using System.Buffers.Binary;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport.Cip;
using ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport.Tests.Captures;
namespace ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport.Tests.Cip;

// CAPTURE DECISION: the brief gave timeout ticks 0x0E. Every libplctag capture (logix-forward-open,
// logix-forward-close) carries priority/tick 0x0A, timeout ticks 0x05, so ConnectionManagerServices
// uses 0x05 (brief: 0x0E -> capture: 0x05). The golden-byte tests below use 0x05 accordingly.
public sealed class ConnectionManagerServicesTests
{
    private static byte[] CapturedRequest(string file) =>
        CaptureFile.CipPayload(CaptureFile.Load(file).First(f => f.FromClient));

    private static CipReply CapturedReply(string file) =>
        CipReply.Parse(CaptureFile.CipPayload(CaptureFile.Load(file).First(f => !f.FromClient)));

    [Fact]
    public void Forward_close_frame()
    {
        var bytes = ConnectionManagerServices.ForwardClose(0x1234, 0x1337, 0xCAFEBABE, [0x01, 0x00]);
        Convert.ToHexString(bytes).ShouldBe("4E02200624010A05" + "3412" + "3713" + "BEBAFECA" + "03" + "00" + "0100" + "20022401");
    }

    [Fact]
    public void Forward_close_matches_capture()
    {
        var cap = CapturedRequest("logix-forward-close.hex");
        var serial = BinaryPrimitives.ReadUInt16LittleEndian(cap.AsSpan(8));
        var vendor = BinaryPrimitives.ReadUInt16LittleEndian(cap.AsSpan(10));
        var orig = BinaryPrimitives.ReadUInt32LittleEndian(cap.AsSpan(12));
        vendor.ShouldBe((ushort)0xF33D);
        ConnectionManagerServices.ForwardClose(serial, vendor, orig, [0x01, 0x00]).ShouldBe(cap);
    }

    [Fact]
    public void Large_forward_open_matches_capture()
    {
        var cap = CapturedRequest("logix-forward-open.hex");
        // Values read out of the capture: T->O id @12, serial @16, vendor @18, originator serial @20,
        // timeout multiplier @24, RPI @28, network params @32 (0x42000FA2 -> size 4002).
        var p = new ForwardOpenParams(
            Large: true, TOConnectionId: BinaryPrimitives.ReadUInt32LittleEndian(cap.AsSpan(12)), ConnectionSerial: BinaryPrimitives.ReadUInt16LittleEndian(cap.AsSpan(16)),
            VendorId: BinaryPrimitives.ReadUInt16LittleEndian(cap.AsSpan(18)), OriginatorSerial: BinaryPrimitives.ReadUInt32LittleEndian(cap.AsSpan(20)),
            TimeoutMultiplier: cap[24], RpiMicros: BinaryPrimitives.ReadUInt32LittleEndian(cap.AsSpan(28)), ConnectionSize: 4002, Route: [0x01, 0x00]);
        p.RpiMicros.ShouldBe(1_000_000u);
        BinaryPrimitives.ReadUInt32LittleEndian(cap.AsSpan(32)).ShouldBe(0x42000FA2u);
        ConnectionManagerServices.ForwardOpen(p).ShouldBe(cap);
    }

    [Fact]
    public void Large_forward_open_reply_parses_from_capture()
    {
        var reply = ConnectionManagerServices.ParseForwardOpenReply(CapturedReply("logix-forward-open.hex"));
        reply.OTConnectionId.ShouldBe(0x2CDF633Fu);
        reply.TOConnectionId.ShouldBe(0x073F9E60u);
        reply.OTApiMicros.ShouldBe(1_000_000u);
        reply.TOApiMicros.ShouldBe(1_000_000u);
    }

    // No small Forward Open 0x54 was captured (the Large FO succeeded), so this layout is checked against
    // the CIP spec / the brief rather than a capture.
    [Fact]
    public void Regular_forward_open_layout_per_spec()
    {
        var bytes = ConnectionManagerServices.ForwardOpen(new ForwardOpenParams(
            false, 0x11223344, 0x5566, 0x7788, 0x99AABBCC, 0x01, 1_000_000, 504, [0x01, 0x00]));
        Convert.ToHexString(bytes).ShouldBe(
            "540220062401" + "0A05" + "00000000" + "44332211" + "6655" + "8877" + "CCBBAA99" + "01000000"
            + "40420F00" + "F843" + "40420F00" + "F843" + "A3" + "03" + "0100" + "20022401");
    }

