add per book reading time tracking and display on home screen

src/activities/home/HomeActivity.cpp

@@ -4,6 +4,7 @@
 #include <GfxRenderer.h>
 #include <SDCardManager.h>
 
+#include <cstdlib>
 #include <cstring>
 #include <vector>
 
@@ -60,6 +61,8 @@ void HomeActivity::onEnter() {
     } else if (StringUtils::checkFileExtension(lastBookTitle, ".xtc")) {
       lastBookTitle.resize(lastBookTitle.length() - 4);
     }
+
+    loadReadingTime();
   }
 
   selectorIndex = 0;
@@ -256,6 +259,10 @@ void HomeActivity::render() const {
     if (!lastBookAuthor.empty()) {
       totalTextHeight += renderer.getLineHeight(UI_10_FONT_ID) * 3 / 2;
     }
+    const bool showReadTime = lastBookSeconds > 0;
+    if (showReadTime) {
+      totalTextHeight += renderer.getLineHeight(UI_10_FONT_ID);
+    }
 
     // Vertically center the title block within the card
     int titleYStart = bookY + (bookHeight - totalTextHeight) / 2;
@@ -274,8 +281,15 @@ void HomeActivity::render() const {
         trimmedAuthor.append("...");
       }
       renderer.drawCenteredText(UI_10_FONT_ID, titleYStart, trimmedAuthor.c_str(), !bookSelected);
+      titleYStart += renderer.getLineHeight(UI_10_FONT_ID);
     }
 
+    if (showReadTime) {
+      const std::string timeText = std::string("Read time: ") + formatDuration(lastBookSeconds);
+      renderer.drawCenteredText(UI_10_FONT_ID, titleYStart, timeText.c_str(), !bookSelected);
+    }
+
+    // Footer label stays at the bottom of the card
     renderer.drawCenteredText(UI_10_FONT_ID, bookY + bookHeight - renderer.getLineHeight(UI_10_FONT_ID) * 3 / 2,
                               "Continue Reading", !bookSelected);
   } else {
@@ -337,3 +351,72 @@ void HomeActivity::render() const {
 
   renderer.displayBuffer();
 }
+
+void HomeActivity::loadReadingTime() {
+  lastBookSeconds = 0;
+  if (APP_STATE.openEpubPath.empty()) {
+    return;
+  }
+
+  FsFile f;
+  if (!SdMan.openFileForRead("ERS", "/ReadingStats.csv", f)) {
+    return;
+  }
+
+  const size_t fileSize = f.size();
+  if (fileSize == 0) {
+    f.close();
+    return;
+  }
+
+  std::string content;
+  content.resize(fileSize);
+  const auto bytesRead = f.read(reinterpret_cast<uint8_t*>(&content[0]), fileSize);
+  f.close();
+  if (bytesRead != fileSize) {
+    return;
+  }
+
+  size_t pos = 0;
+  while (pos < content.size()) {
+    const size_t eol = content.find('\n', pos);
+    const size_t lineEnd = (eol == std::string::npos) ? content.size() : eol;
+    const auto line = content.substr(pos, lineEnd - pos);
+
+    const auto comma = line.find(',');
+    if (comma != std::string::npos) {
+      const auto path = line.substr(0, comma);
+      if (path == APP_STATE.openEpubPath) {
+        lastBookSeconds = static_cast<uint32_t>(strtoul(line.c_str() + comma + 1, nullptr, 10));
+        break;
+      }
+    }
+
+    if (eol == std::string::npos) {
+      break;
+    }
+    pos = eol + 1;
+  }
+}
+
+std::string HomeActivity::formatDuration(const uint32_t seconds) {
+  if (seconds < 60) {
+    return std::to_string(seconds) + "s";
+  }
+
+  const uint32_t minutesTotal = seconds / 60;
+  if (minutesTotal < 60) {
+    return std::to_string(minutesTotal) + "m";
+  }
+
+  const uint32_t hours = minutesTotal / 60;
+  const uint32_t minutes = minutesTotal % 60;
+
+  if (hours < 24) {
+    return std::to_string(hours) + "h " + std::to_string(minutes) + "m";
+  }
+
+  const uint32_t days = hours / 24;
+  const uint32_t remHours = hours % 24;
+  return std::to_string(days) + "d " + std::to_string(remHours) + "h";
+}

