/* Libraries / Imports */
const fs = require('fs');
const https = require('https');
const koffi = require('koffi');
const path = require('path');
const os = require('os');
const platform = os.platform();
const cpuArchitecture = os.arch();
const { configName, serverConfig, configUpdate, configSave } = require('./server_config');
let unicode_type;
let shared_Library;

if (platform === 'win32') {
  unicode_type = 'int16_t';
  shared_Library=path.join(__dirname, "libraries", "librdsparser.dll");
} else if (platform === 'linux') {
  unicode_type = 'int32_t';
  shared_Library=path.join(__dirname, "libraries", "librdsparser_" + cpuArchitecture + ".so"); 
} else if (platform === 'darwin') {
  unicode_type = 'int32_t';
  shared_Library=path.join(__dirname, "libraries", "librdsparser" + ".dylib");
}

const lib = koffi.load(shared_Library);
const { fetchTx } = require('./tx_search.js');

koffi.proto('void callback_pi(void *rds, void *user_data)');
koffi.proto('void callback_pty(void *rds, void *user_data)');
koffi.proto('void callback_tp(void *rds, void *user_data)');
koffi.proto('void callback_ta(void *rds, void *user_data)');
koffi.proto('void callback_ms(void *rds, void *user_data)');
koffi.proto('void callback_ecc(void *rds, void *user_data)');
koffi.proto('void callback_country(void *rds, void *user_data)');
koffi.proto('void callback_af(void *rds, uint32_t af, void *user_data)');
koffi.proto('void callback_ps(void *rds, void *user_data)');
koffi.proto('void callback_rt(void *rds, int flag, void *user_data)');
koffi.proto('void callback_ptyn(void *rds, void *user_data)');
koffi.proto('void callback_ct(void *rds, void *ct, void *user_data)');

const rdsparser = {
  new: lib.func('void* rdsparser_new()'),
  free: lib.func('void rdsparser_free(void *rds)'),
  clear: lib.func('void rdsparser_clear(void *rds)'),
  parse_string: lib.func('bool rdsparser_parse_string(void *rds, const char *input)'),
  set_text_correction: lib.func('bool rdsparser_set_text_correction(void *rds, uint8_t text, uint8_t type, uint8_t error)'),
  set_text_progressive: lib.func('bool rdsparser_set_text_progressive(void *rds, uint8_t string, bool state)'),
  get_pi: lib.func('int32_t rdsparser_get_pi(void *rds)'),
  get_pty: lib.func('int8_t rdsparser_get_pty(void *rds)'),
  get_tp: lib.func('int8_t rdsparser_get_tp(void *rds)'),
  get_ta: lib.func('int8_t rdsparser_get_ta(void *rds)'),
  get_ms: lib.func('int8_t rdsparser_get_ms(void *rds)'),
  get_ecc: lib.func('int16_t rdsparser_get_ecc(void *rds)'),
  get_country: lib.func('int rdsparser_get_country(void *rds)'),
  get_ps: lib.func('void* rdsparser_get_ps(void *rds)'),
  get_rt: lib.func('void* rdsparser_get_rt(void *rds, int flag)'),
  get_ptyn: lib.func('void* rdsparser_get_ptyn(void *rds)'),
  register_pi: lib.func('void rdsparser_register_pi(void *rds, void *cb)'),
  register_pty: lib.func('void rdsparser_register_pty(void *rds, void *cb)'),
  register_tp: lib.func('void rdsparser_register_tp(void *rds, void *cb)'),
  register_ta: lib.func('void rdsparser_register_ta(void *rds, void *cb)'),
  register_ms: lib.func('void rdsparser_register_ms(void *rds, void *cb)'),
  register_ecc: lib.func('void rdsparser_register_ecc(void *rds, void *cb)'),
  register_country: lib.func('void rdsparser_register_country(void *rds, void *cb)'),
  register_af: lib.func('void rdsparser_register_af(void *rds, void *cb)'),
  register_ps: lib.func('void rdsparser_register_ps(void *rds, void *cb)'),
  register_rt: lib.func('void rdsparser_register_rt(void *rds, void *cb)'),
  register_ptyn: lib.func('void rdsparser_register_ptyn(void *rds, void *cb)'),
  register_ct: lib.func('void rdsparser_register_ct(void *rds, void *cb)'),
  string_get_content: lib.func(unicode_type + '* rdsparser_string_get_content(void *string)'),
  string_get_errors: lib.func('uint8_t* rdsparser_string_get_errors(void *string)'),
  string_get_length: lib.func('uint8_t rdsparser_string_get_length(void *string)'),
  ct_get_year: lib.func('uint16_t rdsparser_ct_get_year(void *ct)'),
  ct_get_month: lib.func('uint8_t rdsparser_ct_get_month(void *ct)'),
  ct_get_day: lib.func('uint8_t rdsparser_ct_get_day(void *ct)'),
  ct_get_hour: lib.func('uint8_t rdsparser_ct_get_hour(void *ct)'),
  ct_get_minute: lib.func('uint8_t rdsparser_ct_get_minute(void *ct)'),
  ct_get_offset: lib.func('int8_t rdsparser_ct_get_offset(void *ct)'),
  pty_lookup_short: lib.func('const char* rdsparser_pty_lookup_short(int8_t pty, bool rbds)'),
  pty_lookup_long: lib.func('const char* rdsparser_pty_lookup_long(int8_t pty, bool rbds)'),
  country_lookup_name: lib.func('const char* rdsparser_country_lookup_name(int country)'),
  country_lookup_iso: lib.func('const char* rdsparser_country_lookup_iso(int country)')
}

