import 'package:flutter/material.dart';

import '../data/models.dart';
import '../state/app_state.dart';
import 'download_service.dart';
import 'downloads_page.dart';

typedef EnqueueDownload = Future<void> Function({
  required TitleRecord title,
  required MediaSource source,
  EpisodeRecord? episode,
});

/// The primary action always queues inside Reelbox, never an external app.
class DownloadButton extends StatefulWidget {
  const DownloadButton({
    super.key,
    required this.title,
    required this.source,
    this.episode,
    this.enqueue,
    this.openDownloads,
  });

  final TitleRecord title;
  final MediaSource source;
  final EpisodeRecord? episode;
  final EnqueueDownload? enqueue;
  final void Function(BuildContext context)? openDownloads;

  @override
  State<DownloadButton> createState() => _DownloadButtonState();
}

class _DownloadButtonState extends State<DownloadButton> {
  bool _starting = false;

  Future<void> _download() async {
    if (_starting) return;
    setState(() => _starting = true);
    try {
      final host = Uri.tryParse(widget.source.url)?.host.toLowerCase() ?? '';
      if (RegExp(
            'youtube|embed',
            caseSensitive: false,
          ).hasMatch(widget.source.type) ||
          host == 'youtu.be' ||
          host == 'youtube.com' ||
          host.endsWith('.youtube.com')) {
        throw UnsupportedError(
          tr(
            context,
            'Embedded sources cannot be downloaded. Choose a direct media source.',
            'منابع جاسازی‌شده قابل دانلود نیستند. یک منبع رسانه مستقیم انتخاب کنید.',
          ),
        );
      }
      await (widget.enqueue ?? DownloadService.instance.enqueue)(
        title: widget.title,
        source: widget.source,
        episode: widget.episode,
      );
      if (!mounted) return;
      if (widget.openDownloads case final open?) {
        open(context);
      } else {
        Navigator.of(
          context,
        ).push(MaterialPageRoute<void>(builder: (_) => const DownloadsPage()));
      }
    } catch (error) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text(
              '${tr(context, 'Could not start download', 'شروع دانلود ممکن نشد')}: ${downloadErrorMessage(error)}',
            ),
          ),
        );
      }
    } finally {
      if (mounted) setState(() => _starting = false);
    }
  }

  @override
  Widget build(BuildContext context) => FilledButton.icon(
    onPressed: widget.source.url.isEmpty || _starting ? null : _download,
    icon: _starting
        ? const SizedBox.square(
            dimension: 18,
            child: CircularProgressIndicator(strokeWidth: 2),
          )
        : const Icon(Icons.download_outlined),
    label: Text(tr(context, 'Download in Reelbox', 'دانلود در ریلباکس')),
  );
}