use interval as interval, instead of wait time

src/components/settings/Settings.h

@@ -53,7 +53,7 @@ namespace Pinetime {
       enum class HeartRateBackgroundMeasurementInterval : uint8_t {
         Off,
         Continuous,
-        TenSeconds,
+        FifteenSeconds,
         ThirtySeconds,
         OneMinute,
         FiveMinutes,

src/displayapp/screens/settings/SettingHeartRate.h

@@ -32,7 +32,7 @@ namespace Pinetime {
         static constexpr std::array<Option, 8> options = {{
           {Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::Off, " Off"},
           {Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::Continuous, "Cont"},
-          {Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::TenSeconds, " 10s"},
+          {Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::FifteenSeconds, " 15s"},
           {Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::ThirtySeconds, " 30s"},
           {Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::OneMinute, "  1m"},
           {Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::FiveMinutes, "  5m"},

src/heartratetask/HeartRateTask.cpp

@@ -97,11 +97,6 @@ void HeartRateTask::StopMeasurement() {
   vTaskDelay(100);
 }
 
-void HeartRateTask::StartWaiting() {
-  StopMeasurement();
-  backgroundWaitingStart = xTaskGetTickCount();
-}
-
 void HeartRateTask::HandleGoToSleep() {
   switch (state) {
     case States::ScreenOnAndStopped:
@@ -176,8 +171,7 @@ void HeartRateTask::HandleBackgroundWaiting() {
     return;
   }
 
-  TickType_t ticksSinceWaitingStart = xTaskGetTickCount() - backgroundWaitingStart;
-  if (ticksSinceWaitingStart >= GetHeartRateBackgroundMeasurementIntervalInTicks()) {
+  if (ShouldStartBackgroundMeasuring()) {
     state = States::ScreenOffAndMeasuring;
     StartMeasurement();
   }
@@ -198,34 +192,45 @@ void HeartRateTask::HandleSensorData(int* lastBpm) {
     bpm = 0;
   }
 
-  if (*lastBpm == 0 && bpm == 0) {
+  bool notEnoughData = *lastBpm == 0 && bpm == 0;
+  if (notEnoughData) {
     controller.Update(Controllers::HeartRateController::States::NotEnoughData, bpm);
   }
 
   if (bpm != 0) {
     *lastBpm = bpm;
     controller.Update(Controllers::HeartRateController::States::Running, bpm);
-    if (state == States::ScreenOnAndMeasuring || IsContinuousModeActivated()) {
-      return;
-    }
-    if (state == States::ScreenOffAndMeasuring) {
-      state = States::ScreenOffAndWaiting;
-      StartWaiting();
-    }
   }
-  TickType_t ticksSinceMeasurementStart = xTaskGetTickCount() - measurementStart;
-  if (bpm == 0 && state == States::ScreenOffAndMeasuring && !IsContinuousModeActivated() &&
-      ticksSinceMeasurementStart >= DURATION_UNTIL_BACKGROUND_MEASUREMENT_IS_STOPPED) {
+
+  if (state == States::ScreenOnAndMeasuring || IsContinuousModeActivated()) {
+    return;
+  } 
+
+  // state == States::ScreenOffAndMeasuring 
+  //    (because state != ScreenOnAndMeasuring and the only state that enables measuring is ScreenOffAndMeasuring)
+  // !IsContinuousModeActivated()
+
+  if (ShouldStartBackgroundMeasuring()) {
+    // This doesn't change the state but resets the measurment timer, which basically starts the next measurment without resetting the sensor.
+    // This is basically a fall back to continuous mode, when measurments take too long.
+    measurementStart = xTaskGetTickCount();
+    return;
+  }
+
+  bool noDataWithinTimeLimit = bpm == 0 && ShoudStopTryingToGetData();
+  bool dataWithinTimeLimit = bpm != 0;
+  if (dataWithinTimeLimit || noDataWithinTimeLimit) {
     state = States::ScreenOffAndWaiting;
-    StartWaiting();
+    StopMeasurement();
   }
+
 }
 
 TickType_t HeartRateTask::GetHeartRateBackgroundMeasurementIntervalInTicks() {
   int ms;
   switch (settings.GetHeartRateBackgroundMeasurementInterval()) {
-    case Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::TenSeconds:
-      ms = 10 * 1000;
+    case Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::FifteenSeconds:
+      ms = 15 * 1000;
       break;
     case Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::ThirtySeconds:
       ms = 30 * 1000;
@@ -258,3 +263,15 @@ bool HeartRateTask::IsBackgroundMeasurementActivated() {
   return settings.GetHeartRateBackgroundMeasurementInterval() !=
          Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::Off;
 }
+
+TickType_t HeartRateTask::GetTicksSinceLastMeasurementStarted() {
+  return xTaskGetTickCount() - measurementStart;
+}
+
+bool HeartRateTask::ShoudStopTryingToGetData() {
+  return GetTicksSinceLastMeasurementStarted() >= DURATION_UNTIL_BACKGROUND_MEASUREMENT_IS_STOPPED;
+}
+
+bool HeartRateTask::ShouldStartBackgroundMeasuring() {
+  return GetTicksSinceLastMeasurementStarted() >= GetHeartRateBackgroundMeasurementIntervalInTicks();
+}

src/heartratetask/HeartRateTask.h

@@ -45,7 +45,6 @@ namespace Pinetime {
       static void Process(void* instance);
       void StartMeasurement();
       void StopMeasurement();
-      void StartWaiting();
 
       void HandleGoToSleep();
       void HandleWakeUp();
@@ -59,6 +58,10 @@ namespace Pinetime {
       bool IsContinuousModeActivated();
       bool IsBackgroundMeasurementActivated();
 
+      TickType_t GetTicksSinceLastMeasurementStarted();
+      bool ShoudStopTryingToGetData();
+      bool ShouldStartBackgroundMeasuring();
+
       TaskHandle_t taskHandle;
       QueueHandle_t messageQueue;
       States state = States::ScreenOnAndStopped;
@@ -66,7 +69,6 @@ namespace Pinetime {
       Controllers::HeartRateController& controller;
       Controllers::Settings& settings;
       Controllers::Ppg ppg;
-      TickType_t backgroundWaitingStart = 0;
       TickType_t measurementStart = 0;
     };