import 'dart:io';

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

import '../settings/app_settings.dart';
import '../shared/cover.dart';
import '../shared/theme.dart';
import 'category_service.dart';
import 'database.dart';

/// Metadaten eines Songs: Cover, Titel, Künstler und Kategorien (bearbeitbar),
/// darunter der ausklappbare Expertenmodus mit allen weiteren Angaben.
class SongDetailSheet extends StatelessWidget {
  const SongDetailSheet({super.key, required this.song});
  final Song song;

  static Future<void> show(BuildContext context, Song song) {
    return showModalBottomSheet(
      context: context,
      isScrollControlled: true,
      backgroundColor: MeloTheme.surface,
      shape: const RoundedRectangleBorder(
        borderRadius: BorderRadius.vertical(top: Radius.circular(20)),
      ),
      builder: (_) => SongDetailSheet(song: song),
    );
  }

  @override
  Widget build(BuildContext context) {
    final categories = context.watch<CategoryService>();
    final settings = context.watch<AppSettings>();
    final names = categories.of(song.id);
    final cover =
        categories.coverFor(song, groupByCategory: settings.groupCoversByCategory);

    return SafeArea(
      child: SingleChildScrollView(
        padding: const EdgeInsets.fromLTRB(20, 20, 20, 20),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          mainAxisSize: MainAxisSize.min,
          children: [
            Row(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                CoverImage(
                  artUri: cover != null ? Uri.file(cover) : null,
                  size: 88,
                  radius: 10,
                ),
                const SizedBox(width: 16),
                Expanded(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text(song.title,
                          style: const TextStyle(
                              fontSize: 18, fontWeight: FontWeight.w700)),
                      const SizedBox(height: 4),
                      Text(song.artist ?? 'Unbekannter Künstler',
                          style: const TextStyle(color: Colors.white70)),
                      if (song.album != null) ...[
                        const SizedBox(height: 2),
                        Text(song.album!,
                            style: const TextStyle(
                                color: Colors.white38, fontSize: 12)),
                      ],
                    ],
                  ),
                ),
              ],
            ),
            const SizedBox(height: 20),
            Row(
              children: [
                const Text('Kategorien',
                    style: TextStyle(fontWeight: FontWeight.w600)),
                const Spacer(),
                TextButton.icon(
                  icon: const Icon(Icons.edit, size: 16),
                  label: const Text('Bearbeiten'),
                  onPressed: () => _editCategories(context, names),
                ),
              ],
            ),
            if (names.isEmpty)
              const Text('Keine Kategorie',
                  style: TextStyle(color: Colors.white38, fontSize: 13))
            else
              Wrap(
                spacing: 8,
                runSpacing: 4,
                children: [
                  for (var i = 0; i < names.length; i++)
                    Chip(
                      label: Text(names[i]),
                      backgroundColor: MeloTheme.surfaceHigh,
                      side: BorderSide.none,
                      // Die erste Kategorie liefert das Coverbild.
                      avatar: i == 0
                          ? const Icon(Icons.image, size: 16, color: MeloTheme.red)
                          : null,
                    ),
                ],
              ),
            const SizedBox(height: 12),
            _ExpertSection(song: song),
          ],
        ),
      ),
    );
  }

  Future<void> _editCategories(BuildContext context, List<String> current) async {
    final service = context.read<CategoryService>();
    final suggestions = await service.allNames();
    if (!context.mounted) return;
    final result = await showDialog<List<String>>(
      context: context,
      builder: (_) => _CategoryEditor(current: current, suggestions: suggestions),
    );
    if (result == null) return;
    await service.setCategories(song.id, result);
  }
}

/// Ausklappbarer Bereich mit allen weiteren Metadaten.
class _ExpertSection extends StatelessWidget {
  const _ExpertSection({required this.song});
  final Song song;

  @override
  Widget build(BuildContext context) {
    return Theme(
      data: Theme.of(context).copyWith(dividerColor: Colors.transparent),
      child: ExpansionTile(
        tilePadding: EdgeInsets.zero,
        childrenPadding: const EdgeInsets.only(bottom: 8),
        title: const Text('Expertenmodus',
            style: TextStyle(fontWeight: FontWeight.w600)),
        subtitle: const Text('Weitere Metadaten',
            style: TextStyle(color: Colors.white38, fontSize: 12)),
        children: [
          _Row('Titel', song.title),
          _Row('Künstler', song.artist ?? '—'),
          _Row('Album', song.album ?? '—'),
          _Row('Dauer', _formatDuration(song.durationMs)),
          _Row('Wiedergaben', '${song.playCount}'),
          _Row('Hinzugefügt', _formatDate(song.dateAddedMs)),
          _Row('Kategorien', song.categoriesEdited
              ? 'von Hand gesetzt (Scan überschreibt nicht)'
              : 'aus dem Genre-Tag der Datei'),
          _Row('Format', _extension(song.path)),
          _Row('Dateigröße', _fileSize(song.path)),
          _Row('Pfad', song.path),
        ],
      ),
    );
  }
}

