exports.id = 'cloudmqttconnect';
exports.title = 'Cloud connect mqtt';
exports.group = 'MQTT';
exports.color = '#888600';
exports.version = '1.0.2';
exports.icon = 'sign-out';
exports.input = 2;
exports.output = 2;
exports.options = { host: 'tb-stage.worksys.io', port: 1883, clientid: "", username: "" };

exports.html = `<div class="padding">
   <div class="row">
      <div class="col-md-6">
        <div data-jc="textbox" data-jc-path="host" data-jc-config="placeholder:test.mosquitto.org;required:false" class="m">Hostname or IP address (if not empty - setting will override db setting)</div>
      </div>
      <div class="col-md-6">
        <div data-jc="textbox" data-jc-path="port" data-jc-config="placeholder:1883;required:true" class="m">Port</div>
      </div>
    </div>
    <div class="row">
      <div class="col-md-6">
        <div data-jc="textbox" data-jc-path="clientid">@(Client id)</div>
      </div>
      <div class="col-md-6">
        <div data-jc="textbox" data-jc-path="topic" class="m">topic</div>
      </div>
    </div>
  </div>`;



const { promisifyBuilder } = require('./helper/db_helper');
const fs = require('fs');
const mqtt = require('mqtt');
const nosql = NOSQL('tbdatacloud');

const SEND_TO = {
  debug: 0,
  rpcCall: 1,
}

//CONFIG 
let saveTelemetryOnError = true;//backup_on_failure overrides this value
//------------------------

const noSqlFileSizeLimit = 4194304;//use 5MB - 4194304
let insertNoSqlCounter = 0;
let insertBackupNoSqlCounter = 0;
let processingData = false;

let backup_on_failure = true;//== saveTelemetryOnError - create backup client send failure
let restore_from_backup = 50; //how many rows process at once?
let restore_backup_wait = 3;//wait seconds
let lastRestoreTime = 0;

// if there is an error in client connection, flow logs to monitor.txt. Not to log messages every second, we use sendClientError variable
let sendClientError = true;


exports.install = function(instance) {

  var client;
  var opts;
  var clientReady = false;

  let o = null; //options

  function main()
  {
    loadSettings();
  }

  //set opts according to db settings
  function loadSettings()
  {

    o = instance.options;
    if(!o.topic) o.topic = FLOW.GLOBALS.settings.cloud_topic;

    opts = {
        host: o.host,
        port: o.port,
        clientId: o.clientid,
        username: o.username,
        rejectUnauthorized: false,
        resubscribe: false
    };

    console.log("wsmqttpublich -> loadSettings from instance.options",o);

    connectToTbServer();
  }

  function connectToTbServer()
  {
    var url = "mqtt://" + opts.host + ":" + opts.port;
    console.log("MQTT URL: ", url);

    client = mqtt.connect(url, opts);

    client.on('connect', function() {
      client.subscribe(`${o.topic}_backward`, (err) => {
        if (!err) {
          console.log("MQTT subscribed");
        }
      });
      instance.status("Connected", "green");
      clientReady = true;
      sendClientError = true;
    });

    client.on('reconnect', function() {
      instance.status("Reconnecting", "yellow");
      clientReady = false;
    });

    client.on('message', function(topic, message) {
      // message is type of buffer
      message = message.toString();
      if (message[0] === '{') {
        TRY(function() {

          message = JSON.parse(message);
          if (message.hasOwnProperty("device") && message.hasOwnProperty("data")  && message.data.hasOwnProperty("id")) {
              client.publish(`${o.topic}_forward`, `{"device": "${message.device}", "id": ${message.data.id}, "data": {"success": true}}`, {qos:1});     
              instance.send(SEND_TO.rpcCall, {"device": message.device, "id": message.data.id, "RPC response": {"success": true}});
          }

        }, () => instance.debug('MQTT: Error parsing data', message));
      }

      instance.send(SEND_TO.rpcCall, {"topic":o.topic, "content":message });
    });

    client.on('close', function() {
      clientReady = false;

      instance.status("Disconnected", "red");
      instance.send(SEND_TO.debug, {"message":"Client CLOSE signal received !"});
    });

    client.on('error', function(err) {
      instance.status("Err: "+ err.code, "red");
      instance.send(SEND_TO.debug, {"message":"Client ERROR signal received !", "error":err, "opt":opts });
      if(sendClientError) {
          console.log('MQTT client error', err);
          sendClientError = false;
      }
      clientReady = false;
    });

