encoder fails here until the table
///     follows — so the server can never advertise a write this driver refuses (nor hide one it accepts).
/// </summary>
[Trait("Category", "Unit")]
public sealed class ModbusArrayWriteSupportParityTests
{
    private static IEnumerable<(ModbusRegion Region, ModbusDataType DataType)> Shapes() =>
        from region in Enum.GetValues<ModbusRegion>()
        from dt in Enum.GetValues<ModbusDataType>()
        select (region, dt);

    public static TheoryData<ModbusRegion, ModbusDataType> AllShapes()
    {
        var data = new TheoryData<ModbusRegion, ModbusDataType>();
        foreach (var (region, dt) in Shapes()) data.Add(region, dt);
        return data;
    }

    /// <summary>
    ///     Shapes where the driver has moved ahead of the server-side table (review 07 P6 / U3, Modbus lane) and
    ///     <see cref="DriverArrayWriteSupport"/> — owned outside the Modbus lane — has not followed yet
    ///     (follow-up F1): the tag factory now REFUSES a Coils tag with a non-Bool type (so the driver serves no
    ///     such tag), and the driver now encodes String[] and BitInRegister[] holding-register writes.
    ///     <see cref="Pending_F1_divergences_still_exist"/> fails the moment the table follows, so this list
    ///     is removed with it rather than left to rot.
    /// </summary>
    private static bool PendingF1(ModbusRegion region, ModbusDataType dataType) =>
        (region == ModbusRegion.Coils && dataType != ModbusDataType.Bool)
        || (region == ModbusRegion.HoldingRegisters && dataType is ModbusDataType.String or ModbusDataType.BitInRegister && PendingU3);

    // Flipped to true by the U3 commit (String[] / BitInRegister[] encoders).
    private const bool PendingU3 = false;

    public static TheoryData<ModbusRegion, ModbusDataType> PendingShapes()
    {
        var data = new TheoryData<ModbusRegion, ModbusDataType>();
        foreach (var (region, dt) in Shapes().Where(s => PendingF1(s.Region, s.DataType))) data.Add(region, dt);
        return data;
    }

    [Theory]
    [MemberData(nameof(PendingShapes))]
    public void Pending_F1_divergences_still_exist(ModbusRegion region, ModbusDataType dataType)
    {
        var json = $$"""{"region":"{{region}}","address":10,"dataType":"{{dataType}}","stringLength":4,"isArray":true,"arrayLength":2}""";
        var driverAccepts = region == ModbusRegion.HoldingRegisters; // String[] / BitInRegister[] encode; mistyped Coils are refused
        DriverArrayWriteSupport.Supports(DriverTypeNames.Modbus, "Int16", json).ShouldNotBe(driverAccepts,
            "F1 landed — DriverArrayWriteSupport now agrees with the driver for this shape; delete it from PendingF1");
    }

    [Theory]
    [MemberData(nameof(AllShapes))]
    public async Task Table_agrees_with_the_driver_write_path(ModbusRegion region, ModbusDataType dataType)
    {
        if (PendingF1(region, dataType)) return; // covered by Pending_F1_divergences_still_exist
        var json = $$"""{"region":"{{region}}","address":10,"dataType":"{{dataType}}","stringLength":4,"isArray":true,"arrayLength":2}""";
        var fake = new ModbusDriverTests.FakeTransport();
        var drv = new ModbusDriver(
            new ModbusDriverOptions { Host = "fake", RawTags = [new RawTagEntry("cell/modbus/arr", json, false)] },
            "modbus-array-parity", _ => fake);
        await drv.InitializeAsync("{}", CancellationToken.None);

        // A two-element value every element type can convert (Convert.ToBoolean / ToInt16 / ToSingle … of 1).
        var result = await drv.WriteAsync([new WriteRequest("cell/modbus/arr", new object[] { 1, 1 })], CancellationToken.None);
        var driverAccepts = result.Single().StatusCode == 0u;

        DriverArrayWriteSupport.Supports(DriverTypeNames.Modbus, "Int16", json).ShouldBe(
            driverAccepts, $"region={region} dataType={dataType}: driver status 0x{result.Single().StatusCode:X8}");
    }

