import 'dart:io';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:wakelock_plus/wakelock_plus.dart';
import 'package:cached_network_image/cached_network_image.dart';
import 'package:photo_view/photo_view.dart';
import 'package:photo_view/photo_view_gallery.dart';
import 'package:worldhopper/l10n/app_localizations.dart';
import 'package:worldhopper/helpers/l10n_helpers.dart';
import 'package:worldhopper/models/enhanced_metadata.dart';
import 'package:worldhopper/models/entry.dart';
import 'package:worldhopper/models/server.dart';
import 'package:worldhopper/models/publication.dart';
import 'package:worldhopper/models/stream_link.dart';
import 'package:worldhopper/models/reading_progress.dart';
import 'package:worldhopper/providers/sync_progress_provider.dart';
import 'package:worldhopper/providers/cover_page_provider.dart';
import 'package:worldhopper/providers/page_dimensions_provider.dart';
import 'package:worldhopper/providers/publication_cache_provider.dart';
import 'package:worldhopper/providers/reading_progress_provider.dart';
import 'package:worldhopper/providers/server_provider.dart';
import 'package:worldhopper/providers/connectivity_provider.dart';
import 'package:worldhopper/providers/server_software_provider.dart';
import 'package:worldhopper/providers/filter_quality_provider.dart';
import 'package:worldhopper/providers/precache_pages_provider.dart';
import 'package:worldhopper/providers/reading_mode_provider.dart';
import 'package:worldhopper/providers/eink_mode_provider.dart';
import 'package:worldhopper/providers/two_page_mode_provider.dart';
import 'package:worldhopper/screens/reader/page_grouping.dart';
import 'package:worldhopper/screens/reader/two_page_reader.dart';
import 'package:worldhopper/services/auth_service.dart';
import 'package:worldhopper/services/server_software/server_software_service.dart';
import 'package:uuid/uuid.dart';
import 'package:worldhopper/widgets/next_in_series_overlay.dart';

/// Main reader screen for page-by-page reading
class ReaderScreen extends ConsumerStatefulWidget {
  final Entry entry;
  final String serverId;
  final int initialPage;
  final String? feedUrl;
  final String? localContentPath;

  const ReaderScreen({
    super.key,
    required this.entry,
    required this.serverId,
    this.initialPage = 0,
    this.feedUrl,
    this.localContentPath,
  });

  @override
  ConsumerState<ReaderScreen> createState() => _ReaderScreenState();
}

class _ReaderScreenState extends ConsumerState<ReaderScreen> {
  late PageController _pageController;
  late int _currentPage;
  bool _showControls = true;
  bool _isInitialized = false;
  bool _reachedEndThisSession = false;
  ScrollController? _scrollController;
  bool _needsVerticalScrollToPage = false;
  ReadingMode? _previousMode;

  // Two-page spread state
  PageController? _twoPageController;
  List<PageSpread> _spreads = [];
  bool _wasTwoPage = false;

  // E-ink swipe tracking
  double? _einkSwipeStartX;

  // Cached file extension for local content (avoids probing 5 extensions per page)
  String? _localFileExtension;
  bool _localExtensionResolved = false;

  @override
  void initState() {
    super.initState();
    _currentPage = widget.initialPage;
    _pageController = PageController(initialPage: widget.initialPage);

    // Check if already on the last page (e.g. resuming a completed chapter)
    final pageCount = widget.entry.streamLink?.pageCount ?? 0;
    if (pageCount > 0 && widget.initialPage >= pageCount - 1) {
      _reachedEndThisSession = true;
    }

    // Enter fullscreen immersive mode
    SystemChrome.setEnabledSystemUIMode(SystemUiMode.immersiveSticky);

    // Keep screen awake while reading
    WakelockPlus.enable();
  }

  // Provider refs captured in deactivate() for use in dispose().
  // Riverpod invalidates `ref` after deactivate() completes, so reading
  // providers in dispose() throws. We snapshot the values we need here.
  bool _capturedIsOnline = false;
  Future<Server?>? _capturedServerFuture;
  ServerSoftwareService? _capturedSoftwareService;
  ReadingProgressNotifier? _capturedProgressNotifier;
  Future<ReadingProgress?>? _capturedProgressFuture;
  Future<Publication?>? _capturedCachedPubFuture;

  @override
  void deactivate() {
    // Capture all provider references while ref is still valid.
    _capturedIsOnline =
        ref.read(connectivityStateProvider).valueOrNull ?? false;
    _capturedServerFuture = ref.read(serverProvider(widget.serverId).future);
    _capturedSoftwareService = ref.read(serverSoftwareServiceProvider);
    _capturedProgressNotifier =
        ref.read(readingProgressNotifierProvider.notifier);
    _capturedProgressFuture = ref.read(readingProgressProvider(ProgressKey(
      publicationId: widget.entry.id,
      serverId: widget.serverId,
    )).future);
    _capturedCachedPubFuture = ref.read(
        cachedPublicationProvider(widget.serverId, widget.entry.id).future);
    super.deactivate();
  }

  @override
  void dispose() {
    // If the user finished the chapter, remove from recently read;
    // otherwise save progress one final time before disposing.
    // Guard against deactivate() not having been called (captured fields null).
    if (_reachedEndThisSession) {
      if (_capturedProgressNotifier != null &&
          _capturedServerFuture != null &&
          _capturedSoftwareService != null) {
        _deleteCompletedProgressDetached(
          isOnline: _capturedIsOnline,
          serverFuture: _capturedServerFuture!,
          softwareService: _capturedSoftwareService!,
          progressNotifier: _capturedProgressNotifier!,
        );
      }
    } else {
      if (_capturedProgressNotifier != null &&
          _capturedProgressFuture != null &&
          _capturedCachedPubFuture != null) {
        _saveProgressDetached(
          _currentPage,
          progressFuture: _capturedProgressFuture!,
          cachedPubFuture: _capturedCachedPubFuture!,
          progressNotifier: _capturedProgressNotifier!,
        );
      }
    }

