Improve battery percentage calculation and reporting

While charging, percentage should only go up, and while discharging,
percentage should only go down.

2 files changed, 11 insertions, 5 deletions

diff --git a/src/components/battery/BatteryController.cpp b/src/components/battery/BatteryController.cpp
index b43b229f..0ef4ff1a 100644
--- a/src/components/battery/BatteryController.cpp
+++ b/src/components/battery/BatteryController.cpp
@@ -69,18 +69,23 @@ void Battery::SaadcEventHandler(nrfx_saadc_evt_t const* p_event) {
     // p_event->data.done.p_buffer[0] = (adc_voltage / reference_voltage) * 1024
     voltage = p_event->data.done.p_buffer[0] * (8 * 600) / 1024;
 
+    uint8_t newPercent;
     if (isFull) {
-      percentRemaining = 100;
+      newPercent = 100;
     } else if (voltage < battery_min) {
-      percentRemaining = 0;
+      newPercent = 0;
     } else {
-      percentRemaining = std::min((voltage - battery_min) * 100 / (battery_max - battery_min), isCharging ? 99 : 100);
+      newPercent = std::min((voltage - battery_min) * 100 / (battery_max - battery_min), isCharging ? 99 : 100);
+    }
+
+    if ((isPowerPresent && newPercent > percentRemaining) || (!isPowerPresent && newPercent < percentRemaining) || firstMeasurement) {
+      firstMeasurement = false;
+      percentRemaining = newPercent;
+      systemTask->PushMessage(System::Messages::BatteryPercentageUpdated);
     }
 
     nrfx_saadc_uninit();
     isReading = false;
-
-    systemTask->PushMessage(System::Messages::BatteryMeasurementDone);
   }
 }
 
diff --git a/src/components/battery/BatteryController.h b/src/components/battery/BatteryController.h
index c78ffb3f..55c26309 100644
--- a/src/components/battery/BatteryController.h
+++ b/src/components/battery/BatteryController.h
@@ -42,6 +42,7 @@ namespace Pinetime {
       bool isFull = false;
       bool isCharging = false;
       bool isPowerPresent = false;
+      bool firstMeasurement = true;
 
       void SaadcInit();