#include "EpubReaderActivity.h"

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

#include "CrossPointSettings.h"
#include "CrossPointState.h"
#include "EpubReaderChapterSelectionActivity.h"

#include "EpubReaderFootnotesActivity.h"
#include "EpubReaderMenuActivity.h"

#include "MappedInputManager.h"
#include "RecentBooksStore.h"
#include "ScreenComponents.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;
}  // 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();

  FsFile f;
  if (SdMan.openFileForRead("ERS", epub->getCachePath() + "/progress.bin", f)) {
    uint8_t data[4];
    if (f.read(data, 4) == 4) {
      currentSpineIndex = data[0] + (data[1] << 8);
      nextPageNumber = data[2] + (data[3] << 8);
      Serial.printf("[%lu] [ERS] Loaded cache: %d, %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 add to recent books
  APP_STATE.openEpubPath = epub->getPath();
  APP_STATE.saveToFile();
  RECENT_BOOKS.addBook(epub->getPath());

  // Trigger first update
  updateRequired = true;

  xTaskCreate(&EpubReaderActivity::taskTrampoline, "EpubReaderActivityTask",
              24576,              // 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) {
    vTaskDelete(displayTaskHandle);
    displayTaskHandle = nullptr;
  }
  vSemaphoreDelete(renderingMutex);
  renderingMutex = nullptr;
  section.reset();
  epub.reset();
}

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

  // Enter chapter selection activity or menu
  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;

    // Show menu instead of direct chapter selection, to allow access to footnotes
    exitActivity();
    enterNewActivity(new EpubReaderMenuActivity(
        this->renderer, this->mappedInput,
        [this] {
          // onGoBack from menu
          updateRequired = true;
          // Re-enter reader activity logic if needed (handled by stack)
          // Actually ActivityWithSubactivity handles subActivity exit naturally
          exitActivity();
        },
        [this, currentPage, totalPages](EpubReaderMenuActivity::MenuOption option) {
          // onSelectOption - handle menu choice
          if (option == EpubReaderMenuActivity::CHAPTERS) {
             // Show chapter selection
             exitActivity();
             enterNewActivity(new EpubReaderChapterSelectionActivity(
                this->renderer, this->mappedInput, epub, epub->getPath(), currentSpineIndex, currentPage, totalPages,
                [this] {
                  exitActivity();
                  updateRequired = true;
                },
                [this](int newSpineIndex) {
                  if (currentSpineIndex != newSpineIndex) {
                    currentSpineIndex = newSpineIndex;
                    nextPageNumber = 0;
                    section.reset();
                  }
                  exitActivity();
                  updateRequired = true;
                },
                [this](int newSpineIndex, int newPage) {
                  // Handle sync position
                  if (currentSpineIndex != newSpineIndex || (section && section->currentPage != newPage)) {
                    currentSpineIndex = newSpineIndex;
                    nextPageNumber = newPage;
                    section.reset();
                  }
                  exitActivity();
                  updateRequired = true;
                }));
          } else if (option == EpubReaderMenuActivity::FOOTNOTES) {
            // Show footnotes page with current page notes
            exitActivity();
            enterNewActivity(new EpubReaderFootnotesActivity(
                this->renderer, this->mappedInput,
                currentPageFootnotes,  // Pass collected footnotes (reference)
                [this] {
                  // onGoBack from footnotes
                  exitActivity();
                  updateRequired = true;
                },
                [this](const char* href) {
                  // onSelectFootnote - navigate to the footnote location
                  navigateToHref(href, true);  // true = save current position
                  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) {
    if (isViewingFootnote) {
      restoreSavedPosition();
      updateRequired = true;
      return;
    } else {
      onGoBack();
      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 goes back to the last page
  if (currentSpineIndex > 0 && currentSpineIndex >= epub->getSpineItemsCount()) {
    currentSpineIndex = epub->getSpineItemsCount() - 1;
    nextPageNumber = UINT16_MAX;
    updateRequired = true;
    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);
  }
}

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 screen
  if (currentSpineIndex == epub->getSpineItemsCount()) {
    renderer.clearScreen();
    renderer.drawCenteredText(UI_12_FONT_ID, 300, "End of book", true, EpdFontFamily::BOLD);
    renderer.displayBuffer();
    return;
  }

  // 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 += statusBarMargin;

  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;

    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());

      // 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());
    }

    if (nextPageNumber == UINT16_MAX) {
      section->currentPage = section->pageCount - 1;
    } else {
      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();
    }

    Serial.printf("[%lu] [ERS] Page loaded: %d elements, %d footnotes\n", millis(), p->elements.size(), p->footnotes.size());

    // Copy footnotes from page to currentPageFootnotes
    currentPageFootnotes.clear();
    int maxFootnotes = (p->footnotes.size() < 8) ? p->footnotes.size() : 8;

    for (int i = 0; i < maxFootnotes; i++) {
        const FootnoteEntry& footnote = p->footnotes[i];
        if (footnote.href[0] != '\0') {
            currentPageFootnotes.addFootnote(footnote.number, footnote.href);
        }
    }
    Serial.printf("[%lu] [ERS] Loaded %d footnotes for current page\n", millis(), p->footnotes.size());

    const auto start = millis();
    renderContents(std::move(p), orientedMarginTop, orientedMarginRight, orientedMarginBottom, orientedMarginLeft);
    Serial.printf("[%lu] [ERS] Rendered page in %dms\n", millis(), millis() - start);
  }

  FsFile f;
  if (SdMan.openFileForWrite("ERS", epub->getCachePath() + "/progress.bin", f)) {
    uint8_t data[4];
    data[0] = currentSpineIndex & 0xFF;
    data[1] = (currentSpineIndex >> 8) & 0xFF;
    data[2] = section->currentPage & 0xFF;
    data[3] = (section->currentPage >> 8) & 0xFF;
    f.write(data, 4);
    f.close();
  }
}