src/activities/home/HomeActivity.h

@@ -14,6 +14,7 @@ class HomeActivity final : public Activity {
   bool updateRequired = false;
   bool hasContinueReading = false;
   bool hasOpdsUrl = false;
+  uint32_t lastBookSeconds = 0;
   std::string lastBookTitle;
   std::string lastBookAuthor;
   const std::function<void()> onContinueReading;
@@ -26,6 +27,8 @@ class HomeActivity final : public Activity {
   [[noreturn]] void displayTaskLoop();
   void render() const;
   int getMenuItemCount() const;
+  void loadReadingTime();
+  static std::string formatDuration(uint32_t seconds);
 
  public:
   explicit HomeActivity(GfxRenderer& renderer, MappedInputManager& mappedInput,

src/activities/reader/EpubReaderActivity.cpp

@@ -5,6 +5,13 @@
 #include <GfxRenderer.h>
 #include <SDCardManager.h>
 
+#include <algorithm>
+#include <cmath>
+#include <cstdio>
+#include <cstdlib>
+#include <utility>
+#include <vector>
+
 #include "CrossPointSettings.h"
 #include "CrossPointState.h"
 #include "EpubReaderChapterSelectionActivity.h"
@@ -17,6 +24,16 @@ namespace {
 constexpr unsigned long skipChapterMs = 700;
 constexpr unsigned long goHomeMs = 1000;
 constexpr int statusBarMargin = 19;
+constexpr const char* readingStatsFilePath = "/ReadingStats.csv";
+
+std::string formatMinutes(const float minutes) {
+  if (minutes <= 0.0f) {
+    return "";
+  }
+
+  const int totalMinutes = static_cast<int>(std::floor(minutes));
+  return std::to_string(totalMinutes) + "m";
+}
 }  // namespace
 
 void EpubReaderActivity::taskTrampoline(void* param) {
@@ -63,6 +80,9 @@ void EpubReaderActivity::onEnter() {
     }
     f.close();
   }
+
+  loadReadingStats();
+  lastPageInteractionMs = millis();
   // We may want a better condition to detect if we are opening for the first time.
   // This will trigger if the book is re-opened at Chapter 0.
   if (currentSpineIndex == 0) {
@@ -116,6 +136,7 @@ void EpubReaderActivity::loop() {
 
   // Enter chapter selection activity
   if (mappedInput.wasReleased(MappedInputManager::Button::Confirm)) {
+    recordReadingTimeDelta();
     // Don't start activity transition while rendering
     xSemaphoreTake(renderingMutex, portMAX_DELAY);
     exitActivity();
@@ -139,12 +160,14 @@ void EpubReaderActivity::loop() {
 
   // Long press BACK (1s+) goes directly to home
   if (mappedInput.isPressed(MappedInputManager::Button::Back) && mappedInput.getHeldTime() >= goHomeMs) {
+    recordReadingTimeDelta();
     onGoHome();
     return;
   }
 
   // Short press BACK goes to file selection
   if (mappedInput.wasReleased(MappedInputManager::Button::Back) && mappedInput.getHeldTime() < goHomeMs) {
+    recordReadingTimeDelta();
     onGoBack();
     return;
   }
@@ -158,6 +181,8 @@ void EpubReaderActivity::loop() {
     return;
   }
 
+  recordReadingTimeDelta();
+
   // any botton press when at end of the book goes back to the last page
   if (currentSpineIndex > 0 && currentSpineIndex >= epub->getSpineItemsCount()) {
     currentSpineIndex = epub->getSpineItemsCount() - 1;
@@ -409,6 +434,127 @@ void EpubReaderActivity::renderContents(std::unique_ptr<Page> page, const int or
   renderer.restoreBwBuffer();
 }
 
