minstrel/flutter_client/lib/library/library_screen.dart

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';

import '../api/endpoints/library_lists.dart';
import '../api/endpoints/likes.dart';
import '../api/endpoints/me.dart';
import '../cache/metadata_prefetcher.dart';
import '../library/library_providers.dart' show dioProvider;
import '../models/album.dart';
import '../models/artist.dart';
import '../models/history_event.dart';
// Aliased: Flutter's Material exports a `Page` class (Navigator 2.0
// route descriptor) that conflicts with our wire-format Page<T>.
import '../models/page.dart' as wire;
import '../models/quarantine_mine.dart';
import '../models/track.dart';
import '../player/player_provider.dart';
import '../shared/widgets/main_app_bar_actions.dart';
import '../theme/theme_extension.dart';
import 'widgets/album_card.dart';
import 'widgets/artist_card.dart';
import 'widgets/track_row.dart';

// Providers scoped to this screen. Each tab gets its own first page.
// Infinite scroll is a future enhancement; for v1 phone testing the
// first 50 rows per tab is enough.

final _libraryListsApiProvider = FutureProvider<LibraryListsApi>((ref) async {
  return LibraryListsApi(await ref.watch(dioProvider.future));
});

final _likesApiProvider = FutureProvider<LikesApi>((ref) async {
  return LikesApi(await ref.watch(dioProvider.future));
});

final _meApiProvider = FutureProvider<MeApi>((ref) async {
  return MeApi(await ref.watch(dioProvider.future));
});

/// Paginated artist list. AsyncNotifier so the screen can call
/// `loadMore()` when the scroll approaches the bottom; subsequent
/// pages append to the existing items rather than replacing them.
class _LibraryArtistsNotifier extends AsyncNotifier<wire.Paged<ArtistRef>> {
  static const _pageSize = 50;
  bool _loadingMore = false;

  @override
  Future<wire.Paged<ArtistRef>> build() async {
    final api = await ref.watch(_libraryListsApiProvider.future);
    return api.listArtists(limit: _pageSize, offset: 0);
  }

  Future<void> loadMore() async {
    if (_loadingMore) return;
    final cur = state.value;
    if (cur == null) return;
    if (cur.items.length >= cur.total) return;
    _loadingMore = true;
    try {
      final api = await ref.read(_libraryListsApiProvider.future);
      final next = await api.listArtists(
        limit: _pageSize,
        offset: cur.items.length,
      );
      state = AsyncData(wire.Paged(
        items: [...cur.items, ...next.items],
        total: next.total,
        limit: next.limit,
        offset: 0,
      ));
    } catch (_) {
      // Swallow — the next near-bottom event will retry. The current
      // partial list stays visible.
    } finally {
      _loadingMore = false;
    }
  }
}

final _libraryArtistsProvider = AsyncNotifierProvider<
    _LibraryArtistsNotifier,
    wire.Paged<ArtistRef>>(_LibraryArtistsNotifier.new);

class _LibraryAlbumsNotifier extends AsyncNotifier<wire.Paged<AlbumRef>> {
  static const _pageSize = 50;
  bool _loadingMore = false;

  @override
  Future<wire.Paged<AlbumRef>> build() async {
    final api = await ref.watch(_libraryListsApiProvider.future);
    return api.listAlbums(limit: _pageSize, offset: 0);
  }

