using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport.Cip;
namespace ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport.Tests.Cip;

public sealed class MultipleServicePacketTests
{
    [Fact]
    public void Msp_offsets_are_measured_from_the_count_field()
    {
        var a = new byte[] { 0x4C, 0x02, 0x91, 0x01, 0x41, 0x00, 0x01, 0x00 };
        var b = new byte[] { 0x4C, 0x02, 0x91, 0x01, 0x42, 0x00, 0x01, 0x00 };
        Convert.ToHexString(MultipleServicePacket.Build([a, b])).ShouldBe(
            "0A02200224010200" + "0600" + "0E00" + Convert.ToHexString(a) + Convert.ToHexString(b));
        MultipleServicePacket.BuildSize([8, 8]).ShouldBe(6 + 2 + 4 + 16);
    }

    [Fact]
    public void BuildSize_equals_built_length()
    {
        byte[][] reqs = [new byte[7], new byte[20], new byte[1]];
        MultipleServicePacket.Build(reqs).Length.ShouldBe(MultipleServicePacket.BuildSize([7, 20, 1]));
    }

    [Fact]
    public void Parse_splits_replies()
    {
        // outer reply data: count 2, offsets 6 and 14, reply1 (8 bytes), reply2 (6 bytes)
        var r1 = Convert.FromHexString("CC000000C400" + "0100");   // DINT-typed read reply, 8 bytes
        var r2 = Convert.FromHexString("CD000000" + "0000");       // write ok + 2 extra bytes
        var data = Convert.FromHexString("0200" + "0600" + "0E00").Concat(r1).Concat(r2).ToArray();
        var outer = new CipReply(0x0A, 0, [], data);
        var replies = MultipleServicePacket.Parse(outer, 2);
        replies.Count.ShouldBe(2);
        replies[0].Service.ShouldBe((byte)0x4C);
        Convert.ToHexString(replies[0].Data.ToArray()).ShouldBe("C4000100");
        replies[1].Service.ShouldBe((byte)0x4D);
    }

    [Fact]
    public void Parse_embedded_error_status_is_kept_per_reply()
    {
        var r1 = Convert.FromHexString("CC000400");
        var data = Convert.FromHexString("0100" + "0400").Concat(r1).ToArray();
        MultipleServicePacket.Parse(new CipReply(0x0A, 0x1E, [], data), 1)[0].GeneralStatus.ShouldBe((byte)0x04);
    }

    [Fact]
    public void Parse_wrong_count_throws() =>
        Should.Throw<AbTransportException>(() =>
            MultipleServicePacket.Parse(new CipReply(0x0A, 0, [], Convert.FromHexString("0100" + "0400" + "CC000000")), 2));
}