import 'dart:async';

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

import '../../core/theme/app_colors.dart';
import '../../core/widgets/app_icon.dart';
import '../../core/widgets/pressable.dart';
import '../../data/models/jellyfin_library.dart';
import '../../data/models/media_playback.dart';
import '../../data/services/jellyfin_library_service.dart';
import '../home/system_controller.dart';
import 'jellyfin_playback_controller.dart';
import 'widgets/jellyfin_back_button.dart';
import 'widgets/jellyfin_status_strip.dart';

class JellyfinAlbumScreen extends StatefulWidget {
  const JellyfinAlbumScreen({super.key, required this.album});

  final JellyfinAlbum album;

  @override
  State<JellyfinAlbumScreen> createState() => _JellyfinAlbumScreenState();
}

class _JellyfinAlbumScreenState extends State<JellyfinAlbumScreen> {
  late final JellyfinLibraryService _library;
  late Future<List<JellyfinTrack>> _tracksFuture;
  late bool _isFavorite;
  bool _favoriteBusy = false;
  double? _seekDragMs;

  @override
  void initState() {
    super.initState();
    _library = context.read<JellyfinLibraryService>();
    _tracksFuture = _library.albumTracks(widget.album.id);
    _isFavorite = widget.album.isFavorite;
    unawaited(_loadFavorite());
  }

  void _reloadTracks() {
    setState(() {
      _tracksFuture = _library.albumTracks(widget.album.id);
    });
  }

  Future<void> _loadFavorite() async {
    try {
      final favorite = await _library.isFavorite(widget.album.id);
      if (!mounted) return;
      setState(() => _isFavorite = favorite);
    } catch (_) {
      // Keep the album's incoming state if the lookup fails.
    }
  }

  Future<void> _toggleFavorite() async {
    if (_favoriteBusy) return;
    final next = !_isFavorite;
    setState(() => _favoriteBusy = true);
    try {
      await _library.setFavorite(widget.album.id, next);
      if (!mounted) return;
      setState(() {
        _isFavorite = next;
        _favoriteBusy = false;
      });
    } catch (_) {
      if (!mounted) return;
      setState(() => _favoriteBusy = false);
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Could not update favorites.')),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    final colors = context.colors;
    final theme = Theme.of(context);
    final playback = context.watch<JellyfinPlaybackController>();
    final system = context.watch<SystemController>();

    final active = playback.isCurrentAlbum(widget.album);
    final playing = active && playback.playing;
    final currentItem = active ? playback.currentItem : null;
    final currentTitle = active
        ? (currentItem?.title ?? playback.snapshot.title ?? widget.album.name)
        : playback.loading
        ? 'Starting playback…'
        : widget.album.name;
    final currentArtist = active
        ? (currentItem?.artist ??
              playback.snapshot.artist ??
              widget.album.artist)
        : widget.album.artist;
    final currentTrackId = active
        ? (currentItem?.trackId ?? playback.snapshot.itemId)
        : null;
    final media = active
        ? playback.mediaPlayback
        : MediaPlayback(
            hasAccess: true,
            title: widget.album.name,
            artist: widget.album.artist,
          );
    final imageUrl = _library
        .imageUrl(widget.album.id, widget.album.imageTag, maxHeight: 600)
        ?.toString();
    final headers = _library.imageHeaders;

    Widget cover() {
      final placeholder = ColoredBox(
        color: colors.surfaceStrong,
        child: Center(
          child: AppIcon(
            'assets/icons/headphones.svg',
            size: 54,
            color: colors.inkFaint,
          ),
        ),
      );
      return Align(
        alignment: Alignment.topCenter,
        child: ConstrainedBox(
          constraints: const BoxConstraints(maxWidth: 420),
          child: AspectRatio(
            aspectRatio: 1,
            child: Container(
              key: const ValueKey('jellyfin-album-cover'),
              clipBehavior: Clip.antiAlias,
              decoration: BoxDecoration(
                borderRadius: BorderRadius.circular(24),
                border: Border.all(color: colors.border),
              ),
              child: imageUrl == null
                  ? placeholder
                  : Image.network(
                      imageUrl,
                      headers: headers,
                      fit: BoxFit.cover,
                      errorBuilder: (_, _, _) => placeholder,
                    ),
            ),
          ),
        ),
      );
    }