  Future<void> loadMore() async {
    if (_loadingMore) return;
    final cur = state.value;
    if (cur == null) return;
    if (cur.items.length >= cur.total) return;
    _loadingMore = true;
    try {
      final api = await ref.read(_libraryListsApiProvider.future);
      final next = await api.listAlbums(
        limit: _pageSize,
        offset: cur.items.length,
      );
      state = AsyncData(wire.Paged(
        items: [...cur.items, ...next.items],
        total: next.total,
        limit: next.limit,
        offset: 0,
      ));
    } catch (_) {
      // Swallow — next scroll event will retry.
    } finally {
      _loadingMore = false;
    }
  }
}

final _libraryAlbumsProvider = AsyncNotifierProvider<
    _LibraryAlbumsNotifier,
    wire.Paged<AlbumRef>>(_LibraryAlbumsNotifier.new);

final _historyProvider = FutureProvider<HistoryPage>((ref) async {
  return (await ref.watch(_meApiProvider.future)).history();
});

final _likedTracksProvider = FutureProvider<wire.Paged<TrackRef>>((ref) async {
  return (await ref.watch(_likesApiProvider.future)).listTracks();
});

final _likedAlbumsProvider = FutureProvider<wire.Paged<AlbumRef>>((ref) async {
  return (await ref.watch(_likesApiProvider.future)).listAlbums();
});

final _likedArtistsProvider = FutureProvider<wire.Paged<ArtistRef>>((ref) async {
  return (await ref.watch(_likesApiProvider.future)).listArtists();
});

final _quarantineProvider = FutureProvider<List<QuarantineMineRow>>((ref) async {
  return (await ref.watch(_meApiProvider.future)).quarantineMine();
});

class LibraryScreen extends ConsumerStatefulWidget {
  const LibraryScreen({super.key});

  @override
  ConsumerState<LibraryScreen> createState() => _LibraryScreenState();
}

class _LibraryScreenState extends ConsumerState<LibraryScreen>
    with TickerProviderStateMixin {
  late final TabController _ctrl = TabController(length: 5, vsync: this);

  @override
  void dispose() {
    _ctrl.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final fs = Theme.of(context).extension<FabledSwordTheme>()!;
    return Scaffold(
      backgroundColor: fs.obsidian,
      appBar: AppBar(
        backgroundColor: fs.obsidian,
        elevation: 0,
        title: Text('Library', style: TextStyle(color: fs.parchment)),
        actions: const [MainAppBarActions(currentRoute: '/library')],
        bottom: TabBar(
          controller: _ctrl,
          isScrollable: true,
          tabAlignment: TabAlignment.start,
          labelColor: fs.parchment,
          unselectedLabelColor: fs.ash,
          indicatorColor: fs.accent,
          tabs: const [
            Tab(text: 'Artists'),
            Tab(text: 'Albums'),
            Tab(text: 'History'),
            Tab(text: 'Liked'),
            Tab(text: 'Hidden'),
          ],
        ),
      ),
      body: TabBarView(
        controller: _ctrl,
        children: const [
          _ArtistsTab(),
          _AlbumsTab(),
          _HistoryTab(),
          _LikedTab(),
          _HiddenTab(),
        ],
      ),
    );
  }
}

class _ArtistsTab extends ConsumerWidget {
  const _ArtistsTab();

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final fs = Theme.of(context).extension<FabledSwordTheme>()!;
    return ref.watch(_libraryArtistsProvider).when(
          loading: () => const Center(child: CircularProgressIndicator()),
          error: (e, _) => Center(child: Text('$e', style: TextStyle(color: fs.error))),
          data: (page) {
            // Warm details for the first screenful so taps are instant.
            ref
                .read(metadataPrefetcherProvider)
                .warmArtists(page.items.map((a) => a.id));
            return page.items.isEmpty
              ? Center(child: Text("No artists yet — scan a library folder via the server's config.", style: TextStyle(color: fs.ash), textAlign: TextAlign.center))
              : RefreshIndicator(
                  onRefresh: () async {
                    ref.invalidate(_libraryArtistsProvider);
                    await ref.read(_libraryArtistsProvider.future);
                  },
                  // Listen for scroll-near-bottom and ask the notifier
                  // to fetch the next page. 800px lookahead so the next
                  // page lands before the user reaches the visible end.
                  child: NotificationListener<ScrollNotification>(
                    onNotification: (n) {
                      if (n.metrics.pixels >=
                          n.metrics.maxScrollExtent - 800) {
                        ref
                            .read(_libraryArtistsProvider.notifier)
                            .loadMore();
                      }
                      return false;
                    },
                    child: GridView.builder(
                      padding: const EdgeInsets.all(8),
                      gridDelegate:
                          const SliverGridDelegateWithFixedCrossAxisCount(
                        crossAxisCount: 3,
                        mainAxisSpacing: 8,
                        crossAxisSpacing: 8,
                        childAspectRatio: 0.78,
                      ),
                      itemCount: page.items.length,
                      itemBuilder: (ctx, i) {
                        final artist = page.items[i];
                        return ArtistCard(
                          artist: artist,
                          onTap: () => ctx.push('/artists/${artist.id}',
                              extra: artist),
                        );
                      },
                    ),
                  ),
                );
          },
        );
  }
}

