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

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

/// <summary>
///     Review 07 P7: adjacent N/B/F/L elements of one device were never coalesced (one PCCC round trip per tag),
///     although the array path proves the transport can read a span. Scalar tags near each other on one file now
///     ride ONE multi-element read and are decoded from their offsets — with exactly the CLR types the single-tag
///     path produces — and a block the device refuses falls back to per-tag reads.
/// </summary>
[Trait("Category", "Unit")]
public sealed class AbLegacyReadCoalescingTests
{
    private const string Host = "ab://10.0.0.5/1,0";

    private static (AbLegacyDriver Drv, FakeAbLegacyTagFactory Factory, List<AbLegacyTagCreateParams> Created) NewDriver(
        Func<AbLegacyTagCreateParams, FakeAbLegacyTag> make, bool coalesce, params AbLegacyTagDefinition[] tags)
    {
        var created = new List<AbLegacyTagCreateParams>();
        var factory = new FakeAbLegacyTagFactory
        {
            Customise = p =>
            {
                lock (created) created.Add(p);
                return make(p);
            },
        };
        var drv = new AbLegacyDriver(new AbLegacyDriverOptions
        {
            Devices = [new AbLegacyDeviceOptions(Host)],
            RawTags = AbLegacyRawTags.Entries(tags),
            Probe = new AbLegacyProbeOptions { Enabled = false },
            CoalesceReads = coalesce,
        }, "drv-coalesce", factory);
        return (drv, factory, created);
    }

    private static AbLegacyTagDefinition Tag(string name, string address, AbLegacyDataType type) =>
        new(name, Host, address, type);

    [Fact]
    public async Task Nearby_N_file_words_and_bits_ride_one_read_and_decode_like_single_reads()
    {
        var (drv, _, created) = NewDriver(
            p => new FakeAbLegacyTag(p) { ArrayValue = new short[] { 10, 11, 12, 4, 14, -15 } },
            coalesce: true,
            Tag("W0", "N7:0", AbLegacyDataType.Int),
            Tag("W1", "N7:1", AbLegacyDataType.AnalogInt),
            Tag("B32", "N7:3/2", AbLegacyDataType.Bit),
            Tag("B31", "N7:3/1", AbLegacyDataType.Bit),
            Tag("W5", "N7:5", AbLegacyDataType.Int));
        await drv.InitializeAsync("{}", CancellationToken.None);

        var r = await drv.ReadAsync(["W0", "W1", "B32", "B31", "W5"], CancellationToken.None);

        r.ShouldAllBe(s => s.StatusCode == AbLegacyStatusMapper.Good);
        r[0].Value.ShouldBe(10);       // int, exactly as DecodeValue(Int) returns
        r[1].Value.ShouldBe(11);
        r[2].Value.ShouldBe(true);     // word 3 = 0b100: bit 2 set
        r[3].Value.ShouldBe(false);
        r[4].Value.ShouldBe(-15);
        created.Count.ShouldBe(1);
        created[0].TagName.ShouldBe("N7:0");
        created[0].ElementCount.ShouldBe(6);
        await drv.ShutdownAsync(CancellationToken.None);
    }

    [Fact]
    public async Task Float_and_long_files_coalesce_at_their_element_width()
    {
        var (drv, _, created) = NewDriver(
            p => p.TagName.StartsWith('F')
                ? new FakeAbLegacyTag(p) { ArrayValue = new[] { 1.5f, 0f, 2.5f } }
                : new FakeAbLegacyTag(p) { ArrayValue = new[] { 7, int.MinValue } },
            coalesce: true,
            Tag("F0", "F8:0", AbLegacyDataType.Float),
            Tag("F2", "F8:2", AbLegacyDataType.Float),
            Tag("L0", "L9:0", AbLegacyDataType.Long),
            Tag("L1b31", "L9:1/31", AbLegacyDataType.Bit));
        await drv.InitializeAsync("{}", CancellationToken.None);

        var r = await drv.ReadAsync(["F0", "F2", "L0", "L1b31"], CancellationToken.None);

        r.Select(s => s.Value).ShouldBe(new object[] { 1.5f, 2.5f, 7, true });
        created.Select(c => (c.TagName, c.ElementCount)).OrderBy(x => x.TagName)
            .ShouldBe(new[] { ("F8:0", 3), ("L9:0", 2) });
        await drv.ShutdownAsync(CancellationToken.None);
    }

    [Fact]
    public async Task Far_apart_or_ineligible_tags_keep_the_single_tag_path()
    {
        var (drv, _, created) = NewDriver(
            p => new FakeAbLegacyTag(p) { Value = 1 },
            coalesce: true,
            Tag("Near", "N7:0", AbLegacyDataType.Int),
            Tag("Far", "N7:40", AbLegacyDataType.Int),                // gap > MaxCoalesceGap
            Tag("Mistyped", "N7:1", AbLegacyDataType.Float),          // width mismatch: single path answers as before
            Tag("Acc", "T4:0.ACC", AbLegacyDataType.Int),             // sub-element
            Tag("Status", "S:1", AbLegacyDataType.Int),               // no file number
            Tag("Ind", "N7:[N7:0]", AbLegacyDataType.Int));           // indirect
        await drv.InitializeAsync("{}", CancellationToken.None);

