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

import '../playlists/playlists.dart';
import '../state/providers.dart';
import '../subsonic/models.dart';
import '../theme/tokens.dart';
import '../widgets/hairline_panel.dart';
import '../widgets/toast.dart';
import 'add_to_playlist_sheet.dart';

/// Playlists list — server-backed with an offline mirror. Create from the app
/// bar; each row opens its detail. Rename/delete via the row overflow menu.
class PlaylistsScreen extends ConsumerWidget {
  const PlaylistsScreen({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final mine = ref.watch(myPlaylistsProvider);
    final shared = ref.watch(sharedPlaylistsProvider);
    final controller = ref.read(playlistsProvider.notifier);
    final connected = ref.watch(subsonicClientProvider) != null;

    void open(Playlist p) => Navigator.of(context).push(
          MaterialPageRoute(builder: (_) => PlaylistDetailScreen(id: p.id)),
        );

    return Scaffold(
      appBar: AppBar(
        title: const Text('Playlists',
            style: TextStyle(fontWeight: FontWeight.w700)),
        actions: [
          IconButton(
            tooltip: 'New playlist',
            onPressed: connected ? () => _create(context, ref) : null,
            icon: const Icon(Icons.add),
          ),
        ],
      ),
      body: SafeArea(
        child: ListView(
          padding: const EdgeInsets.all(TimbreSpacing.lg),
          children: [
            HairlinePanel(
              title: 'Playlists',
              active: true,
              trailing: mine.isEmpty ? null : '(${mine.length})',
              padding: const EdgeInsets.symmetric(vertical: TimbreSpacing.md),
              child: mine.isEmpty
                  ? Padding(
                      padding: const EdgeInsets.all(TimbreSpacing.lg),
                      child: Text(
                        connected
                            ? 'No playlists yet. Tap + to create one.'
                            : 'Connect to a server to see playlists.',
                        textAlign: TextAlign.center,
                        style: TextStyle(color: TimbreColors.dimmed),
                      ),
                    )
                  : Column(
                      children: [
                        for (final p in mine)
                          _PlaylistRow(
                            name: p.name,
                            subtitle: p.songCount != null
                                ? '${p.songCount} tracks'
                                : null,
                            badge: (p.public ?? false) ? 'Public' : null,
                            isPublic: p.public ?? false,
                            onTap: () => open(p),
                            onToggleShare: connected
                                ? () => _toggleShare(context, controller, p)
                                : null,
                            onRename: connected
                                ? () => _rename(context, controller, p)
                                : null,
                            onDelete: connected
                                ? () => _confirmDelete(context, controller, p)
                                : null,
                          ),
                      ],
                    ),
            ),
            if (shared.isNotEmpty) ...[
              const SizedBox(height: TimbreSpacing.xl),
              HairlinePanel(
                title: 'Shared',
                active: true,
                trailing: '(${shared.length})',
                padding:
                    const EdgeInsets.symmetric(vertical: TimbreSpacing.md),
                child: Column(
                  children: [
                    for (final p in shared)
                      _PlaylistRow(
                        name: p.name,
                        subtitle: p.owner != null ? 'by ${p.owner}' : null,
                        onTap: () => open(p),
                        onSaveCopy: connected
                            ? () => _saveCopy(context, controller, p)
                            : null,
                      ),
                  ],
                ),
              ),
            ],
          ],
        ),
      ),
    );
  }

  Future<void> _create(BuildContext context, WidgetRef ref) async {
    final name = await promptPlaylistName(context, title: 'New playlist');
    if (name != null && name.isNotEmpty) {
      await ref.read(playlistsProvider.notifier).create(name);
    }
  }

  Future<void> _rename(
      BuildContext context, PlaylistsController controller, Playlist p) async {
    final name = await promptPlaylistName(context,
        title: 'Rename playlist', initial: p.name);
    if (name != null && name.isNotEmpty) controller.rename(p.id, name);
  }

  Future<void> _toggleShare(
      BuildContext context, PlaylistsController controller, Playlist p) async {
    final next = !(p.public ?? false);
    await controller.setPublic(p.id, next);
    if (context.mounted) {
      showToast(context,
          next ? 'Shared — now public' : 'No longer shared',
          icon: Icons.check);
    }
  }

  Future<void> _saveCopy(
      BuildContext context, PlaylistsController controller, Playlist p) async {
    final id = await controller.saveCopy(p);
    if (!context.mounted) return;
    showToast(context, id != null ? 'Saved a copy' : 'Could not save copy',
        icon: id != null ? Icons.check : null);
  }