    Widget controls({double? minHeight}) {
      final error = playback.error;
      final durationMs = media.durationMs > 0
          ? media.durationMs
          : (playback.currentItem?.durationMs ?? 0);
      final total = Duration(milliseconds: durationMs);
      final rawPosition = (_seekDragMs ?? media.positionMs.toDouble()).clamp(
        0.0,
        durationMs > 0 ? durationMs.toDouble() : 1.0,
      );
      final position = Duration(milliseconds: rawPosition.round());
      final canSeek = active && durationMs > 0;
      final canToggle = !playback.loading;

      final content = Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        mainAxisSize: MainAxisSize.min,
        children: [
          Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                active
                    ? (playing ? 'Now playing' : 'Paused')
                    : playback.loading
                    ? 'Starting playback…'
                    : 'Ready',
                style: theme.textTheme.labelLarge?.copyWith(
                  color: colors.inkMuted,
                ),
              ),
              const SizedBox(height: 4),
              Text(
                currentTitle,
                maxLines: 2,
                overflow: TextOverflow.ellipsis,
                style: theme.textTheme.headlineSmall,
              ),
              const SizedBox(height: 2),
              Text(
                currentArtist.isEmpty ? 'Unknown artist' : currentArtist,
                maxLines: 1,
                overflow: TextOverflow.ellipsis,
                style: theme.textTheme.bodyMedium?.copyWith(
                  color: colors.inkMuted,
                ),
              ),
            ],
          ),
          if (error != null) ...[
            const SizedBox(height: 8),
            Row(
              children: [
                Expanded(
                  child: Text(
                    error,
                    style: theme.textTheme.bodySmall?.copyWith(
                      color: colors.danger,
                    ),
                  ),
                ),
                TextButton(
                  onPressed: () {
                    unawaited(playback.playAlbum(widget.album));
                  },
                  style: TextButton.styleFrom(foregroundColor: colors.accent),
                  child: const Text('Retry'),
                ),
              ],
            ),
          ],
        ],
      );
      final card = Container(
        key: const ValueKey('jellyfin-album-progress-card'),
        padding: const EdgeInsets.fromLTRB(18, 12, 18, 14),
        decoration: BoxDecoration(
          color: colors.surface,
          borderRadius: BorderRadius.circular(20),
          border: Border.all(color: colors.border),
        ),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Row(
              children: [
                Expanded(
                  child: SliderTheme(
                    data: SliderTheme.of(context).copyWith(
                      trackHeight: 4,
                      activeTrackColor: colors.accent,
                      inactiveTrackColor: colors.border,
                      thumbColor: colors.accent,
                      overlayColor: colors.accent.withValues(alpha: 0.12),
                      thumbShape: const RoundSliderThumbShape(
                        enabledThumbRadius: 8,
                      ),
                      overlayShape: const RoundSliderOverlayShape(
                        overlayRadius: 18,
                      ),
                    ),
                    child: Slider(
                      min: 0,
                      max: durationMs > 0 ? durationMs.toDouble() : 1,
                      value: durationMs > 0 ? rawPosition : 0,
                      onChanged: canSeek
                          ? (value) {
                              setState(() => _seekDragMs = value);
                            }
                          : null,
                      onChangeEnd: canSeek
                          ? (value) {
                              setState(() => _seekDragMs = null);
                              unawaited(
                                playback.seek(
                                  Duration(milliseconds: value.round()),
                                ),
                              );
                            }
                          : null,
                    ),
                  ),
                ),
                const SizedBox(width: 10),
                Text(
                  '${_formatDuration(position)} / ${_formatDuration(total)}',
                  style: theme.textTheme.bodySmall?.copyWith(
                    color: colors.inkMuted,
                    fontFeatures: const [FontFeature.tabularFigures()],
                  ),
                ),
              ],
            ),
            const SizedBox(height: 10),
            SizedBox(
              height: 80,
              child: Stack(
                alignment: Alignment.center,
                children: [
                  Row(
                    mainAxisAlignment: MainAxisAlignment.center,
                    children: [
                      _AlbumTransportButton(
                        asset: 'assets/icons/skip-back.svg',
                        semanticLabel: 'Previous track',
                        enabled: active && playback.canGoPrevious,
                        onTap: () => unawaited(playback.previous()),
                      ),
                      const SizedBox(width: 20),
                      _AlbumTransportButton(
                        asset: playing
                            ? 'assets/icons/pause.svg'
                            : 'assets/icons/play.svg',
                        semanticLabel: playing ? 'Pause music' : 'Play music',
                        primary: true,
                        enabled: canToggle,
                        onTap: () {
                          if (playback.loading) return;
                          if (active) {
                            unawaited(playback.toggle());
                          } else {
                            unawaited(playback.playAlbum(widget.album));
                          }
                        },
                      ),
                      const SizedBox(width: 20),
                      _AlbumTransportButton(
                        asset: 'assets/icons/skip-forward.svg',
                        semanticLabel: 'Next track',
                        enabled: active && playback.canGoNext,
                        onTap: () => unawaited(playback.next()),
                      ),
                    ],
                  ),
                  Align(
                    alignment: Alignment.centerLeft,
                    child: _FavoriteButton(
                      isFavorite: _isFavorite,
                      busy: _favoriteBusy,
                      onTap: _toggleFavorite,
                    ),
                  ),
                  Align(
                    alignment: Alignment.centerRight,
                    child: _AlbumVolumeControls(system: system),
                  ),
                ],
              ),
            ),
          ],
        ),
      );
      final column = Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        mainAxisSize: MainAxisSize.min,
        mainAxisAlignment: MainAxisAlignment.spaceBetween,
        children: [
          content,
          Padding(padding: const EdgeInsets.only(top: 14), child: card),
        ],
      );
      if (minHeight == null) return column;
      return ConstrainedBox(
        constraints: BoxConstraints(minHeight: minHeight),
        child: column,
      );
    }

