const log    = require('../utils/logs.utils');          // Log Helper
const db     = require('../services/dbAccess.services');
const os     = require('os');
const vers   = require('../configs/version.configs');

async function buildJson() {
  let json = {};
  json.count = {};
  // Async call all db queries
  const counters = db.query('meta', {target: 'counters'});
  const versions = db.query('meta', {target: 'versions'});
  const userCount = db.colCount('users');
  const regCount = db.colCount('registrations');
  const pisCount = db.colCount('pis');
  const corpusCount = db.colCount('corpus');
  const stationsCount = db.colCount('stations');
  const timetableCount = db.colCount('timetable');
  
  // Insert data
  json.mode = process.env.NODE_ENV;
  json.verBkend = vers.app;
  json.verApi = vers.api;
  json.host = os.hostname();
  // Await and insert async calls
  json.dat = await counters;
  json.ver = await versions;
  json.count.users = await userCount;
  json.count.reg = await regCount;
  json.count.pis = await pisCount;
  json.count.corpus = await corpusCount;
  json.count.stations = await stationsCount;
  json.count.timetable = await timetableCount;
  return json;
}

async function hits(){
  log.out('statsServices.hits: Statistics Requested', 'info');
  const out = await buildJson();
  log.out(`statsServices.hits: Sending Data: ${JSON.stringify(out)}`, 'info');
  return out;
}

async function getVersions() {
  log.out('statsServices.getVersions: Fetching versions', 'info');
  const dbMan = await db.query('versions', {target: 'dbmanager'});
  const mqClt = await db.query('versions', {target: 'mq-client'});
  const data = {
    'backend': vers.app,
    'db-manager': dbMan[0]?.['version'] || '',
    'mq-client': mqClt[0]?.['version'] || '',
  }
  return data
}

async function statistics() {
  log.out('statsServices.statistics: Fetching statistics', 'info');

  const countersPromise = db.query('meta', { target: 'counters' });
  const timetablePromise = db.query('meta', { target: 'timetable' });
  const pisPromise = db.query('meta', { target: 'pis' });
  const corpusPromise = db.query('meta', { target: 'corpus' });
  const reasonCodesPromise = db.query('meta', { target: 'reasonCodes' });

  const lengthUsersPromise = db.colCount('users');
  const lengthRegistrationsPromise = db.colCount('registrations');
  const lengthCorpusPromise = db.colCount('corpus');
  const lengthStationsPromise = db.colCount('stations');
  const lengthPisPromise = db.colCount('pis');
  const lengthTimetablePromise = db.colCount('timetable');
  const lengthReasonCodesPromise = db.colCount('reasonCodes');

  const [
    counters,
    timetable,
    pis,
    corpus,
    reasonCodes,
    lengthUsers,
    lengthRegistrations,
    lengthCorpus,
    lengthStations,
    lengthPis,
    lengthTimetable,
    lengthReasonCodes
  ] = await Promise.all([
    countersPromise,
    timetablePromise,
    pisPromise,
    corpusPromise,
    reasonCodesPromise,
    lengthUsersPromise,
    lengthRegistrationsPromise,
    lengthCorpusPromise,
    lengthStationsPromise,
    lengthPisPromise,
    lengthTimetablePromise,
    lengthReasonCodesPromise
  ]);

  return {
    hostname: os.hostname() || 'Unknown',
    runtimeMode: process.env.NODE_ENV || 'Unknown',
    reset: counters[0]['since'],
    updateTimes: {
      timetable: timetable[0]['updated'],
      pis: pis[0]['updated'],
      corpus: corpus[0]['updated'],
      reasonCodes: reasonCodes[0]['updated']
    },
    requestCounts: {
      ldbws_api: counters[0]['ldbws'] || 0,
      lsbsvws_api: counters[0]['ldbsvws'] || 0,
      corpus_api: counters[0]['corpus_api'] || 0,
      timetable_db: counters[0]['timetable'] || 0,
      pis_db: counters[0]['pis'] || 0,
      corpus_db: counters[0]['corpus'] || 0,
      stations_db: counters[0]['stations'] || 0
    },
    dbLengths: {
      users: lengthUsers,
      registrations: lengthRegistrations,
      corpus: lengthCorpus,
      stations: lengthStations,
      pis: lengthPis,
      timetable: lengthTimetable,
      reasonCodes: lengthReasonCodes
    },
  };
}


module.exports = {
  hits,
  statistics,
  getVersions
};