#include "HomeActivity.h"

#include <Bitmap.h>
#include <Epub.h>
#include <FsHelpers.h>
#include <GfxRenderer.h>
#include <HalStorage.h>
#include <I18n.h>
#include <Utf8.h>
#include <Xtc.h>

#include <cstring>
#include <vector>

#include "CrossPointSettings.h"
#include "CrossPointState.h"
#include "GlobalBookmarkIndex.h"
#include "MappedInputManager.h"
#include "RecentBooksStore.h"
#include "components/UITheme.h"
#include "fontIds.h"

namespace {
constexpr int CLASSIC_MIN_RECENT_TILE_HEIGHT = 280;
constexpr int LYRA_MIN_RECENT_TILE_HEIGHT = 170;
constexpr int LYRA_3_COVERS_MIN_RECENT_TILE_HEIGHT = 200;
constexpr int CLASSIC_MIN_RECENT_TO_MENU_GAP = 2;
constexpr int LYRA_MIN_RECENT_TO_MENU_GAP = 4;

struct HomeScreenLayout {
  int recentTileHeight;
  int recentToMenuGap;
  int menuHeight;
};

bool isLyraFamilyTheme() {
  const auto theme = static_cast<CrossPointSettings::UI_THEME>(SETTINGS.uiTheme);
  return theme == CrossPointSettings::UI_THEME::LYRA || theme == CrossPointSettings::UI_THEME::LYRA_3_COVERS;
}

bool isLyraExtendedTheme() {
  return static_cast<CrossPointSettings::UI_THEME>(SETTINGS.uiTheme) == CrossPointSettings::UI_THEME::LYRA_3_COVERS;
}

int getMinRecentTileHeight() {
  if (isLyraExtendedTheme()) {
    return LYRA_3_COVERS_MIN_RECENT_TILE_HEIGHT;
  }
  if (isLyraFamilyTheme()) {
    return LYRA_MIN_RECENT_TILE_HEIGHT;
  }
  return CLASSIC_MIN_RECENT_TILE_HEIGHT;
}

int getMinRecentToMenuGap() {
  return isLyraFamilyTheme() ? LYRA_MIN_RECENT_TO_MENU_GAP : CLASSIC_MIN_RECENT_TO_MENU_GAP;
}

HomeScreenLayout computeHomeScreenLayout(const ThemeMetrics& metrics, int contentHeight, int menuItemCount) {
  HomeScreenLayout layout{metrics.homeCoverTileHeight, metrics.verticalSpacing, 0};

  const int menuRequiredHeight =
      menuItemCount * metrics.menuRowHeight + std::max(0, menuItemCount - 1) * metrics.menuSpacing;

  auto computeMenuHeight = [&]() {
    return contentHeight - (metrics.homeTopPadding + layout.recentTileHeight + layout.recentToMenuGap);
  };

  layout.menuHeight = computeMenuHeight();
  if (layout.menuHeight >= menuRequiredHeight) {
    return layout;
  }

  const int gapReduction =
      std::min(layout.recentToMenuGap - getMinRecentToMenuGap(), menuRequiredHeight - layout.menuHeight);
  if (gapReduction > 0) {
    layout.recentToMenuGap -= gapReduction;
    layout.menuHeight = computeMenuHeight();
  }

  if (layout.menuHeight >= menuRequiredHeight) {
    return layout;
  }

  const int tileReduction =
      std::min(layout.recentTileHeight - getMinRecentTileHeight(), menuRequiredHeight - layout.menuHeight);
  if (tileReduction > 0) {
    layout.recentTileHeight -= tileReduction;
    layout.menuHeight = computeMenuHeight();
  }

  layout.menuHeight = std::max(0, layout.menuHeight);
  return layout;
}

int getHomeCoverRenderHeight(const HomeScreenLayout& layout) {
  return isLyraExtendedTheme() ? std::max(120, layout.recentTileHeight - 58)
                               : std::max(120, layout.recentTileHeight - (isLyraFamilyTheme() ? 16 : 0));
}
}  // namespace

