crosspoint-reader/src/activities/reader/EpubReaderActivity.cpp

#include "EpubReaderActivity.h"

#include <Epub/Page.h>
#include <Epub/Section.h>
#include <FsHelpers.h>
#include <GfxRenderer.h>
#include <SDCardManager.h>
#include <Serialization.h>

#include "BookManager.h"
#include "BookmarkStore.h"
#include "CrossPointSettings.h"
#include "CrossPointState.h"
#include "EpubReaderChapterSelectionActivity.h"
#include "MappedInputManager.h"
#include "RecentBooksStore.h"
#include "ScreenComponents.h"
#include "activities/dictionary/DictionaryMenuActivity.h"
#include "activities/dictionary/DictionarySearchActivity.h"
#include "activities/dictionary/EpubWordSelectionActivity.h"
#include "activities/util/QuickMenuActivity.h"
#include "fontIds.h"

namespace {
// pagesPerRefresh now comes from SETTINGS.getRefreshFrequency()
constexpr unsigned long skipChapterMs = 700;
constexpr unsigned long goHomeMs = 1000;
constexpr int statusBarMargin = 19;
constexpr int progressBarMarginTop = 1;

// Progress file version for content offset tracking
// Version 1: Added content offset for position restoration after re-indexing
constexpr uint8_t EPUB_PROGRESS_VERSION = 1;
}  // namespace

void EpubReaderActivity::taskTrampoline(void* param) {
  auto* self = static_cast<EpubReaderActivity*>(param);
  self->displayTaskLoop();
}

void EpubReaderActivity::onEnter() {
  ActivityWithSubactivity::onEnter();

  if (!epub) {
    return;
  }

  // Configure screen orientation based on settings
  switch (SETTINGS.orientation) {
    case CrossPointSettings::ORIENTATION::PORTRAIT:
      renderer.setOrientation(GfxRenderer::Orientation::Portrait);
      break;
    case CrossPointSettings::ORIENTATION::LANDSCAPE_CW:
      renderer.setOrientation(GfxRenderer::Orientation::LandscapeClockwise);
      break;
    case CrossPointSettings::ORIENTATION::INVERTED:
      renderer.setOrientation(GfxRenderer::Orientation::PortraitInverted);
      break;
    case CrossPointSettings::ORIENTATION::LANDSCAPE_CCW:
      renderer.setOrientation(GfxRenderer::Orientation::LandscapeCounterClockwise);
      break;
    default:
      break;
  }

  renderingMutex = xSemaphoreCreateMutex();

  epub->setupCacheDir();

  // Check if cover generation is needed and do it NOW (blocking)
  const bool needsThumb = !SdMan.exists(epub->getThumbBmpPath().c_str());
  const bool needsMicroThumb = !SdMan.exists(epub->getMicroThumbBmpPath().c_str());
  const bool needsCoverFit = !SdMan.exists(epub->getCoverBmpPath(false).c_str());
  const bool needsCoverCrop = !SdMan.exists(epub->getCoverBmpPath(true).c_str());

  if (needsThumb || needsMicroThumb || needsCoverFit || needsCoverCrop) {
    // Show "Preparing book... [X%]" popup, updating every 3 seconds
    constexpr int boxMargin = 20;
    const int textWidth = renderer.getTextWidth(UI_12_FONT_ID, "Preparing book... [100%]");
    const int boxWidth = textWidth + boxMargin * 2;
    const int boxHeight = renderer.getLineHeight(UI_12_FONT_ID) + boxMargin * 2;
    const int boxX = (renderer.getScreenWidth() - boxWidth) / 2;
    constexpr int boxY = 50;

    unsigned long lastUpdate = 0;

    // Draw initial popup
    renderer.clearScreen();
    renderer.fillRect(boxX, boxY, boxWidth, boxHeight, false);
    renderer.drawRect(boxX + 5, boxY + 5, boxWidth - 10, boxHeight - 10);
    renderer.drawText(UI_12_FONT_ID, boxX + boxMargin, boxY + boxMargin, "Preparing book... [0%]");
    renderer.displayBuffer(EInkDisplay::FAST_REFRESH);

    // Generate covers with progress callback
    epub->generateAllCovers([&](int percent) {
      const unsigned long now = millis();
      if ((now - lastUpdate) >= 3000) {
        lastUpdate = now;

        renderer.fillRect(boxX, boxY, boxWidth, boxHeight, false);
        renderer.drawRect(boxX + 5, boxY + 5, boxWidth - 10, boxHeight - 10);

        char progressStr[32];
        snprintf(progressStr, sizeof(progressStr), "Preparing book... [%d%%]", percent);
        renderer.drawText(UI_12_FONT_ID, boxX + boxMargin, boxY + boxMargin, progressStr);
        renderer.displayBuffer(EInkDisplay::FAST_REFRESH);
      }
    });
  }

