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

import '../library/database.dart';
import '../library/permissions.dart';
import '../services/cache_manager.dart';
import '../services/navidrome_service.dart';
import '../services/offline_mode.dart';
import 'library_stats.dart';

/// Settings-Tab: Bibliotheks-Statistik, Berechtigungen, Navidrome, Über Melo.
class SettingsScreen extends StatefulWidget {
  const SettingsScreen({super.key});

  @override
  State<SettingsScreen> createState() => _SettingsScreenState();
}

class _SettingsScreenState extends State<SettingsScreen> {
  late final NavidromeService _navidrome = NavidromeService();
  late final CacheManager _cache = CacheManager();
  int _cacheSize = 0;

  @override
  void initState() {
    super.initState();
    _navidrome.ladeGespeicherteZugangsdaten();
    _cache.init().then((_) => _updateCacheSize());
  }

  Future<void> _updateCacheSize() async {
    final size = await _cache.getCacheSize();
    if (mounted) setState(() => _cacheSize = size);
  }

  @override
  Widget build(BuildContext context) {
    final db = context.read<MeloDb>();
    return Scaffold(
      appBar: AppBar(title: const Text('Settings')),
      body: ListView(
        children: [
          const _SectionLabel('Bibliothek'),
          StreamBuilder<List<Song>>(
            stream: db.watchSongs(),
            builder: (context, snapshot) {
              final songs = snapshot.data ?? const [];
              return Column(
                children: [
                  ListTile(
                    leading: const Icon(Icons.library_music),
                    title: Text('${songs.length} Songs in der Bibliothek'),
                  ),
                  ListTile(
                    leading: const Icon(Icons.schedule),
                    title:
                        Text('${formatTotalDuration(songs)} Gesamtspieldauer'),
                  ),
                ],
              );
            },
          ),
          const Divider(height: 1),
          const _SectionLabel('Musikserver'),
          ListTile(
            leading: const Icon(Icons.cloud_circle),
            title: const Text('🌐 Navidrome'),
            subtitle: _navidrome.istVerbunden
                ? const Text('✅ Verbunden')
                : const Text('Nicht verbunden'),
            trailing: _navidrome.istVerbunden
                ? IconButton(
                    icon: const Icon(Icons.logout),
                    onPressed: () => _trennNavidrome(),
                  )
                : IconButton(
                    icon: const Icon(Icons.login),
                    onPressed: () => _zeigeNavidromeDialog(),
                  ),
          ),
          ListTile(
            leading: const Icon(Icons.wifi_off),
            title: const Text('📴 Offline-Modus'),
            subtitle: const Text('Nur gecachte Lieder abspielen'),
            trailing: Consumer<OfflineMode>(
              builder: (context, offlineMode, _) {
                return Switch(
                  value: offlineMode.enabled,
                  onChanged: (value) => offlineMode.setEnabled(value),
                );
              },
            ),
          ),
          ListTile(
            leading: const Icon(Icons.storage),
            title: const Text('🗄️ Cache-Speicher'),
            subtitle: Text(_formatBytes(_cacheSize)),
            trailing: _cacheSize > 0
                ? IconButton(
                    tooltip: 'Cache löschen',
                    icon: const Icon(Icons.delete),
                    onPressed: () => _clearCache(),
                  )
                : null,
          ),
          const Divider(height: 1),
          const _SectionLabel('Berechtigungen'),
          ListTile(
            leading: const Icon(Icons.mic_none),
            title: const Text('Musik-Berechtigung'),
            trailing: TextButton(
              onPressed: openMusicPermissionSettings,
              child: const Text('Einstellungen öffnen'),
            ),
          ),
          const Divider(height: 1),
          const _SectionLabel('Über Melo'),
          const ListTile(
            leading: Icon(Icons.info_outline),
            title: Text('Melo'),
            subtitle: Text('Deine Musik. Offline. Kein Abo.'),
          ),
        ],
      ),
    );
  }

  void _zeigeNavidromeDialog() {
    final urlCtrl = TextEditingController();
    final userCtrl = TextEditingController();
    final passCtrl = TextEditingController();
    bool verbindet = false;
    String? fehler;