class _AlbumsTab extends ConsumerWidget {
  const _AlbumsTab();

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final fs = Theme.of(context).extension<FabledSwordTheme>()!;
    return ref.watch(_libraryAlbumsProvider).when(
          loading: () => const Center(child: CircularProgressIndicator()),
          error: (e, _) => Center(child: Text('$e', style: TextStyle(color: fs.error))),
          data: (page) {
            return page.items.isEmpty
              ? Center(child: Text("No albums yet — scan a library folder via the server's config.", style: TextStyle(color: fs.ash), textAlign: TextAlign.center))
              : RefreshIndicator(
                  onRefresh: () async {
                    ref.invalidate(_libraryAlbumsProvider);
                    await ref.read(_libraryAlbumsProvider.future);
                  },
                  // Same responsive 3-up grid as the artist detail
                  // album list — LayoutBuilder + AlbumCard sized to the
                  // cell, mainAxisExtent matched to actual card height.
                  child: LayoutBuilder(builder: (ctx, constraints) {
                    const cols = 3;
                    const sidePad = 8.0;
                    const gap = 8.0;
                    final cellW = (constraints.maxWidth -
                            sidePad * 2 -
                            gap * (cols - 1)) /
                        cols;
                    // cover (cellW - 16) + gap (8) + 2-line title (~36)
                    // + artist line (~16) + slack. Slack is generous on
                    // purpose — line-height + font scaling variations
                    // would otherwise overflow the cell by a pixel
                    // (logged as a noisy RenderFlex warning).
                    final cellH = (cellW - 16) + 8 + 36 + 16 + 8;
                    return NotificationListener<ScrollNotification>(
                      onNotification: (n) {
                        if (n.metrics.pixels >=
                            n.metrics.maxScrollExtent - 800) {
                          ref
                              .read(_libraryAlbumsProvider.notifier)
                              .loadMore();
                        }
                        return false;
                      },
                      child: GridView.builder(
                        padding: const EdgeInsets.all(sidePad),
                        gridDelegate:
                            SliverGridDelegateWithFixedCrossAxisCount(
                          crossAxisCount: cols,
                          mainAxisExtent: cellH,
                          mainAxisSpacing: gap,
                          crossAxisSpacing: gap,
                        ),
                        itemCount: page.items.length,
                        itemBuilder: (ctx, i) {
                          final album = page.items[i];
                          return AlbumCard(
                            album: album,
                            width: cellW,
                            titleMaxLines: 2,
                            onTap: () => ctx.push('/albums/${album.id}',
                                extra: album),
                          );
                        },
                      ),
                    );
                  }),
                );
          },
        );
  }
}

class _HistoryTab extends ConsumerWidget {
  const _HistoryTab();