  FsFile f;
  if (SdMan.openFileForRead("ERS", epub->getCachePath() + "/progress.bin", f)) {
    const size_t fileSize = f.size();
    
    if (fileSize >= 9) {
      // New format: version (1) + spineIndex (2) + pageNumber (2) + contentOffset (4) = 9 bytes
      uint8_t version;
      serialization::readPod(f, version);
      
      if (version == EPUB_PROGRESS_VERSION) {
        uint16_t spineIndex, pageNumber;
        serialization::readPod(f, spineIndex);
        serialization::readPod(f, pageNumber);
        serialization::readPod(f, savedContentOffset);
        
        currentSpineIndex = spineIndex;
        nextPageNumber = pageNumber;
        hasContentOffset = true;
        
        Serial.printf("[%lu] [ERS] Loaded progress v1: spine %d, page %d, offset %u\n", 
                      millis(), currentSpineIndex, nextPageNumber, savedContentOffset);
      } else {
        // Unknown version, try legacy format
        f.seek(0);
        uint8_t data[4];
        if (f.read(data, 4) == 4) {
          currentSpineIndex = data[0] + (data[1] << 8);
          nextPageNumber = data[2] + (data[3] << 8);
          hasContentOffset = false;
          Serial.printf("[%lu] [ERS] Loaded legacy progress (unknown version %d): spine %d, page %d\n", 
                        millis(), version, currentSpineIndex, nextPageNumber);
        }
      }
    } else if (fileSize >= 4) {
      // Legacy format: just spineIndex (2) + pageNumber (2) = 4 bytes
      uint8_t data[4];
      if (f.read(data, 4) == 4) {
        currentSpineIndex = data[0] + (data[1] << 8);
        nextPageNumber = data[2] + (data[3] << 8);
        hasContentOffset = false;
        Serial.printf("[%lu] [ERS] Loaded legacy progress: spine %d, page %d\n", 
                      millis(), currentSpineIndex, nextPageNumber);
      }
    }
    f.close();
  }
  // 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) {
    int textSpineIndex = epub->getSpineIndexForTextReference();
    if (textSpineIndex != 0) {
      currentSpineIndex = textSpineIndex;
      Serial.printf("[%lu] [ERS] Opened for first time, navigating to text reference at index %d\n", millis(),
                    textSpineIndex);
    }
  }

  // Save current epub as last opened epub and cache title/author for home screen
  APP_STATE.openEpubPath = epub->getPath();
  APP_STATE.openBookTitle = epub->getTitle();
  APP_STATE.openBookAuthor = epub->getAuthor();
  APP_STATE.saveToFile();
  RECENT_BOOKS.addBook(epub->getPath(), epub->getTitle(), epub->getAuthor());

  // Trigger first update
  updateRequired = true;

  xTaskCreate(&EpubReaderActivity::taskTrampoline, "EpubReaderActivityTask",
              8192,               // Stack size
              this,               // Parameters
              1,                  // Priority
              &displayTaskHandle  // Task handle
  );
}

void EpubReaderActivity::onExit() {
  ActivityWithSubactivity::onExit();

  // Reset orientation back to portrait for the rest of the UI
  renderer.setOrientation(GfxRenderer::Orientation::Portrait);

  // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
  xSemaphoreTake(renderingMutex, portMAX_DELAY);
  if (displayTaskHandle) {
    // Log stack high-water mark before deleting task (stack size: 8192 bytes)
    LOG_STACK_WATERMARK("EpubReaderActivity", displayTaskHandle);
    vTaskDelete(displayTaskHandle);
    displayTaskHandle = nullptr;
    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
  }
  vSemaphoreDelete(renderingMutex);
  renderingMutex = nullptr;
  section.reset();
  epub.reset();
}

void EpubReaderActivity::loop() {
  // Pass input responsibility to sub activity if exists
  if (subActivity) {
    subActivity->loop();
    return;
  }

  // Handle end-of-book prompt
  if (showingEndOfBookPrompt) {
    if (mappedInput.wasReleased(MappedInputManager::Button::Up)) {
      endOfBookSelection = (endOfBookSelection + 2) % 3;
      updateRequired = true;
      return;
    }
    if (mappedInput.wasReleased(MappedInputManager::Button::Down)) {
      endOfBookSelection = (endOfBookSelection + 1) % 3;
      updateRequired = true;
      return;
    }
    if (mappedInput.wasReleased(MappedInputManager::Button::Confirm)) {
      handleEndOfBookAction();
      return;
    }
    if (mappedInput.wasReleased(MappedInputManager::Button::Back)) {
      // Go back to last page instead
      currentSpineIndex = epub->getSpineItemsCount() - 1;
      nextPageNumber = UINT16_MAX;
      showingEndOfBookPrompt = false;
      updateRequired = true;
      return;
    }
    return;
  }

  // Enter chapter selection activity
  if (mappedInput.wasReleased(MappedInputManager::Button::Confirm)) {
    // Don't start activity transition while rendering
    xSemaphoreTake(renderingMutex, portMAX_DELAY);
    const int currentPage = section ? section->currentPage : 0;
    const int totalPages = section ? section->pageCount : 0;
    exitActivity();
    enterNewActivity(new EpubReaderChapterSelectionActivity(
        this->renderer, this->mappedInput, epub, epub->getPath(), currentSpineIndex, currentPage, totalPages,
        [this] {
          exitActivity();
          updateRequired = true;
        },
        [this](const int newSpineIndex) {
          if (currentSpineIndex != newSpineIndex) {
            currentSpineIndex = newSpineIndex;
            nextPageNumber = 0;
            section.reset();
          }
          exitActivity();
          updateRequired = true;
        },
        [this](const int newSpineIndex, const int newPage) {
          // Handle sync position
          if (currentSpineIndex != newSpineIndex || (section && section->currentPage != newPage)) {
            currentSpineIndex = newSpineIndex;
            nextPageNumber = newPage;
            section.reset();
          }
          exitActivity();
          updateRequired = true;
        }));
    xSemaphoreGive(renderingMutex);
  }

