//https://www.dontpanicblog.co.uk/2016/04/17/websocket-push-notifications-with-node-js/

//!!!!!!!!!!!!!!!!
//!!! if express server is running, but it's not servig pages - try to unblock PORT
//!!!!!!!!!!!!!!!!

let wss = undefined;
let startWebSocketServer = false;
//startWebSocketServer = false;//KONSBERG

if(startWebSocketServer)
{
  var WebSocketServer = require('ws').Server;
  wss = new WebSocketServer({ port: 9090 });
}

const express = require("express");
const bodyParser = require('body-parser');
const app = express(); // create express app

//const SerialPort = require('serialport');
const { exec } = require('child_process');

const { crc8, crc16, crc32 } = require('easy-crc');
const http = require('http');
const status = require('http-status');

const username = "admin";
const password = "admin";

const decodeValue = require('./decodeValue.js');
const { openPort, runSyncExec, writeData } = require('./serialport_helper.js');

//const hostname = "10.0.0.5";
const hostname = "localhost";

process.on('uncaughtException', function(error) {
  // do something clever here

  //TODO send message to services!!!

  console.log("errors", error); // do NOT do this for real!
});



function httpRequest(params, postData) {
  return new Promise(function(resolve, reject) {
  
      console.log(params);
      var req = http.request(params, function(res) {
          // reject on bad status
          if (res.statusCode < 200 || res.statusCode >= 300) {
              return reject(new Error(res.statusCode + " " + status[res.statusCode]));
          }
          // cumulate data
          var body = [];
          res.on('data', function(chunk) {
              body.push(chunk);
          });
          // resolve on end
          res.on('end', function() {
              try {
                  console.log("body", body);
                  body = JSON.parse(Buffer.concat(body).toString());
              } catch(e) {
                  reject(e);
              }
              resolve(body);
          });
      });

      // reject on request error
      req.on('error', function(err) {
          // This is not a "Second reject", just a different sort of failure
          reject(err);
      });

      if (postData) {
          req.write(postData);
      }
      // IMPORTANT
      req.end();
  });
}

//terminal----------------------------------
function detectIfResponseIsValid(bytes)
{
  let type = "RESPONSE";
  if(bytes[4] == 0) type = "RESPONSE";
  else if(bytes[4] == 1) type = "ERROR";
  else if(bytes[4] == 2) type = "EVENT";
  else type = "UNKNOWN";
  
  let crc = crc16('ARC', bytes.slice(0, 9));
  let c1 = (crc >> 8) & 0xFF;
  let c2 = crc & 0xFF;

  let message = "OK";
  let error = "";
  if(c1 != bytes[9])
  {
    //CRC_ERROR
    message = "NOK";
    error = "CRC_ERROR c1";
  }

  if(c2 != bytes[10])
  {
    //CRC_ERROR
    message = "NOK";
    error = "CRC_ERROR c2";
  }
  
  //crc error
  if(type != "RESPONSE") 
  {
    message = "NOK";
  }

  return {message: message, type: type, error: error};
}

handleResponse = (bytes, cmd) =>
{

  console.log("handleResponse");

  let result = detectIfResponseIsValid(bytes);
  let message = result.message;
  let type = result.type;
  let error = result.error;

  if(message != "OK")
  {
    return {type: type, message: message + " " + error + " " + bytes.join(", "), 'date': (new Date()).getTime()};
  }

  let add = (bytes[0] >> 24) | (bytes[1] >> 16) | (bytes[2] >> 8) | bytes[3];

  let decodedValue = "cmd: " + cmd;
  if(cmd >= 0x8000)
  {
    return decodeValue(add, cmd, bytes[5],bytes[6],bytes[7],bytes[8]);
  }

  return {type: type, message: message + " " + bytes.join(", "),  'date': (new Date()).getTime()};
}

com_generic = (adresa, rec, rw, register, name, byte1, byte2, byte3, byte4) =>{
  let resp = [];
  
  let cmd = register;
  