    _pageController.dispose();
    _twoPageController?.dispose();
    _scrollController?.dispose();
    // Restore system UI
    SystemChrome.setEnabledSystemUIMode(SystemUiMode.edgeToEdge);
    // Allow screen to sleep again
    WakelockPlus.disable();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);

    if (!widget.entry.hasStreamLink) {
      return Scaffold(
        appBar: AppBar(
          title: Text(l10n.readerError),
        ),
        body: Center(
          child: Text(l10n.readerNoStreamLink),
        ),
      );
    }

    final streamLink = widget.entry.streamLink!;
    final serverAsync = ref.watch(serverProvider(widget.serverId));

    // Initialize or update reading progress
    if (!_isInitialized) {
      _isInitialized = true;
      WidgetsBinding.instance.addPostFrameCallback((_) {
        _initializeProgress();
      });
    }

    return PopScope(
      canPop: true,
      onPopInvokedWithResult: (bool didPop, Object? result) {
        if (didPop) {
          if (_reachedEndThisSession) {
            _deleteCompletedProgress();
          } else {
            _saveProgress(_currentPage);
          }
        }
      },
      child: Scaffold(
        backgroundColor: Colors.black,
        body: Stack(
          children: [
            // Page viewer
            serverAsync.when(
              data: (server) {
                if (server == null) {
                  return Center(
                    child: Text(
                      l10n.readerServerNotFound,
                      style: const TextStyle(color: Colors.white),
                    ),
                  );
                }

                final globalMode = ref.watch(readingModeNotifierProvider);
                final seriesOverride = widget.feedUrl != null
                    ? ref.watch(
                        seriesReadingModeNotifierProvider(widget.feedUrl!))
                    : null;
                final readingMode = seriesOverride ?? globalMode;

                // Determine if two-page mode should activate
                final globalTwoPage = ref.watch(twoPageModeNotifierProvider);
                final seriesToPageOverride = widget.feedUrl != null
                    ? ref.watch(
                        seriesToPageModeNotifierProvider(widget.feedUrl!))
                    : null;
                final twoPageMode = seriesToPageOverride ?? globalTwoPage;
                final screenWidth = MediaQuery.of(context).size.width;
                final isPaged = readingMode != ReadingMode.verticalContinuous;
                final useTwoPage = isPaged &&
                    twoPageMode == TwoPageMode.auto &&
                    screenWidth >= 768;

                // Handle mode switching mid-read
                if (_previousMode != null && _previousMode != readingMode) {
                  if (readingMode == ReadingMode.verticalContinuous) {
                    // Switching to vertical: create new scroll controller
                    _scrollController?.dispose();
                    _scrollController = null;
                  } else {
                    // Switching to paged: jump to current page after frame
                    WidgetsBinding.instance.addPostFrameCallback((_) {
                      if (_pageController.hasClients) {
                        _pageController.jumpToPage(_currentPage);
                      }
                    });
                  }
                }
                _previousMode = readingMode;

                // Handle transition between single-page and two-page modes
                if (_wasTwoPage && !useTwoPage) {
                  // Transitioning from two-page to single-page
                  _wasTwoPage = false;
                  WidgetsBinding.instance.addPostFrameCallback((_) {
                    if (_pageController.hasClients) {
                      _pageController.jumpToPage(_currentPage);
                    }
                  });
                } else if (!_wasTwoPage && useTwoPage) {
                  // Transitioning from single-page to two-page
                  _wasTwoPage = true;
                }

                if (useTwoPage) {
                  final isRtl = readingMode == ReadingMode.rtl;
                  final globalCover = ref.watch(coverPageNotifierProvider);
                  final seriesCoverOverride = widget.feedUrl != null
                      ? ref.watch(
                          seriesCoverPageNotifierProvider(widget.feedUrl!))
                      : null;
                  final firstPageIsCover = seriesCoverOverride ?? globalCover;
                  return _buildTwoPageReader(streamLink, server,
                      rtl: isRtl, firstPageIsCover: firstPageIsCover);
                }

                return switch (readingMode) {
                  ReadingMode.ltr =>
                    _buildPagedReader(streamLink, server, reverse: false),
                  ReadingMode.rtl =>
                    _buildPagedReader(streamLink, server, reverse: true),
                  ReadingMode.verticalContinuous =>
                    _buildVerticalReader(streamLink, server),
                };
              },
              loading: () => const Center(
                child: CircularProgressIndicator(color: Colors.white),
              ),
              error: (error, stack) => Center(
                child: Text(
                  l10n.readerErrorLoadingServer(error.toString()),
                  style: const TextStyle(color: Colors.white),
                ),
              ),
            ),

            // Top controls
            if (_showControls)
              Positioned(
                top: 0,
                left: 0,
                right: 0,
                child: _buildTopBar(context, streamLink),
              ),

            // Bottom controls
            if (_showControls)
              Positioned(
                bottom: 0,
                left: 0,
                right: 0,
                child: _buildBottomBar(context, streamLink),
              ),