  // Long press BACK (1s+) goes directly to home
  if (mappedInput.isPressed(MappedInputManager::Button::Back) && mappedInput.getHeldTime() >= goHomeMs) {
    onGoHome();
    return;
  }

  // Short press BACK goes to file selection
  if (mappedInput.wasReleased(MappedInputManager::Button::Back) && mappedInput.getHeldTime() < goHomeMs) {
    onGoBack();
    return;
  }

  // Dictionary power button press
  if (SETTINGS.shortPwrBtn == CrossPointSettings::SHORT_PWRBTN::DICTIONARY &&
      mappedInput.wasReleased(MappedInputManager::Button::Power)) {
    xSemaphoreTake(renderingMutex, portMAX_DELAY);
    exitActivity();
    enterNewActivity(new DictionaryMenuActivity(
        renderer, mappedInput,
        [this](DictionaryMode mode) {
          // CRITICAL: Cache all needed values BEFORE exitActivity() destroys the lambda's owner
          // The lambda is stored in DictionaryMenuActivity, so exitActivity() destroys it
          GfxRenderer& cachedRenderer = renderer;
          MappedInputManager& cachedMappedInput = mappedInput;
          Section* cachedSection = section.get();
          SemaphoreHandle_t cachedMutex = renderingMutex;
          EpubReaderActivity* self = this;
          
          // Handle dictionary mode selection - exitActivity deletes DictionaryMenuActivity
          exitActivity();
          
          if (mode == DictionaryMode::ENTER_WORD) {
            // Enter word mode - show keyboard and search
            self->enterNewActivity(new DictionarySearchActivity(cachedRenderer, cachedMappedInput,
                                                          [self]() {
                                                            // On back from dictionary
                                                            self->exitActivity();
                                                            self->updateRequired = true;
                                                          },
                                                          ""));  // Empty string = show keyboard
          } else {
            // Select from screen mode - show word selection on current page
            if (cachedSection) {
              xSemaphoreTake(cachedMutex, portMAX_DELAY);
              auto page = cachedSection->loadPageFromSectionFile();
              if (page) {
                // Get margins for word selection positioning
                int orientedMarginTop, orientedMarginRight, orientedMarginBottom, orientedMarginLeft;
                cachedRenderer.getOrientedViewableTRBL(&orientedMarginTop, &orientedMarginRight, &orientedMarginBottom,
                                                 &orientedMarginLeft);
                orientedMarginTop += SETTINGS.screenMargin;
                orientedMarginLeft += SETTINGS.screenMargin;

                // Cache the font ID before creating activity
                const int cachedFontId = SETTINGS.getReaderFontId();

                self->enterNewActivity(new EpubWordSelectionActivity(
                    cachedRenderer, cachedMappedInput, std::move(page), cachedFontId, orientedMarginLeft,
                    orientedMarginTop,
                    [self](const std::string& selectedWord) {
                      // Word selected - look it up
                      self->exitActivity();
                      self->enterNewActivity(new DictionarySearchActivity(self->renderer, self->mappedInput,
                                                                    [self]() {
                                                                      self->exitActivity();
                                                                      self->updateRequired = true;
                                                                    },
                                                                    selectedWord));
                    },
                    [self]() {
                      // Cancelled word selection
                      self->exitActivity();
                      self->updateRequired = true;
                    }));
                xSemaphoreGive(cachedMutex);
              } else {
                xSemaphoreGive(cachedMutex);
                self->updateRequired = true;
              }
            } else {
              self->updateRequired = true;
            }
          }
        },
        [this]() {
          // Cancelled dictionary menu - cache self before exitActivity destroys the lambda
          EpubReaderActivity* self = this;
          exitActivity();
          self->updateRequired = true;
        },
        section != nullptr));  // Word selection only available if section is loaded
    xSemaphoreGive(renderingMutex);
    return;
  }

  // Quick Menu power button press
  if (SETTINGS.shortPwrBtn == CrossPointSettings::SHORT_PWRBTN::QUICK_MENU &&
      mappedInput.wasReleased(MappedInputManager::Button::Power)) {
    xSemaphoreTake(renderingMutex, portMAX_DELAY);
    