const callbacks = {
  pi: koffi.register(rds => (
    value = rdsparser.get_pi(rds)
    //console.log('PI: ' + value.toString(16).toUpperCase())
  ), 'callback_pi*'),

  pty: koffi.register(rds => (
    value = rdsparser.get_pty(rds),
    dataToSend.pty = value
  ), 'callback_pty*'),

  tp: koffi.register(rds => (
    value = rdsparser.get_tp(rds),
    dataToSend.tp = value
  ), 'callback_tp*'),

  ta: koffi.register(rds => (
    value = rdsparser.get_ta(rds),
    dataToSend.ta = value
  ), 'callback_ta*'),

  ms: koffi.register(rds => (
    value = rdsparser.get_ms(rds),
    dataToSend.ms = value
  ), 'callback_ms*'),

  af: koffi.register((rds, value) => (
    dataToSend.af.push(value)
  ), 'callback_af*'),

  ecc: koffi.register(rds => (
    value = rdsparser.get_ecc(rds),
    dataToSend.ecc = value
  ), 'callback_ecc*'),

  country: koffi.register(rds => (
    value = rdsparser.get_country(rds),
    display = rdsparser.country_lookup_name(value),
    iso = rdsparser.country_lookup_iso(value),
    dataToSend.country_name = display,
    dataToSend.country_iso = iso
  ), 'callback_country*'),

  ps: koffi.register(rds => (
    ps = rdsparser.get_ps(rds),
    dataToSend.ps = decode_unicode(ps),
    dataToSend.ps_errors = decode_errors(ps)
  ), 'callback_ps*'),

  rt: koffi.register((rds, flag) => {
    const rt = rdsparser.get_rt(rds, flag);

    if (flag === 0) {
      dataToSend.rt0 = decode_unicode(rt);
      dataToSend.rt0_errors = decode_errors(rt);
    }

    if (flag === 1) {
      dataToSend.rt1 = decode_unicode(rt);
      dataToSend.rt1_errors = decode_errors(rt);
    }
    dataToSend.rt_flag = flag;
  }, 'callback_rt*'),

  ptyn: koffi.register((rds, flag) => (
    value = decode_unicode(rdsparser.get_ptyn(rds))
    /*console.log('PTYN: ' + value)*/
  ), 'callback_ptyn*'),