        _ = await drv.ReadAsync(["Near", "Far", "Mistyped", "Acc", "Status", "Ind"], CancellationToken.None);

        created.ShouldAllBe(c => c.ElementCount == 1);
        created.Select(c => c.TagName).ShouldContain("N7:40");
        created.Select(c => c.TagName).ShouldContain("T4:0.ACC");
        await drv.ShutdownAsync(CancellationToken.None);
    }

    [Fact]
    public async Task A_refused_block_falls_back_to_single_reads_and_is_remembered_after_a_repeat()
    {
        // N7:9 is past the end of the file: the BLOCK is refused; singly, only that tag is.
        var (drv, _, created) = NewDriver(
            p => p.ElementCount > 1 || p.TagName == "N7:9"
                ? new FakeAbLegacyTag(p) { Status = (int)AbStatus.OutOfBounds }
                : new FakeAbLegacyTag(p) { Value = 3 },
            coalesce: true,
            Tag("A", "N7:0", AbLegacyDataType.Int),
            Tag("B", "N7:2", AbLegacyDataType.Int),
            Tag("C", "N7:9", AbLegacyDataType.Int));
        await drv.InitializeAsync("{}", CancellationToken.None);

        for (var poll = 0; poll < 3; poll++)
        {
            var r = await drv.ReadAsync(["A", "B", "C"], CancellationToken.None);
            r[0].StatusCode.ShouldBe(AbLegacyStatusMapper.Good, $"poll {poll}");
            r[1].StatusCode.ShouldBe(AbLegacyStatusMapper.Good, $"poll {poll}");
            r[2].StatusCode.ShouldBe(AbLegacyStatusMapper.MapStatus(AbStatus.OutOfBounds));
        }
        // Refused on polls 0 and 1 (each falling back to singles in the same pass); remembered after the repeat,
        // so poll 2 does not try the block again.
        created.Count(c => c.ElementCount > 1).ShouldBe(2);
        drv.GetHealth().State.ShouldBe(DriverState.Healthy); // refusals are not comms faults
        await drv.ShutdownAsync(CancellationToken.None);
    }

    [Fact]
    public async Task A_block_comms_fault_fails_its_members_together_and_degrades()
    {
        var (drv, _, _) = NewDriver(
            p => new FakeAbLegacyTag(p) { ThrowOnRead = true, Exception = new System.Net.Sockets.SocketException(10054) },
            coalesce: true,
            Tag("A", "N7:0", AbLegacyDataType.Int),
            Tag("B", "N7:1", AbLegacyDataType.Int));
        await drv.InitializeAsync("{}", CancellationToken.None);

        var r = await drv.ReadAsync(["A", "B"], CancellationToken.None);

        r.ShouldAllBe(s => s.StatusCode == AbLegacyStatusMapper.BadCommunicationError);
        drv.GetHealth().State.ShouldBe(DriverState.Degraded);
        await drv.ShutdownAsync(CancellationToken.None);
    }

    [Fact]
    public async Task CoalesceReads_false_reads_every_tag_singly()
    {
        var (drv, _, created) = NewDriver(
            p => new FakeAbLegacyTag(p) { Value = 1 },
            coalesce: false,
            Tag("A", "N7:0", AbLegacyDataType.Int),
            Tag("B", "N7:1", AbLegacyDataType.Int));
        await drv.InitializeAsync("{}", CancellationToken.None);

        var r = await drv.ReadAsync(["A", "B"], CancellationToken.None);

        r.ShouldAllBe(s => s.StatusCode == AbLegacyStatusMapper.Good);
        created.Count.ShouldBe(2);
        created.ShouldAllBe(c => c.ElementCount == 1);
        await drv.ShutdownAsync(CancellationToken.None);
    }

    [Theory]
    [InlineData("""{"devices":[{"hostAddress":"ab://10.0.0.5/1,0"}]}""", true)]
    [InlineData("""{"coalesceReads":false,"devices":[{"hostAddress":"ab://10.0.0.5/1,0"}]}""", false)]
    [InlineData("""{"coalesceReads":true,"someFutureKey":1,"devices":[{"hostAddress":"ab://10.0.0.5/1,0"}]}""", true)]
    public void ParseOptions_reads_coalesceReads_defaulting_true(string json, bool expected) =>
        (AbLegacyDriverFactoryExtensions.ParseOptions("drv", json).CoalesceReads != false).ShouldBe(expected);
}