            // Next in series overlay
            NextInSeriesOverlay(
              serverId: widget.serverId,
              feedUrl: widget.feedUrl,
              entry: widget.entry,
              isVisible: _reachedEndThisSession,
              einkMode: ref.watch(einkModeNotifierProvider),
              isDownloadedContent: widget.localContentPath != null,
              onBeforeNavigate: _deleteCompletedProgress,
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildPagedReader(StreamLink streamLink, dynamic server,
      {required bool reverse}) {
    final filterQuality = ref.watch(filterQualityNotifierProvider);
    final einkMode = ref.watch(einkModeNotifierProvider);

    Widget gallery = GestureDetector(
      onTap: () {
        setState(() {
          _showControls = !_showControls;
        });
      },
      child: PhotoViewGallery.builder(
        scrollPhysics: einkMode
            ? const NeverScrollableScrollPhysics()
            : const BouncingScrollPhysics(),
        reverse: reverse,
        builder: (context, index) {
          return PhotoViewGalleryPageOptions(
            imageProvider: _getPageImageProvider(index, streamLink, server),
            filterQuality: filterQuality,
            minScale: PhotoViewComputedScale.contained,
            maxScale: PhotoViewComputedScale.covered * 3,
            heroAttributes: PhotoViewHeroAttributes(
              tag: 'page-$index',
            ),
          );
        },
        itemCount: streamLink.pageCount,
        loadingBuilder: (context, event) => Center(
          child: CircularProgressIndicator(
            value: event == null
                ? 0
                : event.cumulativeBytesLoaded / (event.expectedTotalBytes ?? 1),
            color: Colors.white,
          ),
        ),
        backgroundDecoration: const BoxDecoration(
          color: Colors.black,
        ),
        pageController: _pageController,
        onPageChanged: (index) {
          setState(() {
            _currentPage = index;
            if (index >= streamLink.pageCount - 1) {
              _reachedEndThisSession = true;
            }
          });
          _saveProgress(index);
          _reportPageToServer(index);
          _precacheUpcomingPages(index);
        },
      ),
    );

    if (einkMode) {
      gallery = _wrapWithEinkSwipe(
        child: gallery,
        controller: _pageController,
        itemCount: streamLink.pageCount,
        reverse: reverse,
      );
    }

    return gallery;
  }

  Widget _buildTwoPageReader(StreamLink streamLink, dynamic server,
      {required bool rtl, required bool firstPageIsCover}) {
    final filterQuality = ref.watch(filterQualityNotifierProvider);
    final dimensions =
        ref.watch(pageDimensionsNotifierProvider(widget.entry.id));

    // Recompute spreads whenever dimensions change
    _spreads = computePageSpreads(
      pageCount: streamLink.pageCount,
      dimensions: dimensions,
      rtl: rtl,
      firstPageIsCover: firstPageIsCover,
    );

    // Find the spread index for the current page
    final currentSpreadIndex = spreadIndexForPage(_spreads, _currentPage);

    // Create or update the two-page controller
    if (_twoPageController == null || !_twoPageController!.hasClients) {
      _twoPageController?.dispose();
      _twoPageController = PageController(initialPage: currentSpreadIndex);
    }

    final einkMode = ref.watch(einkModeNotifierProvider);

    Widget reader = TwoPageReader(
      spreads: _spreads,
      pageController: _twoPageController!,
      getImageProvider: (index) =>
          _getPageImageProvider(index, streamLink, server),
      filterQuality: filterQuality,
      reverse: rtl,
      einkMode: einkMode,
      onTap: () {
        setState(() {
          _showControls = !_showControls;
        });
      },
      onPageChanged: (spreadIndex) {
        if (spreadIndex < 0 || spreadIndex >= _spreads.length) return;
        final primaryPage = primaryPageForSpread(_spreads, spreadIndex);
        final lastPage = lastPageInSpread(_spreads, spreadIndex);
        setState(() {
          _currentPage = primaryPage;
          if (lastPage >= streamLink.pageCount - 1) {
            _reachedEndThisSession = true;
          }
        });
        _saveProgress(primaryPage);
        _reportPageToServer(lastPage);
        _precacheUpcomingPages(lastPage);
      },
    );

    if (einkMode) {
      reader = _wrapWithEinkSwipe(
        child: reader,
        controller: _twoPageController!,
        itemCount: _spreads.length,
        reverse: rtl,
      );
    }

    return reader;
  }

  Widget _buildVerticalReader(StreamLink streamLink, dynamic server) {
    final filterQuality = ref.watch(filterQualityNotifierProvider);

    // Lazily initialize scroll controller
    if (_scrollController == null) {
      _scrollController = ScrollController();
      if (_currentPage > 0) {
        _needsVerticalScrollToPage = true;
      }
    }

    // Restore scroll position to the saved page on resume
    if (_needsVerticalScrollToPage) {
      _needsVerticalScrollToPage = false;
      WidgetsBinding.instance.addPostFrameCallback((_) {
        if (_scrollController != null &&
            _scrollController!.hasClients &&
            _scrollController!.position.maxScrollExtent > 0) {
          final pageCount = streamLink.pageCount;
          if (pageCount <= 1) return;
          final targetOffset = (_currentPage / (pageCount - 1)) *
              _scrollController!.position.maxScrollExtent;
          _scrollController!.jumpTo(
            targetOffset.clamp(
                0.0, _scrollController!.position.maxScrollExtent),
          );
        }
      });
    }

