import 'package:flutter/material.dart';
import 'package:path_provider/path_provider.dart';
import 'package:shared_preferences/shared_preferences.dart';
import '../services/download_service.dart';
import '../utils/farb_theme.dart';
import '../services/melo_logger.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> {
  final _urlController = TextEditingController();
  bool _ladt = false;
  String? _fehler;
  String? _erfolg;
  String _speicherOrt = 'App-intern';
  bool _speichertInDownloads = false;

  @override
  void initState() {
    super.initState();
    _ladeSpeicherPfad();
  }

  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(() {
          _speichertInDownloads = true;
          _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),
            const Divider(color: MeloTheme.dunkel2),
            _optionTile(ctx, '⬇ Downloads/Melo', 'downloads',
                icon: Icons.download),
          ],
        ),
      ),
    );

    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(() {
          _speichertInDownloads = true;
          _speicherOrt = '⬇ Downloads/Melo';
        });
      }
    } else {
      await prefs.setBool('download_in_downloads', false);
      widget.downloader.setzeSpeicherPfad('');
      setState(() {
        _speichertInDownloads = false;
        _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('Downloads', 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: [
            // ─── 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),

            // ─── Download- & Abbruch-Button ───
            Row(
              children: [
                Expanded(
                  flex: _ladt ? 3 : 1,
                  child: SizedBox(
                    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 ? 'Lade herunter...' : '⬇ Download'),
                      style: ElevatedButton.styleFrom(
                        backgroundColor: MeloTheme.rot,
                        foregroundColor: Colors.white,
                        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
                      ),
                    ),
                  ),
                ),
                if (_ladt) ...[
                  const SizedBox(width: 8),
                  Expanded(
                    flex: 1,
                    child: SizedBox(
                      height: 48,
                      child: ElevatedButton.icon(
                        onPressed: _abbrechen,
                        icon: const Icon(Icons.cancel, size: 20),
                        label: const Text('Stop'),
                        style: ElevatedButton.styleFrom(
                          backgroundColor: Colors.red.shade800,
                          foregroundColor: Colors.white,
                          shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
                        ),
                      ),
                    ),
                  ),
                ],
              ],
            ),
            const SizedBox(height: 16),

            // ─── Live-Status via ListenableBuilder ───
            if (_ladt)
              ListenableBuilder(
                listenable: widget.downloader,
                builder: (context, _) {
                  final status = widget.downloader.aktuellerTitel;
                  final fortschritt = widget.downloader.fortschritt;

                  return Container(
                    width: double.infinity,
                    padding: const EdgeInsets.all(12),
                    decoration: BoxDecoration(
                      color: MeloTheme.dunkel1,
                      borderRadius: BorderRadius.circular(12),
                    ),
                    child: Column(children: [
                      if (status != null) ...[
                        Text(status,
                            style: const TextStyle(color: Colors.white70, fontSize: 13),
                            textAlign: TextAlign.center),
                      ],
                      if (fortschritt > 0) ...[
                        const SizedBox(height: 8),
                        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))),
      ]),
    );
  }
}