// Builds the menu entry list in display order. Single source of truth for both loop() (which
// dispatches Confirm based on action) and render() (which draws labels/icons).
void HomeActivity::rebuildMenuEntries() {
  menuEntries.clear();
  menuEntries.reserve(7);

  menuEntries.push_back({MenuAction::FileBrowser, StrId::STR_BROWSE_FILES, Folder});
  menuEntries.push_back({MenuAction::Recents, StrId::STR_MENU_RECENT_BOOKS, Recent});
  if (!GLOBAL_BOOKMARKS.isEmpty()) {
    menuEntries.push_back({MenuAction::GlobalBookmarks, StrId::STR_GLOBAL_BOOKMARKS, Book});
  }
  if (hasOpdsUrl) {
    menuEntries.push_back({MenuAction::OpdsBrowser, StrId::STR_OPDS_BROWSER, Library});
  }
  menuEntries.push_back({MenuAction::FileTransfer, StrId::STR_FILE_TRANSFER, Transfer});
  if (SETTINGS.useWeather) {
    menuEntries.push_back({MenuAction::Weather, StrId::STR_WEATHER, Weather});
  }
  menuEntries.push_back({MenuAction::Settings, StrId::STR_SETTINGS_TITLE, Settings});
}

void HomeActivity::loadRecentBooks(int maxBooks) {
  recentBooks.clear();
  const auto& books = RECENT_BOOKS.getBooks();
  recentBooks.reserve(std::min(static_cast<int>(books.size()), maxBooks));

  for (const RecentBook& book : books) {
    // Limit to maximum number of recent books
    if (recentBooks.size() >= maxBooks) {
      break;
    }

    // Skip if file no longer exists
    if (!Storage.exists(book.path.c_str())) {
      continue;
    }

    recentBooks.push_back(book);
  }
}

void HomeActivity::loadRecentCovers(int coverHeight) {
  recentsLoading = true;

  for (; nextRecentCoverIndex < recentBooks.size(); nextRecentCoverIndex++) {
    RecentBook& book = recentBooks[nextRecentCoverIndex];
    if (!book.coverBmpPath.empty()) {
      std::string coverPath = UITheme::getCoverThumbPath(book.coverBmpPath, coverHeight);
      if (!Storage.exists(coverPath.c_str())) {
        // If epub, try to load the metadata for title/author and cover
        if (FsHelpers::hasEpubExtension(book.path)) {
          Epub epub(book.path, "/.crosspoint");
          // Skip loading css since we only need metadata here
          epub.load(false, true);

          // Try to generate thumbnail image for Continue Reading card
          bool success = epub.generateThumbBmp(coverHeight);
          if (!success) {
            RECENT_BOOKS.updateBook(book.path, book.title, book.author, book.series, "");
            book.coverBmpPath = "";
          }
          coverRendered = false;
          nextRecentCoverIndex++;
          recentsLoading = false;
          requestUpdate();
          return;
        } else if (FsHelpers::hasXtcExtension(book.path)) {
          // Handle XTC file
          Xtc xtc(book.path, "/.crosspoint");
          if (xtc.load()) {
            // Try to generate thumbnail image for Continue Reading card
            bool success = xtc.generateThumbBmp(coverHeight);
            if (!success) {
              RECENT_BOOKS.updateBook(book.path, book.title, book.author, book.series, "");
              book.coverBmpPath = "";
            }
            coverRendered = false;
            nextRecentCoverIndex++;
            recentsLoading = false;
            requestUpdate();
            return;
          }
        }
      }
    }
  }

  recentsLoaded = true;
  recentsLoading = false;
}

void HomeActivity::onEnter() {
  Activity::onEnter();

  // Check if OPDS browser URL is configured
  hasOpdsUrl = strlen(SETTINGS.opdsServerUrl) > 0;

  selectorIndex = 0;
  recentsLoading = false;
  recentsLoaded = false;
  firstRenderDone = false;
  nextRecentCoverIndex = 0;
  coverRendered = false;
  freeCoverBuffer();

  const auto& metrics = UITheme::getInstance().getMetrics();
  loadRecentBooks(metrics.homeRecentBooksCount);
  if (recentBooks.empty()) {
    recentsLoaded = true;
  }

  // Trigger first update
  requestUpdate();
}

void HomeActivity::onExit() {
  Activity::onExit();

  // Free the stored cover buffer if any
  freeCoverBuffer();
}

bool HomeActivity::storeCoverBuffer() {
  uint8_t* frameBuffer = renderer.getFrameBuffer();
  if (!frameBuffer) {
    return false;
  }

