melo-app/lib/screens/download_screen.dart

import 'dart:io';
import 'package:flutter/material.dart';
import 'package:path_provider/path_provider.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:just_audio/just_audio.dart';
import '../services/download_service.dart';
import '../services/cloud_service.dart';
import '../models/song.dart';
import '../database/db_helper.dart';
import '../utils/farb_theme.dart';
import '../utils/sanitize.dart';
import '../services/melo_logger.dart';
import '../config/app_config.dart';
import '../widgets/melo_loader.dart';

class DownloadScreen extends StatefulWidget {
  final DownloadService downloader;
  final VoidCallback onSongsChanged;

  const DownloadScreen({
    super.key,
    required this.downloader,
    required this.onSongsChanged,
  });

  @override
  State<DownloadScreen> createState() => _DownloadScreenState();
}

class _DownloadScreenState extends State<DownloadScreen> with WidgetsBindingObserver {
  final _urlController = TextEditingController();
  final _cloud = CloudService();
  final _previewPlayer = AudioPlayer();
  bool _ladt = false;
  List<Map<String, dynamic>> _globalSongs = [];
  String? _previewSid;
  String? _fehler;
  String? _erfolg;
  String _speicherOrt = 'App-intern (Music/)';

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    _previewPlayer.dispose();
    super.dispose();
  }

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    if (state == AppLifecycleState.paused || state == AppLifecycleState.inactive) {
      _stopPreview();
    }
  }

  Future<void> _ladeGlobalListe() async {
    final songs = await _cloud.globalList();
    if (mounted) setState(() => _globalSongs = songs.cast<Map<String, dynamic>>());
  }

  Future<void> _addFromRegistry(String sid, String title) async {
    setState(() => _ladt = true);
    try {
      final dir = Directory('${(await getApplicationDocumentsDirectory()).path}/music');
      if (!await dir.exists()) await dir.create(recursive: true);
      // Server-ID defensiv sanitizen — kein Path-Traversal über sid
      final dest = '${dir.path}/cloud_${sanitizeDateiname(sid)}.mp3';
      final ok = await _cloud.download(sid, dest);
      if (ok && mounted) {
        final song = Song(
          titel: title.isNotEmpty ? title : 'Cloud-Song $sid',
          kuenstler: 'Melo Registry',
          dauerSekunden: 0,
          dateiPfad: dest,
          downloadQuelle: 'cloud',
          istHeruntergeladen: true,
        );
        await DbHelper().songEinfuegen(song);
        setState(() => _erfolg = 'Song "$title" hinzugefügt!');
        widget.onSongsChanged();
        await _ladeGlobalListe();
      }
    } catch (e) {
      setState(() => _fehler = 'Fehler beim Hinzufügen');
      MeloLogger().fehler('add_from_registry', e);
    }
    if (mounted) setState(() => _ladt = false);
  }

  Future<void> _startPreview(String sid) async {
    if (_previewSid == sid && _previewPlayer.playing) {
      await _stopPreview();
      return;
    }
    _previewSid = sid;
    try {
      final url = '${AppConfig.cloudUrl}/api/cloud/stream/$sid';
      await _previewPlayer.setUrl(url);
      await _previewPlayer.seek(const Duration(seconds: 11));
      await _previewPlayer.play();
      Future.delayed(const Duration(seconds: 10), () {
        if (_previewSid == sid) _stopPreview();
      });
    } catch (e) {
      MeloLogger().fehler('preview', e);
    }
  }

  Future<void> _stopPreview() async {
    _previewSid = null;
    await _previewPlayer.stop();
  }

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
    _ladeSpeicherPfad();
    _ladeGlobalListe();
  }

  Future<void> _ladeSpeicherPfad() async {
    final prefs = await SharedPreferences.getInstance();
    final inDownloads = prefs.getBool('download_in_downloads') ?? false;
    if (inDownloads) {
      final dir = await getDownloadsDirectory();
      if (dir != null) {
        final pfad = '${dir.path}/Melo';
        widget.downloader.setzeSpeicherPfad(pfad);
        setState(() {
          _speicherOrt = '⬇ Downloads/Melo';
        });
      }
    }
  }

