// Capture client for scripts/ab-capture/capture.sh.
//
// One libplctag tag, one operation, then Dispose + plc_tag_shutdown so the Forward Close
// reaches the wire. The tag is built with exactly the properties the drivers set
// (LibplctagTagRuntime / LibplctagLegacyTagRuntime / LibplctagTagEnumerator): Gateway, Path,
// PlcType, Protocol=ab_eip, Name, Timeout, and ElementCount when > 1. Nothing else.
//
// usage:
//   ab-capture-client version
//   ab-capture-client read  <host:port> <path|-> <plc> <name> <type> [count]
//   ab-capture-client write <host:port> <path|-> <plc> <name> <type> <count> <value>
//
// <plc>   a libplctag.PlcType name: ControlLogix, Micro800, Slc500, MicroLogix, Plc5, LogixPccc
// <type>  dint | int | real | string | bool | raw (read only: hex dump of the buffer)
//         dintseq (write only): element i (0-based) = ((i+1) << 24) | (i+1), for <count> elements;
//         <value> is ignored but required.
// env UNCONNECTED=1 sets UseConnectedMessaging=false (ignored by libplctag 2.6.0 for Micro800).
using libplctag;
using libplctag.NativeImport;

if (args.Length == 0)
{
    Console.Error.WriteLine("usage: see the header of Program.cs");
    return 2;
}

if (args[0] == "seed-bool")
{
    // ab_server rejects libplctag's BOOL write with CIP 0x03: libplctag sends two data bytes for a
    // one-byte BOOL and ab_server's "too much data" check refuses it. This seeds a BOOL for a
    // later libplctag READ capture with one raw UCMM Write Tag carrying exactly one data byte.
    // usage: seed-bool <host> <port> <tag> <0|1>   (route is port 1 / slot 0)
    return await SeedBoolAsync(args[1], int.Parse(args[2]), args[3], args[4] == "1" ? (byte)1 : (byte)0);
}

if (args[0] == "version")
{
    Console.WriteLine($"{plctag.plc_tag_get_int_attribute(0, "version_major", -1)}." +
                      $"{plctag.plc_tag_get_int_attribute(0, "version_minor", -1)}." +
                      $"{plctag.plc_tag_get_int_attribute(0, "version_patch", -1)}");
    return 0;
}

var op = args[0];
var gateway = args[1];
var path = args[2] == "-" ? null : args[2];
var plc = Enum.Parse<PlcType>(args[3], ignoreCase: true);
var name = args[4];
var type = args[5];
var count = args.Length > 6 ? int.Parse(args[6]) : 1;

var tag = new Tag
{
    Gateway = gateway,
    Path = path,
    PlcType = plc,
    Protocol = Protocol.ab_eip,
    Name = name,
    Timeout = TimeSpan.FromSeconds(5),
};
if (count > 1) tag.ElementCount = count;
if (Environment.GetEnvironmentVariable("UNCONNECTED") == "1") tag.UseConnectedMessaging = false;

var exit = 0;
try
{
    await tag.InitializeAsync();
    if (op == "write")
    {
        var value = args[7];
        switch (type)
        {
            case "dint": tag.SetInt32(0, int.Parse(value)); break;
            case "int": tag.SetInt16(0, short.Parse(value)); break;
            case "real": tag.SetFloat32(0, float.Parse(value)); break;
            case "string": tag.SetString(0, value); break;
            // As LibplctagTagRuntime does: a whole-byte write (SetBit on a Logix BOOL is ErrorBadParam).
            case "bool": tag.SetInt8(0, value is "1" or "true" ? (sbyte)1 : (sbyte)0); break;
            case "dintseq":
                for (var i = 0; i < count; i++) tag.SetInt32(i * 4, ((i + 1) << 24) | (i + 1));
                break;
            default: throw new ArgumentException($"unknown write type {type}");
        }
        await tag.WriteAsync();
        Console.WriteLine("write ok");
    }
    else
    {
        await tag.ReadAsync();
        Console.WriteLine($"read ok size={tag.GetSize()}");
        Console.WriteLine(type switch
        {
            "dint" => tag.GetInt32(0).ToString(),
            "int" => tag.GetInt16(0).ToString(),
            "real" => tag.GetFloat32(0).ToString(),
            "string" => tag.GetString(0),
            "bool" => tag.GetBit(0).ToString(),
            _ => Convert.ToHexString(tag.GetBuffer()),
        });
    }
}
catch (Exception ex)
{
    Console.WriteLine($"EXC {ex.GetType().Name}: {ex.Message}");
    exit = 1;
}
finally
{
    tag.Dispose();
}

plctag.plc_tag_shutdown();
await Task.Delay(500);   // let the Forward Close flush before the process exits
return exit;

static async Task<int> SeedBoolAsync(string host, int port, string tagName, byte value)
{
    using var tcp = new System.Net.Sockets.TcpClient();
    await tcp.ConnectAsync(host, port);
    var s = tcp.GetStream();

    // RegisterSession
    var reg = new byte[28];
    reg[0] = 0x65; reg[2] = 4; reg[24] = 1;
    await s.WriteAsync(reg);
    var regReply = await ReadFrameAsync(s);
    var session = BitConverter.ToUInt32(regReply, 4);

    // Write Tag (0x4D): ANSI symbol segment, type BOOL 0xC1, count 1, ONE data byte.
    var name = System.Text.Encoding.ASCII.GetBytes(tagName);
    var sym = new List<byte> { 0x91, (byte)name.Length };
    sym.AddRange(name);
    if (sym.Count % 2 == 1) sym.Add(0);
    var write = new List<byte> { 0x4D, (byte)(sym.Count / 2) };
    write.AddRange(sym);
    write.AddRange([0xC1, 0x00, 0x01, 0x00, value]);

    // Unconnected Send (0x52) to the Connection Manager, routed to port 1 / slot 0.
    var ucmm = new List<byte> { 0x52, 0x02, 0x20, 0x06, 0x24, 0x01, 0x0A, 0x05 };
    ucmm.AddRange(BitConverter.GetBytes((ushort)write.Count));
    ucmm.AddRange(write);
    if (write.Count % 2 == 1) ucmm.Add(0);
    ucmm.AddRange([0x01, 0x00, 0x01, 0x00]);

    // SendRRData: interface handle, timeout, 2 items (null address, unconnected data).
    var data = new List<byte> { 0, 0, 0, 0, 0x0A, 0, 2, 0, 0, 0, 0, 0, 0xB2, 0 };
    data.AddRange(BitConverter.GetBytes((ushort)ucmm.Count));
    data.AddRange(ucmm);
    var frame = new byte[24 + data.Count];
    frame[0] = 0x6F;
    BitConverter.GetBytes((ushort)data.Count).CopyTo(frame, 2);
    BitConverter.GetBytes(session).CopyTo(frame, 4);
    data.CopyTo(frame, 24);
    await s.WriteAsync(frame);

    var reply = await ReadFrameAsync(s);
    var cip = reply.AsSpan(24 + 16).ToArray();   // after handle, timeout, count, null item, data item header
    Console.WriteLine($"seed-bool reply CIP: {Convert.ToHexString(cip)}");
    return cip.Length >= 3 && cip[0] == 0xCD && cip[2] == 0 ? 0 : 1;
}

static async Task<byte[]> ReadFrameAsync(System.Net.Sockets.NetworkStream s)
{
    var header = new byte[24];
    await s.ReadExactlyAsync(header);
    var body = new byte[BitConverter.ToUInt16(header, 2)];
    await s.ReadExactlyAsync(body);
    return [.. header, .. body];
}