  Future<void> _confirmDelete(
      BuildContext context, PlaylistsController controller, Playlist p) async {
    final ok = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        backgroundColor: TimbreColors.surface,
        title: Text('Delete "${p.name}"?'),
        actions: [
          TextButton(
              onPressed: () => Navigator.pop(ctx, false),
              child: const Text('Cancel')),
          TextButton(
              onPressed: () => Navigator.pop(ctx, true),
              child: const Text('Delete')),
        ],
      ),
    );
    if (ok == true) controller.delete(p.id);
  }
}

class _PlaylistRow extends StatelessWidget {
  const _PlaylistRow({
    required this.name,
    required this.onTap,
    this.subtitle,
    this.badge,
    this.isPublic = false,
    this.onRename,
    this.onDelete,
    this.onToggleShare,
    this.onSaveCopy,
  });

  final String name;
  final String? subtitle;

  /// Optional pill after the name, e.g. "Public".
  final String? badge;

  /// Current share state, so the toggle can label itself correctly.
  final bool isPublic;
  final VoidCallback onTap;
  final VoidCallback? onRename;
  final VoidCallback? onDelete;
  final VoidCallback? onToggleShare;
  final VoidCallback? onSaveCopy;

  @override
  Widget build(BuildContext context) {
    final hasMenu = onRename != null ||
        onDelete != null ||
        onToggleShare != null ||
        onSaveCopy != null;
    return InkWell(
      onTap: onTap,
      child: Container(
        constraints:
            const BoxConstraints(minHeight: TimbreSpacing.minTouchTarget),
        padding: const EdgeInsets.only(left: TimbreSpacing.lg),
        child: Row(
          children: [
            Icon(Icons.queue_music, size: 18, color: TimbreColors.dimmed),
            const SizedBox(width: TimbreSpacing.md),
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Row(
                    children: [
                      Flexible(
                        child: Text(name,
                            maxLines: 1,
                            overflow: TextOverflow.ellipsis,
                            style: TextStyle(
                                color: TimbreColors.foreground)),
                      ),
                      if (badge != null) ...[
                        const SizedBox(width: TimbreSpacing.sm),
                        _Pill(badge!),
                      ],
                    ],
                  ),
                  if (subtitle != null)
                    Text(subtitle!,
                        style: TextStyle(
                            color: TimbreColors.dimmed, fontSize: 12)),
                ],
              ),
            ),
            if (hasMenu)
              PopupMenuButton<String>(
                icon: Icon(Icons.more_vert,
                    size: 20, color: TimbreColors.dimmed),
                color: TimbreColors.surface,
                onSelected: (v) {
                  switch (v) {
                    case 'share':
                      onToggleShare?.call();
                    case 'copy':
                      onSaveCopy?.call();
                    case 'rename':
                      onRename?.call();
                    case 'delete':
                      onDelete?.call();
                  }
                },
                itemBuilder: (_) => [
                  if (onToggleShare != null)
                    PopupMenuItem(
                        value: 'share',
                        child:
                            Text(isPublic ? 'Make private' : 'Make public')),
                  if (onSaveCopy != null)
                    const PopupMenuItem(
                        value: 'copy', child: Text('Save a copy')),
                  if (onRename != null)
                    const PopupMenuItem(value: 'rename', child: Text('Rename')),
                  if (onDelete != null)
                    const PopupMenuItem(value: 'delete', child: Text('Delete')),
                ],
              ),
          ],
        ),
      ),
    );
  }
}

/// A small accent-outlined label — used to flag a playlist as "Public".
class _Pill extends StatelessWidget {
  const _Pill(this.text);
  final String text;

  @override
  Widget build(BuildContext context) {
    final accent = Theme.of(context).colorScheme.primary;
    return Container(
      padding: const EdgeInsets.symmetric(
          horizontal: TimbreSpacing.sm, vertical: 1),
      decoration: BoxDecoration(
        border: Border.all(color: accent),
        color: accent.withValues(alpha: 0.12),
      ),
      child: Text(text,
          style: TextStyle(
              color: accent, fontSize: 11, fontWeight: FontWeight.w700)),
    );
  }
}

/// One playlist's tracks: play all / download all from the app bar, remove a
/// track via its trailing control.
class PlaylistDetailScreen extends ConsumerStatefulWidget {
  const PlaylistDetailScreen({super.key, required this.id});

  final String id;

  @override
  ConsumerState<PlaylistDetailScreen> createState() =>
      _PlaylistDetailScreenState();
}

class _PlaylistDetailScreenState extends ConsumerState<PlaylistDetailScreen> {
  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      ref.read(playlistsProvider.notifier).loadDetail(widget.id);
    });
  }

  @override
  Widget build(BuildContext context) {
    final detail = ref.watch(
        playlistsProvider.select((s) => s.details[widget.id]));
    final summary = ref.watch(playlistsProvider.select((s) =>
        s.playlists.where((p) => p.id == widget.id).firstOrNull));
    final connected = ref.watch(subsonicClientProvider) != null;
    final me = ref.watch(currentUsernameProvider);
    final playback = ref.read(playbackCommandsProvider);
    final songs = detail?.songs ?? const <Song>[];

