using System;
using System.IO.Ports;
using System.Threading;
using System.Threading.Tasks;

namespace RJ2RoomConSimulator
{
    // RJ2-232 룸콘(마스터) 시뮬레이터 프로토콜
    //  규격 : Protocol/ROOMCON/힘펠_환기장치프로토콜V3.7 (펌웨어 My_RJ2.c / ERVSimulator RoomConProtocol.cs)
    //  프레임 : AA | CMD | D[2..12] | XOR(0~12) | EE  (15 byte 고정), RS-232 9600 8N1
    //  역할 : 룸콘이 마스터 — 모드/풍량/예약 변경(EVENT) 송신 + 주기 폴링(NORMAL), ERV 응답 수신/표시
    //  ERV(ERVSimulator)가 응답측. 모드코드 : 0환기/1자동/2바이패스/3공청 (ERVSim RunMode enum 일치)
    public class RoomConProtocol : IDisposable
    {
        public const byte HEADER = 0xAA;
        public const byte TAIL   = 0xEE;
        public const int  LEN    = 15;

        // CMD
        public const byte CMD_NORMAL   = 0x00;  // 상태 폴링
        public const byte CMD_EVENT    = 0x01;  // 모드/팬/예약 변경 이벤트
        public const byte CMD_RESTART1 = 0x02;  // 환기 preset 조회
        public const byte CMD_RESTART2 = 0x12;  // bypass/air preset 조회
        public const byte CMD_VSP      = 0x03;  // 테스트(VSP) 진입/설정
        public const byte CMD_EXIT     = 0x04;  // 테스트 종료
        public const byte CMD_CONTROL  = 0x07;  // ERV→룸콘 상태응답(COMMAND_CONTROLL)
        public const byte CMD_HOOD_INFO = 0x0A; // ERV→룸콘 후드 연동 통지(힘펠 V3.7 RX_DATA_HOOD_INFO)

        SerialPort? _port;
        CancellationTokenSource? _cts;
        readonly object _lock = new();
        bool _disposed;

        // ---- 룸콘 제어 상태 (UI) ----
        public bool PowerOn;
        public byte RunMode;        // 0환기/1자동/2바이패스/3공청
        public byte FanMode;        // 0~4
        public int  ReserveHours;   // 0~8 (0=취소)
        public byte DeviceId = 1;   // id 설정 (RS232 점대점 — 표시/로그용)

        // ---- ERV 응답 파싱 결과 ----
        public byte ErvRunMode, ErvFanMode, ErvError;
        public bool HoodLinked;   // 후드 연동중(HOOD_INFO byte[6] bit0 = 0x81 ON / 0x80 OFF)
        public int  ErvInTemp, ErvOutTemp;
        public readonly int[] VentSa = new int[5], VentEa = new int[5];   // index 1~4
        public readonly int[] BypassSa = new int[2], BypassEa = new int[2];
        public readonly int[] AirSa = new int[5];

        readonly byte[] _rx = new byte[LEN];
        int _rxPos;

        public event Action<string>? Log;
        public event Action<bool>? ConnectionChanged;
        public event Action<byte>? ResponseReceived;   // 파싱 완료된 CMD 전달

        public bool IsConnected => _port?.IsOpen == true;

        public static byte Xor(byte[] d, int start, int len)
        {
            byte x = 0;
            for (int i = 0; i < len; i++) x ^= d[start + i];
            return x;
        }

        public string[] GetAvailablePorts() => SerialPort.GetPortNames();

        public bool Connect(string portName)
        {
            try
            {
                Disconnect();
                _port = new SerialPort(portName, 9600, Parity.None, 8, StopBits.One)
                {
                    ReadTimeout = 100, WriteTimeout = 300
                };
                _port.Open();
                _cts = new CancellationTokenSource();
                _ = Task.Run(() => ReadLoop(_cts.Token));
                Logm($"[연결] {portName} (9600, 8N1)");
                ConnectionChanged?.Invoke(true);
                return true;
            }
            catch (Exception ex)
            {
                Logm($"[오류] 연결 실패: {ex.Message}");
                ConnectionChanged?.Invoke(false);
                return false;
            }
        }

        public void Disconnect()
        {
            try { _cts?.Cancel(); } catch { }
            try { if (_port?.IsOpen == true) { _port.Close(); Logm("[연결 해제]"); } } catch { }
            _port?.Dispose(); _port = null;
            ConnectionChanged?.Invoke(false);
        }

        // ================= 수신 (ERV 응답 파싱) =================
        void ReadLoop(CancellationToken ct)
        {
            var buf = new byte[64];
            while (!ct.IsCancellationRequested && _port != null && _port.IsOpen)
            {
                try
                {
                    int n = _port.Read(buf, 0, buf.Length);
                    for (int i = 0; i < n; i++) FeedByte(buf[i]);
                }
                catch (TimeoutException) { }
                catch (Exception ex) { if (!ct.IsCancellationRequested) Logm($"[오류] {ex.Message}"); break; }
            }
        }