  ct: koffi.register((rds, ct) => (
    year = rdsparser.ct_get_year(ct),
    month = String(rdsparser.ct_get_month(ct)).padStart(2, '0'),
    day = String(rdsparser.ct_get_day(ct)).padStart(2, '0'),
    hour = String(rdsparser.ct_get_hour(ct)).padStart(2, '0'),
    minute = String(rdsparser.ct_get_minute(ct)).padStart(2, '0'),
    offset = rdsparser.ct_get_offset(ct),
    tz_sign = (offset >= 0 ? '+' : '-'),
    tz_hour = String(Math.abs(Math.floor(offset / 60))).padStart(2, '0'),
    tz_minute = String(Math.abs(offset % 60)).padStart(2, '0')
    //console.log('CT: ' + year + '-' + month + '-' + day + ' ' + hour + ':' + minute + ' (' + tz_sign + tz_hour + ':' + tz_minute + ')')
  ), 'callback_ct*')
};

let rds = rdsparser.new()
rdsparser.set_text_correction(rds, 0, 0, 2);
rdsparser.set_text_correction(rds, 0, 1, 2);
rdsparser.set_text_correction(rds, 1, 0, 2);
rdsparser.set_text_correction(rds, 1, 1, 2);
rdsparser.set_text_progressive(rds, 0, true)
rdsparser.set_text_progressive(rds, 1, true)
rdsparser.register_pi(rds, callbacks.pi);
rdsparser.register_pty(rds, callbacks.pty);
rdsparser.register_tp(rds, callbacks.tp);
rdsparser.register_ta(rds, callbacks.ta);
rdsparser.register_ms(rds, callbacks.ms);
rdsparser.register_ecc(rds, callbacks.ecc);
rdsparser.register_country(rds, callbacks.country);
rdsparser.register_af(rds, callbacks.af);
rdsparser.register_ps(rds, callbacks.ps);
rdsparser.register_rt(rds, callbacks.rt);
rdsparser.register_ptyn(rds, callbacks.ptyn);
rdsparser.register_ct(rds, callbacks.ct);

const decode_unicode = function(string) {
    let length = rdsparser.string_get_length(string);
    if (length) {
      let content = rdsparser.string_get_content(string);
      let array = koffi.decode(content, unicode_type + ' [' + length + ']');
      return String.fromCodePoint.apply(String, array);
    }
    return '';
};

const decode_errors = function(string) {
    let length = rdsparser.string_get_length(string);
    if (length) {
      let errors = rdsparser.string_get_errors(string);
      let array = koffi.decode(errors, 'uint8_t [' + length + ']');
      return Uint8Array.from(array).toString();
    }
    return '';
};

const updateInterval = 75;

// Initialize the data object
var dataToSend = {
  pi: '?',
  freq: 87.500.toFixed(3),
  sig: 0,
  sigRaw: '',
  sigTop: -Infinity,
  bw: 0,
  st: false,
  stForced: false,
  rds: false,
  ps: '',
  tp: 0,
  ta: 0,
  ms: -1,
  pty: 0,
  ecc: null,
  af: [],
  rt0: '',
  rt1: '',
  rt_flag: '',
  ims: 0,
  eq: 0,
  ant: 0,
  txInfo: {
    tx: '',
    pol: '',
    erp: '',
    city: '',
    itu: '',
    dist: '',
    azi: '',
    id: '',
    reg: false,
    pi: '',
  },
  country_name: '',
  country_iso: 'UN',
  users: 0,
};

const filterMappings = {
  'G11': { eq: 1, ims: 1 },
  'G01': { eq: 0, ims: 1 },
  'G10': { eq: 1, ims: 0 },
  'G00': { eq: 0, ims: 0 }
};


var legacyRdsPiBuffer = null;
var lastUpdateTime = Date.now();
const initialData = { ...dataToSend };
const resetToDefault = dataToSend => Object.assign(dataToSend, initialData);