  if (rw === 0)
  {
      cmd = cmd + 0x8000;
  }
  
  if (rec === 3)
  {
      resp.push(0xFF);
      resp.push(0xFF);
      resp.push(0xFF);
      resp.push(0xFF);
      resp.push( adresa & 0xFF );//band
  }
  else
  {
      resp.push( (adresa >> 24) &  0xFF);//rshift
      resp.push( (adresa >> 16) &  0xFF);
      resp.push( (adresa >> 8) &  0xFF);
      resp.push( adresa & 0xFF );

      if (rec === 2)
      {
          resp.push(0xFF);
      }
      else resp.push(0);
  }

  resp.push( (cmd >> 8) &  0xFF);//rshift
  resp.push( cmd & 0xFF );//band
  resp.push( byte1 & 0xFF );//band
  resp.push( byte2 & 0xFF );//band
  resp.push( byte3 & 0xFF );//band
  resp.push( byte4 & 0xFF );//band

  //let data = '12345';
  let crc = crc16('ARC', resp);
  let c1 = (crc >> 8) & 0xFF;
  let c2 = crc & 0xFF;

  resp.push(c1);
  resp.push(c2);

  console.log("checksum", crc);
  console.log("resp", resp);

  return resp;

}
//-------------

//https://expressjs.com/en/resources/middleware/cors.html
var cors = require('cors');
const { report } = require("process");
app.use(cors());
app.use(bodyParser.urlencoded({ extended: true }));
app.use(bodyParser.json());

// add middleware
//app.use(express.static("public"));
app.use(express.static(__dirname + "/public"));

app.get('/restart', function (req, res) {
  console.log('restart');

  exec(`service nodejs restart`, (err, stdout, stderr) => {
    if (err || stderr) {
      console.log("failed to restart nodejs");
      console.error(err);
      console.log(stderr);

      let response = {"message": "failed to restart nodejs " + err};
      res.json(response);

    } else {
      console.log(stdout);
      console.log(`Successfully restarted service nodejs ${stdout}`);

      let response = {"message": "restarted"};
      res.json(response);
    }
  });

  //res.sendStatus(200);
});


//KONBERG
// Broadcast updates to all WebSocketServer clients
//app.post('/notify', function (req, res) {
app.get('/notify', function (req, res) {
  if(wss == undefined) 
  {
    res.sendStatus(200);
    return;
  }

  console.log('Event: notify');
  wss.clients.forEach(function each(client) {
     client.send("broadcast: updated");

     //console.log('broadcast', client);
   });
  res.sendStatus(200);
});


//---general
app.get('/db', function(req, res) {
  //res.sendStatus(404);  

  let params = {table: "settings", action: "read"};
  const data = JSON.stringify(params);

  let h = hostname;

  const httpRequestParams = {
    hostname: h,
    port: 12345,
    path: '/db_connector',
    method: 'POST',
    headers: {
    'Content-Type': 'application/json',
    'Content-Length': data.length
    }
  }

  httpRequest(httpRequestParams, data).then(function(body) {
    console.log("response", body);

    let response = {"data": body.data};
    res.json(response);
    

  }).catch(function (e) {
    //console.log(e);

    //messages.push({type: "ERROR", message: e.message});
    
    let response = {"message":  e.message, "type": "ERROR"};
    res.json(response);
    // and so on
  });
});

app.post('/db', function(req, res) {
  //res.sendStatus(404);

  console.log("request", req.body);

  //let params = {table: req.body.table, action: req.body.action};
  let params = req.body;
  const data = JSON.stringify(params);

  let h = hostname;
  if(req.body.hostname !== undefined) h = req.body.hostname;

  const httpRequestParams = {
    hostname: h,
    port: 12345,
    path: '/db_connector',
    method: 'POST',
    headers: {
    'Content-Type': 'application/json',
    'Content-Length': data.length
    }
  }

  httpRequest(httpRequestParams, data).then(function(body) {
    console.log("response", body.data);