    showDialog(
      context: context,
      builder: (ctx) => StatefulBuilder(
        builder: (ctx, setDialogState) => AlertDialog(
          backgroundColor: Colors.grey.shade900,
          title: const Text('🌐 Navidrome Verbinden',
              style: TextStyle(color: Colors.white, fontSize: 16)),
          content: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              TextField(
                controller: urlCtrl,
                style: const TextStyle(color: Colors.white),
                decoration: const InputDecoration(
                  labelText: 'Server-URL',
                  hintText: 'https://musik.example.com',
                  labelStyle: TextStyle(color: Colors.grey),
                  hintStyle: TextStyle(color: Colors.grey),
                  border: OutlineInputBorder(),
                ),
              ),
              const SizedBox(height: 8),
              TextField(
                controller: userCtrl,
                style: const TextStyle(color: Colors.white),
                decoration: const InputDecoration(
                  labelText: 'Benutzer',
                  labelStyle: TextStyle(color: Colors.grey),
                  border: OutlineInputBorder(),
                ),
              ),
              const SizedBox(height: 8),
              TextField(
                controller: passCtrl,
                style: const TextStyle(color: Colors.white),
                obscureText: true,
                decoration: const InputDecoration(
                  labelText: 'Passwort',
                  labelStyle: TextStyle(color: Colors.grey),
                  border: OutlineInputBorder(),
                ),
              ),
              if (fehler != null) ...[
                const SizedBox(height: 8),
                Text(fehler!,
                    style: const TextStyle(color: Colors.red, fontSize: 12)),
              ],
              if (verbindet)
                const Padding(
                  padding: EdgeInsets.only(top: 12),
                  child: SizedBox(
                    width: 20,
                    height: 20,
                    child: CircularProgressIndicator(
                        strokeWidth: 2, color: Colors.redAccent),
                  ),
                ),
            ],
          ),
          actions: [
            TextButton(
                onPressed: () => Navigator.pop(ctx),
                child: const Text('Abbrechen')),
            TextButton(
              onPressed: verbindet
                  ? null
                  : () async {
                      setDialogState(() => verbindet = true);
                      _navidrome.setCredentials(
                          urlCtrl.text, userCtrl.text, passCtrl.text);
                      final ok = await _navidrome.ping();
                      setDialogState(() => verbindet = false);
                      if (ok && ctx.mounted) {
                        await _navidrome.speichereZugangsdaten(
                            urlCtrl.text, userCtrl.text, passCtrl.text);
                        if (ctx.mounted) Navigator.pop(ctx);
                        if (mounted) setState(() {});
                      } else if (ctx.mounted) {
                        setDialogState(() =>
                            fehler = '❌ Verbindung fehlgeschlagen\nPrüfe URL + Zugangsdaten');
                      }
                    },
              child: const Text('Verbinden',
                  style: TextStyle(color: Colors.redAccent)),
            ),
          ],
        ),
      ),
    ).then((_) {
      urlCtrl.dispose();
      userCtrl.dispose();
      passCtrl.dispose();
    });
  }

  Future<void> _trennNavidrome() async {
    await _navidrome.loescheZugangsdaten();
    if (mounted) setState(() {});
  }

  Future<void> _clearCache() async {
    await _cache.clearCache();
    if (mounted) {
      setState(() => _cacheSize = 0);
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Cache gelöscht')),
      );
    }
  }

  String _formatBytes(int bytes) {
    if (bytes < 1024) return '$bytes B';
    if (bytes < 1024 * 1024) return '${(bytes / 1024).toStringAsFixed(1)} KB';
    return '${(bytes / (1024 * 1024)).toStringAsFixed(1)} MB';
  }
}

/// Kleine graue Überschrift über einer Einstellungs-Gruppe.
class _SectionLabel extends StatelessWidget {
  const _SectionLabel(this.label);
  final String label;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.fromLTRB(16, 16, 16, 4),
      child: Text(
        label,
        style: const TextStyle(
          color: Colors.white54,
          fontSize: 12,
          fontWeight: FontWeight.bold,
        ),
      ),
    );
  }
}