    // Check if current page is bookmarked
    bool isBookmarked = false;
    if (section) {
      const uint32_t contentOffset = section->getContentOffsetForPage(section->currentPage);
      isBookmarked = BookmarkStore::isPageBookmarked(epub->getPath(), currentSpineIndex, contentOffset);
    }
    
    exitActivity();
    enterNewActivity(new QuickMenuActivity(
        renderer, mappedInput,
        [this](QuickMenuAction action) {
          // Cache values before exitActivity
          EpubReaderActivity* self = this;
          GfxRenderer& cachedRenderer = renderer;
          MappedInputManager& cachedMappedInput = mappedInput;
          Section* cachedSection = section.get();
          SemaphoreHandle_t cachedMutex = renderingMutex;
          
          exitActivity();
          
          if (action == QuickMenuAction::DICTIONARY) {
            // Open dictionary menu
            self->enterNewActivity(new DictionaryMenuActivity(
                cachedRenderer, cachedMappedInput,
                [self](DictionaryMode mode) {
                  GfxRenderer& r = self->renderer;
                  MappedInputManager& m = self->mappedInput;
                  Section* s = self->section.get();
                  SemaphoreHandle_t mtx = self->renderingMutex;
                  
                  self->exitActivity();
                  
                  if (mode == DictionaryMode::ENTER_WORD) {
                    self->enterNewActivity(new DictionarySearchActivity(r, m,
                        [self]() {
                          self->exitActivity();
                          self->updateRequired = true;
                        }, ""));
                  } else if (s) {
                    xSemaphoreTake(mtx, portMAX_DELAY);
                    auto page = s->loadPageFromSectionFile();
                    if (page) {
                      int mt, mr, mb, ml;
                      r.getOrientedViewableTRBL(&mt, &mr, &mb, &ml);
                      mt += SETTINGS.screenMargin;
                      ml += SETTINGS.screenMargin;
                      const int fontId = SETTINGS.getReaderFontId();
                      
                      self->enterNewActivity(new EpubWordSelectionActivity(
                          r, m, std::move(page), fontId, ml, mt,
                          [self](const std::string& word) {
                            self->exitActivity();
                            self->enterNewActivity(new DictionarySearchActivity(
                                self->renderer, self->mappedInput,
                                [self]() {
                                  self->exitActivity();
                                  self->updateRequired = true;
                                }, word));
                          },
                          [self]() {
                            self->exitActivity();
                            self->updateRequired = true;
                          }));
                      xSemaphoreGive(mtx);
                    } else {
                      xSemaphoreGive(mtx);
                      self->updateRequired = true;
                    }
                  } else {
                    self->updateRequired = true;
                  }
                },
                [self]() {
                  self->exitActivity();
                  self->updateRequired = true;
                },
                self->section != nullptr));
          } else if (action == QuickMenuAction::ADD_BOOKMARK) {
            // Toggle bookmark on current page
            if (self->section) {
              const uint32_t contentOffset = self->section->getContentOffsetForPage(self->section->currentPage);
              const std::string& bookPath = self->epub->getPath();
              
              if (BookmarkStore::isPageBookmarked(bookPath, self->currentSpineIndex, contentOffset)) {
                // Remove bookmark
                BookmarkStore::removeBookmark(bookPath, self->currentSpineIndex, contentOffset);
              } else {
                // Add bookmark with auto-generated name
                Bookmark bm;
                bm.spineIndex = self->currentSpineIndex;
                bm.contentOffset = contentOffset;
                bm.pageNumber = self->section->currentPage;
                bm.timestamp = millis() / 1000;  // Approximate timestamp
                
                // Generate name: "Chapter - Page X" or fallback
                std::string chapterTitle;
                const int tocIndex = self->epub->getTocIndexForSpineIndex(self->currentSpineIndex);
                if (tocIndex >= 0) {
                  chapterTitle = self->epub->getTocItem(tocIndex).title;
                }
                if (!chapterTitle.empty()) {
                  bm.name = chapterTitle + " - Page " + std::to_string(self->section->currentPage + 1);
                } else {
                  bm.name = "Page " + std::to_string(self->section->currentPage + 1);
                }
                
                BookmarkStore::addBookmark(bookPath, bm);
              }
            }
            self->updateRequired = true;
          } else if (action == QuickMenuAction::CLEAR_CACHE) {
            // Navigate to Clear Cache activity
            if (self->onGoToClearCache) {
              xSemaphoreGive(cachedMutex);
              self->onGoToClearCache();
              return;
            }
            self->updateRequired = true;
          } else if (action == QuickMenuAction::GO_TO_SETTINGS) {
            // Navigate to Settings activity
            if (self->onGoToSettings) {
              xSemaphoreGive(cachedMutex);
              self->onGoToSettings();
              return;
            }
            self->updateRequired = true;
          }
        },
        [this]() {
          EpubReaderActivity* self = this;
          exitActivity();
          self->updateRequired = true;
        },
        isBookmarked));
    xSemaphoreGive(renderingMutex);
    return;
  }

  const bool prevReleased = mappedInput.wasReleased(MappedInputManager::Button::PageBack) ||
                            mappedInput.wasReleased(MappedInputManager::Button::Left);
  const bool nextReleased = mappedInput.wasReleased(MappedInputManager::Button::PageForward) ||
                            (SETTINGS.shortPwrBtn == CrossPointSettings::SHORT_PWRBTN::PAGE_TURN &&
                             mappedInput.wasReleased(MappedInputManager::Button::Power)) ||
                            mappedInput.wasReleased(MappedInputManager::Button::Right);

  if (!prevReleased && !nextReleased) {
    return;
  }

  // any button press when at end of the book - this is now handled by the prompt
  // Just ensure we don't go past the end
  if (currentSpineIndex >= epub->getSpineItemsCount()) {
    return;
  }

  const bool skipChapter = SETTINGS.longPressChapterSkip && mappedInput.getHeldTime() > skipChapterMs;

  if (skipChapter) {
    // We don't want to delete the section mid-render, so grab the semaphore
    xSemaphoreTake(renderingMutex, portMAX_DELAY);
    nextPageNumber = 0;
    currentSpineIndex = nextReleased ? currentSpineIndex + 1 : currentSpineIndex - 1;
    section.reset();
    xSemaphoreGive(renderingMutex);
    updateRequired = true;
    return;
  }