    Widget trackList() {
      return Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          Row(
            children: [
              Text(
                'Tracks',
                style: theme.textTheme.titleMedium?.copyWith(
                  color: colors.ink,
                  fontWeight: FontWeight.w700,
                ),
              ),
            ],
          ),
          const SizedBox(height: 6),
          Expanded(
            child: FutureBuilder<List<JellyfinTrack>>(
              future: _tracksFuture,
              builder: (context, snapshot) {
                if (snapshot.connectionState == ConnectionState.waiting) {
                  return const Center(child: CircularProgressIndicator());
                }
                if (snapshot.hasError) {
                  return Center(
                    child: Column(
                      mainAxisSize: MainAxisSize.min,
                      children: [
                        Text(
                          'Could not load tracks.',
                          style: theme.textTheme.bodySmall?.copyWith(
                            color: colors.inkMuted,
                          ),
                        ),
                        TextButton(
                          onPressed: _reloadTracks,
                          style: TextButton.styleFrom(
                            foregroundColor: colors.accent,
                          ),
                          child: const Text('Retry'),
                        ),
                      ],
                    ),
                  );
                }
                final tracks = snapshot.data ?? const <JellyfinTrack>[];
                if (tracks.isEmpty) {
                  return Center(
                    child: Text(
                      'No tracks in this album.',
                      style: theme.textTheme.bodySmall?.copyWith(
                        color: colors.inkMuted,
                      ),
                    ),
                  );
                }
                return ListView.separated(
                  padding: EdgeInsets.zero,
                  itemCount: tracks.length,
                  separatorBuilder: (_, _) =>
                      Divider(color: colors.border, height: 1),
                  itemBuilder: (context, index) {
                    final track = tracks[index];
                    return _TrackRow(
                      track: track,
                      isCurrent: track.id == currentTrackId,
                      isPlaying: playing,
                      onTap: () => _playTrack(tracks, index),
                    );
                  },
                );
              },
            ),
          ),
        ],
      );
    }

    Widget body(BoxConstraints constraints) {
      final coverWidth = (constraints.maxWidth * 0.21).clamp(140.0, 252.0);
      return Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          Row(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              SizedBox(width: coverWidth, child: cover()),
              const SizedBox(width: 18),
              Expanded(child: controls(minHeight: coverWidth)),
            ],
          ),
          const SizedBox(height: 16),
          Expanded(
            child: SizedBox.expand(
              key: const ValueKey('jellyfin-album-track-list'),
              child: trackList(),
            ),
          ),
        ],
      );
    }

    return Scaffold(
      backgroundColor: colors.canvas,
      body: Container(
        decoration: homeBackground(colors, theme.brightness),
        child: SafeArea(
          child: Padding(
            padding: const EdgeInsets.fromLTRB(36, 22, 36, 16),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: [
                _AlbumHeader(album: widget.album),
                const SizedBox(height: 14),
                Expanded(
                  child: LayoutBuilder(
                    builder: (context, constraints) => body(constraints),
                  ),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }

