'use strict';

const AWS = require('aws-sdk');
const mysql = require('mysql');
const async = require('async');
const connection = mysql.createConnection({
  host: process.env.MYSQL_HOST,
  user: process.env.MYSQL_USER,
  password: process.env.MYSQL_PASSWORD,
  database: process.env.MYSQL_DATABASE_NAME
});
const dynamodb = new AWS.DynamoDB.DocumentClient();

function getResult(sql) {
  return new Promise(function(resolve, reject){
    connection.query(sql, function(err, result){
      if(err){
        console.log(err);
        reject(err);
      }else{
        resolve(result);
      }
    })
  })
}

let updateDevAppUsage = function updateUser(appid, mcuIn, mcuOut, turnIn, turnOut) {
  // apparently we sum turn usage on dynamo
  let turn = parseInt(turnIn) + parseInt(turnOut);

  console.log('Updating ' + appid + ' with mcuIn:' + mcuIn + ' mcuOut: ' + mcuOut + ' turn: ' + turn);

  let params = {
    TableName: 'devapps',
    Key: { 'appid': appid },
    UpdateExpression: 'set #mcuIn = :mcuIn, #mcuOut = :mcuOut, #turn = :turn',
    ConditionExpression: '#appid = :appid',
    ExpressionAttributeNames: {
      '#appid': 'appid',
      '#mcuIn': 'mcuInboundMonthly',
      '#mcuOut': 'mcuOutboundMonthly',
      '#turn': 'turnUsageMonthly'
    },
    ExpressionAttributeValues: {
      ':appid': appid,
      ':mcuIn': mcuIn,
      ':mcuOut': mcuOut,
      ':turn': turn
    }
  };

  console.log('Updating dynamo...');

  return dynamodb.update(params).promise();
};

// --------------- Main handler -----------------------

exports.handler = (event, context, callback) => {
  try {
    // connect to MySQL
    connection.connect();

    // we have 1,440 minutes in a day.
    // we have around < 14,500 keys
    // adjust number of keys depending on how much
    // we want to process per minute
    let numOfKeysToProcess = process.env.NUM_OF_KEYS_TO_PROCESS || 10;
    let time = new Date();
    let month = time.getMonth() + 1;
    let year = time.getFullYear();

    let minutesFromMidnight = time.getMinutes() + (60 * time.getHours());
    let lowerIdRange = 6708;//(numOfKeysToProcess * minutesFromMidnight) - numOfKeysToProcess + 1;
    let higherIdRange = 6711; //(numOfKeysToProcess * minutesFromMidnight);

    console.log('Doing IDs from ' + lowerIdRange + ' to ' + higherIdRange);

    let appQuery = 'SELECT id, appid from dev_apps where id between ' + lowerIdRange + ' and ' + higherIdRange;

    getResult(appQuery).then(function (results) {
      async.eachSeries(results, function(res, cb){
        let appid = res.appid;

        console.log('Running for key: ' + appid);

        let mcuQuery = 'select sum(mcu_usages.inbound) as mcu_inbound, ' +
          'sum(mcu_usages.outbound) as mcu_outbound ' +
          'from mcu_usages ' +
          'where appid="' + appid + '" ' +
          'and month(created_at) = ' + month + ' ' +
          'and year(created_at) = ' + year + ';';

        let turnQuery = 'select sum(turn_usages.inbound) as turn_inbound, ' +
          'sum(turn_usages.outbound) as turn_outbound ' +
          'from turn_usages ' +
          'where appid="' + appid + '" ' +
          'and month(created_at) = ' + month + ' ' +
          'and year(created_at) = ' + year + ';';

        console.log(mcuQuery);
        console.log(turnQuery);

        let mcuInbound = 0;
        let mcuOutbound = 0;
        let turnInbound = 0;
        let turnOutbound = 0;

        getResult(turnQuery).then(function(res){
          console.log(res);
          turnInbound = res[0].turn_inbound || 0;
          turnOutbound = res[0].turn_outbound || 0;
        }).then(function(){
          getResult(mcuQuery).then(function(res){
            console.log(res);
            mcuInbound = res[0].mcu_inbound || 0;
            mcuOutbound = res[0].mcu_outbound || 0;
          }).then(function(){
            updateDevAppUsage(appid, mcuInbound, mcuOutbound, turnInbound, turnOutbound).catch(console.error.bind(console));
            cb();
          });
        });
      }, function(err){
        console.log(err);
        connection.end();
      })
    });
  } catch (err) {
    callback(err);
  }
};