  // No current section, attempt to rerender the book
  if (!section) {
    updateRequired = true;
    return;
  }

  if (prevReleased) {
    if (section->currentPage > 0) {
      section->currentPage--;
    } else {
      // We don't want to delete the section mid-render, so grab the semaphore
      xSemaphoreTake(renderingMutex, portMAX_DELAY);
      nextPageNumber = UINT16_MAX;
      currentSpineIndex--;
      section.reset();
      xSemaphoreGive(renderingMutex);
    }
    updateRequired = true;
  } else {
    if (section->currentPage < section->pageCount - 1) {
      section->currentPage++;
    } else {
      // We don't want to delete the section mid-render, so grab the semaphore
      xSemaphoreTake(renderingMutex, portMAX_DELAY);
      nextPageNumber = 0;
      currentSpineIndex++;
      section.reset();
      xSemaphoreGive(renderingMutex);
    }
    updateRequired = true;
  }
}

void EpubReaderActivity::displayTaskLoop() {
  while (true) {
    if (updateRequired) {
      updateRequired = false;
      xSemaphoreTake(renderingMutex, portMAX_DELAY);
      renderScreen();
      xSemaphoreGive(renderingMutex);
    }
    vTaskDelay(10 / portTICK_PERIOD_MS);
  }
}

// TODO: Failure handling
void EpubReaderActivity::renderScreen() {
  if (!epub) {
    return;
  }

  // edge case handling for sub-zero spine index
  if (currentSpineIndex < 0) {
    currentSpineIndex = 0;
  }
  // based bounds of book, show end of book screen
  if (currentSpineIndex > epub->getSpineItemsCount()) {
    currentSpineIndex = epub->getSpineItemsCount();
  }

  // Show end of book prompt
  if (currentSpineIndex == epub->getSpineItemsCount()) {
    showingEndOfBookPrompt = true;
    renderEndOfBookPrompt();
    return;
  }
  showingEndOfBookPrompt = false;

  // Apply screen viewable areas and additional padding
  int orientedMarginTop, orientedMarginRight, orientedMarginBottom, orientedMarginLeft;
  renderer.getOrientedViewableTRBL(&orientedMarginTop, &orientedMarginRight, &orientedMarginBottom,
                                   &orientedMarginLeft);
  orientedMarginTop += SETTINGS.screenMargin;
  orientedMarginLeft += SETTINGS.screenMargin;
  orientedMarginRight += SETTINGS.screenMargin;
  orientedMarginBottom += SETTINGS.screenMargin;

  // Add status bar margin
  if (SETTINGS.statusBar != CrossPointSettings::STATUS_BAR_MODE::NONE) {
    // Add additional margin for status bar if progress bar is shown
    const bool showProgressBar = SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::FULL_WITH_PROGRESS_BAR ||
                                 SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::ONLY_PROGRESS_BAR;
    orientedMarginBottom += statusBarMargin - SETTINGS.screenMargin +
                            (showProgressBar ? (ScreenComponents::BOOK_PROGRESS_BAR_HEIGHT + progressBarMarginTop) : 0);
  }

  if (!section) {
    const auto filepath = epub->getSpineItem(currentSpineIndex).href;
    Serial.printf("[%lu] [ERS] Loading file: %s, index: %d\n", millis(), filepath.c_str(), currentSpineIndex);
    section = std::unique_ptr<Section>(new Section(epub, currentSpineIndex, renderer));

    const uint16_t viewportWidth = renderer.getScreenWidth() - orientedMarginLeft - orientedMarginRight;
    const uint16_t viewportHeight = renderer.getScreenHeight() - orientedMarginTop - orientedMarginBottom;

    bool sectionWasReIndexed = false;
    
    if (!section->loadSectionFile(SETTINGS.getReaderFontId(), SETTINGS.getReaderLineCompression(),
                                  SETTINGS.extraParagraphSpacing, SETTINGS.paragraphAlignment, viewportWidth,
                                  viewportHeight, SETTINGS.hyphenationEnabled)) {
      Serial.printf("[%lu] [ERS] Cache not found, building...\n", millis());
      sectionWasReIndexed = true;