  Future<void> _playTrack(List<JellyfinTrack> tracks, int index) async {
    final playback = context.read<JellyfinPlaybackController>();
    if (playback.loading) {
      await playback.playTrackAt(index);
      return;
    }
    if (!playback.isCurrentAlbum(widget.album)) {
      final error = await playback.playAlbum(widget.album);
      if (error != null) return;
    }
    await playback.playTrackAt(index);
  }
}

class _AlbumHeader extends StatelessWidget {
  const _AlbumHeader({required this.album});

  final JellyfinAlbum album;

  @override
  Widget build(BuildContext context) {
    final colors = context.colors;
    final theme = Theme.of(context);
    final year = album.year;
    final title = year == null || year <= 0 || album.name.contains('($year)')
        ? album.name
        : '${album.name} ($year)';
    return Row(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        const JellyfinBackButton(),
        const SizedBox(width: 18),
        Expanded(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                'Album',
                style: theme.textTheme.labelLarge?.copyWith(
                  color: colors.inkMuted,
                ),
              ),
              const SizedBox(height: 2),
              Text(
                title,
                maxLines: 2,
                overflow: TextOverflow.ellipsis,
                style: theme.textTheme.headlineLarge,
              ),
              const SizedBox(height: 2),
              Text(
                album.artist.isEmpty ? 'Unknown artist' : album.artist,
                maxLines: 1,
                overflow: TextOverflow.ellipsis,
                style: theme.textTheme.bodySmall?.copyWith(
                  color: colors.inkMuted,
                ),
              ),
            ],
          ),
        ),
        const SizedBox(width: 12),
        const JellyfinStatusStrip(),
      ],
    );
  }
}

class _FavoriteButton extends StatelessWidget {
  const _FavoriteButton({
    required this.isFavorite,
    required this.busy,
    required this.onTap,
  });

  final bool isFavorite;
  final bool busy;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    final colors = context.colors;
    return Pressable(
      onTap: busy ? null : onTap,
      semanticLabel: isFavorite ? 'Remove from favorites' : 'Add to favorites',
      pressedScale: 0.94,
      child: Container(
        width: 69,
        height: 69,
        decoration: BoxDecoration(
          color: isFavorite ? colors.accentSoft : colors.surface,
          shape: BoxShape.circle,
          border: Border.all(
            color: isFavorite
                ? colors.accent.withValues(alpha: 0.3)
                : colors.border,
          ),
        ),
        alignment: Alignment.center,
        child: busy
            ? SizedBox(
                width: 24,
                height: 24,
                child: CircularProgressIndicator(
                  strokeWidth: 2,
                  color: colors.accent,
                ),
              )
            : AppIcon(
                isFavorite
                    ? 'assets/icons/heart-filled.svg'
                    : 'assets/icons/heart.svg',
                size: 32,
                color: isFavorite ? colors.accent : colors.inkMuted,
              ),
      ),
    );
  }
}

class _AlbumVolumeControls extends StatelessWidget {
  const _AlbumVolumeControls({required this.system});

  final SystemController system;

  @override
  Widget build(BuildContext context) {
    final colors = context.colors;
    final enabled = !system.isVolumeFixed;
    return Row(
      mainAxisSize: MainAxisSize.min,
      children: [
        _AlbumVolumeStep(
          icon: Icons.remove_rounded,
          semanticLabel: 'Volume down',
          onTap: enabled ? () => unawaited(system.adjustVolume(-1)) : null,
        ),
        const SizedBox(width: 8),
        Pressable(
          onTap: enabled ? () => unawaited(system.toggleMute()) : null,
          semanticLabel: system.isMuted ? 'Unmute' : 'Mute',
          pressedScale: 0.92,
          child: Container(
            width: 60,
            height: 60,
            decoration: BoxDecoration(
              color: system.isMuted ? colors.accentSoft : colors.surfaceStrong,
              shape: BoxShape.circle,
              border: Border.all(
                color: system.isMuted
                    ? colors.accent.withValues(alpha: 0.25)
                    : colors.border,
              ),
            ),
            alignment: Alignment.center,
            child: AppIcon(
              system.isMuted
                  ? 'assets/icons/volume-x.svg'
                  : 'assets/icons/volume-2.svg',
              size: 26,
              color: system.isMuted ? colors.accent : colors.inkMuted,
            ),
          ),
        ),
        const SizedBox(width: 8),
        _AlbumVolumeStep(
          icon: Icons.add_rounded,
          semanticLabel: 'Volume up',
          onTap: enabled ? () => unawaited(system.adjustVolume(1)) : null,
        ),
      ],
    );
  }
}

class _AlbumVolumeStep extends StatelessWidget {
  const _AlbumVolumeStep({
    required this.icon,
    required this.semanticLabel,
    required this.onTap,
  });

  final IconData icon;
  final String semanticLabel;
  final VoidCallback? onTap;