  // Free any existing buffer first
  freeCoverBuffer();

  const size_t bufferSize = renderer.getBufferSize();
  coverBuffer = static_cast<uint8_t*>(malloc(bufferSize));
  if (!coverBuffer) {
    return false;
  }

  memcpy(coverBuffer, frameBuffer, bufferSize);
  return true;
}

bool HomeActivity::restoreCoverBuffer() {
  if (!coverBuffer) {
    return false;
  }

  uint8_t* frameBuffer = renderer.getFrameBuffer();
  if (!frameBuffer) {
    return false;
  }

  const size_t bufferSize = renderer.getBufferSize();
  memcpy(frameBuffer, coverBuffer, bufferSize);
  return true;
}

void HomeActivity::freeCoverBuffer() {
  if (coverBuffer) {
    free(coverBuffer);
    coverBuffer = nullptr;
  }
  coverBufferStored = false;
}

void HomeActivity::loop() {
  rebuildMenuEntries();
  const int totalItems = static_cast<int>(recentBooks.size() + menuEntries.size());

  if (firstRenderDone && !recentsLoaded && !recentsLoading) {
    const auto& metrics = UITheme::getInstance().getMetrics();
    const Rect contentRect = UITheme::getContentRect(renderer, true, false);
    const HomeScreenLayout layout =
        computeHomeScreenLayout(metrics, contentRect.height, static_cast<int>(menuEntries.size()));
    loadRecentCovers(getHomeCoverRenderHeight(layout));
    return;
  }

  buttonNavigator.onNext([this, totalItems] {
    selectorIndex = ButtonNavigator::nextIndex(selectorIndex, totalItems);
    requestUpdate();
  });

  buttonNavigator.onPrevious([this, totalItems] {
    selectorIndex = ButtonNavigator::previousIndex(selectorIndex, totalItems);
    requestUpdate();
  });

  if (mappedInput.wasReleased(MappedInputManager::Button::Confirm)) {
    const int recentsCount = static_cast<int>(recentBooks.size());
    if (selectorIndex < recentsCount) {
      onSelectBook(recentBooks[selectorIndex].path);
    } else {
      const int menuIdx = selectorIndex - recentsCount;
      if (menuIdx >= 0 && menuIdx < static_cast<int>(menuEntries.size())) {
        dispatchMenuAction(menuEntries[menuIdx].action);
      }
    }
  }
}

void HomeActivity::render(RenderLock&&) {
  const auto& metrics = UITheme::getInstance().getMetrics();
  const Rect contentRect = UITheme::getContentRect(renderer, true, false);

  renderer.clearScreen();
  bool bufferRestored = coverBufferStored && restoreCoverBuffer();

  GUI.drawHeader(renderer, Rect{contentRect.x, metrics.topPadding, contentRect.width, metrics.homeTopPadding}, nullptr);

  rebuildMenuEntries();

  const int totalItems = static_cast<int>(recentBooks.size() + menuEntries.size());
  if (selectorIndex >= totalItems) {
    selectorIndex = std::max(0, totalItems - 1);
  }

  const int menuCount = static_cast<int>(menuEntries.size());
  const HomeScreenLayout layout = computeHomeScreenLayout(metrics, contentRect.height, menuCount);

  GUI.drawRecentBookCover(renderer,
                          Rect{contentRect.x, metrics.homeTopPadding, contentRect.width, layout.recentTileHeight},
                          recentBooks, selectorIndex, coverRendered, coverBufferStored, bufferRestored,
                          std::bind(&HomeActivity::storeCoverBuffer, this));

  GUI.drawButtonMenu(
      renderer,
      Rect{contentRect.x, metrics.homeTopPadding + layout.recentTileHeight + layout.recentToMenuGap, contentRect.width,
           layout.menuHeight},
      menuCount, selectorIndex - static_cast<int>(recentBooks.size()),
      [this](int index) { return std::string(I18N.get(menuEntries[index].label)); },
      [this](int index) { return menuEntries[index].icon; });

  const auto labels = mappedInput.mapLabels("", tr(STR_SELECT), tr(STR_DIR_UP), tr(STR_DIR_DOWN));
  GUI.drawButtonHints(renderer, labels.btn1, labels.btn2, labels.btn3, labels.btn4);

  renderer.displayBuffer();

  if (!firstRenderDone) {
    firstRenderDone = true;
    requestUpdate();
  }
}

void HomeActivity::onSelectBook(const std::string& path) { activityManager.pushReader(path); }

void HomeActivity::dispatchMenuAction(MenuAction action) {
  switch (action) {
    case MenuAction::FileBrowser:
      activityManager.goToFileBrowser();
      break;
    case MenuAction::Recents:
      activityManager.goToRecentBooks();
      break;
    case MenuAction::GlobalBookmarks:
      activityManager.goToGlobalBookmarks();
      break;
    case MenuAction::OpdsBrowser:
      activityManager.goToBrowser();
      break;
    case MenuAction::FileTransfer:
      activityManager.goToFileTransfer();
      break;
    case MenuAction::Weather:
      activityManager.goToWeather();
      break;
    case MenuAction::Settings:
      activityManager.goToSettings();
      break;
  }
}