const { exec } = require('child_process');

function openPort(port){
    return new Promise((resolve, reject) => {

      var callbackError = function(err) {
        port.removeListener('error', callbackError);
        port.removeListener('open', callbackError);

        reject(err.message);
      };

      var callbackOpen = function(data) {
        port.removeListener('error', callbackError);
        port.removeListener('open', callbackOpen);

        resolve("port open: ok");
      };

      port.on('error', callbackError);
      port.on('open', callbackOpen);

      port.open();

    })
  }

  function runSyncExec(command){
    return new Promise((resolve, reject) => {
  
      exec(command, (error, stdout, stderr) => {
        if(error == null) resolve(stdout);
        reject(error);
      });
  
    })
  }

  async function writeData(port, data, readbytes, timeout){
    return new Promise((resolve, reject) => {

      if(readbytes == undefined) readbytes = 0;
      if(timeout == undefined) timeout = 10000;
      
      var callback = function(data) {
        rsPortReceivedData.push(...data);
        let l = rsPortReceivedData.length;

        if(l >= readbytes)
        {
          port.removeListener('data', callback);

          clearTimeout(t);
          resolve(rsPortReceivedData);
        }
      };

      let t = setTimeout(() => {
        port.removeListener('data', callback);
        reject("TIMEOUT READING");
      }, timeout);

      let rsPortReceivedData = [];

      if(readbytes > 0) port.on('data', callback);

      port.write(Buffer.from(data), function(err) {
        if (err) {
          port.removeListener('data', callback);
          reject(err.message);
        }

        if(readbytes == 0)
        {
            resolve(rsPortReceivedData);
        }

      });
    })
}

module.exports = {
  openPort,
  runSyncExec,
  writeData
}