using System;
using System.Windows.Threading;
using ERVSimulator.Model;
using ErvProtocol;   // 공용 Crc16 (bunbaegi CRC 도 표준 MODBUS 동일)
using RunMode = ERVSimulator.Model.RunMode;   // ErvProtocol.RunMode 와 이름 충돌 해소

namespace ERVSimulator.Protocol
{
    // 디퓨저 버스 마스터 (115200) <-> DiffuserSimulator(슬레이브)
    //  규격 : Protocol/수정_Each_Room_Jushin_protocol_RS485_Rev1.2  (펌웨어 My_Uart.c bunbaegi 미러)
    //  목적 : DiffuserSimulator 로부터 각실 센서값(PM2.5/PM10/VOC/CO2) 수신 → ErvState → 자동로직
    //  - 마스터 폴(29B, 0x10): 실/타입(SA/RA)별 전원·모드·풍량·LED·댐퍼 송신 (poll-response 구조상 필수)
    //  - 슬레이브 응답(39B, 0x01): 센서값 수신
    //  ※ ERVSim 은 각실 댐퍼+LED 를 자체 표시하지 않음(DiffuserSimulator 가 표시). 통신만 수행.
    public class DiffuserMasterProtocol
    {
        readonly SerialChannel _ch;
        readonly ErvState _state;
        readonly Dispatcher _dispatcher;
        readonly DispatcherTimer _pollTimer;

        int _pollIdx;   // (room1 SA),(room1 RA)...(room4 RA) round-robin

        readonly byte[] _rx = new byte[39];
        int _rxPos;
        DateTime _lastByte = DateTime.MinValue;
        static readonly TimeSpan FrameGap = TimeSpan.FromMilliseconds(40);

        public event Action<string>? PacketReceived;
        public event Action<string>? PacketSent;
        public bool Verbose { get; set; } = false;   // true면 모든 폴 로그

        public DiffuserMasterProtocol(SerialChannel ch, ErvState state, Dispatcher dispatcher)
        {
            _ch = ch; _state = state; _dispatcher = dispatcher;
            _ch.ByteReceived += OnByte;
            _pollTimer = new DispatcherTimer(DispatcherPriority.Background) { Interval = TimeSpan.FromMilliseconds(80) };
            _pollTimer.Tick += (_, _) => { if (_ch.IsConnected) PollNext(); };
            _pollTimer.Start();
        }

        byte DiffRunMode() => _state.RunMode switch
        {
            RunMode.Ventilation => 0x01,
            RunMode.Auto => 0x02,
            RunMode.Bypass => 0x04,
            RunMode.AirClean => 0x08,
            _ => 0x01,
        };

        void PollNext()
        {
            int room = _pollIdx / 2 + 1;        // 1~4
            byte id1 = (byte)(_pollIdx % 2 == 0 ? 0x01 : 0x02);  // SA / RA
            _pollIdx = (_pollIdx + 1) % 8;

            var rm = _state.GetRoom(room);
            var p = new byte[29];
            p[0] = 0xAA; p[1] = 0x10; p[2] = id1; p[3] = (byte)room; p[4] = 0x00;
            p[5] = (byte)(_state.PowerOn ? 1 : 0);
            p[6] = DiffRunMode();
            p[7] = _state.FanMode;
            p[8] = (byte)rm.LightBright;
            p[9] = (byte)rm.AirQuality;
            p[10] = (byte)rm.CurrentSA;
            p[11] = (byte)rm.CurrentRA;
            ushort crc = Crc16.Modbus(p, 0, 27);
            // lo-first : 펌웨어 CRC16()이 표준MODBUS 바이트스왑값 반환 + [27]=icrc>>8 배치 → 와이어는 리틀엔디안
            p[27] = (byte)(crc & 0xFF);
            p[28] = (byte)(crc >> 8);
            _ch.Send(p, 29);
            if (Verbose) PacketSent?.Invoke($"Diff TX poll room{room} {(id1 == 1 ? "SA" : "RA")} SA={rm.CurrentSA} RA={rm.CurrentRA} LED={rm.LightBright}");
        }

        void OnByte(byte b)
        {
            var now = DateTime.UtcNow;
            if (now - _lastByte > FrameGap) _rxPos = 0;
            _lastByte = now;

            if (_rxPos == 0)
            {
                if (b == 0xAA) { _rx[0] = b; _rxPos = 1; }
            }
            else if (_rxPos == 1)
            {
                if (b == 0x01) { _rx[1] = b; _rxPos = 2; }
                else _rxPos = (b == 0xAA) ? 1 : 0;
            }
            else
            {
                _rx[_rxPos++] = b;
                if (_rxPos >= 39)
                {
                    var copy = (byte[])_rx.Clone();
                    _dispatcher.BeginInvoke(new Action(() => HandleResponse(copy)));
                    _rxPos = 0;
                }
            }
        }

        void HandleResponse(byte[] p)
        {
            ushort rxcrc = (ushort)(p[37] | (p[38] << 8));   // lo-first (표준 리틀엔디안)
            if (Crc16.Modbus(p, 0, 37) != rxcrc)
            {
                PacketReceived?.Invoke($"Diff RX CRC오류 {HexFormat.Bytes(p, 39)}");
                return;
            }

            int id1 = p[2];     // 0x01 SA / 0x02 RA
            int room = p[3];    // 1~4
            if (room < 1 || room > 4) return;

            // 센서 (응답 39B, 빅엔디안) : LED[8] PM10[12,13] PM2.5[16,17] 습도[20,21] 온도[22,23] VOC[24,25] CO2[28,29]
            int led = p[8];     // 디퓨저가 echo 한 실제 LED 단수 (수동 제어 시 ERV 명령과 다를 수 있음)
            int pm10 = (p[12] << 8) | p[13];
            int pm25 = (p[16] << 8) | p[17];
            int humi = (p[20] << 8) | p[21];
            int temp = (p[22] << 8) | p[23];
            int voc = (p[24] << 8) | p[25];
            int co2 = (p[28] << 8) | p[29];

            var rm = _state.GetRoom(room);
            bool changed = rm.Co2 != co2 || rm.Pm25 != pm25 || rm.Pm10 != pm10 || rm.Voc != voc || rm.Temp != temp || rm.Humi != humi || rm.LedReported != led;
            rm.Pm10 = pm10; rm.Pm25 = pm25; rm.Voc = voc; rm.Co2 = co2; rm.Temp = temp; rm.Humi = humi; rm.LedReported = led;

            if (changed || Verbose)
                PacketReceived?.Invoke($"Diff RX {rm.Name} 센서 CO2={co2} PM2.5={pm25} PM10={pm10} VOC={voc} 온도={temp} 습도={humi} LED={led} (from {(id1 == 1 ? "SA" : "RA")})");
        }
    }
}