using System;
using System.IO.Ports;

namespace leak_test_project.Infrastructure
{
    /// <summary>
    /// RS232 시리얼 통신을 담당하는 구현체.
    /// 연결 안정성 강화를 위한 예외 처리 및 상태 감지 로직 포함.
    /// </summary>
    public class SerialProvider : ICommunication, IDisposable
    {
        private SerialPort _serialPort;
        private bool _disposed = false;

        public string Name { get; private set; }
        public bool IsOpen => _serialPort != null && !_disposed && _serialPort.IsOpen;

        public event EventHandler<string> DataReceived;
        public event EventHandler<bool> ConnectionStatusChanged;

        public SerialProvider(string portName, int baudRate)
        {
            Name = portName;
            _serialPort = new SerialPort(portName, baudRate, Parity.None, 8, StopBits.One);
            _serialPort.Handshake = Handshake.None;
            _serialPort.DtrEnable = true; // 터미널 프로그램(포트몬)과 동일하게 제어 신호 활성화
            _serialPort.RtsEnable = true;
            _serialPort.ReadTimeout = 500;
            _serialPort.WriteTimeout = 500;

            _serialPort.DataReceived += (s, e) => {
                try {
                    string data = _serialPort.ReadExisting();
                    if (!string.IsNullOrEmpty(data))
                        DataReceived?.Invoke(this, data);
                } catch (Exception ex) {
                    Console.WriteLine($"[Serial Error] Read error on {Name}: {ex.Message}");
                }
            };

            // 기기가 끊겼을 때 감지 (일부 환경에서는 PinChanged 등으로 감지 가능)
            _serialPort.ErrorReceived += (s, e) => {
                ConnectionStatusChanged?.Invoke(this, false);
            };
        }

        public bool Open()
        {
            if (_disposed) return false;
            try {
                if (IsOpen) return true;
                _serialPort.Open();
                ConnectionStatusChanged?.Invoke(this, true);
                return true;
            } catch (Exception ex) {
                Console.WriteLine($"[Serial Error] Failed to open {Name}: {ex.Message}");
                ConnectionStatusChanged?.Invoke(this, false);
                return false;
            }
        }

        public void Close()
        {
            try {
                if (IsOpen) {
                    _serialPort.Close();
                    ConnectionStatusChanged?.Invoke(this, false);
                }
            } catch (Exception ex) {
                Console.WriteLine($"[Serial Error] Error closing {Name}: {ex.Message}");
            }
        }

        public bool Write(string data)
        {
            if (!IsOpen) return false;
            try {
                _serialPort.Write(data);
                return true;
            } catch (Exception ex) {
                Console.WriteLine($"[Serial Error] Write error on {Name}: {ex.Message}");
                return false;
            }
        }

        public void ClearBuffer()
        {
            if (IsOpen) {
                try {
                    _serialPort.DiscardInBuffer();
                    _serialPort.DiscardOutBuffer();
                    _serialPort.ReadExisting();
                } catch { }
            }
        }

        public void Dispose()
        {
            if (!_disposed)
            {
                _disposed = true;
                Close();
                _serialPort?.Dispose();
                _serialPort = null;
            }
        }
    }
}