    return GestureDetector(
      onTap: () {
        setState(() {
          _showControls = !_showControls;
        });
      },
      child: NotificationListener<ScrollNotification>(
        onNotification: (notification) {
          if (notification is ScrollUpdateNotification &&
              notification.metrics.maxScrollExtent > 0) {
            final scrollOffset = notification.metrics.pixels;
            final maxExtent = notification.metrics.maxScrollExtent;
            final estimatedPage =
                (scrollOffset / maxExtent * (streamLink.pageCount - 1)).round();
            final clampedPage =
                estimatedPage.clamp(0, streamLink.pageCount - 1);

            if (clampedPage != _currentPage) {
              setState(() {
                _currentPage = clampedPage;
                if (clampedPage >= streamLink.pageCount - 1) {
                  _reachedEndThisSession = true;
                }
              });
              _saveProgress(clampedPage);
              _reportPageToServer(clampedPage);
            }
          }
          return false;
        },
        child: ListView.builder(
          controller: _scrollController,
          itemCount: streamLink.pageCount,
          itemBuilder: (context, index) {
            return InteractiveViewer(
              minScale: 1.0,
              maxScale: 3.0,
              child: _buildPageImage(index, streamLink, server, filterQuality),
            );
          },
        ),
      ),
    );
  }

  /// Wraps [child] with a [Listener] that detects horizontal swipes and calls
  /// [jumpToPage] on [controller], giving instant page turns with no animation.
  Widget _wrapWithEinkSwipe({
    required Widget child,
    required PageController controller,
    required int itemCount,
    required bool reverse,
  }) {
    return Listener(
      onPointerDown: (e) => _einkSwipeStartX = e.position.dx,
      onPointerUp: (e) {
        if (_einkSwipeStartX == null) return;
        final dx = e.position.dx - _einkSwipeStartX!;
        _einkSwipeStartX = null;
        if (dx.abs() < 50) return; // below swipe threshold

        // Swipe left (dx < 0) → next page, swipe right (dx > 0) → previous
        final direction = dx < 0 ? 1 : -1;
        final effectiveDirection = reverse ? -direction : direction;
        final currentIdx = controller.page?.round() ?? 0;
        final target = currentIdx + effectiveDirection;
        if (target >= 0 && target < itemCount) {
          controller.jumpToPage(target);
        }
      },
      onPointerCancel: (_) => _einkSwipeStartX = null,
      child: child,
    );
  }

  Widget _buildTopBar(BuildContext context, StreamLink streamLink) {
    return Container(
      decoration: BoxDecoration(
        gradient: LinearGradient(
          begin: Alignment.topCenter,
          end: Alignment.bottomCenter,
          colors: [
            Colors.black.withValues(alpha: 0.7),
            Colors.transparent,
          ],
        ),
      ),
      padding: EdgeInsets.only(
        top: MediaQuery.of(context).padding.top,
        left: 8,
        right: 8,
        bottom: 16,
      ),
      child: Consumer(
        builder: (context, ref, _) {
          final l10n = AppLocalizations.of(context);

          // Watch connectivity state
          final connectivityState = ref.watch(connectivityStateProvider);

          // Check if offline (default to online while loading)
          final isOffline = connectivityState.whenOrNull(
                data: (isOnline) => !isOnline,
              ) ??
              false;

          return Row(
            children: [
              IconButton(
                icon: const Icon(Icons.arrow_back, color: Colors.white),
                onPressed: () => Navigator.of(context).pop(),
              ),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  mainAxisSize: MainAxisSize.min,
                  children: [
                    Text(
                      widget.entry.title,
                      style: const TextStyle(
                        color: Colors.white,
                        fontSize: 16,
                        fontWeight: FontWeight.bold,
                      ),
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                    ),
                    if (widget.entry.authors.isNotEmpty)
                      Text(
                        widget.entry.authors.join(', '),
                        style: TextStyle(
                          color: Colors.white.withValues(alpha: 0.7),
                          fontSize: 12,
                        ),
                        maxLines: 1,
                        overflow: TextOverflow.ellipsis,
                      ),
                  ],
                ),
              ),
              // Offline indicator
              if (isOffline)
                Padding(
                  padding: const EdgeInsets.only(right: 8),
                  child: Icon(
                    Icons.cloud_off,
                    color: Colors.redAccent,
                    semanticLabel: l10n.offlineSemanticLabel,
                  ),
                ),
              // Settings menu
              _buildSettingsMenu(ref),
            ],
          );
        },
      ),
    );
  }

  void _setReadingMode(WidgetRef ref, ReadingMode mode) {
    if (widget.feedUrl != null) {
      ref
          .read(seriesReadingModeNotifierProvider(widget.feedUrl!).notifier)
          .setReadingMode(mode);
    } else {
      ref.read(readingModeNotifierProvider.notifier).setReadingMode(mode);
    }
  }

  void _setTwoPageMode(WidgetRef ref, TwoPageMode mode) {
    if (widget.feedUrl != null) {
      ref
          .read(seriesToPageModeNotifierProvider(widget.feedUrl!).notifier)
          .setTwoPageMode(mode);
    } else {
      ref.read(twoPageModeNotifierProvider.notifier).setTwoPageMode(mode);
    }
  }

  void _setCoverPage(WidgetRef ref, bool value) {
    if (widget.feedUrl != null) {
      ref
          .read(seriesCoverPageNotifierProvider(widget.feedUrl!).notifier)
          .setCoverPage(value);
    } else {
      ref.read(coverPageNotifierProvider.notifier).setCoverPage(value);
    }
  }

