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';

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(
              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() {
      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;

      return Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        mainAxisSize: MainAxisSize.min,
        children: [
          Row(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Expanded(
                child: 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,
                      ),
                    ),
                  ],
                ),
              ),
              const SizedBox(width: 12),
              _AlbumVolumeCard(system: system),
            ],
          ),
          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'),
                ),
              ],
            ),
          ],
          const SizedBox(height: 14),
          Container(
            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: 7,
                          ),
                          overlayShape: const RoundSliderOverlayShape(
                            overlayRadius: 16,
                          ),
                        ),
                        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),
                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: 18),
                    _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: 18),
                    _AlbumTransportButton(
                      asset: 'assets/icons/skip-forward.svg',
                      semanticLabel: 'Next track',
                      enabled: active && playback.canGoNext,
                      onTap: () => unawaited(playback.next()),
                    ),
                  ],
                ),
              ],
            ),
          ),
        ],
      );
    }

    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 wideBody(BoxConstraints constraints) {
      final coverWidth = (constraints.maxWidth * 0.30).clamp(280.0, 380.0);
      final controlsWidth = (constraints.maxWidth * 0.44).clamp(520.0, 600.0);
      return Row(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          SizedBox(width: coverWidth, child: cover()),
          const SizedBox(width: 22),
          Expanded(child: trackList()),
          const SizedBox(width: 22),
          SizedBox(
            width: controlsWidth,
            child: SingleChildScrollView(child: controls()),
          ),
        ],
      );
    }

    Widget narrowBody(BoxConstraints constraints) {
      final coverWidth = (constraints.maxWidth * 0.34).clamp(200.0, 260.0);
      return SingleChildScrollView(
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            Row(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                SizedBox(width: coverWidth, child: cover()),
                const SizedBox(width: 18),
                Expanded(child: controls()),
              ],
            ),
            const SizedBox(height: 16),
            SizedBox(height: 260, 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,
                  isFavorite: _isFavorite,
                  favoriteBusy: _favoriteBusy,
                  onToggleFavorite: _toggleFavorite,
                ),
                const SizedBox(height: 14),
                Expanded(
                  child: LayoutBuilder(
                    builder: (context, constraints) {
                      return constraints.maxWidth >= 1180
                          ? wideBody(constraints)
                          : narrowBody(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,
    required this.isFavorite,
    required this.favoriteBusy,
    required this.onToggleFavorite,
  });

  final JellyfinAlbum album;
  final bool isFavorite;
  final bool favoriteBusy;
  final VoidCallback onToggleFavorite;

  @override
  Widget build(BuildContext context) {
    final colors = context.colors;
    final theme = Theme.of(context);
    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(
                album.name,
                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),
        _FavoriteButton(
          isFavorite: isFavorite,
          busy: favoriteBusy,
          onTap: onToggleFavorite,
        ),
      ],
    );
  }
}

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',
      child: Container(
        width: 46,
        height: 46,
        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: 16,
                height: 16,
                child: CircularProgressIndicator(
                  strokeWidth: 2,
                  color: colors.accent,
                ),
              )
            : AppIcon(
                isFavorite
                    ? 'assets/icons/heart-filled.svg'
                    : 'assets/icons/heart.svg',
                size: 21,
                color: isFavorite ? colors.accent : colors.inkMuted,
              ),
      ),
    );
  }
}

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

  final SystemController system;

  @override
  Widget build(BuildContext context) {
    final colors = context.colors;
    final theme = Theme.of(context);
    final enabled = !system.isVolumeFixed;
    return Container(
      padding: const EdgeInsets.all(8),
      decoration: BoxDecoration(
        color: colors.surface,
        borderRadius: BorderRadius.circular(18),
        border: Border.all(color: colors.border),
      ),
      child: Row(
        mainAxisSize: MainAxisSize.min,
        children: [
          _AlbumVolumeStep(
            icon: Icons.remove_rounded,
            semanticLabel: 'Volume down',
            onTap: enabled ? () => unawaited(system.adjustVolume(-1)) : null,
          ),
          const SizedBox(width: 6),
          Pressable(
            onTap: enabled ? () => unawaited(system.toggleMute()) : null,
            semanticLabel: system.isMuted ? 'Unmute' : 'Mute',
            pressedScale: 0.94,
            child: Container(
              height: 36,
              padding: const EdgeInsets.symmetric(horizontal: 10),
              decoration: BoxDecoration(
                color: system.isMuted
                    ? colors.accentSoft
                    : colors.surfaceStrong,
                borderRadius: BorderRadius.circular(999),
                border: Border.all(
                  color: system.isMuted
                      ? colors.accent.withValues(alpha: 0.25)
                      : colors.border,
                ),
              ),
              child: Row(
                mainAxisSize: MainAxisSize.min,
                children: [
                  AppIcon(
                    system.isMuted
                        ? 'assets/icons/volume-x.svg'
                        : 'assets/icons/volume-2.svg',
                    size: 16,
                    color: system.isMuted ? colors.accent : colors.inkMuted,
                  ),
                  const SizedBox(width: 6),
                  Text(
                    system.isMuted ? 'Unmute' : 'Mute',
                    style: theme.textTheme.labelMedium?.copyWith(
                      color: system.isMuted ? colors.accent : colors.inkMuted,
                    ),
                  ),
                ],
              ),
            ),
          ),
          const SizedBox(width: 6),
          _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: 36,
        height: 36,
        decoration: BoxDecoration(
          color: colors.surfaceStrong,
          shape: BoxShape.circle,
          border: Border.all(color: colors.border),
        ),
        alignment: Alignment.center,
        child: Icon(
          icon,
          size: 18,
          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 ? 68.0 : 54.0;
    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 ? 28 : 22,
            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: 7),
          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)}';
}