#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 "MappedInputManager.h"
#include "RecentBooksStore.h"
#include "components/UITheme.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;

}  // 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[6];
    int dataSize = f.read(data, 6);
    if (dataSize == 4 || dataSize == 6) {
      currentSpineIndex = data[0] + (data[1] << 8);
      nextPageNumber = data[2] + (data[3] << 8);
      cachedSpineIndex = currentSpineIndex;
      Serial.printf("[%lu] [ERS] Loaded cache: %d, %d\n", millis(), currentSpineIndex, nextPageNumber);
    }
    if (dataSize == 6) {
      cachedChapterTotalPageCount = data[4] + (data[5] << 8);
    }
    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(), epub->getTitle(), epub->getAuthor(), epub->getThumbBmpPath());

  // 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) {
    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
  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 EpubReaderMenuActivity(
        this->renderer, this->mappedInput, epub->getTitle(), [this]() { onReaderMenuBack(); },
        [this](EpubReaderMenuActivity::MenuAction action) { onReaderMenuConfirm(action); }));
    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;
  }

  // When long-press chapter skip is disabled, turn pages on press instead of release.
  const bool usePressForPageTurn = !SETTINGS.longPressChapterSkip;
  const bool prevTriggered = usePressForPageTurn ? (mappedInput.wasPressed(MappedInputManager::Button::PageBack) ||
                                                    mappedInput.wasPressed(MappedInputManager::Button::Left))
                                                 : (mappedInput.wasReleased(MappedInputManager::Button::PageBack) ||
                                                    mappedInput.wasReleased(MappedInputManager::Button::Left));
  const bool powerPageTurn = SETTINGS.shortPwrBtn == CrossPointSettings::SHORT_PWRBTN::PAGE_TURN &&
                             mappedInput.wasReleased(MappedInputManager::Button::Power);
  const bool nextTriggered = usePressForPageTurn
                                 ? (mappedInput.wasPressed(MappedInputManager::Button::PageForward) || powerPageTurn ||
                                    mappedInput.wasPressed(MappedInputManager::Button::Right))
                                 : (mappedInput.wasReleased(MappedInputManager::Button::PageForward) || powerPageTurn ||
                                    mappedInput.wasReleased(MappedInputManager::Button::Right));

  if (!prevTriggered && !nextTriggered) {
    return;
  }

  // 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;
    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 = nextTriggered ? 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 (prevTriggered) {
    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::onReaderMenuBack() {
  exitActivity();
  updateRequired = true;
}

void EpubReaderActivity::onReaderMenuConfirm(EpubReaderMenuActivity::MenuAction action) {
  switch (action) {
    case EpubReaderMenuActivity::MenuAction::SELECT_CHAPTER: {
      // Calculate values BEFORE we start destroying things
      const int currentP = section ? section->currentPage : 0;
      const int totalP = section ? section->pageCount : 0;
      const int spineIdx = currentSpineIndex;
      const std::string path = epub->getPath();

      xSemaphoreTake(renderingMutex, portMAX_DELAY);

      // 1. Close the menu
      exitActivity();

      // 2. Open the Chapter Selector
      enterNewActivity(new EpubReaderChapterSelectionActivity(
          this->renderer, this->mappedInput, epub, path, spineIdx, currentP, totalP,
          [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) {
            if (currentSpineIndex != newSpineIndex || (section && section->currentPage != newPage)) {
              currentSpineIndex = newSpineIndex;
              nextPageNumber = newPage;
              section.reset();
            }
            exitActivity();
            updateRequired = true;
          }));

      xSemaphoreGive(renderingMutex);
      break;
    }
    case EpubReaderMenuActivity::MenuAction::GO_HOME: {
      // 2. Trigger the reader's "Go Home" callback
      if (onGoHome) {
        onGoHome();
      }

      break;
    }
    case EpubReaderMenuActivity::MenuAction::DELETE_CACHE: {
      xSemaphoreTake(renderingMutex, portMAX_DELAY);
      if (epub) {
        // 2. BACKUP: Read current progress
        // We use the current variables that track our position
        uint16_t backupSpine = currentSpineIndex;
        uint16_t backupPage = section->currentPage;
        uint16_t backupPageCount = section->pageCount;

        section.reset();
        // 3. WIPE: Clear the cache directory
        epub->clearCache();

        // 4. RESTORE: Re-setup the directory and rewrite the progress file
        epub->setupCacheDir();

        saveProgress(backupSpine, backupPage, backupPageCount);
      }
      exitActivity();
      updateRequired = true;
      xSemaphoreGive(renderingMutex);
      if (onGoHome) onGoHome();
      break;
    }
  }
}

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 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 += SETTINGS.screenMargin;

  auto metrics = UITheme::getInstance().getMetrics();

  // 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 ? (metrics.bookProgressBarHeight + 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;

    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());

      const auto popupFn = [this]() { GUI.drawPopup(renderer, "Indexing..."); };

      if (!section->createSectionFile(SETTINGS.getReaderFontId(), SETTINGS.getReaderLineCompression(),
                                      SETTINGS.extraParagraphSpacing, SETTINGS.paragraphAlignment, viewportWidth,
                                      viewportHeight, SETTINGS.hyphenationEnabled, popupFn)) {
        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;
    }

    // handles changes in reader settings and reset to approximate position based on cached progress
    if (cachedChapterTotalPageCount > 0) {
      // only goes to relative position if spine index matches cached value
      if (currentSpineIndex == cachedSpineIndex && section->pageCount != cachedChapterTotalPageCount) {
        float progress = static_cast<float>(section->currentPage) / static_cast<float>(cachedChapterTotalPageCount);
        int newPage = static_cast<int>(progress * section->pageCount);
        section->currentPage = newPage;
      }
      cachedChapterTotalPageCount = 0;  // resets to 0 to prevent reading cached progress again
    }
  }

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

void EpubReaderActivity::saveProgress(int spineIndex, int currentPage, int pageCount) {
  FsFile f;
  if (SdMan.openFileForWrite("ERS", epub->getCachePath() + "/progress.bin", f)) {
    uint8_t data[6];
    data[0] = currentSpineIndex & 0xFF;
    data[1] = (currentSpineIndex >> 8) & 0xFF;
    data[2] = currentPage & 0xFF;
    data[3] = (currentPage >> 8) & 0xFF;
    data[4] = pageCount & 0xFF;
    data[5] = (pageCount >> 8) & 0xFF;
    f.write(data, 6);
    f.close();
    Serial.printf("[ERS] Progress saved: Chapter %d, Page %d\n", spineIndex, currentPage);
  } else {
    Serial.printf("[ERS] Could not save progress!\n");
  }
}
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(HalDisplay::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 {
  auto metrics = UITheme::getInstance().getMetrics();

  // 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
    GUI.drawBookProgressBar(renderer, static_cast<size_t>(bookProgress));
  }

  if (showBattery) {
    GUI.drawBattery(renderer, Rect{orientedMarginLeft + 1, textY, metrics.batteryWidth, metrics.batteryHeight},
                    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;
      }
      if (titleWidth > availableTitleSpace) {
        title = renderer.truncatedText(SMALL_FONT_ID, title.c_str(), availableTitleSpace);
        titleWidth = renderer.getTextWidth(SMALL_FONT_ID, title.c_str());
      }
    }

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