  Widget _buildSettingsMenu(WidgetRef ref) {
    final l10n = AppLocalizations.of(context);

    final globalMode = ref.watch(readingModeNotifierProvider);
    final seriesOverride = widget.feedUrl != null
        ? ref.watch(seriesReadingModeNotifierProvider(widget.feedUrl!))
        : null;
    final readingMode = seriesOverride ?? globalMode;

    final modeShortLabel = readingModeShortLabel(l10n, readingMode);

    final globalTwoPage = ref.watch(twoPageModeNotifierProvider);
    final seriesToPageOverride = widget.feedUrl != null
        ? ref.watch(seriesToPageModeNotifierProvider(widget.feedUrl!))
        : null;
    final twoPageMode = seriesToPageOverride ?? globalTwoPage;
    final isPaged = readingMode != ReadingMode.verticalContinuous;

    final globalCover = ref.watch(coverPageNotifierProvider);
    final seriesCoverOverride = widget.feedUrl != null
        ? ref.watch(seriesCoverPageNotifierProvider(widget.feedUrl!))
        : null;
    final firstPageIsCover = seriesCoverOverride ?? globalCover;

    return MenuAnchor(
      builder: (context, controller, child) {
        return IconButton(
          icon: const Icon(Icons.settings, color: Colors.white),
          onPressed: () {
            if (controller.isOpen) {
              controller.close();
            } else {
              controller.open();
            }
          },
        );
      },
      menuChildren: [
        SubmenuButton(
          leadingIcon: const Icon(Icons.chrome_reader_mode_outlined),
          trailingIcon: const Icon(Icons.chevron_right, size: 18),
          menuChildren: [
            MenuItemButton(
              leadingIcon: const Icon(Icons.arrow_forward),
              trailingIcon: readingMode == ReadingMode.ltr
                  ? const Icon(Icons.check, size: 18)
                  : null,
              onPressed: () => _setReadingMode(ref, ReadingMode.ltr),
              child: Text(l10n.readingModeLtr),
            ),
            MenuItemButton(
              leadingIcon: const Icon(Icons.arrow_back),
              trailingIcon: readingMode == ReadingMode.rtl
                  ? const Icon(Icons.check, size: 18)
                  : null,
              onPressed: () => _setReadingMode(ref, ReadingMode.rtl),
              child: Text(l10n.readingModeRtl),
            ),
            MenuItemButton(
              leadingIcon: const Icon(Icons.swap_vert),
              trailingIcon: readingMode == ReadingMode.verticalContinuous
                  ? const Icon(Icons.check, size: 18)
                  : null,
              onPressed: () =>
                  _setReadingMode(ref, ReadingMode.verticalContinuous),
              child: Text(l10n.readingModeVertical),
            ),
          ],
          child: Text(l10n.readerReadingDirectionWithMode(modeShortLabel)),
        ),
        if (isPaged)
          MenuItemButton(
            leadingIcon: const Icon(Icons.auto_stories),
            trailingIcon: twoPageMode == TwoPageMode.auto
                ? const Icon(Icons.check, size: 18)
                : null,
            onPressed: () {
              final newMode = twoPageMode == TwoPageMode.auto
                  ? TwoPageMode.off
                  : TwoPageMode.auto;
              _setTwoPageMode(ref, newMode);
            },
            child: Text(l10n.readersTwoPageSpread),
          ),
        if (isPaged)
          MenuItemButton(
            leadingIcon: const Icon(Icons.looks_one),
            trailingIcon:
                firstPageIsCover ? const Icon(Icons.check, size: 18) : null,
            onPressed: () => _setCoverPage(ref, !firstPageIsCover),
            child: Text(l10n.readersFirstPageIsCover),
          ),
      ],
    );
  }

  Widget _buildBottomBar(BuildContext context, StreamLink streamLink) {
    final l10n = AppLocalizations.of(context);
    final einkMode = ref.watch(einkModeNotifierProvider);
    final progress = (_currentPage + 1) / streamLink.pageCount;
    final globalMode = ref.watch(readingModeNotifierProvider);
    final seriesOverride = widget.feedUrl != null
        ? ref.watch(seriesReadingModeNotifierProvider(widget.feedUrl!))
        : null;
    final readingMode = seriesOverride ?? globalMode;
    final isVertical = readingMode == ReadingMode.verticalContinuous;
    final isRtl = readingMode == ReadingMode.rtl;

    // Determine if we're in two-page mode
    final globalTwoPage = ref.watch(twoPageModeNotifierProvider);
    final seriesToPageOverride = widget.feedUrl != null
        ? ref.watch(seriesToPageModeNotifierProvider(widget.feedUrl!))
        : null;
    final twoPageMode = seriesToPageOverride ?? globalTwoPage;
    final screenWidth = MediaQuery.of(context).size.width;
    final isPaged = readingMode != ReadingMode.verticalContinuous;
    final isTwoPage = isPaged &&
        twoPageMode == TwoPageMode.auto &&
        screenWidth >= 768 &&
        _spreads.isNotEmpty;

    // Build page indicator text
    String pageIndicator;
    if (isTwoPage) {
      final spreadIdx = spreadIndexForPage(_spreads, _currentPage);
      final spread = _spreads[spreadIdx];
      if (spread.isPair) {
        final lo = spread.primaryPage + 1;
        final hi = spread.lastPage + 1;
        pageIndicator = l10n.readerPagesOf(lo, hi, streamLink.pageCount);
      } else {
        pageIndicator =
            l10n.readerPageOf(_currentPage + 1, streamLink.pageCount);
      }
    } else {
      pageIndicator = l10n.readerPageOf(_currentPage + 1, streamLink.pageCount);
    }