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final fs = Theme.of(context).extension<FabledSwordTheme>()!;
    return ref.watch(_historyProvider).when(
          loading: () => const Center(child: CircularProgressIndicator()),
          error: (e, _) => Center(child: Text('$e', style: TextStyle(color: fs.error))),
          data: (page) => page.events.isEmpty
              ? Center(child: Text('No listening history yet.', style: TextStyle(color: fs.ash)))
              : RefreshIndicator(
                  onRefresh: () async => ref.refresh(_historyProvider.future),
                  child: ListView.separated(
                    itemCount: page.events.length,
                    separatorBuilder: (_, __) => Divider(height: 1, color: fs.iron),
                    itemBuilder: (ctx, i) {
                      final event = page.events[i];
                      return TrackRow(
                        track: event.track,
                        onTap: () => ref
                            .read(playerActionsProvider)
                            .playTracks([event.track]),
                        trailing: Text(
                          _relativeTime(event.playedAt),
                          style: TextStyle(color: fs.ash, fontSize: 12),
                        ),
                      );
                    },
                  ),
                ),
        );
  }
}

class _LikedTab extends ConsumerWidget {
  const _LikedTab();

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final fs = Theme.of(context).extension<FabledSwordTheme>()!;
    final tracksA = ref.watch(_likedTracksProvider);
    final albumsA = ref.watch(_likedAlbumsProvider);
    final artistsA = ref.watch(_likedArtistsProvider);

    if (tracksA.isLoading || albumsA.isLoading || artistsA.isLoading) {
      return const Center(child: CircularProgressIndicator());
    }
    final t = tracksA.value;
    final al = albumsA.value;
    final ar = artistsA.value;
    if (t == null || al == null || ar == null) {
      return Center(child: Text("Couldn't load liked items.", style: TextStyle(color: fs.error)));
    }
    if (t.items.isEmpty && al.items.isEmpty && ar.items.isEmpty) {
      return Center(child: Text('No liked artists, albums, or tracks yet.', style: TextStyle(color: fs.ash), textAlign: TextAlign.center));
    }
    return RefreshIndicator(
      onRefresh: () async {
        await Future.wait([
          ref.refresh(_likedTracksProvider.future),
          ref.refresh(_likedAlbumsProvider.future),
          ref.refresh(_likedArtistsProvider.future),
        ]);
      },
      child: ListView(children: [
        if (ar.items.isNotEmpty) ...[
          _SectionHeader(label: 'Artists', count: ar.total),
          SizedBox(
            height: 168,
            child: ListView.builder(
              scrollDirection: Axis.horizontal,
              padding: const EdgeInsets.symmetric(horizontal: 8),
              itemCount: ar.items.length,
              itemBuilder: (ctx, i) {
                final artist = ar.items[i];
                return ArtistCard(
                  artist: artist,
                  onTap: () =>
                      ctx.push('/artists/${artist.id}', extra: artist),
                );
              },
            ),
          ),
        ],
        if (al.items.isNotEmpty) ...[
          _SectionHeader(label: 'Albums', count: al.total),
          SizedBox(
            height: 200,
            child: ListView.builder(
              scrollDirection: Axis.horizontal,
              padding: const EdgeInsets.symmetric(horizontal: 8),
              itemCount: al.items.length,
              itemBuilder: (ctx, i) {
                final album = al.items[i];
                return AlbumCard(
                  album: album,
                  onTap: () =>
                      ctx.push('/albums/${album.id}', extra: album),
                );
              },
            ),
          ),
        ],
        if (t.items.isNotEmpty) ...[
          _SectionHeader(label: 'Tracks', count: t.total),
          ...t.items.asMap().entries.map((e) {
            return TrackRow(
              track: e.value,
              onTap: () => ref
                  .read(playerActionsProvider)
                  .playTracks(t.items, initialIndex: e.key),
            );
          }),
        ],
        const SizedBox(height: 96),
      ]),
    );
  }
}

class _HiddenTab extends ConsumerWidget {
  const _HiddenTab();