    //let response = {"data": body.data};
    let response = body.data;
    //res.sendStatus(200);
    res.json(response);
    return;
    

  }).catch(function (e) {
    //console.log(e);
    
    let response = {"message":  e.message, "type": "ERROR"};
    res.json(response);
    // and so on
  });

});

app.post('/validate', function(req, res) {

  let response = {"valid": false};
  if(username === req.body.username && password === req.body.password)
  {
    response.valid = true;
  }

  res.json(response);
});

//--terminal
app.get('/cmd', function(req, res) {
  //console.log('GET: Got body:', req.body);
  //res.send("error: use POST request instead");
  res.sendStatus(501);
});


//https://zellwk.com/blog/async-await-express/
app.post('/cmd', async(req, res, next) => {
  console.log('POST: Got body:', req.body);

  if(username != req.body.username && password != req.body.password)
  {
    res.sendStatus(501);
    return;
  }

  let message = "";//TODO remove
  let messages = [];
  let makeHttpRequest = true;

  //make http request
  let params = req.body.command;
  let cmd = params.register;

  //hostname: req.body.hostname,
  let h = hostname;
  if(req.body.hostname !== undefined) h = req.body.hostname;

  if(makeHttpRequest)
  {
    const data = JSON.stringify(params);
      
    const httpRequestParams = {
		  hostname: h,
		  port: 12345,
		  path: '/terminal',
		  method: 'POST',
		  headers: {
		  'Content-Type': 'application/json',
		  'Content-Length': data.length
      }
    }

    await httpRequest(httpRequestParams, data).then(function(body) {

        if (params.rw === 0)
        {
            cmd = cmd + 0x8000;
        }

        let bytes = body.bytes;
		console.log("body", body, bytes, typeof body);
		
		let type = "RESPONSE";
		if(bytes === undefined)
		{		
			if(typeof body === 'object')
			{
				type = body.type;
				messages.push({type: "ERROR", message: body.message});
			}
		}
		else
		{
			if(bytes[4] == 0) type = "RESPONSE";
			else if(bytes[4] == 1) type = "ERROR";
			else if(bytes[4] == 2) type = "EVENT";
			else type = "UNKNOWN";
			
			//ake data sme zapisali?
			message = bytes.join(", ");
			messages.push({type: type, message: "RESP: " + message});
			
			let result = handleResponse(bytes, cmd);
			if(result == undefined) messages.push({type: "ERROR", message: "ERROR: handleResponse undefined", 'date': (new Date()).getTime()});

			if(Array.isArray(result))
			{
			  messages = messages.concat(result);
			}
			else 
			{
			  messages.push({type: "RESPONSE", message: result});
			  //messages.push(result);
			}
		}
		      
        if(cmd >= 0x8000)
        {
          console.log("params.register", params.register);
        }

        let response = {"message": message, messages: messages, hostname: h, "type": "SUCESS"};
        res.json(response);

      }).catch(function (e) {
        
		console.log(e, new Date());

        messages.push({type: "ERROR", message: "express exception: " + e.message});
        
        let response = {"message": message, messages: messages, hostname: h, "type": "ERROR"};
        res.json(response);
        // and so on
    });

    return;
  }


  //if we want to use serial port directly

  let portOpened = false;
  let error = false;
  let port = "/dev/ttymxc4";

  try {

    const rsPort = new SerialPort(port, { autoOpen: false });

    /*
    await runSyncExec("ping localhost").then(function (status) {
      console.log("Promise Resolved:", status);
      message = status;
    }).catch(function (reason) {
        console.log("Promise Rejected:", reason);

        error = true;
        message = reason;

    });
    */
  
    messages.push({type: "INFO", message: "trying to open port directly (express.js): " + port, 'date': (new Date()).getTime()});

    await openPort(rsPort).then(function (status) {
        console.log("Promise Resolved:", status, new Date());
        
        portOpened = true;
        message = status;
        //messages.push(message);


    }).catch(function (reason) {
        console.log("Promise Rejected:", reason);

        error = true;
        message = reason;

        messages.push({type: "ERROR", message: message, 'date': (new Date()).getTime()});