    // Select active controller for navigation buttons
    final activeController = isTwoPage && _twoPageController != null
        ? _twoPageController!
        : _pageController;
    final totalItems = isTwoPage ? _spreads.length : streamLink.pageCount;
    final currentIdx =
        isTwoPage ? spreadIndexForPage(_spreads, _currentPage) : _currentPage;

    return Container(
      decoration: BoxDecoration(
        gradient: LinearGradient(
          begin: Alignment.bottomCenter,
          end: Alignment.topCenter,
          colors: [
            Colors.black.withValues(alpha: 0.7),
            Colors.transparent,
          ],
        ),
      ),
      padding: EdgeInsets.only(
        bottom: MediaQuery.of(context).padding.bottom + 8,
        left: 16,
        right: 16,
        top: 16,
      ),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          // Page indicator
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: [
              Text(
                pageIndicator,
                style: const TextStyle(
                  color: Colors.white,
                  fontSize: 14,
                ),
              ),
              Text(
                '${(progress * 100).toInt()}%',
                style: const TextStyle(
                  color: Colors.white,
                  fontSize: 14,
                  fontWeight: FontWeight.bold,
                ),
              ),
            ],
          ),
          const SizedBox(height: 8),

          // Progress bar
          LinearProgressIndicator(
            value: progress,
            backgroundColor: Colors.white.withValues(alpha: 0.3),
            valueColor: const AlwaysStoppedAnimation<Color>(Colors.white),
            minHeight: 4,
          ),

          // Navigation buttons (hidden in vertical mode)
          if (!isVertical) ...[
            const SizedBox(height: 12),
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceEvenly,
              children: isRtl
                  ? [
                      IconButton(
                        icon: const Icon(Icons.last_page, color: Colors.white),
                        onPressed: currentIdx < totalItems - 1
                            ? () => activeController.jumpToPage(totalItems - 1)
                            : null,
                        iconSize: 28,
                      ),
                      IconButton(
                        icon: const Icon(Icons.chevron_right,
                            color: Colors.white),
                        onPressed: currentIdx > 0
                            ? () => einkMode
                                ? activeController.jumpToPage(currentIdx - 1)
                                : activeController.previousPage(
                                    duration: const Duration(milliseconds: 300),
                                    curve: Curves.easeInOut,
                                  )
                            : null,
                        iconSize: 32,
                      ),
                      IconButton(
                        icon:
                            const Icon(Icons.chevron_left, color: Colors.white),
                        onPressed: currentIdx < totalItems - 1
                            ? () => einkMode
                                ? activeController.jumpToPage(currentIdx + 1)
                                : activeController.nextPage(
                                    duration: const Duration(milliseconds: 300),
                                    curve: Curves.easeInOut,
                                  )
                            : null,
                        iconSize: 32,
                      ),
                      IconButton(
                        icon: const Icon(Icons.first_page, color: Colors.white),
                        onPressed: currentIdx > 0
                            ? () => activeController.jumpToPage(0)
                            : null,
                        iconSize: 28,
                      ),
                    ]
                  : [
                      IconButton(
                        icon: const Icon(Icons.first_page, color: Colors.white),
                        onPressed: currentIdx > 0
                            ? () => activeController.jumpToPage(0)
                            : null,
                        iconSize: 28,
                      ),
                      IconButton(
                        icon:
                            const Icon(Icons.chevron_left, color: Colors.white),
                        onPressed: currentIdx > 0
                            ? () => einkMode
                                ? activeController.jumpToPage(currentIdx - 1)
                                : activeController.previousPage(
                                    duration: const Duration(milliseconds: 300),
                                    curve: Curves.easeInOut,
                                  )
                            : null,
                        iconSize: 32,
                      ),
                      IconButton(
                        icon: const Icon(Icons.chevron_right,
                            color: Colors.white),
                        onPressed: currentIdx < totalItems - 1
                            ? () => einkMode
                                ? activeController.jumpToPage(currentIdx + 1)
                                : activeController.nextPage(
                                    duration: const Duration(milliseconds: 300),
                                    curve: Curves.easeInOut,
                                  )
                            : null,
                        iconSize: 32,
                      ),
                      IconButton(
                        icon: const Icon(Icons.last_page, color: Colors.white),
                        onPressed: currentIdx < totalItems - 1
                            ? () => activeController.jumpToPage(totalItems - 1)
                            : null,
                        iconSize: 28,
                      ),
                    ],
            ),
          ],
        ],
      ),
    );
  }

  Future<void> _deleteCompletedProgress() async {
    _markAsReadOnServer();
    await ref
        .read(readingProgressNotifierProvider.notifier)
        .deleteProgress(widget.entry.id, widget.serverId);
    if (mounted) {
      ref.invalidate(recentlyReadProvider);
      ref.invalidate(inProgressCountProvider);
      ref.invalidate(completedCountProvider);
    }
  }