  Future<void> _ordnerDialog() async {
    final auswahl = await showDialog<String>(
      context: context,
      builder: (ctx) => AlertDialog(
        backgroundColor: MeloTheme.dunkel1,
        title: const Text('Speicherort', style: TextStyle(color: Colors.white, fontSize: 16)),
        content: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            _optionTile(ctx, '📁 App-intern (Music/)', 'intern',
                icon: Icons.phone_android),
            if (!Platform.isIOS) ...[
              const Divider(color: MeloTheme.dunkel2),
              _optionTile(ctx, '⬇ Downloads/Melo', 'downloads',
                  icon: Icons.download),
              const Divider(color: MeloTheme.dunkel2),
              _optionTile(ctx, '💾 SD-Karte / Extern', 'extern',
                  icon: Icons.sd_storage),
            ],
          ],
        ),
      ),
    );

    if (auswahl == null) return;

    final prefs = await SharedPreferences.getInstance();
    if (auswahl == 'downloads') {
      final dir = await getDownloadsDirectory();
      if (dir != null) {
        final pfad = '${dir.path}/Melo';
        await prefs.setBool('download_in_downloads', true);
        widget.downloader.setzeSpeicherPfad(pfad);
        setState(() {
          _speicherOrt = '⬇ Downloads/Melo';
        });
      }
    } else if (auswahl == 'extern') {
      final dirs = await getExternalStorageDirectories();
      if (dirs != null && dirs.isNotEmpty) {
        final pfad = '${dirs.first.path}/Melo';
        await prefs.setBool('download_in_downloads', false);
        widget.downloader.setzeSpeicherPfad(pfad);
        setState(() {
          _speicherOrt = '💾 ${dirs.first.path.split('/').last}/Melo';
        });
      } else {
        if (mounted) setState(() => _fehler = 'Kein externer Speicher gefunden');
      }
    } else {
      await prefs.setBool('download_in_downloads', false);
      widget.downloader.setzeSpeicherPfad('');
      setState(() {
        _speicherOrt = '📁 App-intern (Music/)';
      });
    }
  }

  Widget _optionTile(BuildContext ctx, String label, String wert,
      {required IconData icon}) {
    return ListTile(
      leading: Icon(icon, color: MeloTheme.rot, size: 20),
      title: Text(label,
          style: const TextStyle(color: Colors.white, fontSize: 13)),
      onTap: () => Navigator.pop(ctx, wert),
    );
  }

  void _starteDownload() async {
    final input = _urlController.text.trim();
    if (input.isEmpty) {
      setState(() => _fehler = 'Bitte eine YouTube-URL einfügen');
      return;
    }

    setState(() { _ladt = true; _fehler = null; _erfolg = null; });
    MeloLogger().aktion('download_start', {'url': input.substring(0, 40)});

    final anzahl = await widget.downloader.downloadBatch(input);
    if (mounted) {
      setState(() {
        _ladt = false;
        if (anzahl > 0) {
          _erfolg = '✅ $anzahl Song${anzahl > 1 ? 's' : ''} gespeichert';
        } else {
          _fehler = widget.downloader.fehler ?? 'Download fehlgeschlagen';
        }
      });
      widget.onSongsChanged();
    }
  }