// Serialport reconnect variables
const ServerStartTime = process.hrtime();
var serialportUpdateTime = process.hrtime();
let checkSerialport = false;
let rdsTimeoutTimer = null;

function rdsReceived() {
  if (rdsTimeoutTimer) {
    clearTimeout(rdsTimeoutTimer);
    rdsTimeoutTimer = null;
  }
  if (serverConfig.webserver.rdsTimeout && serverConfig.webserver.rdsTimeout != 0) {
    rdsTimeoutTimer = setInterval(rdsReset, serverConfig.webserver.rdsTimeout * 1000);
  }
}

function rdsReset() {
  resetToDefault(dataToSend);
  dataToSend.af.length = 0;
  rdsparser.clear(rds);
  if (rdsTimeoutTimer) {
    clearTimeout(rdsTimeoutTimer);
    rdsTimeoutTimer = null;
  }
}

function handleData(wss, receivedData, rdsWss) {
  // Retrieve the last update time for this client
  const currentTime = Date.now();

  let modifiedData, parsedValue;
  const receivedLines = receivedData.split('\n');
  
  for (const receivedLine of receivedLines) {
    switch (true) {
      case receivedLine.startsWith('F'): // Bandwidth
        initialData.bw = receivedLine.substring(1);
        dataToSend.bw = receivedLine.substring(1);
        break;
      case receivedLine.startsWith('P'): // PI Code
        rdsReceived();
        modifiedData = receivedLine.slice(1);
        legacyRdsPiBuffer = modifiedData;
        if (dataToSend.pi.length >= modifiedData.length || dataToSend.pi == '?') {
          dataToSend.pi = modifiedData;
        }
        break;
      case receivedLine.startsWith('T'): // Frequency
        modifiedData = receivedLine.substring(1).split(",")[0];

        rdsReset();
        if((modifiedData / 1000).toFixed(3) == dataToSend.freq) {
          return; // Prevent tune spamming using scrollwheel
        }

        parsedValue = parseFloat(modifiedData);

        if (!isNaN(parsedValue)) {
          initialData.freq = (parsedValue / 1000).toFixed(3);
          dataToSend.freq = (parsedValue / 1000).toFixed(3);
          dataToSend.pi = '?';
          dataToSend.txInfo.reg = false;

          rdsWss.clients.forEach((client) => {
            client.send("G:\r\nRESET-------\r\n\r\n");
          });
        }
        break;
      case receivedLine.startsWith('Z'): // Antenna
        dataToSend.ant = receivedLine.substring(1);
        initialData.ant = receivedLine.substring(1);
        rdsReset();
        break;
      case receivedLine.startsWith('G'): // EQ / iMS (RF+/IF+)
        const mapping = filterMappings[receivedLine];
        if (mapping) {
          initialData.eq = mapping.eq;
          initialData.ims = mapping.ims;
          dataToSend.eq = mapping.eq;
          dataToSend.ims = mapping.ims;
        }
        break;
      case receivedLine.startsWith('W'): // Bandwidth
        initialData.bw = receivedLine.substring(1);
        dataToSend.bw = receivedLine.substring(1);
        break;
      case receivedLine.startsWith('Sm'):
        processSignal(receivedLine, false, false);
        break;
      case receivedLine.startsWith('Ss'):
        processSignal(receivedLine, true, false);
        break;
      case receivedLine.startsWith('SS'):
        processSignal(receivedLine, true, true);
        break;
      case receivedLine.startsWith('SM'):
          processSignal(receivedLine, false, true);
          break;
      case receivedLine.startsWith('R'): // RDS HEX
        rdsReceived();
        modifiedData = receivedLine.slice(1);
        dataToSend.rds = true;

        if (modifiedData.length == 14) {
          // Handle legacy RDS message
          var errorsNew = 0;
          var pi;

          if (legacyRdsPiBuffer !== null &&
              legacyRdsPiBuffer.length >= 4) {
            pi = legacyRdsPiBuffer.slice(0, 4);
            // PI message does not carry explicit information about
            // error correction, but this is a good substitute.
            errorsNew = (legacyRdsPiBuffer.length - 4) << 6;
          } else {
            pi = '0000';
            errorsNew = (0x03 << 6);
          }

          let errorsOld = parseInt(modifiedData.slice(12), 16);
          errorsNew |= (errorsOld & 0x03) << 4;
          errorsNew |= (errorsOld & 0x0C);
          errorsNew |= (errorsOld & 0x30) >> 4;

          modifiedData = pi + modifiedData.slice(0, 12);
          modifiedData += errorsNew.toString(16).padStart(2, '0');
        }