    });


  if(!error)
  {
    await runSyncExec("stty -F /dev/ttymxc4 115200 min 1 time 5 ignbrk -brkint -icrnl -imaxbel -opost -isig -icanon -iexten -echo -echoe -echok -echoctl -echoke").then(function (status) {
      console.log("Promise Resolved:", status, new Date());

      //message = status;
    }).catch(function (reason) {
        console.log("Promise Rejected:", reason);
  
        error = true;
        //message = escapeSpecialChars(reason);
        if(typeof reason == "object")
        {
          message = JSON.stringify(reason); 

          messages.push({type: "ERROR", message: message, 'date': (new Date()).getTime()});
        }
    });
  }

  //WRITE DATA & READ RESPONSE
  /*
if(error)
{

  //print(P.decodeValue(add, L.last_cmd, bytes[6],bytes[7],bytes[8],bytes[9]).."<br>")
  let decodedValue = decodeValue(1, 5,0, 0, 0, 0 );
  console.log(decodedValue);

  let params = req.body.command;
  let resp = com_generic(params.address, params.recipient, params.rw, params.register, params.name, params.byte1, params.byte2, params.byte3, params.byte4);

  //messages.push("WRITE: " + resp.join(", "));
  messages.push({type: "INFO", message: "TEST WRITE " + resp.join(", "), 'date': (new Date()).getTime()});
}
*/

  if(!error)
  {
      let params = req.body.command;

      let cmd = params.register;
      if (params.rw === 0)
      {
          //cmd = cmd + 0x8000;
      }

      let resp = com_generic(params.address, params.recipient, params.rw, cmd, params.name, params.byte1, params.byte2, params.byte3, params.byte4);
      //messages.push({type: "WRITE", message: "WRITE " + resp.join(", "), 'date': (new Date()).getTime()});

    await writeData(rsPort, resp, 11).then(function (data) {
      console.log("Promise Resolved:", data, new Date());

      //process data
      /*
      RESPONSE = 0,
      ERROR = 1,
      EVENT = 2,
      TIMEOUT = 3,
      CRC_ERROR = 4
      */

      let bytes = data.slice(0);

      let type = "RESPONSE";
      if(bytes[4] == 0) type = "RESPONSE";
      else if(bytes[4] == 1) type = "ERROR";
      else if(bytes[4] == 2) type = "EVENT";
      else type = "UNKNOWN";
      
      //ake data sme zapisali?
      message = data.join(", ");
      messages.push({type: type, message: "RESP: " + message});

      if(cmd >= 0x8000)
      {
        console.log("params.register", params.register);
      }

      let result = handleResponse(bytes, cmd);
      if(result == undefined) messages.push({type: "ERROR", message: "ERROR: handleResponse undefined", 'date': (new Date()).getTime()});

      console.log("handleResponse: ", result);

      if(Array.isArray(result))
      {
        messages = messages.concat(result);
      }
      else 
      {
        messages.push({type: "RESPONSE", message: result});
        //messages.push(result);
      }

    }).catch(function (reason) {
        console.log("Promise Rejected:", reason,  new Date());

        error = true;
        message = reason;

        messages.push({type: "ERROR", message: message, 'date': (new Date()).getTime()});

    });
  }

  if(portOpened) rsPort.close();

}
catch(err) {
  console.log("Exception", err.message);

  error = true;
  message = err.message;

  messages.push({type: "ERROR", message: message, 'date': (new Date()).getTime()});
}

  console.log("END", new Date());

  if(!error)
  {
    //let response = {"message": "OK" + JSON.stringify(req.body)};
    let response = {"message": message, messages: messages, "type": "SUCESS"};
    res.json(response);
    return;
  }
  else
  {
    let response = {"message": message, messages: messages, "type": "ERROR"};
    res.json(response);
  }

});

// start express server on port 5000
app.listen(5000, () => {
  console.log("server started on port 5000");
});