      // Progress bar dimensions
      constexpr int barWidth = 200;
      constexpr int barHeight = 10;
      constexpr int boxMargin = 20;
      const int textWidth = renderer.getTextWidth(UI_12_FONT_ID, "Indexing...");
      const int boxWidthWithBar = (barWidth > textWidth ? barWidth : textWidth) + boxMargin * 2;
      const int boxWidthNoBar = textWidth + boxMargin * 2;
      const int boxHeightWithBar = renderer.getLineHeight(UI_12_FONT_ID) + barHeight + boxMargin * 3;
      const int boxHeightNoBar = renderer.getLineHeight(UI_12_FONT_ID) + boxMargin * 2;
      const int boxXWithBar = (renderer.getScreenWidth() - boxWidthWithBar) / 2;
      const int boxXNoBar = (renderer.getScreenWidth() - boxWidthNoBar) / 2;
      constexpr int boxY = 50;
      const int barX = boxXWithBar + (boxWidthWithBar - barWidth) / 2;
      const int barY = boxY + renderer.getLineHeight(UI_12_FONT_ID) + boxMargin * 2;

      // Always show "Indexing..." text first
      {
        renderer.fillRect(boxXNoBar, boxY, boxWidthNoBar, boxHeightNoBar, false);
        renderer.drawText(UI_12_FONT_ID, boxXNoBar + boxMargin, boxY + boxMargin, "Indexing...");
        renderer.drawRect(boxXNoBar + 5, boxY + 5, boxWidthNoBar - 10, boxHeightNoBar - 10);
        renderer.displayBuffer();
        pagesUntilFullRefresh = 0;
      }

      // Setup callback - only called for chapters >= 50KB, redraws with progress bar
      auto progressSetup = [this, boxXWithBar, boxWidthWithBar, boxHeightWithBar, barX, barY] {
        renderer.fillRect(boxXWithBar, boxY, boxWidthWithBar, boxHeightWithBar, false);
        renderer.drawText(UI_12_FONT_ID, boxXWithBar + boxMargin, boxY + boxMargin, "Indexing...");
        renderer.drawRect(boxXWithBar + 5, boxY + 5, boxWidthWithBar - 10, boxHeightWithBar - 10);
        renderer.drawRect(barX, barY, barWidth, barHeight);
        renderer.displayBuffer();
      };

      // Progress callback to update progress bar
      auto progressCallback = [this, barX, barY, barWidth, barHeight](int progress) {
        const int fillWidth = (barWidth - 2) * progress / 100;
        renderer.fillRect(barX + 1, barY + 1, fillWidth, barHeight - 2, true);
        renderer.displayBuffer(EInkDisplay::FAST_REFRESH);
      };

        if (!section->createSectionFile(SETTINGS.getReaderFontId(), SETTINGS.getReaderLineCompression(),
                                      SETTINGS.extraParagraphSpacing, SETTINGS.paragraphAlignment, viewportWidth,
                                      viewportHeight, SETTINGS.hyphenationEnabled, progressSetup, progressCallback)) {
        Serial.printf("[%lu] [ERS] Failed to persist page data to SD\n", millis());
        section.reset();
        return;
      }
    } else {
      Serial.printf("[%lu] [ERS] Cache found, skipping build...\n", millis());
    }

    // Determine the correct page to display
    if (nextPageNumber == UINT16_MAX) {
      // Special case: go to last page
      section->currentPage = section->pageCount - 1;
    } else if (sectionWasReIndexed && hasContentOffset) {
      // Section was re-indexed (settings changed) and we have a content offset
      // Use the offset to find the correct page
      const int restoredPage = section->findPageForContentOffset(savedContentOffset);
      section->currentPage = restoredPage;
      Serial.printf("[%lu] [ERS] Restored position via offset: %u -> page %d (was page %d)\n", 
                    millis(), savedContentOffset, restoredPage, nextPageNumber);
      // Clear the offset flag since we've used it
      hasContentOffset = false;
    } else {
      // Normal case: use the saved page number
      section->currentPage = nextPageNumber;
    }
  }

  renderer.clearScreen();

  if (section->pageCount == 0) {
    Serial.printf("[%lu] [ERS] No pages to render\n", millis());
    renderer.drawCenteredText(UI_12_FONT_ID, 300, "Empty chapter", true, EpdFontFamily::BOLD);
    renderStatusBar(orientedMarginRight, orientedMarginBottom, orientedMarginLeft);
    renderer.displayBuffer();
    return;
  }

  if (section->currentPage < 0 || section->currentPage >= section->pageCount) {
    Serial.printf("[%lu] [ERS] Page out of bounds: %d (max %d)\n", millis(), section->currentPage, section->pageCount);
    renderer.drawCenteredText(UI_12_FONT_ID, 300, "Out of bounds", true, EpdFontFamily::BOLD);
    renderStatusBar(orientedMarginRight, orientedMarginBottom, orientedMarginLeft);
    renderer.displayBuffer();
    return;
  }

  {
    auto p = section->loadPageFromSectionFile();
    if (!p) {
      Serial.printf("[%lu] [ERS] Failed to load page from SD - clearing section cache\n", millis());
      section->clearCache();
      section.reset();
      return renderScreen();
    }
    
    // Handle empty pages (e.g., from malformed chapters that couldn't be parsed)
    if (p->elements.empty()) {
      Serial.printf("[%lu] [ERS] Page has no content (possibly malformed chapter)\n", millis());
      renderer.drawCenteredText(UI_12_FONT_ID, 280, "Chapter content unavailable", true, EpdFontFamily::BOLD);
      renderer.drawCenteredText(UI_10_FONT_ID, 320, "(File may be malformed)");
      renderStatusBar(orientedMarginRight, orientedMarginBottom, orientedMarginLeft);
      renderer.displayBuffer();
      return;
    }
    
    const auto start = millis();
    renderContents(std::move(p), orientedMarginTop, orientedMarginRight, orientedMarginBottom, orientedMarginLeft);
    Serial.printf("[%lu] [ERS] Rendered page in %dms\n", millis(), millis() - start);
  }

