Add daily kWH usage total for last 30 days

1 files changed, 69 insertions, 2 deletions

diff --git a/routes/energy-usage.js b/routes/energy-usage.js
index 847248d..5706c75 100644
--- a/routes/energy-usage.js
+++ b/routes/energy-usage.js
@@ -2,16 +2,17 @@ const express = require('express');
 const router = express.Router();
 
 const deviceManager = require('../services/device-manager');
+const moment = require('moment');
 
 router.get('/:deviceId/realtime', function(req, res, next) {
-  
+
   let deviceId = req.params.deviceId;
 
   let realtimeUsage = {};
   // TODO - cache results with a short TTL so we don't hammer the plug if multiple clients are requesting data
   deviceManager.getDevice(deviceId).emeter.getRealtime().then(response => {
 
-    // Voltage seems to be reported as its peak to peak voltage, not RMS.
+    // 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);
@@ -21,4 +22,70 @@ router.get('/:deviceId/realtime', function(req, res, next) {
 
 });
 
+router.get('/:deviceId/day-stats', function(req, res, next) {
+  
+  let deviceId = req.params.deviceId;
+
+  // 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);
+
+        res.json(trimDayStatResults(combinedStats, totalDaysRequired));
+
+      });
+    }
+    else {
+      let dayStats = fillMissingDays(currentPeriodStats, currentMoment);
+  
+      res.json(trimDayStatResults(dayStats, totalDaysRequired));
+    }
+
+  });
+
+});
+
+function fillMissingDays(sparseDayStats, statsMoment) {
+  let denseDayStats = [];
+
+  // Fill in any missing days
+  let totalDays = statsMoment.date();
+  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 trimDayStatResults(stats, maxSamples) {
+  return stats.splice(stats.length - maxSamples, stats.length);
+}
+
 module.exports = router;
\ No newline at end of file