  void _abbrechen() {
    widget.downloader.abbrechen();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: MeloTheme.schwarz,
      appBar: AppBar(
        backgroundColor: MeloTheme.dunkel1,
        title: const Row(children: [
          Icon(Icons.download, color: MeloTheme.rot, size: 20),
          SizedBox(width: 8),
          Text('Lied +', style: TextStyle(color: Colors.white, fontSize: 18)),
        ]),
        actions: [
          if (_erfolg != null || _fehler != null)
            IconButton(
              icon: const Icon(Icons.refresh, color: Colors.grey, size: 20),
              onPressed: () => setState(() { _fehler = null; _erfolg = null; _urlController.clear(); }),
            ),
        ],
      ),
      body: Padding(
        padding: const EdgeInsets.all(20),
        child: Column(
          children: [
            // ─── Globale Registry (Lied +) ───
            if (_globalSongs.isNotEmpty) ...[
              Row(children: [
                const Icon(Icons.public, color: MeloTheme.rot, size: 16),
                const SizedBox(width: 6),
                Text('Globale Songs (${_globalSongs.length})',
                    style: const TextStyle(color: Colors.white70, fontSize: 13, fontWeight: FontWeight.w600)),
                const Spacer(),
                GestureDetector(
                  onTap: _ladeGlobalListe,
                  child: const Icon(Icons.refresh, color: Colors.grey, size: 16),
                ),
              ]),
              const SizedBox(height: 8),
              SizedBox(
                height: 100,
                child: ListView.builder(
                  scrollDirection: Axis.horizontal,
                  itemCount: _globalSongs.length,
                  itemBuilder: (_, i) {
                    final s = _globalSongs[i];
                    final sid = s['id']?.toString() ?? '';
                    final title = s['title']?.toString() ?? '?';
                    final isPreviewing = _previewSid == sid;
                    return Container(
                      width: 140,
                      margin: const EdgeInsets.only(right: 8),
                      decoration: BoxDecoration(
                        color: isPreviewing ? const Color(0xFF2A0000) : MeloTheme.dunkel1,
                        borderRadius: BorderRadius.circular(10),
                        border: Border.all(color: isPreviewing ? MeloTheme.rot : MeloTheme.dunkel2),
                      ),
                      child: Column(
                        mainAxisAlignment: MainAxisAlignment.center,
                        children: [
                          Text(title, style: TextStyle(fontSize: 11, color: Colors.white, fontWeight: FontWeight.w500),
                              maxLines: 2, overflow: TextOverflow.ellipsis, textAlign: TextAlign.center),
                          const SizedBox(height: 4),
                          Row(
                            mainAxisAlignment: MainAxisAlignment.center,
                            children: [
                              GestureDetector(
                                onTap: () => _startPreview(sid),
                                child: Icon(isPreviewing ? Icons.stop : Icons.play_arrow,
                                    color: isPreviewing ? Colors.white : MeloTheme.rot, size: 20),
                              ),
                              const SizedBox(width: 10),
                              GestureDetector(
                                onTap: () => _addFromRegistry(sid, title),
                                child: const Icon(Icons.add_circle_outline, color: Colors.grey, size: 18),
                              ),
                            ],
                          ),
                        ],
                      ),
                    );
                  },
                ),
              ),
              const Divider(color: MeloTheme.dunkel2),
            ],
            // ─── Zielordner ───
            GestureDetector(
              onTap: _ladt ? null : _ordnerDialog,
              child: Container(
                width: double.infinity,
                padding: const EdgeInsets.all(12),
                decoration: BoxDecoration(
                  color: MeloTheme.dunkel1,
                  borderRadius: BorderRadius.circular(12),
                  border: Border.all(color: MeloTheme.dunkel2),
                ),
                child: Row(children: [
                  const Icon(Icons.folder, color: MeloTheme.rot, size: 18),
                  const SizedBox(width: 8),
                  Expanded(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        const Text('Speicherort', style: TextStyle(color: Colors.grey, fontSize: 11)),
                        Text(_speicherOrt, style: const TextStyle(color: Colors.white, fontSize: 13)),
                      ],
                    ),
                  ),
                  const Icon(Icons.chevron_right, color: Colors.grey, size: 18),
                ]),
              ),
            ),
            const SizedBox(height: 12),

            // ─── Eingabefeld ───
            TextField(
              controller: _urlController,
              enabled: !_ladt,
              maxLines: 3,
              style: const TextStyle(color: Colors.white, fontSize: 14),
              decoration: InputDecoration(
                hintText: 'YouTube-URL hier einfügen...\n\nMehrere URLs: eine pro Zeile\nPlaylists werden erkannt 🎯',
                hintStyle: const TextStyle(color: Colors.grey, fontSize: 13),
                border: OutlineInputBorder(borderRadius: BorderRadius.circular(12)),
                filled: true,
                fillColor: MeloTheme.dunkel1,
                contentPadding: const EdgeInsets.all(16),
              ),
            ),
            const SizedBox(height: 12),

            // ─── Animierte Ladeanzeige (während Download) ───
            if (_ladt) ...[
              MeloLoader(
                titel: widget.downloader.aktuellerTitel ?? 'Lade herunter...',
              ),
              const SizedBox(height: 16),
            ],