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final fs = Theme.of(context).extension<FabledSwordTheme>()!;
    return ref.watch(_quarantineProvider).when(
          loading: () => const Center(child: CircularProgressIndicator()),
          error: (e, _) => Center(child: Text('$e', style: TextStyle(color: fs.error))),
          data: (rows) => rows.isEmpty
              ? Center(
                  child: Text(
                    'No hidden tracks.\nUse a track\'s menu to flag bad rips or wrong tags.',
                    textAlign: TextAlign.center,
                    style: TextStyle(color: fs.ash),
                  ),
                )
              : RefreshIndicator(
                  onRefresh: () async => ref.refresh(_quarantineProvider.future),
                  child: ListView.separated(
                    itemCount: rows.length,
                    separatorBuilder: (_, __) => Divider(height: 1, color: fs.iron),
                    itemBuilder: (ctx, i) => _QuarantineTile(row: rows[i]),
                  ),
                ),
        );
  }
}

class _QuarantineTile extends StatelessWidget {
  const _QuarantineTile({required this.row});
  final QuarantineMineRow row;

  @override
  Widget build(BuildContext context) {
    final fs = Theme.of(context).extension<FabledSwordTheme>()!;
    final reasonLabel = switch (row.reason) {
      'bad_rip' => 'Bad rip',
      'wrong_file' => 'Wrong file',
      'wrong_tags' => 'Wrong tags',
      'duplicate' => 'Duplicate',
      _ => 'Other',
    };
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 10),
      child: Row(crossAxisAlignment: CrossAxisAlignment.start, children: [
        Expanded(
          child: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
            Text(
              row.trackTitle,
              maxLines: 1,
              overflow: TextOverflow.ellipsis,
              style: TextStyle(color: fs.parchment, fontSize: 14),
            ),
            Text(
              '${row.artistName} · ${row.albumTitle}',
              maxLines: 1,
              overflow: TextOverflow.ellipsis,
              style: TextStyle(color: fs.ash, fontSize: 12),
            ),
            Padding(
              padding: const EdgeInsets.only(top: 4),
              child: Container(
                padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 2),
                decoration: BoxDecoration(
                  color: fs.iron,
                  borderRadius: BorderRadius.circular(4),
                ),
                child: Text(reasonLabel, style: TextStyle(color: fs.ash, fontSize: 11)),
              ),
            ),
          ]),
        ),
      ]),
    );
  }
}

class _SectionHeader extends StatelessWidget {
  const _SectionHeader({required this.label, required this.count});
  final String label;
  final int count;

  @override
  Widget build(BuildContext context) {
    final fs = Theme.of(context).extension<FabledSwordTheme>()!;
    return Padding(
      padding: const EdgeInsets.fromLTRB(16, 16, 16, 8),
      child: Row(children: [
        Text(label,
            style: TextStyle(
                color: fs.parchment, fontSize: 18, fontWeight: FontWeight.w500)),
        const SizedBox(width: 8),
        Text('$count', style: TextStyle(color: fs.ash, fontSize: 13)),
      ]),
    );
  }
}

/// Lightweight relative-time formatter: <1h "23m ago" / <24h "3h ago"
/// / <7d "Tue 14:32" / older "May 1" / older diff-year "May 1, 2025".
/// Mirrors web/src/lib/components/HistoryRow.svelte's relativeTime.
String _relativeTime(String iso) {
  final t = DateTime.tryParse(iso);
  if (t == null) return '';
  final now = DateTime.now();
  final diff = now.difference(t);
  if (diff.inMinutes < 60) {
    final m = diff.inMinutes < 1 ? 1 : diff.inMinutes;
    return '${m}m ago';
  }
  if (diff.inHours < 24) return '${diff.inHours}h ago';
  if (diff.inDays < 7) {
    const days = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'];
    final hh = t.hour.toString().padLeft(2, '0');
    final mm = t.minute.toString().padLeft(2, '0');
    return '${days[t.weekday - 1]} $hh:$mm';
  }
  const months = [
    'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
    'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec',
  ];
  if (t.year == now.year) return '${months[t.month - 1]} ${t.day}';
  return '${months[t.month - 1]} ${t.day}, ${t.year}';
}