  }


  instance.on('0', function(data) {

    if(clientReady)
    {
	  //do we have some data in backup file? if any, process data from database
      if(saveTelemetryOnError)
      {
        //read telemetry data and send back to server
        if(!processingData) processDataFromDatabase();
      }
      
	  let stringifiedJson = JSON.stringify(data.data)
      client.publish(`${o.topic}_forward`, stringifiedJson, {qos: 1});  
    }
    else
    {
      //logger.debug("Client unavailable. Data not sent !", JSON.stringify(data.data));
      instance.send(SEND_TO.debug, {"message":"Client unavailable. Data not sent !", "data": data.data });

      if(saveTelemetryOnError)
      {
        //create new file from tbdata.nosql, if file size exceeds given limit, and clear tbdata.nosql
        makeBackupFromDbFile();

        //write to tb
        data.data.id = UID();
        nosql.insert(data.data);
      }
    }
  });

  instance.on("1", _ => {
    main();
  })

  instance.close = function(done) {
    if(clientReady){
      client.end();
    }
  };
  

  function getDbBackupFileCounter(type)
  {
    var files = fs.readdirSync(__dirname + "/../databases");

    let counter = 0;
    for(var i = 0; i < files.length; i++)
    {

      if(files[i] == "tbdatacloud.nosql") continue;

      if(files[i].endsWith(".nosql")) 
      {

        let pos = files[i].indexOf(".");
        if(pos > -1)
        {

          let fileCounter = counter;
          let firstDigit = files[i].slice(0, pos);

          fileCounter = parseInt(firstDigit);
          if(isNaN(fileCounter)) fileCounter = 0; 
          //console.log("getDbBackupFileCounter digit:", files[i], firstDigit, fileCounter, isNaN(fileCounter), type);
          
          if(type == "max")
          {
            if(fileCounter > counter)
            {
              counter = fileCounter;
            }
          }
          else if(type == "min")
          {
            if(counter == 0) counter = fileCounter;

            if(fileCounter < counter)
            {
              counter = fileCounter;
            }
          }
        }
      }
      
    }
    
    if(type == "max") counter++;

    return counter;
  }

  const makeBackupFromDbFile = async () => {

    if(!saveTelemetryOnError) return;

    //to avoid large file: tbdata.nosql

    //init value is 0!
    if(insertNoSqlCounter > 0)
    {
      --insertNoSqlCounter;
      return;
    }

    insertNoSqlCounter = 100;

    let source = __dirname + "/../databases/tbdatacloud.nosql";

    var stats = fs.statSync(source);
    var fileSizeInBytes = stats.size;

    if(fileSizeInBytes > noSqlFileSizeLimit)
    {

      let counter = 1;
      counter = getDbBackupFileCounter("max");

      let destination = __dirname + "/../databases/" + counter + "." + "tbdatacloud.nosql";

      //make backup file
      fs.copyFileSync(source, destination);
      //fs.renameSync(p, p + "." + counter);

      //clear tbdata.nosql
      fs.writeFileSync(source, "");
      fs.truncateSync(source, 0);
      
    }
  }

  const processDataFromDatabase = async () => {
    
    if(restore_from_backup <= 0) return;

    //calculate diff
    const now = new Date();
    let currentTime = now.getTime();
    let diff = currentTime - lastRestoreTime;

    if( (diff / 1000) < restore_backup_wait)
    {
      //console.log("*********restore_backup_wait", diff, restore_backup_wait);
      return;
    }

    processingData = true;

    //get filename to process
    let counter = getDbBackupFileCounter("min");

    //we have some backup files
    let dataBase = 'tbdata';

    var nosql;
    if(counter == 0) dataBase = 'tbdatacloud';
    else dataBase = counter + "." + 'tbdatacloud';

    nosql = NOSQL(dataBase);

    //select all data - use limit restore_from_backup
    let records = await promisifyBuilder(nosql.find().take(restore_from_backup));
    
    for(let i = 0; i < records.length; i++)
    {
      if(clientReady) {

        let item = records[i];
        let id = item.id;

        if(id !== undefined)
        {
          //console.log("------------processDataFromDatabase - remove", id, dataBase, i);

          try {

            let message = JSON.parse(JSON.stringify(item));
            delete message.id;
            client.publish(`${o.topic}_forward`, JSON.stringify(message), {qos:1});
   
            //remove from database
            await promisifyBuilder(nosql.remove().where("id", id));

          } catch(error) {
            //process error
            console.log("processDataFromDatabase", error);
          }

        }
        
      }
      else
      {
        processingData = false;
        return;
      }
    }

    if(records.length > 0)
    {
      //clean backup file
      if(counter > 0) nosql.clean();
    }

    //no data in db, remove
    if(records.length == 0)
    {
      if(counter > 0) nosql.drop();
    }

    const d = new Date();
    lastRestoreTime = d.getTime();

    processingData = false;

  }

  instance.on('options', main);

};