            // ─── Download-Button ───
            SizedBox(
              width: double.infinity,
              height: 48,
              child: ElevatedButton.icon(
                onPressed: _ladt ? null : _starteDownload,
                icon: _ladt
                    ? const SizedBox(width: 20, height: 20,
                        child: CircularProgressIndicator(strokeWidth: 2, color: Colors.white))
                    : const Icon(Icons.download, size: 20),
                label: Text(_ladt ? 'Lädt...' : '⬇ Download'),
                style: ElevatedButton.styleFrom(
                  backgroundColor: MeloTheme.rot,
                  foregroundColor: Colors.white,
                  shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
                ),
              ),
            ),
            if (_ladt) ...[
              const SizedBox(height: 8),
              SizedBox(
                width: double.infinity,
                height: 40,
                child: ElevatedButton.icon(
                  onPressed: _abbrechen,
                  icon: const Icon(Icons.cancel, size: 18),
                  label: const Text('Abbrechen'),
                  style: ElevatedButton.styleFrom(
                    backgroundColor: Colors.red.shade800,
                    foregroundColor: Colors.white,
                    shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
                  ),
                ),
              ),
            ],
            const SizedBox(height: 16),

            // ─── Fortschritt ───
            if (_ladt)
              ListenableBuilder(
                listenable: widget.downloader,
                builder: (context, _) {
                  final fortschritt = widget.downloader.fortschritt;

                  if (fortschritt <= 0) return const SizedBox.shrink();
                  return Container(
                    width: double.infinity,
                    padding: const EdgeInsets.all(12),
                    decoration: BoxDecoration(
                      color: MeloTheme.dunkel1,
                      borderRadius: BorderRadius.circular(12),
                    ),
                    child: Column(children: [
                      LinearProgressIndicator(
                          value: fortschritt,
                          color: MeloTheme.rot,
                          backgroundColor: MeloTheme.dunkel2),
                      const SizedBox(height: 4),
                      Text('${(fortschritt * 100).toStringAsFixed(0)}%',
                          style: const TextStyle(color: Colors.grey, fontSize: 11)),
                    ]),
                  );
                },
              ),

            // ─── Erfolg ───
            if (_erfolg != null)
              Container(
                width: double.infinity,
                padding: const EdgeInsets.all(16),
                decoration: BoxDecoration(
                  color: MeloTheme.dunkel1,
                  borderRadius: BorderRadius.circular(12),
                  border: Border.all(color: Colors.green.withValues(alpha: 0.3)),
                ),
                child: Row(children: [
                  const Icon(Icons.check_circle, color: Colors.green, size: 24),
                  const SizedBox(width: 12),
                  Expanded(child: Text(_erfolg!, style: const TextStyle(color: Colors.green, fontSize: 13))),
                ]),
              ),

            // ─── Fehler ───
            if (_fehler != null)
              Container(
                width: double.infinity,
                padding: const EdgeInsets.all(16),
                decoration: BoxDecoration(
                  color: MeloTheme.dunkel1,
                  borderRadius: BorderRadius.circular(12),
                  border: Border.all(color: Colors.red.withValues(alpha: 0.3)),
                ),
                child: Row(children: [
                  const Icon(Icons.error_outline, color: Colors.red, size: 24),
                  const SizedBox(width: 12),
                  Expanded(child: Text(_fehler!, style: const TextStyle(color: Colors.red, fontSize: 13))),
                ]),
              ),

            const Spacer(),

            // ─── Tipps ───
            Container(
              padding: const EdgeInsets.all(12),
              decoration: BoxDecoration(
                color: MeloTheme.dunkel1,
                borderRadius: BorderRadius.circular(12),
              ),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  const Text('💡 Tipps', style: TextStyle(color: Colors.grey, fontSize: 12, fontWeight: FontWeight.w600)),
                  const SizedBox(height: 6),
                  _tipp('Einzel-URL: youtube.com/watch?v=...'),
                  _tipp('Playlist: youtube.com/playlist?list=...'),
                  _tipp('Mehrere: eine URL pro Zeile'),
                  _tipp('Cooldown: 5s zwischen Downloads ⏱'),
                ],
              ),
            ),
            const SizedBox(height: 20),
          ],
        ),
      ),
    );
  }

  Widget _tipp(String text) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 4),
      child: Row(children: [
        const Text('• ', style: TextStyle(color: MeloTheme.rot, fontSize: 12)),
        Expanded(child: Text(text, style: const TextStyle(color: Colors.grey, fontSize: 11))),
      ]),
    );
  }
}