class _Row extends StatelessWidget {
  const _Row(this.label, this.value);
  final String label;
  final String value;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 4),
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          SizedBox(
            width: 110,
            child: Text(label,
                style: const TextStyle(color: Colors.white38, fontSize: 13)),
          ),
          Expanded(
            child: Text(value, style: const TextStyle(fontSize: 13)),
          ),
        ],
      ),
    );
  }
}

String _formatDuration(int? ms) {
  if (ms == null) return '—';
  final d = Duration(milliseconds: ms);
  final minutes = d.inMinutes;
  final seconds = d.inSeconds.remainder(60).toString().padLeft(2, '0');
  return '$minutes:$seconds';
}

String _formatDate(int ms) {
  final d = DateTime.fromMillisecondsSinceEpoch(ms);
  String two(int v) => v.toString().padLeft(2, '0');
  return '${two(d.day)}.${two(d.month)}.${d.year} ${two(d.hour)}:${two(d.minute)}';
}

String _extension(String path) {
  final dot = path.lastIndexOf('.');
  return dot == -1 ? '—' : path.substring(dot + 1).toUpperCase();
}

String _fileSize(String path) {
  try {
    final bytes = File(path).lengthSync();
    if (bytes < 1024 * 1024) return '${(bytes / 1024).toStringAsFixed(0)} KB';
    return '${(bytes / (1024 * 1024)).toStringAsFixed(1)} MB';
  } catch (_) {
    return '—';
  }
}

/// Dialog zum Hinzufügen und Entfernen von Kategorien.
class _CategoryEditor extends StatefulWidget {
  const _CategoryEditor({required this.current, required this.suggestions});
  final List<String> current;
  final List<String> suggestions;

  @override
  State<_CategoryEditor> createState() => _CategoryEditorState();
}

class _CategoryEditorState extends State<_CategoryEditor> {
  late final List<String> _names = [...widget.current];
  final _controller = TextEditingController();

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

  void _add(String raw) {
    final name = raw.trim();
    if (name.isEmpty) return;
    if (_names.any((n) => n.toLowerCase() == name.toLowerCase())) return;
    setState(() => _names.add(name));
    _controller.clear();
  }

  @override
  Widget build(BuildContext context) {
    final offen = widget.suggestions
        .where((s) => !_names.any((n) => n.toLowerCase() == s.toLowerCase()))
        .toList();
    return AlertDialog(
      backgroundColor: MeloTheme.surface,
      title: const Text('Kategorien'),
      content: SingleChildScrollView(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            const Text(
              'Die erste Kategorie liefert das Coverbild.',
              style: TextStyle(color: Colors.white38, fontSize: 12),
            ),
            const SizedBox(height: 12),
            if (_names.isEmpty)
              const Text('Noch keine Kategorie',
                  style: TextStyle(color: Colors.white38, fontSize: 13))
            else
              Wrap(
                spacing: 8,
                children: [
                  for (final name in _names)
                    InputChip(
                      label: Text(name),
                      backgroundColor: MeloTheme.surfaceHigh,
                      side: BorderSide.none,
                      onDeleted: () => setState(() => _names.remove(name)),
                    ),
                ],
              ),
            const SizedBox(height: 12),
            TextField(
              controller: _controller,
              decoration: const InputDecoration(
                labelText: 'Kategorie hinzufügen',
                border: OutlineInputBorder(),
              ),
              onSubmitted: _add,
            ),
            if (offen.isNotEmpty) ...[
              const SizedBox(height: 12),
              const Text('Bereits vergeben',
                  style: TextStyle(color: Colors.white38, fontSize: 12)),
              const SizedBox(height: 4),
              Wrap(
                spacing: 8,
                children: [
                  for (final name in offen.take(12))
                    ActionChip(
                      label: Text(name),
                      backgroundColor: MeloTheme.surfaceHigh,
                      side: BorderSide.none,
                      onPressed: () => _add(name),
                    ),
                ],
              ),
            ],
          ],
        ),
      ),
      actions: [
        TextButton(
          onPressed: () => Navigator.pop(context),
          child: const Text('Abbrechen'),
        ),
        FilledButton(
          onPressed: () {
            // Ein noch nicht bestätigter Text im Feld soll nicht verloren gehen.
            _add(_controller.text);
            Navigator.pop(context, _names);
          },
          child: const Text('Speichern'),
        ),
      ],
    );
  }
}