    [Fact]
    public void Regular_forward_open_network_params_encoding()
    {
        var bytes = ConnectionManagerServices.ForwardOpen(new ForwardOpenParams(false, 1, 2, 3, 4, 1, 1_000_000, 504, []));
        // 504 = 0x1F8; 0x4200 | 0x1F8 = 0x43F8 -> LE F8 43
        Convert.ToHexString(bytes).ShouldContain("40420F00" + "F843");
        bytes[0].ShouldBe((byte)0x54);
    }

    [Fact]
    public void Unconnected_send_even_embedded()
    {
        byte[] embedded = [0x4C, 0x02, 0x91, 0x01, 0x41, 0x00, 0x01, 0x00]; // 8 bytes
        Convert.ToHexString(ConnectionManagerServices.UnconnectedSend(embedded, [0x01, 0x00])).ShouldBe(
            "520220062401" + "0A05" + "0800" + Convert.ToHexString(embedded) + "01" + "00" + "0100");
    }

    [Fact]
    public void Unconnected_send_pads_odd_embedded()
    {
        byte[] embedded = [0x01, 0x02, 0x03];
        Convert.ToHexString(ConnectionManagerServices.UnconnectedSend(embedded, [0x01, 0x00])).ShouldBe(
            "520220062401" + "0A05" + "0300" + "010203" + "00" + "01" + "00" + "0100");
    }

    [Fact]
    public void Refused_forward_open_surfaces_statuses()
    {
        var reply = CipReply.Parse(Convert.FromHexString("DB000101" + "0901"));
        var ex = Should.Throw<AbTransportException>(() => ConnectionManagerServices.ParseForwardOpenReply(reply));
        ex.Message.ShouldContain("0x01");
        ex.Message.ShouldContain("0x0109");
    }

    [Fact]
    public void Refused_forward_open_carries_the_statuses_as_structured_data()
    {
        var reply = CipReply.Parse(Convert.FromHexString("DB000102" + "09010203"));
        var ex = Should.Throw<ForwardOpenRefusedException>(() => ConnectionManagerServices.ParseForwardOpenReply(reply));
        ex.GeneralStatus.ShouldBe((byte)0x01);
        ex.ExtendedStatus.ShouldBe(new ushort[] { 0x0109, 0x0302 });
        ex.Status.ShouldBe(AbStatus.BadConnection);   // general 0x01 has no specific mapping
    }

    [Fact]
    public void Refused_forward_open_exception_is_not_aliased_to_the_reply_array()
    {
        var reply = CipReply.Parse(Convert.FromHexString("DB000101" + "0901"));
        var ex = Should.Throw<ForwardOpenRefusedException>(() => ConnectionManagerServices.ParseForwardOpenReply(reply));
        reply.ExtendedStatus[0] = 0xFFFF;
        ex.ExtendedStatus[0].ShouldBe((ushort)0x0109);
    }

    [Theory]
    [InlineData("DB000800", true)]              // Service Not Supported
    [InlineData("DB0001010901", true)]          // general 1 / extended 0x0109
    [InlineData("DB0001010001", false)]         // general 1 / extended 0x0100 (connection in use): no fallback
    [InlineData("DB000000", false)]
    public void Fallback_rules(string hex, bool expected) =>
        ConnectionManagerServices.ShouldFallBackToRegularOpen(CipReply.Parse(Convert.FromHexString(hex))).ShouldBe(expected);

    [Theory]
    [InlineData(true, 0)] [InlineData(true, 0x10000)] [InlineData(false, 0)] [InlineData(false, 0x200)]
    public void Connection_size_out_of_range_throws(bool large, int size) =>
        Should.Throw<ArgumentOutOfRangeException>(() => ConnectionManagerServices.ForwardOpen(
            new ForwardOpenParams(large, 1, 2, 3, 4, 1, 1_000_000, size, [])));

    [Theory]
    [InlineData(true, 1)] [InlineData(true, 0xFFFF)] [InlineData(false, 1)] [InlineData(false, 0x1FF)]
    public void Connection_size_bounds_accepted(bool large, int size) =>
        ConnectionManagerServices.ForwardOpen(new ForwardOpenParams(large, 1, 2, 3, 4, 1, 1_000_000, size, [])).ShouldNotBeEmpty();
}