  /// Dispose-safe counterpart of [_deleteCompletedProgress].
  /// Wrapped in Future() to defer past widget tree finalization.
  void _deleteCompletedProgressDetached({
    required bool isOnline,
    required Future<Server?> serverFuture,
    required ServerSoftwareService softwareService,
    required ReadingProgressNotifier progressNotifier,
  }) {
    Future(() async {
      try {
        await _markAsReadDetached(
          isOnline: isOnline,
          serverFuture: serverFuture,
          softwareService: softwareService,
        );
        await progressNotifier.deleteProgress(widget.entry.id, widget.serverId);
      } catch (e, stackTrace) {
        debugPrint(
            'Failed to delete completed progress on dispose: $e\n$stackTrace');
      }
    });
  }

  void _initializeProgress() async {
    // Cache the publication entry (skip image downloads when offline)
    final isOnline = ref.read(connectivityStateProvider).valueOrNull ?? false;
    final cachedPub =
        await ref.read(publicationCacheProvider.notifier).cachePublication(
              serverId: widget.serverId,
              entry: widget.entry,
              metadata: const EnhancedMetadata.empty(),
              downloadImages: isOnline,
            );

    final progressKey = ProgressKey(
      publicationId: widget.entry.id,
      serverId: widget.serverId,
    );

    final existingProgress =
        await ref.read(readingProgressProvider(progressKey).future);

    if (existingProgress == null) {
      // Create new progress
      final progress = ReadingProgress(
        id: const Uuid().v4(),
        publicationId: widget.entry.id,
        serverId: widget.serverId,
        currentPage: _currentPage,
        totalPages: widget.entry.streamLink!.pageCount,
        lastReadAt: DateTime.now(),
        publicationCacheId: cachedPub.id,
        seriesFeedUrl: widget.feedUrl,
      );

      await ref
          .read(readingProgressNotifierProvider.notifier)
          .saveProgress(progress);

      // Invalidate to refresh library
      ref.invalidate(recentlyReadProvider);
    } else if (existingProgress.publicationCacheId == null ||
        (widget.feedUrl != null && existingProgress.seriesFeedUrl == null)) {
      // Update existing progress with cache ID or feed URL if missing
      final updatedProgress = existingProgress.copyWith(
        publicationCacheId: cachedPub.id,
        lastReadAt: DateTime.now(),
        seriesFeedUrl: widget.feedUrl ?? existingProgress.seriesFeedUrl,
      );

      await ref
          .read(readingProgressNotifierProvider.notifier)
          .saveProgress(updatedProgress);

      // Invalidate to refresh library
      ref.invalidate(recentlyReadProvider);
    }

    // Pre-cache upcoming pages from the starting page
    _precacheUpcomingPages(_currentPage);
  }

  void _saveProgress(int page) async {
    final progressKey = ProgressKey(
      publicationId: widget.entry.id,
      serverId: widget.serverId,
    );

    final existingProgress =
        await ref.read(readingProgressProvider(progressKey).future);

    // Get or cache the publication
    final cachedPub = await ref.read(
        cachedPublicationProvider(widget.serverId, widget.entry.id).future);

    if (existingProgress != null) {
      // Update existing progress with cache ID
      final updatedProgress = existingProgress.copyWith(
        currentPage: page,
        lastReadAt: DateTime.now(),
        publicationCacheId:
            cachedPub?.id ?? existingProgress.publicationCacheId,
        seriesFeedUrl: widget.feedUrl ?? existingProgress.seriesFeedUrl,
      );

      await ref
          .read(readingProgressNotifierProvider.notifier)
          .saveProgress(updatedProgress);
    } else {
      // Create new progress
      final progress = ReadingProgress(
        id: const Uuid().v4(),
        publicationId: widget.entry.id,
        serverId: widget.serverId,
        currentPage: page,
        totalPages: widget.entry.streamLink!.pageCount,
        lastReadAt: DateTime.now(),
        publicationCacheId: cachedPub?.id,
        seriesFeedUrl: widget.feedUrl,
      );

      await ref
          .read(readingProgressNotifierProvider.notifier)
          .saveProgress(progress);
    }

    // Invalidate progress provider to refresh UI
    ref.invalidate(readingProgressProvider(progressKey));
    ref.invalidate(recentlyReadProvider);
  }

  /// Dispose-safe version: all provider refs passed in as arguments.
  /// Wrapped in Future() to defer past widget tree finalization.
  void _saveProgressDetached(
    int page, {
    required Future<ReadingProgress?> progressFuture,
    required Future<Publication?> cachedPubFuture,
    required ReadingProgressNotifier progressNotifier,
  }) {
    Future(() async {
      try {
        final existingProgress = await progressFuture;
        final cachedPub = await cachedPubFuture;

        if (existingProgress != null) {
          final updatedProgress = existingProgress.copyWith(
            currentPage: page,
            lastReadAt: DateTime.now(),
            publicationCacheId:
                cachedPub?.id ?? existingProgress.publicationCacheId,
            seriesFeedUrl: widget.feedUrl ?? existingProgress.seriesFeedUrl,
          );
          await progressNotifier.saveProgress(updatedProgress);
        } else {
          final progress = ReadingProgress(
            id: const Uuid().v4(),
            publicationId: widget.entry.id,
            serverId: widget.serverId,
            currentPage: page,
            totalPages: widget.entry.streamLink!.pageCount,
            lastReadAt: DateTime.now(),
            publicationCacheId: cachedPub?.id,
            seriesFeedUrl: widget.feedUrl,
          );
          await progressNotifier.saveProgress(progress);
        }
      } catch (e, stackTrace) {
        debugPrint('Failed to save progress on dispose: $e\n$stackTrace');
      }
    });
  }

  /// Fire-and-forget page progress report so the server tracks reading.
  void _reportPageToServer(int page) {
    if (!ref.read(syncProgressNotifierProvider)) return;
    if (!widget.entry.hasStreamLink) return;
    final isOnline = ref.read(connectivityStateProvider).valueOrNull ?? false;
    if (!isOnline) return;
    final server = ref.read(serverProvider(widget.serverId)).valueOrNull;
    if (server == null) return;
    final software =
        ref.read(serverSoftwareServiceProvider).getImplementation(server);
    software
        .reportPageProgress(server, widget.entry.streamLink!, page)
        .catchError((e) => debugPrint('reportPageToServer: $e'));
  }