+void EpubReaderActivity::recordReadingTimeDelta() {
+  if (!epub) {
+    return;
+  }
+
+  const unsigned long now = millis();
+  const unsigned long deltaMs = now - lastPageInteractionMs;
+  lastPageInteractionMs = now;
+
+  const unsigned long sleepTimeoutMs = SETTINGS.getSleepTimeoutMs();
+  if (deltaMs < 1000 || deltaMs > sleepTimeoutMs) {
+    return;  // ignore very short taps and anything longer than the sleep timeout
+  }
+
+  currentBookSeconds += static_cast<uint32_t>(deltaMs / 1000);  // whole seconds only
+  persistReadingStats();
+}
+
+void EpubReaderActivity::loadReadingStats() {
+  currentBookSeconds = 0;
+
+  FsFile f;
+  if (!SdMan.openFileForRead("ERS", readingStatsFilePath, f)) {
+    return;  // No stats file yet
+  }
+
+  const size_t fileSize = f.size();
+  if (fileSize == 0) {
+    f.close();
+    return;
+  }
+
+  std::string content;
+  content.resize(fileSize);
+  const auto bytesRead = f.read(reinterpret_cast<uint8_t*>(&content[0]), fileSize);
+  f.close();
+  if (bytesRead != fileSize) {
+    return;
+  }
+
+  size_t pos = 0;
+  while (pos < content.size()) {
+    const size_t eol = content.find('\n', pos);
+    const size_t lineEnd = (eol == std::string::npos) ? content.size() : eol;
+    const auto line = content.substr(pos, lineEnd - pos);
+
+    const auto comma = line.find(',');
+    if (comma != std::string::npos) {
+      const auto path = line.substr(0, comma);
+      if (path == epub->getPath()) {
+        currentBookSeconds = static_cast<uint32_t>(strtoul(line.c_str() + comma + 1, nullptr, 10));
+        break;
+      }
+    }
+
+    if (eol == std::string::npos) {
+      break;
+    }
+    pos = eol + 1;
+  }
+}
+
+void EpubReaderActivity::persistReadingStats() const {
+  if (!epub) {
+    return;
+  }
+
+  std::vector<std::pair<std::string, uint32_t>> rows;
+
+  FsFile f;
+  if (SdMan.openFileForRead("ERS", readingStatsFilePath, f)) {
+    const size_t fileSize = f.size();
+    if (fileSize > 0) {
+      std::string content;
+      content.resize(fileSize);
+      const auto bytesRead = f.read(reinterpret_cast<uint8_t*>(&content[0]), fileSize);
+      if (bytesRead == fileSize) {
+        size_t pos = 0;
+        while (pos < content.size()) {
+          const size_t eol = content.find('\n', pos);
+          const size_t lineEnd = (eol == std::string::npos) ? content.size() : eol;
+          const auto line = content.substr(pos, lineEnd - pos);
+
+          const auto comma = line.find(',');
+          if (comma != std::string::npos) {
+            const auto path = line.substr(0, comma);
+            const uint32_t seconds = static_cast<uint32_t>(strtoul(line.c_str() + comma + 1, nullptr, 10));
+            rows.emplace_back(path, seconds);
+          }
+
+          if (eol == std::string::npos) {
+            break;
+          }
+          pos = eol + 1;
+        }
+      }
+    }
+    f.close();
+  }
+
+  const auto existing = std::find_if(rows.begin(), rows.end(), [this](const std::pair<std::string, uint32_t>& row) {
+    return row.first == epub->getPath();
+  });
+
+  if (existing != rows.end()) {
+    existing->second = currentBookSeconds;
+  } else {
+    rows.emplace_back(epub->getPath(), currentBookSeconds);
+  }
+
+  if (!SdMan.openFileForWrite("ERS", readingStatsFilePath, f)) {
+    return;
+  }
+
+  for (const auto& row : rows) {
+    const std::string line = row.first + "," + std::to_string(row.second) + "\n";
+    f.write(reinterpret_cast<const uint8_t*>(line.c_str()), line.size());
+  }
+  f.close();
+}
+
 void EpubReaderActivity::renderStatusBar(const int orientedMarginRight, const int orientedMarginBottom,
                                          const int orientedMarginLeft) const {
   // determine visible status bar elements

src/activities/reader/EpubReaderActivity.h

@@ -16,6 +16,8 @@ class EpubReaderActivity final : public ActivityWithSubactivity {
   int nextPageNumber = 0;
   int pagesUntilFullRefresh = 0;
   bool updateRequired = false;
+  unsigned long lastPageInteractionMs = 0;
+  uint32_t currentBookSeconds = 0;
   const std::function<void()> onGoBack;
   const std::function<void()> onGoHome;
 
@@ -25,6 +27,9 @@ class EpubReaderActivity final : public ActivityWithSubactivity {
   void renderContents(std::unique_ptr<Page> page, int orientedMarginTop, int orientedMarginRight,
                       int orientedMarginBottom, int orientedMarginLeft);
   void renderStatusBar(int orientedMarginRight, int orientedMarginBottom, int orientedMarginLeft) const;
+  void recordReadingTimeDelta();
+  void loadReadingStats();
+  void persistReadingStats() const;
 
  public:
   explicit EpubReaderActivity(GfxRenderer& renderer, MappedInputManager& mappedInput, std::unique_ptr<Epub> epub,