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);
  renderStatusBar(orientedMarginRight, orientedMarginBottom, orientedMarginLeft);
  if (pagesUntilFullRefresh <= 1) {
    renderer.displayBuffer(EInkDisplay::HALF_REFRESH);
    pagesUntilFullRefresh = SETTINGS.getRefreshFrequency();
  } else {
    renderer.displayBuffer();
    pagesUntilFullRefresh--;
  }

  // Save bw buffer to reset buffer state after grayscale data sync
  renderer.storeBwBuffer();

  // grayscale rendering
  // TODO: Only do this if font supports it
  if (SETTINGS.textAntiAliasing) {
    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 showProgress = SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::FULL;
  const bool showBattery = SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::NO_PROGRESS ||
                           SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::FULL;
  const bool showChapterTitle = SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::NO_PROGRESS ||
                                SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::FULL;
  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;
  

  if (showProgress) {
    // Calculate progress in book
    // TODO: use progress values for UI

    // cppcheck-suppress unreadVariable
    const float sectionChapterProg = static_cast<float>(section->currentPage) / section->pageCount;
    // cppcheck-suppress unreadVariable
    const float bookProgress = epub->calculateProgress(currentSpineIndex, sectionChapterProg) * 100;
  }

  // Left aligned battery icon and percentage
  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;

    int progressTextWidth = 0;
    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::navigateToHref(const char* href, bool savePosition) {
  if (!epub || !href) return;

  // Save current position if requested
  if (savePosition && section) {
    savedSpineIndex = currentSpineIndex;
    savedPageNumber = section->currentPage;
    isViewingFootnote = true;
    Serial.printf("[%lu] [ERS] Saved position: spine %d, page %d\n", millis(), savedSpineIndex, savedPageNumber);
  }

  // Parse href: "filename.html#anchor"
  std::string hrefStr(href);
  std::string filename;
  std::string anchor;

  size_t hashPos = hrefStr.find('#');
  if (hashPos != std::string::npos) {
    filename = hrefStr.substr(0, hashPos);
    anchor = hrefStr.substr(hashPos + 1);
  } else {
    filename = hrefStr;
  }

  // Extract just filename without path
  size_t lastSlash = filename.find_last_of('/');
  if (lastSlash != std::string::npos) {
    filename = filename.substr(lastSlash + 1);
  }

  Serial.printf("[%lu] [ERS] Navigate to: %s (anchor: %s)\n", millis(), filename.c_str(), anchor.c_str());

  int targetSpineIndex = -1;

  // FIRST: Check if we have an inline footnote or paragraph note for this anchor
  if (!anchor.empty()) {
    // Try inline footnote first
    std::string inlineFilename = "inline_" + anchor + ".html";
    Serial.printf("[%lu] [ERS] Looking for inline footnote: %s\n", millis(), inlineFilename.c_str());

    targetSpineIndex = epub->findVirtualSpineIndex(inlineFilename);

    // If not found, try paragraph note
    if (targetSpineIndex == -1) {
      std::string pnoteFilename = "pnote_" + anchor + ".html";
      Serial.printf("[%lu] [ERS] Looking for paragraph note: %s\n", millis(), pnoteFilename.c_str());

      targetSpineIndex = epub->findVirtualSpineIndex(pnoteFilename);
    }

    if (targetSpineIndex != -1) {
      Serial.printf("[%lu] [ERS] Found note at virtual index: %d\n", millis(), targetSpineIndex);

      // Navigate to the note
      xSemaphoreTake(renderingMutex, portMAX_DELAY);
      currentSpineIndex = targetSpineIndex;
      nextPageNumber = 0;
      section.reset();
      xSemaphoreGive(renderingMutex);

      updateRequired = true;
      return;
    } else {
      Serial.printf("[%lu] [ERS] No virtual note found, trying normal navigation\n", millis());
    }
  }

  // FALLBACK: Try to find the file in normal spine items
  for (int i = 0; i < epub->getSpineItemsCount(); i++) {
    if (epub->isVirtualSpineItem(i)) continue;

    BookMetadataCache::SpineEntry entry = epub->getSpineItem(i);
    std::string spineItem = entry.href;
    size_t lastslash = spineItem.find_last_of('/');
    std::string spineFilename = (lastslash != std::string::npos) ? spineItem.substr(lastslash + 1) : spineItem;

    if (spineFilename == filename) {
      targetSpineIndex = i;
      break;
    }
  }

  if (targetSpineIndex == -1) {
    Serial.printf("[%lu] [ERS] Could not find spine index for: %s\n", millis(), filename.c_str());
    return;
  }

  // Navigate to the target chapter
  xSemaphoreTake(renderingMutex, portMAX_DELAY);
  currentSpineIndex = targetSpineIndex;
  nextPageNumber = 0;
  section.reset();
  xSemaphoreGive(renderingMutex);

  updateRequired = true;

  Serial.printf("[%lu] [ERS] Navigated to spine index: %d\n", millis(), targetSpineIndex);
}

void EpubReaderActivity::restoreSavedPosition() {
  if (savedSpineIndex >= 0 && savedPageNumber >= 0) {
    Serial.printf("[%lu] [ERS] Restoring position: spine %d, page %d\n", millis(), savedSpineIndex, savedPageNumber);

    xSemaphoreTake(renderingMutex, portMAX_DELAY);
    currentSpineIndex = savedSpineIndex;
    nextPageNumber = savedPageNumber;
    section.reset();
    xSemaphoreGive(renderingMutex);

    savedSpineIndex = -1;
    savedPageNumber = -1;
    isViewingFootnote = false;
    updateRequired = true;
  }
}