var linebot = require('linebot');

var express = require('express');

var SerialPort = require('serialport');

var bot = linebot({

  channelId: '這裡改成自己Line的channelId',

  channelSecret: '這裡改成自己Line的channelSecret',

  channelAccessToken: '這裡改成自己Line的channelAccessToken'

});

//以下的com5請自行修改成自己的micro:bit和電腦連接時的com port名稱

//但是baudRate，115200的值，請勿修改

var mySerial = new SerialPort('com5', {baudRate: 115200});

const Delimiter = SerialPort.parsers.Delimiter;

var myId;

const parser = mySerial.pipe(new Delimiter({ delimiter: Buffer.from('\n') }));

//LineBot處理文字訊息的函式

//這一段的程式是專門處理當有人傳送文字訊息給LineBot時，我們的處理回應

bot.on('message', function(event) {

  if (event.message.type = 'text') {

    myId=event.source.userId;

    var msg = event.message.text;

    console.log(msg);

    sendToMicrobit(msg);

  }

});

function sendToMicrobit(msgFromLine){

  var myMsg='';

  if (msgFromLine=='溫度')

     myMsg='temperature\n';

  else if (msgFromLine=='前進'){

     myMsg='foreward\n';

  } else if (msgFromLine=='後退'){

     myMsg='backward\n';

  } else if (msgFromLine=='左轉'){

     myMsg='leftward\n';

  } else if (msgFromLine=='右轉'){

     myMsg='rightward\n';

  } else if (msgFromLine=='停車'){

     myMsg='stop\n';

  }

  if (myMsg!=''){

     if (msgFromLine!='溫度')

        bot.push(myId,msgFromLine+'中......');

        mySerial.write(myMsg, function(err) {

           if (err) {

              return console.log('Error on write: ', err.message);

           }

           console.log('訊息已傳送至micro:bit:'+myMsg);

        });

  }

}

parser.on('data', function (data) {

  var myString=data.toString();

  console.log('Data:',myString);

  if (myString.startsWith('temperature')){

     myString=myString.replace('temperature','溫度');

  } else if (myString.startsWith('light')){

     myString=myString.replace('light','光線');

  }  else if (myString==='A\r' || myString==='B\r'){

     myString=myString.replace('\r','')+'鍵已被按下！';

  }

  bot.push(myId,myString);

});

//LineBot處理使用者按下選單的函式

bot.on('postback', function (event) {

   var myMsg=event.postback.text;

   if (myMsg!=''){

      console.log(myMsg);

   }

});

const app = express();

const linebotParser = bot.parser();

app.post('/', linebotParser);

//因為 express 預設走 port 3000，而 heroku 上預設卻不是，要透過下列程式轉換

var server = app.listen(process.env.PORT || 8080, function() {

  var port = server.address().port;

  console.log("App now running on port", port);

});