  @override
  Widget build(BuildContext context) {
    final colors = context.colors;
    return Pressable(
      onTap: onTap,
      semanticLabel: semanticLabel,
      pressedScale: 0.92,
      child: Container(
        width: 60,
        height: 60,
        decoration: BoxDecoration(
          color: colors.surfaceStrong,
          shape: BoxShape.circle,
          border: Border.all(color: colors.border),
        ),
        alignment: Alignment.center,
        child: Icon(
          icon,
          size: 26,
          color: onTap == null ? colors.inkFaint : colors.inkMuted,
        ),
      ),
    );
  }
}

class _AlbumTransportButton extends StatelessWidget {
  const _AlbumTransportButton({
    required this.asset,
    required this.semanticLabel,
    required this.onTap,
    this.enabled = true,
    this.primary = false,
  });

  final String asset;
  final String semanticLabel;
  final VoidCallback onTap;
  final bool enabled;
  final bool primary;

  @override
  Widget build(BuildContext context) {
    final colors = context.colors;
    final size = primary ? 80.0 : 62.0;
    return Opacity(
      opacity: enabled ? 1 : 0.4,
      child: Pressable(
        onTap: enabled ? onTap : null,
        semanticLabel: semanticLabel,
        pressedScale: 0.92,
        child: Container(
          width: size,
          height: size,
          decoration: BoxDecoration(
            color: primary ? colors.accent : colors.surfaceStrong,
            shape: BoxShape.circle,
            border: primary ? null : Border.all(color: colors.border),
          ),
          alignment: Alignment.center,
          child: AppIcon(
            asset,
            size: primary ? 32 : 26,
            color: primary ? colors.accentInk : colors.ink,
          ),
        ),
      ),
    );
  }
}

class _TrackRow extends StatelessWidget {
  const _TrackRow({
    required this.track,
    required this.isCurrent,
    required this.isPlaying,
    required this.onTap,
  });

  final JellyfinTrack track;
  final bool isCurrent;
  final bool isPlaying;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    final colors = context.colors;
    final theme = Theme.of(context);
    final color = isCurrent ? colors.accent : colors.ink;
    return Material(
      color: isCurrent ? colors.accentSoft : Colors.transparent,
      borderRadius: BorderRadius.circular(12),
      child: InkWell(
        borderRadius: BorderRadius.circular(12),
        onTap: onTap,
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 12),
          child: Row(
            children: [
              SizedBox(
                width: 28,
                child: Text(
                  track.displayIndex,
                  style: theme.textTheme.bodySmall?.copyWith(
                    color: isCurrent ? colors.accent : colors.inkFaint,
                  ),
                ),
              ),
              const SizedBox(width: 6),
              Expanded(
                child: Text(
                  track.name,
                  maxLines: 1,
                  overflow: TextOverflow.ellipsis,
                  style: theme.textTheme.bodyMedium?.copyWith(
                    color: color,
                    fontWeight: isCurrent ? FontWeight.w600 : FontWeight.w400,
                  ),
                ),
              ),
              const SizedBox(width: 8),
              Text(
                _formatDuration(track.duration),
                style: theme.textTheme.bodySmall?.copyWith(
                  color: isCurrent ? colors.accent : colors.inkMuted,
                ),
              ),
              if (isCurrent) ...[
                const SizedBox(width: 8),
                AppIcon(
                  isPlaying
                      ? 'assets/icons/volume-2.svg'
                      : 'assets/icons/play.svg',
                  size: 14,
                  color: colors.accent,
                ),
              ],
            ],
          ),
        ),
      ),
    );
  }
}

String _formatDuration(Duration duration) {
  final totalSeconds = duration.inSeconds;
  final minutes = totalSeconds ~/ 60;
  final seconds = totalSeconds % 60;
  final hours = minutes ~/ 60;
  final remainingMinutes = minutes % 60;
  String two(int value) => value.toString().padLeft(2, '0');
  if (hours > 0) {
    return '$hours:${two(remainingMinutes)}:${two(seconds)}';
  }
  return '$minutes:${two(seconds)}';
}