using Modbus.Device;
using RobotNet10.Script.IO;
using System.Net.Sockets;

namespace RobotNet10.ScriptEngine.IO;

/// <summary>
/// Implementation of ModbusTCP connection using NModbus4 library.
/// </summary>
public class ModbusTcpConnection(string ipAddress, int port = 502, byte slaveId = 1, int connectTimeoutMs = 5000) : IModbusTcpConnection
{
    private TcpClient? _tcpClient;
    private ModbusMaster? _modbusMaster;
    private bool _disposed;

    public string IpAddress { get; } = ipAddress;
    public int Port { get; } = port;
    public byte SlaveId { get; } = slaveId;
    public int ConnectTimeoutMs { get; } = connectTimeoutMs;
    public bool IsConnected { get; private set; } = false;

    public async Task ConnectAsync()
    {
        if (IsConnected)
            return;

        try
        {
            _tcpClient = new TcpClient();
            
            // Sử dụng ConnectTimeout
            using (var cts = new CancellationTokenSource(TimeSpan.FromMilliseconds(ConnectTimeoutMs)))
            {
                await _tcpClient.ConnectAsync(IpAddress, Port).WaitAsync(cts.Token);
            }
            
            _modbusMaster = ModbusIpMaster.CreateIp(_tcpClient);
            IsConnected = true;
        }
        catch (OperationCanceledException)
        {
            Disconnect();
            throw new TimeoutException($"Connection to {IpAddress}:{Port} timed out after {ConnectTimeoutMs}ms");
        }
        catch
        {
            Disconnect();
            throw;
        }
    }

    public Task DisconnectAsync()
    {
        Disconnect();
        return Task.CompletedTask;
    }

    private void Disconnect()
    {
        IsConnected = false;
        _modbusMaster?.Dispose();
        _modbusMaster = null;
        _tcpClient?.Close();
        _tcpClient?.Dispose();
        _tcpClient = null;
    }

    public async Task<ushort[]> ReadHoldingRegistersAsync(ushort startAddress, ushort numberOfPoints)
    {
        EnsureConnected();
        return await Task.Run(() => _modbusMaster!.ReadHoldingRegisters(SlaveId, startAddress, numberOfPoints));
    }

    public async Task<ushort[]> ReadInputRegistersAsync(ushort startAddress, ushort numberOfPoints)
    {
        EnsureConnected();
        return await Task.Run(() => _modbusMaster!.ReadInputRegisters(SlaveId, startAddress, numberOfPoints));
    }

    public async Task<bool[]> ReadCoilsAsync(ushort startAddress, ushort numberOfPoints)
    {
        EnsureConnected();
        return await Task.Run(() => _modbusMaster!.ReadCoils(SlaveId, startAddress, numberOfPoints));
    }

    public async Task<bool[]> ReadDiscreteInputsAsync(ushort startAddress, ushort numberOfPoints)
    {
        EnsureConnected();
        return await Task.Run(() => _modbusMaster!.ReadInputs(SlaveId, startAddress, numberOfPoints));
    }

    public async Task WriteSingleCoilAsync(ushort coilAddress, bool value)
    {
        EnsureConnected();
        await Task.Run(() => _modbusMaster!.WriteSingleCoil(SlaveId, coilAddress, value));
    }

    public async Task WriteMultipleCoilsAsync(ushort startAddress, bool[] values)
    {
        EnsureConnected();
        await Task.Run(() => _modbusMaster!.WriteMultipleCoils(SlaveId, startAddress, values));
    }

    public async Task WriteSingleRegisterAsync(ushort registerAddress, ushort value)
    {
        EnsureConnected();
        await Task.Run(() => _modbusMaster!.WriteSingleRegister(SlaveId, registerAddress, value));
    }

    public async Task WriteMultipleRegistersAsync(ushort startAddress, ushort[] values)
    {
        EnsureConnected();
        await Task.Run(() => _modbusMaster!.WriteMultipleRegisters(SlaveId, startAddress, values));
    }

    private void EnsureConnected()
    {
        if (!IsConnected || _modbusMaster == null)
        {
            throw new InvalidOperationException("ModbusTCP connection is not connected. Call ConnectAsync() first.");
        }
    }

    public void Dispose()
    {
        if (!_disposed)
        {
            Disconnect();
            _disposed = true;
        }
        GC.SuppressFinalize(this);
    }
}