  // Save progress with content offset for position restoration after re-indexing
  FsFile f;
  if (SdMan.openFileForWrite("ERS", epub->getCachePath() + "/progress.bin", f)) {
    // Get content offset for current page
    const uint32_t contentOffset = section->getContentOffsetForPage(section->currentPage);
    
    // New format: version (1) + spineIndex (2) + pageNumber (2) + contentOffset (4) = 9 bytes
    serialization::writePod(f, EPUB_PROGRESS_VERSION);
    serialization::writePod(f, static_cast<uint16_t>(currentSpineIndex));
    serialization::writePod(f, static_cast<uint16_t>(section->currentPage));
    serialization::writePod(f, contentOffset);
    
    f.close();
    Serial.printf("[%lu] [ERS] Saved progress: spine %d, page %d, offset %u\n", 
                  millis(), currentSpineIndex, section->currentPage, contentOffset);
  }
}

void EpubReaderActivity::renderContents(std::unique_ptr<Page> page, const int orientedMarginTop,
                                        const int orientedMarginRight, const int orientedMarginBottom,
                                        const int orientedMarginLeft) {
  page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
  
  // Draw bookmark indicator (folded corner) if this page is bookmarked
  if (section) {
    const uint32_t contentOffset = section->getContentOffsetForPage(section->currentPage);
    if (BookmarkStore::isPageBookmarked(epub->getPath(), currentSpineIndex, contentOffset)) {
      // Draw folded corner in top-right
      const int screenWidth = renderer.getScreenWidth();
      constexpr int cornerSize = 20;
      const int cornerX = screenWidth - orientedMarginRight - cornerSize;
      const int cornerY = orientedMarginTop;
      
      // Draw triangle (folded corner effect)
      const int xPoints[3] = {cornerX, cornerX + cornerSize, cornerX + cornerSize};
      const int yPoints[3] = {cornerY, cornerY, cornerY + cornerSize};
      renderer.fillPolygon(xPoints, yPoints, 3, true);  // Black triangle
    }
  }
  
  renderStatusBar(orientedMarginRight, orientedMarginBottom, orientedMarginLeft);
  if (pagesUntilFullRefresh <= 1) {
    renderer.displayBuffer(EInkDisplay::HALF_REFRESH);
    pagesUntilFullRefresh = SETTINGS.getRefreshFrequency();
  } else {
    renderer.displayBuffer();
    pagesUntilFullRefresh--;
  }

  // grayscale rendering requires storing the BW buffer first
  // If we can't allocate memory for the backup, skip grayscale to avoid artifacts
  // TODO: Only do this if font supports it
  if (SETTINGS.textAntiAliasing) {
    // Try to save BW buffer - if this fails, skip grayscale rendering entirely
    const bool bwBufferStored = renderer.storeBwBuffer();

    if (bwBufferStored) {
      renderer.clearScreen(0x00);
      renderer.setRenderMode(GfxRenderer::GRAYSCALE_LSB);
      page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
      renderer.copyGrayscaleLsbBuffers();

      // Render and copy to MSB buffer
      renderer.clearScreen(0x00);
      renderer.setRenderMode(GfxRenderer::GRAYSCALE_MSB);
      page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
      renderer.copyGrayscaleMsbBuffers();

      // display grayscale part
      renderer.displayGrayBuffer();
      renderer.setRenderMode(GfxRenderer::BW);

      // restore the bw data
      renderer.restoreBwBuffer();
    }
  }
}

void EpubReaderActivity::renderStatusBar(const int orientedMarginRight, const int orientedMarginBottom,
                                         const int orientedMarginLeft) const {
  // determine visible status bar elements
  const bool showProgressPercentage = SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::FULL;
  const bool showProgressBar = SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::FULL_WITH_PROGRESS_BAR ||
                               SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::ONLY_PROGRESS_BAR;
  const bool showProgressText = SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::FULL ||
                                SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::FULL_WITH_PROGRESS_BAR;
  const bool showBattery = SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::NO_PROGRESS ||
                           SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::FULL ||
                           SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::FULL_WITH_PROGRESS_BAR;
  const bool showChapterTitle = SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::NO_PROGRESS ||
                                SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::FULL ||
                                SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::FULL_WITH_PROGRESS_BAR;
  const bool showBatteryPercentage =
      SETTINGS.hideBatteryPercentage == CrossPointSettings::HIDE_BATTERY_PERCENTAGE::HIDE_NEVER;

  // Position status bar near the bottom of the logical screen, regardless of orientation
  const auto screenHeight = renderer.getScreenHeight();
  const auto textY = screenHeight - orientedMarginBottom - 4;
  int progressTextWidth = 0;

