feat: wakeup target detection (#731)

## Summary

* If going to sleep was from the Reader view, wake up to the same book.
Otherwise, wakeup to the Home view

src/CrossPointState.cpp

@@ -5,7 +5,7 @@
 #include <Serialization.h>
 
 namespace {
-constexpr uint8_t STATE_FILE_VERSION = 3;
+constexpr uint8_t STATE_FILE_VERSION = 4;
 constexpr char STATE_FILE[] = "/.crosspoint/state.bin";
 }  // namespace
 
@@ -21,6 +21,7 @@ bool CrossPointState::saveToFile() const {
   serialization::writeString(outputFile, openEpubPath);
   serialization::writePod(outputFile, lastSleepImage);
   serialization::writePod(outputFile, readerActivityLoadCount);
+  serialization::writePod(outputFile, lastSleepFromReader);
   outputFile.close();
   return true;
 }
@@ -50,6 +51,12 @@ bool CrossPointState::loadFromFile() {
     serialization::readPod(inputFile, readerActivityLoadCount);
   }
 
+  if (version >= 4) {
+    serialization::readPod(inputFile, lastSleepFromReader);
+  } else {
+    lastSleepFromReader = false;
+  }
+
   inputFile.close();
   return true;
 }

src/CrossPointState.h

@@ -10,6 +10,7 @@ class CrossPointState {
   std::string openEpubPath;
   uint8_t lastSleepImage;
   uint8_t readerActivityLoadCount = 0;
+  bool lastSleepFromReader = false;
   ~CrossPointState() = default;
 
   // Get singleton instance

src/activities/Activity.h

@@ -23,4 +23,5 @@ class Activity {
   virtual void loop() {}
   virtual bool skipLoopDelay() { return false; }
   virtual bool preventAutoSleep() { return false; }
+  virtual bool isReaderActivity() const { return false; }
 };

src/activities/reader/ReaderActivity.h

@@ -34,4 +34,5 @@ class ReaderActivity final : public ActivityWithSubactivity {
         onGoBack(onGoBack),
         onGoToLibrary(onGoToLibrary) {}
   void onEnter() override;
+  bool isReaderActivity() const override { return true; }
 };

src/main.cpp

@@ -194,6 +194,8 @@ void waitForPowerRelease() {
 
 // Enter deep sleep mode
 void enterDeepSleep() {
+  APP_STATE.lastSleepFromReader = currentActivity && currentActivity->isReaderActivity();
+  APP_STATE.saveToFile();
   exitActivity();
   enterNewActivity(new SleepActivity(renderer, mappedInputManager));
 
@@ -331,9 +333,10 @@ void setup() {
   APP_STATE.loadFromFile();
   RECENT_BOOKS.loadFromFile();
 
-  // Boot to home screen directly when back button is held or when reader activity crashes 3 times
+  // Boot to home screen if no book is open, last sleep was not from reader, back button is held, or reader activity
-  if (APP_STATE.openEpubPath.empty() || mappedInputManager.isPressed(MappedInputManager::Button::Back) ||
+  // crashed (indicated by readerActivityLoadCount > 0)
-      APP_STATE.readerActivityLoadCount > 0) {
+  if (APP_STATE.openEpubPath.empty() || !APP_STATE.lastSleepFromReader ||
+      mappedInputManager.isPressed(MappedInputManager::Button::Back) || APP_STATE.readerActivityLoadCount > 0) {
     onGoHome();
   } else {
     // Clear app state to avoid getting into a boot loop if the epub doesn't load