    // Ownership drives which sharing affordance shows: owner → share toggle;
    // someone else's shared playlist → save-a-copy.
    final isMine = summary == null || isOwnedBy(summary, me);
    final isPublic = summary?.public ?? false;

    return Scaffold(
      appBar: AppBar(
        title: Text(detail?.name ?? summary?.name ?? 'Playlist',
            maxLines: 1,
            overflow: TextOverflow.ellipsis,
            style: const TextStyle(fontWeight: FontWeight.w700)),
        actions: [
          IconButton(
            tooltip: 'Play all',
            onPressed:
                songs.isEmpty ? null : () => playback.playSongs(songs),
            icon: const Icon(Icons.play_arrow),
          ),
          IconButton(
            tooltip: 'Download all',
            onPressed: songs.isEmpty
                ? null
                : () {
                    ref
                        .read(downloadManagerProvider.notifier)
                        .downloadAll(songs);
                    showToast(context, 'Downloading playlist…');
                  },
            icon: const Icon(Icons.download),
          ),
          if (connected && summary != null)
            if (isMine)
              IconButton(
                tooltip: isPublic ? 'Make private' : 'Make public',
                onPressed: () => _toggleShare(summary, isPublic),
                icon: Icon(isPublic ? Icons.public : Icons.public_off),
              )
            else
              IconButton(
                tooltip: 'Save a copy',
                onPressed: () => _saveCopy(summary),
                icon: const Icon(Icons.save_alt),
              ),
        ],
      ),
      body: SafeArea(
        child: detail == null
            ? Center(
                child: Text('Loading…',
                    style: TextStyle(color: TimbreColors.dimmed)),
              )
            : songs.isEmpty
                ? Center(
                    child: Text('This playlist is empty.',
                        style: TextStyle(color: TimbreColors.dimmed)),
                  )
                : ListView.builder(
                    padding: const EdgeInsets.symmetric(
                        vertical: TimbreSpacing.md),
                    itemCount: songs.length,
                    itemBuilder: (context, i) {
                      final song = songs[i];
                      return _TrackRow(
                        index: i + 1,
                        song: song,
                        onTap: () => playback.playSongs(songs, startIndex: i),
                        onPlayNext: () => playback.playNext(song),
                        onAddToQueue: () => playback.addToQueue(song),
                        onRemove: connected
                            ? () => ref
                                .read(playlistsProvider.notifier)
                                .removeAt(widget.id, i)
                            : null,
                      );
                    },
                  ),
      ),
    );
  }

  Future<void> _toggleShare(Playlist p, bool isPublic) async {
    await ref.read(playlistsProvider.notifier).setPublic(p.id, !isPublic);
    if (mounted) {
      showToast(context, !isPublic ? 'Shared — now public' : 'No longer shared',
          icon: Icons.check);
    }
  }

  Future<void> _saveCopy(Playlist p) async {
    final id = await ref.read(playlistsProvider.notifier).saveCopy(p);
    if (!mounted) return;
    showToast(context, id != null ? 'Saved a copy' : 'Could not save copy',
        icon: id != null ? Icons.check : null);
  }
}

class _TrackRow extends StatelessWidget {
  const _TrackRow({
    required this.index,
    required this.song,
    required this.onTap,
    required this.onPlayNext,
    required this.onAddToQueue,
    this.onRemove,
  });

  final int index;
  final Song song;
  final VoidCallback onTap;
  final VoidCallback onPlayNext;
  final VoidCallback onAddToQueue;
  final VoidCallback? onRemove;

  @override
  Widget build(BuildContext context) {
    return InkWell(
      onTap: onTap,
      child: Container(
        constraints:
            const BoxConstraints(minHeight: TimbreSpacing.minTouchTarget),
        padding: const EdgeInsets.only(left: TimbreSpacing.lg),
        child: Row(
          children: [
            SizedBox(
              width: 28,
              child: Text('$index',
                  style: TextStyle(color: TimbreColors.dimmed)),
            ),
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Text(song.title ?? 'Untitled',
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                      style: TextStyle(color: TimbreColors.foreground)),
                  if (song.artist != null)
                    Text(song.artist!,
                        maxLines: 1,
                        overflow: TextOverflow.ellipsis,
                        style: TextStyle(
                            color: TimbreColors.dimmed, fontSize: 12)),
                ],
              ),
            ),
            PopupMenuButton<String>(
              icon: Icon(Icons.more_vert,
                  size: 20, color: TimbreColors.dimmed),
              color: TimbreColors.surface,
              onSelected: (v) {
                switch (v) {
                  case 'next':
                    onPlayNext();
                    showToast(context, 'Playing next', icon: Icons.check);
                  case 'queue':
                    onAddToQueue();
                    showToast(context, 'Added to queue', icon: Icons.check);
                  case 'remove':
                    onRemove?.call();
                }
              },
              itemBuilder: (_) => [
                const PopupMenuItem(value: 'next', child: Text('Play next')),
                const PopupMenuItem(
                    value: 'queue', child: Text('Add to queue')),
                if (onRemove != null)
                  const PopupMenuItem(
                      value: 'remove', child: Text('Remove from playlist')),
              ],
            ),
          ],
        ),
      ),
    );
  }
}