Amend back button handling, add "use as sleep screen" feature

lib/I18n/translations/english.yaml

@@ -442,5 +442,7 @@ STR_UPTIME: "Uptime"
 STR_CHARGING: "Charging"
 STR_GATHERING_DATA: "Gathering data..."
 STR_READING: "Reading..."
+STR_SET_SLEEP_SCREEN: "Set Sleep"
+STR_SLEEP_SCREEN_SET: "Sleep screen updated!"
 STR_WEATHER_MOON_INFO: "Moon"
 STR_WEATHER_SUN_INFO: "Sun"

lib/hal/HalStorage.cpp

@@ -7,6 +7,7 @@
 #include <SdFat.h>
 
 #include <cassert>
+#include <new>
 
 #define SDCard SDCardManager::getInstance()
 
@@ -138,6 +139,35 @@ bool HalStorage::openFileForWrite(const char* moduleName, const String& path, Ha
 
 bool HalStorage::removeDir(const char* path) { HAL_STORAGE_WRAPPED_CALL(removeDir, path); }
 
+bool HalStorage::copyFile(const char* moduleName, const std::string& srcPath, const char* dstPath) {
+  HalFile src, dst;
+  if (!openFileForRead(moduleName, srcPath, src)) return false;
+  if (!openFileForWrite(moduleName, dstPath, dst)) {
+    src.close();
+    return false;
+  }
+  constexpr size_t BUF_SIZE = 4096;
+  auto* buf = new (std::nothrow) uint8_t[BUF_SIZE];
+  if (!buf) {
+    dst.close();
+    src.close();
+    return false;
+  }
+  bool ok = true;
+  while (src.available()) {
+    const auto bytesRead = src.read(buf, BUF_SIZE);
+    if (bytesRead <= 0) break;
+    if (dst.write(buf, bytesRead) != static_cast<size_t>(bytesRead)) {
+      ok = false;
+      break;
+    }
+  }
+  delete[] buf;
+  dst.close();
+  src.close();
+  return ok;
+}
+
 // HalFile implementation
 // Allow doing file operations while ensuring thread safety via HalStorage's mutex.
 // Please keep the list below in sync with the HalFile.h header

lib/hal/HalStorage.h

@@ -44,6 +44,7 @@ class HalStorage {
   bool openFileForWrite(const char* moduleName, const std::string& path, HalFile& file);
   bool openFileForWrite(const char* moduleName, const String& path, HalFile& file);
   bool removeDir(const char* path);
+  bool copyFile(const char* moduleName, const std::string& srcPath, const char* dstPath);
 
   uint64_t sdTotalBytes() const;
   uint64_t sdUsedBytes();

src/activities/util/BmpViewerActivity.cpp

@@ -5,9 +5,15 @@
 #include <HalStorage.h>
 #include <I18n.h>
 
+#include "../reader/ReaderUtils.h"
+#include "CrossPointSettings.h"
 #include "components/UITheme.h"
 #include "fontIds.h"
 
+namespace {
+constexpr const char* SLEEP_BMP_PATH = "/sleep.bmp";
+}  // namespace
+
 BmpViewerActivity::BmpViewerActivity(GfxRenderer& renderer, MappedInputManager& mappedInput, std::string path)
     : Activity("BmpViewer", renderer, mappedInput), filePath(std::move(path)) {}
 
@@ -49,7 +55,7 @@ void BmpViewerActivity::onEnter() {
       }
 
       // 4. Prepare Rendering
-      const auto labels = mappedInput.mapLabels(tr(STR_BACK), "", "", "");
+      const auto labels = mappedInput.mapLabels(tr(STR_BACK), "", "", tr(STR_SET_SLEEP_SCREEN));
       GUI.fillPopupProgress(renderer, popupRect, 50);
 
       renderer.clearScreen();
@@ -89,12 +95,44 @@ void BmpViewerActivity::onExit() {
   renderer.displayBuffer(HalDisplay::FULL_REFRESH);
 }
 
+void BmpViewerActivity::setAsSleepScreen() {
+  // Only copy if the source isn't already /sleep.bmp
+  if (filePath != SLEEP_BMP_PATH) {
+    if (!Storage.copyFile("BMP", filePath, SLEEP_BMP_PATH)) {
+      LOG_ERR("BMP", "Failed to copy %s to %s", filePath.c_str(), SLEEP_BMP_PATH);
+      return;
+    }
+  }
+
+  // Switch sleep screen mode to CUSTOM so the copied image is used
+  SETTINGS.sleepScreen = CrossPointSettings::SLEEP_SCREEN_MODE::CUSTOM;
+  SETTINGS.saveToFile();
+  LOG_INF("BMP", "Set %s as sleep screen", filePath.c_str());
+
+  GUI.drawPopup(renderer, tr(STR_SLEEP_SCREEN_SET));
+  renderer.displayBuffer(HalDisplay::HALF_REFRESH);
+}
+
 void BmpViewerActivity::loop() {
   // Keep CPU awake/polling so 1st click works
   Activity::loop();
 
-  if (mappedInput.wasReleased(MappedInputManager::Button::Back)) {
+  // Long press BACK (1s+) goes to home screen
+  if (mappedInput.isPressed(MappedInputManager::Button::Back) && mappedInput.getHeldTime() >= ReaderUtils::GO_HOME_MS) {
     onGoHome();
     return;
   }
+
+  // Short press BACK returns to the calling activity
+  if (mappedInput.wasReleased(MappedInputManager::Button::Back) &&
+      mappedInput.getHeldTime() < ReaderUtils::GO_HOME_MS) {
+    finish();
+    return;
+  }
+
+  // Next/Right button: set this image as the sleep screen
+  if (mappedInput.wasReleased(MappedInputManager::Button::Right)) {
+    setAsSleepScreen();
+    return;
+  }
 }

src/activities/util/BmpViewerActivity.h

@@ -16,4 +16,5 @@ class BmpViewerActivity final : public Activity {
 
  private:
   std::string filePath;
+  void setAsSleepScreen();
 };