        rdsWss.clients.forEach((client) => {
          const errors = parseInt(modifiedData.slice(-2), 16);
          let data = (((errors & 0xC0) == 0) ? modifiedData.slice(0, 4) : '----');
          data += (((errors & 0x30) == 0) ? modifiedData.slice(4, 8) : '----');
          data += (((errors & 0x0C) == 0) ? modifiedData.slice(8, 12) : '----');
          data += (((errors & 0x03) == 0) ? modifiedData.slice(12, 16) : '----');

          const newDataString = "G:\r\n" + data + "\r\n\r\n";
          const finalBuffer = Buffer.from(newDataString, 'utf-8');
          client.send(finalBuffer);
        });

        rdsparser.parse_string(rds, modifiedData);
        legacyRdsPiBuffer = null;
        break;
    }
  }

  // Get the received TX info
  fetchTx(parseFloat(dataToSend.freq).toFixed(1), dataToSend.pi, dataToSend.ps)
  .then((currentTx) => {
      if (currentTx && currentTx.station !== undefined && parseInt(currentTx.distance) < 4000) {
          dataToSend.txInfo = {
              tx: currentTx.station,
              pol: currentTx.pol,
              erp: currentTx.erp,
              city: currentTx.city,
              itu: currentTx.itu,
              dist: currentTx.distance,
              azi: currentTx.azimuth,
              id: currentTx.id,
              pi: currentTx.pi,
              reg: currentTx.reg,
              otherMatches: currentTx.others
          };
      }
  })
  .catch((error) => {
      console.log("Error fetching Tx info:", error);
  });

    // Send the updated data to the client
    const dataToSendJSON = JSON.stringify(dataToSend);
    if (currentTime - lastUpdateTime >= updateInterval) {
      wss.clients.forEach((client) => {
          client.send(dataToSendJSON);
      });
      lastUpdateTime = Date.now();
      serialportUpdateTime = process.hrtime();
    }
}

// Serialport retry code when port is open but communication is lost (additional code in index.js)
let state = {
  isSerialportAlive: true,
  isSerialportRetrying: false,
  lastFrequencyAlive: '87.500'
};

setInterval(() => {
  state.lastFrequencyAlive = initialData.freq;
  const serialportElapsedTime = process.hrtime(serialportUpdateTime)[0];
  // Activate serialport retry if handleData has not been executed for over 8 seconds
  if (checkSerialport && (serialportElapsedTime > 8) && !state.isSerialportRetrying && serverConfig.xdrd.wirelessConnection === false) {
    state.isSerialportAlive = false;
    state.isSerialportRetrying = true;
  }
}, 2000);

// Delay checking Serialport status on startup for 10 seconds
async function checkSerialPortStatus() {
    const ServerStartTime = process.hrtime();

    while (!checkSerialport) {
        const ServerElapsedSeconds = process.hrtime(ServerStartTime)[0];

        if (ServerElapsedSeconds > 10) {
            checkSerialport = true;
        }

        await new Promise(resolve => setTimeout(resolve, 100));
    }
}
checkSerialPortStatus();

function showOnlineUsers(currentUsers) {
  dataToSend.users = currentUsers;
  initialData.users = currentUsers;
}

let prevFreq = initialData.freq || '87.500';
function processSignal(receivedData, st, stForced) {
  if (initialData.freq !== prevFreq) {
    prevFreq = initialData.freq;
    dataToSend.ps_errors = '';
  }

  const modifiedData = receivedData.substring(2);
  const parsedValue = parseFloat(modifiedData);
  dataToSend.st = st;
  dataToSend.stForced = stForced;
  initialData.st = st;
  initialData.stForced = stForced;

  if (!isNaN(parsedValue)) {
    // Convert parsedValue to a number
    var signal = parseFloat(parsedValue.toFixed(2));
    dataToSend.sig = signal;
    initialData.sig = signal;
    dataToSend.sigRaw = receivedData;
    initialData.sigRaw = receivedData;

    // Convert highestSignal to a number for comparison
    var highestSignal = parseFloat(dataToSend.sigTop);
    if (signal > highestSignal) {
        dataToSend.sigTop = signal.toString(); // Convert back to string for consistency
    }
}

}

module.exports = {
  handleData, showOnlineUsers, dataToSend, initialData, resetToDefault, state
};