import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:url_launcher/url_launcher.dart';

import '../data/models.dart';
import '../theme/reclaim_tokens.dart';
import 'reclaim_card.dart';

/// Renders the actual paragraphs of a norm right next to the
/// evaluation. Solves the "I want to read the law in place"
/// requirement so a reviewer never has to context-switch to a
/// browser tab just to confirm what the score is about.
///
/// Two side-buttons at the top:
///   - "Im Browser öffnen" — pop the canonical source URL
///   - "URL kopieren"      — clipboard, useful for citations
///
/// On macOS the browser-open uses the system `open` command —
/// no extra package, no permission prompt. iOS/Linux/Windows
/// branches would need `url_launcher` later; Phase 0 ships
/// macOS first.
class NormTextCard extends StatelessWidget {
  const NormTextCard({super.key, required this.norm});

  final Norm norm;

  @override
  Widget build(BuildContext context) {
    final t = Theme.of(context).textTheme;
    final paragraphs = norm.paragraphs;
    return ReclaimCard(
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          Row(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text('Gesetzestext', style: t.headlineSmall),
                    const SizedBox(height: 4),
                    Text(
                      '${norm.jurabk} ${norm.paragraph} — Stand '
                      '${_isoDate(norm.standDate)}',
                      style: t.labelSmall?.copyWith(
                        color: ReclaimColors.mute,
                      ),
                    ),
                  ],
                ),
              ),
              IconButton(
                tooltip: 'URL kopieren',
                onPressed: () =>
                    Clipboard.setData(ClipboardData(text: norm.sourceUrl)),
                icon: const Icon(Icons.link),
              ),
              FilledButton.icon(
                onPressed: () => _openInBrowser(context, norm.sourceUrl),
                icon: const Icon(Icons.open_in_new),
                label: const Text('Im Browser öffnen'),
              ),
            ],
          ),
          const SizedBox(height: ReclaimSpace.lg),
          if (paragraphs.isEmpty)
            Text(
              'Für diese Norm ist noch kein normalisierter Text '
              'eingebunden. Wenn Ch∆In mit `text.akoma-normalize@^0` '
              'gegen die Quell-URL läuft, erscheinen die Absätze hier.',
              style: t.bodyLarge?.copyWith(color: ReclaimColors.mute),
            )
          else
            for (final p in paragraphs)
              Padding(
                padding:
                    const EdgeInsets.only(bottom: ReclaimSpace.md),
                child: Row(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    SizedBox(
                      width: 64,
                      child: Text(
                        p.number,
                        style: t.labelLarge?.copyWith(
                          color: ReclaimColors.signal,
                          fontFamily: ReclaimTypography.mono,
                        ),
                      ),
                    ),
                    Expanded(
                      child: SelectableText(
                        p.text,
                        style: t.bodyLarge?.copyWith(height: 1.55),
                      ),
                    ),
                  ],
                ),
              ),
          const SizedBox(height: ReclaimSpace.sm),
          SelectableText(
            norm.sourceUrl,
            style: t.labelSmall?.copyWith(
              color: ReclaimColors.mute,
              fontFamily: ReclaimTypography.mono,
            ),
          ),
        ],
      ),
    );
  }

  String _isoDate(DateTime d) =>
      '${d.year.toString().padLeft(4, "0")}-'
      '${d.month.toString().padLeft(2, "0")}-'
      '${d.day.toString().padLeft(2, "0")}';

  Future<void> _openInBrowser(BuildContext context, String url) async {
    final messenger = ScaffoldMessenger.of(context);
    final uri = Uri.tryParse(url);
    if (uri == null) {
      messenger.showSnackBar(
        SnackBar(content: Text('Ungültige URL: $url')),
      );
      return;
    }
    try {
      final ok =
          await launchUrl(uri, mode: LaunchMode.externalApplication);
      if (!ok) {
        messenger.showSnackBar(
          const SnackBar(content: Text('Browser-Aufruf abgelehnt.')),
        );
      }
    } catch (e) {
      messenger.showSnackBar(
        SnackBar(content: Text('Konnte Browser nicht öffnen: $e')),
      );
    }
  }
}