path: root/services/data-fetcher.js

const deviceManager = require('./device-manager');
const dataBroadcaster = require('./data-broadcaster');
const app = require('../app');
const moment = require('moment');

// Get initial data after a short delay to allow the device manager to find devices
// TODO run once device manager notifies its complete instead
setTimeout(function() {
  fetchRealtimeUsage();
  fetchDailyUsage();
  fetchMonthlyUsage();
  fetchPowerState();
}, 5000)

let cachedRealtimeUsageData = {};
let cachedDailyUsageData = {};
let cachedMonthlyUsageData = {};
let cachedPowerState = {};

function fetchRealtimeUsage() {

  let deviceId = 1; // TODO

  console.log('connected clients', app.getWsClientCount());
  if(app.getWsClientCount() > 0) {
    deviceManager.getDevice(deviceId).emeter.getRealtime().then(response => {

      // Voltage seems to be reported as its peak to peak value, not RMS.
      // Show the RMS value since thats what would you expect to see.
      // i.e. 220v not 310v (in the U.K)
      response.voltage = response.voltage / Math.sqrt(2);

      cachedRealtimeUsageData = response;
  
      dataBroadcaster.broadcastRealtimeUsageUpdate(response);
  
    });
  }

  setTimeout(fetchRealtimeUsage, 1000);
}

function fetchDailyUsage() {

  let deviceId = 1;

  // Get last x days
  let totalDaysRequired = 30; // TODO currently only works for up to 2 months spans
  let currentMoment = moment();
  let previousMoment = moment().subtract(totalDaysRequired, 'days');

  // Month + 1 as the API months are index 1 based.
  deviceManager.getDevice(deviceId).emeter.getDayStats(currentMoment.year(), currentMoment.month() +1).then(currentPeriodStats => {

    // Check if we also need the previous month to meet the required total number of samples
    if(currentMoment.month() !== previousMoment.month()) {
      
      // Get previous month. This currently wont work if the previousMoment is more than 1 month before the currentMoment (see above)
      deviceManager.getDevice(deviceId).emeter.getDayStats(previousMoment.year(), previousMoment.month() +1).then(previousPeriodStats => {

        let currentMonthStats = fillMissingDays(currentPeriodStats, currentMoment);
        let previousMonthStats = fillMissingDays(previousPeriodStats, previousMoment);
        let combinedStats = previousMonthStats.concat(currentMonthStats);

        let result = trimStatResults(combinedStats, totalDaysRequired);

        cachedDailyUsageData = result;

        dataBroadcaster.broadcastDailyUsageUpdate(result);

      });
    }
    else {
      let dayStats = fillMissingDays(currentPeriodStats, currentMoment);
  
      let result = trimStatResults(dayStats, totalDaysRequired);
      cachedDailyUsageData = result;

      dataBroadcaster.broadcastDailyUsageUpdate(result);
    }

  });

  setTimeout(fetchDailyUsage, 300000); // 5 mins;
}

function fetchMonthlyUsage() {

  let deviceId = 1;

  // Get last x months
  let totalMonthsRequired = 12; // TODO currently only works for up to 14 month (2 year) spans
  let currentMoment = moment();
  let previousMoment = moment().subtract(totalMonthsRequired, 'months');

  deviceManager.getDevice(deviceId).emeter.getMonthStats(currentMoment.year()).then(currentPeriodStats => {

    // Check if we also need the previous year to meet the required total number of samples
    if(currentMoment.month() + 1 < totalMonthsRequired) {
      
      // Get previous year (assuming the totalMonthsRequired limit described above).
      deviceManager.getDevice(deviceId).emeter.getMonthStats(previousMoment.year()).then(previousPeriodStats => {

        let currentYearStats = fillMissingMonths(currentPeriodStats, currentMoment);
        let previousYearStats = fillMissingMonths(previousPeriodStats, previousMoment);
        let combinedStats = previousYearStats.concat(currentYearStats);

        let result = trimStatResults(combinedStats, totalMonthsRequired);

        cachedMonthlyUsageData = result;

        dataBroadcaster.broadcastMonthlyUsageUpdate(result);

      });
    }
    else {
      let monthStats = fillMissingMonths(currentPeriodStats, currentMoment);

      let result = trimStatResults(monthStats, totalMonthsRequired);

      cachedMonthlyUsageData = result;

      dataBroadcaster.broadcastMonthlyUsageUpdate(result);
    }

  });

  setTimeout(fetchMonthlyUsage, 1800000);  // 30 mins
}

function fetchPowerState() {

  let deviceId = 1

  deviceManager.getDevice(deviceId).getSysInfo().then(response => {

    let powerState = {
      isOn: (response.relay_state === 1),
      uptime: response.on_time
    };

    cachedPowerState = powerState;
    dataBroadcaster.broadcastPowerStateUpdate(powerState);
  });

  setTimeout(fetchPowerState, 60000);
}


function fillMissingDays(sparseDayStats, statsMoment) {
  let denseDayStats = [];

  let totalDays;
  // If these stats are for the current month, fill up to the current day of the month
  // Otherwise fill the whole month
  if(moment().month() === statsMoment.month()) {
    totalDays = statsMoment.date();
  }
  else {
    totalDays = statsMoment.daysInMonth();
  }

  Array.from({length: totalDays}, (x,i) => i + 1).forEach(d => {

    let stat = sparseDayStats.day_list.find(i => i.day === d);

    if(stat === undefined) {
      denseDayStats.push({
        year: statsMoment.year(),
        month: statsMoment.month() +1,
        day: d,
        energy: 0
      })
    }
    else {
      denseDayStats.push(stat);
    }

  });

  return denseDayStats;
}

function fillMissingMonths(sparseMonthStats, statsMoment) {
  let denseMonthStats = [];

  let maxMonths;
  // Dont fill in months which exist in the future
  if(statsMoment.year() === moment().year()) {
    maxMonths = moment().month() + 1; // API months are 1 based
  }
  else {
    maxMonths = 12;
  }

  // Fill in any missing months up to the max amount
  Array.from({length: maxMonths}, (x,i) => i + 1).forEach(m => {

    let stat = sparseMonthStats.month_list.find(i => i.month === m);

    if(stat === undefined) {
      denseMonthStats.push({
        year: statsMoment.year(),
        month: m,
        energy: 0
      })
    }
    else {
      denseMonthStats.push(stat);
    }

  });

  return denseMonthStats;
}

function trimStatResults(stats, maxSamples) {
  return stats.splice(stats.length - maxSamples, stats.length);
}

module.exports.getCachedData = function() {
  return {
    realtimeUsage: cachedRealtimeUsageData,
    dailyUsage: cachedDailyUsageData,
    monthlyUsage: cachedMonthlyUsageData,
    powerState: cachedPowerState
  }
}