Properly implement low battery notification service (#577)

* Properly implement low battery notification service

* Apply suggestions from code review

---------

Co-authored-by: Jas Singh <jaskiratpal.singh@outlook.com>

src/lib/behaviors/batteryWarning.ts

@@ -3,7 +3,18 @@ import icons from '../icons/icons';
 import { Notify } from '../utils';
 
 export function warnOnLowBattery(): void {
-    batteryService.connect('notify::percent', () => {
+    let sentLowNotification = false;
+    let sentHalfLowNotification = false;
+
+    batteryService.connect('notify::charging', () => {
+        // Reset it when the battery is put to charge
+        if (batteryService.charging) {
+            sentLowNotification = false;
+            sentHalfLowNotification = false;
+        }
+    });
+
+    batteryService.connect('notify::percentage', () => {
         const { lowBatteryThreshold, lowBatteryNotification, lowBatteryNotificationText, lowBatteryNotificationTitle } =
             options.menus.power;
 
@@ -11,14 +22,26 @@ export function warnOnLowBattery(): void {
             return;
         }
 
+        // batteryService.percentage will be a double in between 0 and 1, so we multiply it by 100 to convert it to the percentage
+        const batteryPercentage = Math.floor(batteryService.percentage * 100);
         const lowThreshold = lowBatteryThreshold.get();
 
-        if (batteryService.percentage === lowThreshold || batteryService.percentage === lowThreshold / 2) {
+        // To avoid double notifications, we check each of the thresholds and set the correct `sentNotification`, but then
+        // combine them into one notification only
+        let sendNotification = false;
+        if (!sentLowNotification && batteryPercentage < lowThreshold) {
+            sentLowNotification = true;
+            sendNotification = true;
+        }
+        if (!sentHalfLowNotification && batteryPercentage < lowThreshold / 2) {
+            sentHalfLowNotification = true;
+            sendNotification = true;
+        }
+
+        if (sendNotification) {
             Notify({
-                summary: lowBatteryNotificationTitle
+                summary: lowBatteryNotificationTitle.get().replace('$POWER_LEVEL', batteryPercentage.toString()),
-                    .get()
+                body: lowBatteryNotificationText.get().replace('$POWER_LEVEL', batteryPercentage.toString()),
-                    .replace('/$POWER_LEVEL/g', batteryService.percentage.toString()),
-                body: lowBatteryNotificationText.get().replace('/$POWER_LEVEL/g', batteryService.percentage.toString()),
                 iconName: icons.ui.warning,
                 urgency: 'critical',
                 timeout: 7000,