  /// Mark the entry as read on the server via the appropriate implementation.
  void _markAsReadOnServer() async {
    debugPrint(
        'markAsRead: called for entry=${widget.entry.id} server=${widget.serverId}');
    final isOnline = ref.read(connectivityStateProvider).valueOrNull ?? false;
    if (!isOnline) {
      debugPrint('markAsRead: skipped — offline');
      return;
    }

    try {
      final server = await ref.read(serverProvider(widget.serverId).future);
      if (server == null) return;
      final software =
          ref.read(serverSoftwareServiceProvider).getImplementation(server);
      await software.markAsRead(server, widget.entry);
    } catch (e) {
      debugPrint('markAsRead: error: $e');
    }
  }

  /// Dispose-safe version: all provider refs passed in as arguments.
  Future<void> _markAsReadDetached({
    required bool isOnline,
    required Future<Server?> serverFuture,
    required ServerSoftwareService softwareService,
  }) async {
    debugPrint(
        'markAsRead: called for entry=${widget.entry.id} server=${widget.serverId}');
    if (!isOnline) {
      debugPrint('markAsRead: skipped — offline');
      return;
    }

    try {
      final server = await serverFuture;
      if (server == null) return;
      final software = softwareService.getImplementation(server);
      await software.markAsRead(server, widget.entry);
    } catch (e) {
      debugPrint('markAsRead: error: $e');
    }
  }

  void _precacheUpcomingPages(int currentPage) {
    if (!mounted) return;

    final count = ref.read(precachePagesNotifierProvider);
    if (count == 0) return;

    final streamLink = widget.entry.streamLink;
    if (streamLink == null) return;

    // Server is only needed for network images; local content can precache without it
    final serverAsync = ref.read(serverProvider(widget.serverId));
    final server = serverAsync.valueOrNull;
    if (server == null && widget.localContentPath == null) return;

    final totalPages = streamLink.pageCount;
    final dimNotifier =
        ref.read(pageDimensionsNotifierProvider(widget.entry.id).notifier);

    for (var i = currentPage + 1;
        i <= currentPage + count && i < totalPages;
        i++) {
      final imageProvider = _getPageImageProvider(i, streamLink, server);
      precacheImage(imageProvider, context).catchError((e) {
        debugPrint('Failed to precache page $i: $e');
      });
      // Also resolve dimensions as the image loads
      dimNotifier.resolvePage(i, imageProvider);
    }

    // Resolve current page dimensions too
    if (currentPage >= 0 && currentPage < totalPages) {
      final currentProvider =
          _getPageImageProvider(currentPage, streamLink, server);
      dimNotifier.resolvePage(currentPage, currentProvider);
    }
  }

  /// Get the image provider for a page, using local files if available
  ImageProvider _getPageImageProvider(
    int pageIndex,
    StreamLink streamLink,
    dynamic server,
  ) {
    if (widget.localContentPath != null) {
      final localFile = _findLocalPageFile(pageIndex);
      if (localFile != null) {
        return FileImage(localFile);
      }
    }
    return CachedNetworkImageProvider(
      streamLink.getPageUrl(pageIndex),
      headers: server != null ? AuthService().getAuthHeaders(server) : {},
    );
  }

  /// Build a page image widget for vertical scroll mode
  Widget _buildPageImage(
    int pageIndex,
    StreamLink streamLink,
    dynamic server,
    FilterQuality filterQuality,
  ) {
    if (widget.localContentPath != null) {
      final localFile = _findLocalPageFile(pageIndex);
      if (localFile != null) {
        return Image.file(
          localFile,
          filterQuality: filterQuality,
          width: double.infinity,
          fit: BoxFit.fitWidth,
          errorBuilder: (_, __, ___) => const SizedBox(
            height: 400,
            child: Center(child: Icon(Icons.error, color: Colors.white)),
          ),
        );
      }
    }
    return CachedNetworkImage(
      imageUrl: streamLink.getPageUrl(pageIndex),
      httpHeaders: AuthService().getAuthHeaders(server),
      filterQuality: filterQuality,
      width: double.infinity,
      fit: BoxFit.fitWidth,
      placeholder: (context, url) => const SizedBox(
        height: 400,
        child: Center(
          child: CircularProgressIndicator(color: Colors.white),
        ),
      ),
      errorWidget: (context, url, error) => const SizedBox(
        height: 400,
        child: Center(child: Icon(Icons.error, color: Colors.white)),
      ),
    );
  }

  /// Resolve the file extension used in the local content directory.
  /// Probes once using page 0 and caches the result for all subsequent calls.
  String? _resolveLocalExtension() {
    if (_localExtensionResolved) return _localFileExtension;
    _localExtensionResolved = true;
    if (widget.localContentPath == null) return null;
    for (final ext in ['.jpg', '.png', '.gif', '.webp', '.jpeg']) {
      if (File('${widget.localContentPath}/0$ext').existsSync()) {
        _localFileExtension = ext;
        return ext;
      }
    }
    return null;
  }

  /// Find a local page file using the cached extension
  File? _findLocalPageFile(int pageIndex) {
    if (widget.localContentPath == null) return null;
    final ext = _resolveLocalExtension();
    if (ext == null) return null;
    final file = File('${widget.localContentPath}/$pageIndex$ext');
    if (file.existsSync()) return file;
    return null;
  }
}