        DateTime _lastByte = DateTime.MinValue;
        static readonly TimeSpan FrameGap = TimeSpan.FromMilliseconds(50);
        void FeedByte(byte b)
        {
            var now = DateTime.UtcNow;
            if (now - _lastByte > FrameGap) _rxPos = 0;
            _lastByte = now;

            if (_rxPos == 0) { if (b == HEADER) _rx[_rxPos++] = b; return; }
            if (_rxPos <= 12) { _rx[_rxPos++] = b; return; }
            if (_rxPos == 13) { if (Xor(_rx, 0, 13) == b) _rx[_rxPos++] = b; else _rxPos = 0; return; }
            if (_rxPos == 14)
            {
                _rxPos = 0;
                if (b != TAIL) return;
                HandleResponse((byte[])_rx.Clone());
            }
        }

        void HandleResponse(byte[] p)
        {
            Logm($"RX: {Hex(p, 14)} EE");
            byte cmd = p[1];
            switch (cmd)
            {
                case CMD_EVENT:    // ERV ack : runMode/fanMode/err/temp
                    ErvRunMode = p[2]; ErvFanMode = p[3]; ErvError = p[7];
                    ErvOutTemp = (p[9] == 0xFF) ? 100 : (p[8] == 0x01 ? -(p[9] - 20) : p[9] - 20);
                    ErvInTemp  = (p[10] == 0xFF) ? 100 : p[10] - 20;
                    break;
                case CMD_CONTROL:  // 상태 폴링 응답
                    ErvRunMode = p[2]; ErvFanMode = p[3]; ErvError = p[7];
                    break;
                case CMD_RESTART1: // 환기 preset
                    VentSa[1] = p[5]; VentEa[1] = p[6]; VentSa[2] = p[7]; VentEa[2] = p[8];
                    VentSa[3] = p[9]; VentEa[3] = p[10]; VentSa[4] = p[11]; VentEa[4] = p[12];
                    break;
                case CMD_RESTART2: // bypass/air preset
                    BypassSa[1] = p[5]; BypassEa[1] = p[6];
                    AirSa[1] = p[7]; AirSa[2] = p[8]; AirSa[3] = p[9]; AirSa[4] = p[10];
                    break;
                case CMD_HOOD_INFO: // 후드 연동 통지 : byte[6] 0x81=ON / 0x80=OFF
                    HoodLinked = (p[6] & 0x01) != 0;
                    break;
            }
            ResponseReceived?.Invoke(cmd);
        }

        // ================= 송신 (룸콘 → ERV) =================
        byte[] NewPacket(byte cmd)
        {
            var p = new byte[LEN];
            p[0] = HEADER; p[1] = cmd;
            return p;
        }
        void Send(byte[] p)
        {
            p[13] = Xor(p, 0, 13);
            p[14] = TAIL;
            if (_port?.IsOpen != true) return;
            try { lock (_lock) { _port.Write(p, 0, LEN); } Logm($"TX: {Hex(p, LEN)}"); }
            catch (Exception ex) { Logm($"[송신오류] {ex.Message}"); }
        }

        // 모드/풍량/예약 변경 이벤트 (EVENT). 전원 OFF는 환기+풍량0으로 표현(ERV가 Power OFF 처리).
        public void SendEvent()
        {
            var p = NewPacket(CMD_EVENT);
            p[2] = PowerOn ? RunMode : (byte)0;             // OFF → 환기(0)
            p[3] = PowerOn ? FanMode : (byte)0;             // OFF → 풍량 0
            p[5] = 0;                                       // Heater/UV/Kijer
            p[10] = 1; p[11] = (byte)ReserveHours; p[12] = 0;   // 예약(시) — 0이면 해제. flag=1로 항상 전달
            Send(p);
        }

        // 상태 폴링 (NORMAL)
        public void SendNormal()
        {
            var p = NewPacket(CMD_NORMAL);
            if (ReserveHours > 0) { p[11] = (byte)ReserveHours; p[12] = 0; }
            Send(p);
        }

        public void SendRestart1() => Send(NewPacket(CMD_RESTART1));   // 환기 preset 조회
        public void SendRestart2() => Send(NewPacket(CMD_RESTART2));   // bypass/air preset 조회
        public void SendExit()     => Send(NewPacket(CMD_EXIT));       // 테스트 종료

        // VSP(테스트) 설정 : select / sa / ea
        public void SendVsp(byte select, byte sa, byte ea)
        {
            var p = NewPacket(CMD_VSP);
            p[3] = select; p[4] = sa; p[5] = ea;
            Send(p);
        }

        void Logm(string m) => Log?.Invoke($"[{DateTime.Now:HH:mm:ss.fff}] {m}");
        static string Hex(byte[] d, int n)
        {
            var sb = new System.Text.StringBuilder(n * 3);
            for (int i = 0; i < n; i++) { if (i > 0) sb.Append(' '); sb.Append(d[i].ToString("X2")); }
            return sb.ToString();
        }

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