    /// <summary>Positive control: the theory above is not vacuously "everything refused".</summary>
    [Fact]
    public void The_matrix_contains_both_answers()
    {
        var answers = Shapes()
            .Select(s => DriverArrayWriteSupport.Supports(
                DriverTypeNames.Modbus, "Int16",
                $$"""{"region":"{{s.Region}}","address":10,"dataType":"{{s.DataType}}","isArray":true,"arrayLength":2}"""))
            .ToHashSet();
        answers.ShouldBe(new[] { true, false }, ignoreOrder: true);
    }

    /// <summary>
    ///     #610 review MINOR-1/-2 — the table must also agree with the driver on the SHAPE edges: the FC16 write cap
    ///     (the driver refuses rather than chunks an over-cap array; default 123 registers, or the configured
    ///     <c>MaxRegistersPerWrite</c>) and a missing / zero <c>arrayLength</c> (the factory maps it to a scalar tag,
    ///     whose scalar encoder refuses an array value).
    /// </summary>
    [Theory]
    [InlineData("Int32", "\"arrayLength\":61", 0, 61)]   // 122 registers — fits the default cap
    [InlineData("Int32", "\"arrayLength\":62", 0, 62)]   // 124 registers — over it
    [InlineData("Float64", "\"arrayLength\":31", 0, 31)] // 124 registers
    [InlineData("Int16", "\"arrayLength\":10", 10, 10)]  // exactly a configured cap
    [InlineData("Int16", "\"arrayLength\":11", 10, 11)]  // one over it
    [InlineData("Int16", "\"arrayLength\":0", 0, 2)]     // declared length 0 ⇒ scalar to the driver
    [InlineData("Int16", "\"isArrayLengthMissing\":true", 0, 2)]
    public async Task Table_agrees_with_the_driver_on_write_cap_and_declared_length(
        string dataType, string lengthProp, ushort maxRegistersPerWrite, int elements)
    {
        var json = $$"""{"region":"HoldingRegisters","address":10,"dataType":"{{dataType}}","isArray":true,{{lengthProp}}}""";
        var driverConfig = maxRegistersPerWrite == 0 ? "{}" : $$"""{"maxRegistersPerWrite":{{maxRegistersPerWrite}}}""";
        var fake = new ModbusDriverTests.FakeTransport();
        var options = new ModbusDriverOptions
        {
            Host = "fake", RawTags = [new RawTagEntry("cell/modbus/arr", json, false)],
            MaxRegistersPerWrite = maxRegistersPerWrite == 0 ? (ushort)123 : maxRegistersPerWrite,
        };
        var drv = new ModbusDriver(options, "modbus-array-cap-parity", _ => fake);
        await drv.InitializeAsync("{}", CancellationToken.None);

        var value = Enumerable.Repeat<object>(1, elements).ToArray();
        var result = await drv.WriteAsync([new WriteRequest("cell/modbus/arr", value)], CancellationToken.None);
        var driverAccepts = result.Single().StatusCode == 0u;

        DriverArrayWriteSupport.Supports(DriverTypeNames.Modbus, "Int16", json, driverConfig).ShouldBe(
            driverAccepts, $"{dataType} {lengthProp} cap={maxRegistersPerWrite}: driver status 0x{result.Single().StatusCode:X8}");
    }

    /// <summary>Positive control for the theory above: both answers occur, so it is not vacuously all-refused.</summary>
    [Fact]
    public void The_shape_edges_contain_both_answers()
    {
        DriverArrayWriteSupport.Supports(DriverTypeNames.Modbus, "Int32",
            """{"region":"HoldingRegisters","address":10,"dataType":"Int32","isArray":true,"arrayLength":61}""").ShouldBeTrue();
        DriverArrayWriteSupport.Supports(DriverTypeNames.Modbus, "Int32",
            """{"region":"HoldingRegisters","address":10,"dataType":"Int32","isArray":true,"arrayLength":62}""").ShouldBeFalse();
    }
}