  // Calculate progress in book
  const float sectionChapterProg = static_cast<float>(section->currentPage) / section->pageCount;
  const float bookProgress = epub->calculateProgress(currentSpineIndex, sectionChapterProg) * 100;

  if (showProgressText || showProgressPercentage) {
    // Right aligned text for progress counter
    char progressStr[32];

    // Hide percentage when progress bar is shown to reduce clutter
    if (showProgressPercentage) {
      snprintf(progressStr, sizeof(progressStr), "%d/%d  %.0f%%", section->currentPage + 1, section->pageCount,
               bookProgress);
    } else {
      snprintf(progressStr, sizeof(progressStr), "%d/%d", section->currentPage + 1, section->pageCount);
    }

    progressTextWidth = renderer.getTextWidth(SMALL_FONT_ID, progressStr);
    renderer.drawText(SMALL_FONT_ID, renderer.getScreenWidth() - orientedMarginRight - progressTextWidth, textY,
                      progressStr);
  }

  if (showProgressBar) {
    // Draw progress bar at the very bottom of the screen, from edge to edge of viewable area
    ScreenComponents::drawBookProgressBar(renderer, static_cast<size_t>(bookProgress));
  }

  if (showBattery) {
    ScreenComponents::drawBattery(renderer, orientedMarginLeft + 1, textY, showBatteryPercentage);
  }

  if (showChapterTitle) {
    // Centered chatper title text
    // Page width minus existing content with 30px padding on each side
    const int rendererableScreenWidth = renderer.getScreenWidth() - orientedMarginLeft - orientedMarginRight;

    const int batterySize = showBattery ? (showBatteryPercentage ? 50 : 20) : 0;
    const int titleMarginLeft = batterySize + 30;
    const int titleMarginRight = progressTextWidth + 30;

    // Attempt to center title on the screen, but if title is too wide then later we will center it within the
    // available space.
    int titleMarginLeftAdjusted = std::max(titleMarginLeft, titleMarginRight);
    int availableTitleSpace = rendererableScreenWidth - 2 * titleMarginLeftAdjusted;
    const int tocIndex = epub->getTocIndexForSpineIndex(currentSpineIndex);

    std::string title;
    int titleWidth;
    if (tocIndex == -1) {
      title = "Unnamed";
      titleWidth = renderer.getTextWidth(SMALL_FONT_ID, "Unnamed");
    } else {
      const auto tocItem = epub->getTocItem(tocIndex);
      title = tocItem.title;
      titleWidth = renderer.getTextWidth(SMALL_FONT_ID, title.c_str());
      if (titleWidth > availableTitleSpace) {
        // Not enough space to center on the screen, center it within the remaining space instead
        availableTitleSpace = rendererableScreenWidth - titleMarginLeft - titleMarginRight;
        titleMarginLeftAdjusted = titleMarginLeft;
      }
      while (titleWidth > availableTitleSpace && title.length() > 11) {
        title.replace(title.length() - 8, 8, "...");
        titleWidth = renderer.getTextWidth(SMALL_FONT_ID, title.c_str());
      }
    }

    renderer.drawText(SMALL_FONT_ID,
                      titleMarginLeftAdjusted + orientedMarginLeft + (availableTitleSpace - titleWidth) / 2, textY,
                      title.c_str());
  }
}

void EpubReaderActivity::renderEndOfBookPrompt() {
  const int pageWidth = renderer.getScreenWidth();
  const int pageHeight = renderer.getScreenHeight();

  renderer.clearScreen();

  // Title
  renderer.drawCenteredText(UI_12_FONT_ID, 80, "Finished!", true, EpdFontFamily::BOLD);

  // Book title (truncated if needed)
  std::string bookTitle = epub->getTitle();
  if (bookTitle.length() > 30) {
    bookTitle = bookTitle.substr(0, 27) + "...";
  }
  renderer.drawCenteredText(UI_10_FONT_ID, 120, bookTitle.c_str());

  // Menu options
  const int menuStartY = pageHeight / 2 - 30;
  constexpr int menuLineHeight = 45;
  constexpr int menuItemWidth = 140;
  const int menuX = (pageWidth - menuItemWidth) / 2;

  const char* options[] = {"Archive", "Delete", "Keep"};
  for (int i = 0; i < 3; i++) {
    const int optionY = menuStartY + i * menuLineHeight;
    if (endOfBookSelection == i) {
      renderer.fillRect(menuX - 10, optionY - 5, menuItemWidth + 20, menuLineHeight - 5);
    }
    renderer.drawCenteredText(UI_10_FONT_ID, optionY, options[i], endOfBookSelection != i);
  }

  // Button hints
  const auto labels = mappedInput.mapLabels("« Back", "Select", "", "");
  renderer.drawButtonHints(UI_10_FONT_ID, labels.btn1, labels.btn2, labels.btn3, labels.btn4);

  renderer.displayBuffer();
}

void EpubReaderActivity::handleEndOfBookAction() {
  const std::string bookPath = epub->getPath();

  switch (endOfBookSelection) {
    case 0:  // Archive
      BookManager::archiveBook(bookPath);
      onGoHome();
      break;
    case 1:  // Delete
      BookManager::deleteBook(bookPath);
      onGoHome();
      break;
    case 2:  // Keep
    default:
      onGoHome();
      break;
  }
}