KC-APP/client/app/lib/screens/admin_screen.dart

import 'package:flutter/material.dart';

import '../api.dart';
import '../main.dart';

/// Leitungsteam admin: KCs, their Gemeinden, and pending self-registrations.
class AdminScreen extends StatefulWidget {
  const AdminScreen({super.key});

  @override
  State<AdminScreen> createState() => _AdminScreenState();
}

class _AdminScreenState extends State<AdminScreen> {
  Future<List<Kc>>? _future;

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
    _future ??= AppScope.of(context).api.kcs();
  }

  void _reload() => setState(() => _future = AppScope.of(context).api.kcs());

  Future<void> _createKc() async {
    final api = AppScope.of(context).api;
    final name = await _promptText(context, 'Neues KC', 'Name');
    if (name == null || name.isEmpty || !mounted) return;
    try {
      await api.createKc(name);
      if (mounted) _reload();
    } catch (e) {
      if (mounted) _toast(context, '$e');
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Verwaltung')),
      floatingActionButton: FloatingActionButton.extended(
        onPressed: _createKc,
        icon: const Icon(Icons.add),
        label: const Text('KC'),
      ),
      body: FutureBuilder<List<Kc>>(
        future: _future,
        builder: (context, snap) {
          if (snap.connectionState != ConnectionState.done) {
            return const Center(child: CircularProgressIndicator());
          }
          if (snap.hasError) {
            return Center(
              child: Padding(
                padding: const EdgeInsets.all(24),
                child: Text('${snap.error}', textAlign: TextAlign.center),
              ),
            );
          }
          final kcs = snap.data!;
          if (kcs.isEmpty) {
            return const Center(child: Text('Noch keine KCs. Unten anlegen.'));
          }
          return ListView(
            children: [
              for (final kc in kcs)
                ListTile(
                  leading: const Icon(Icons.festival),
                  title: Text(kc.name),
                  subtitle: Text('Code ${kc.inviteCode}'),
                  trailing: const Icon(Icons.chevron_right),
                  onTap: () => Navigator.of(context).push(
                    MaterialPageRoute(builder: (_) => KcDetailScreen(kc: kc)),
                  ),
                ),
            ],
          );
        },
      ),
    );
  }
}

class KcDetailScreen extends StatefulWidget {
  const KcDetailScreen({super.key, required this.kc});
  final Kc kc;

  @override
  State<KcDetailScreen> createState() => _KcDetailScreenState();
}

class _KcDetailScreenState extends State<KcDetailScreen> {
  Future<List<Gemeinde>>? _gemeinden;
  Future<List<OnboardingRequest>>? _requests;

  Api get _api => AppScope.of(context).api;

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
    _gemeinden ??= _api.gemeinden(widget.kc.id);
    _requests ??= _api.onboardingRequests(widget.kc.id);
  }

  void _reloadGemeinden() =>
      setState(() => _gemeinden = _api.gemeinden(widget.kc.id));
  void _reloadRequests() =>
      setState(() => _requests = _api.onboardingRequests(widget.kc.id));

  Future<void> _addGemeinde() async {
    final api = _api;
    final name = await _promptText(context, 'Neue Gemeinde', 'Name');
    if (name == null || name.isEmpty || !mounted) return;
    try {
      await api.createGemeinde(widget.kc.id, name);
      if (mounted) _reloadGemeinden();
    } catch (e) {
      if (mounted) _toast(context, '$e');
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text(widget.kc.name)),
      body: ListView(
        padding: const EdgeInsets.all(16),
        children: [
          Card(
            child: ListTile(
              title: const Text('Einladungscode'),
              subtitle: Text(widget.kc.inviteCode),
              trailing: const Icon(Icons.qr_code_2),
            ),
          ),
          const SizedBox(height: 16),
          Row(
            children: [
              Expanded(
                child: Text('Gemeinden',
                    style: Theme.of(context).textTheme.titleMedium),
              ),
              TextButton.icon(
                onPressed: _addGemeinde,
                icon: const Icon(Icons.add),
                label: const Text('Hinzufügen'),
              ),
            ],
          ),
          _GemeindeList(future: _gemeinden!, onRetry: _reloadGemeinden),
          const Divider(height: 40),
          Text('Offene Verantwortlichen-Anfragen',
              style: Theme.of(context).textTheme.titleMedium),
          const SizedBox(height: 8),
          _RequestList(
            future: _requests!,
            onAction: (id, approve) async {
              try {
                approve
                    ? await _api.approveOnboarding(id)
                    : await _api.rejectOnboarding(id);
                _reloadRequests();
              } catch (e) {
                if (context.mounted) _toast(context, '$e');
              }
            },
          ),
        ],
      ),
    );
  }
}

class _GemeindeList extends StatelessWidget {
  const _GemeindeList({required this.future, required this.onRetry});
  final Future<List<Gemeinde>> future;
  final VoidCallback onRetry;

  @override
  Widget build(BuildContext context) {
    return FutureBuilder<List<Gemeinde>>(
      future: future,
      builder: (context, snap) {
        if (snap.connectionState != ConnectionState.done) {
          return const Padding(
            padding: EdgeInsets.all(12),
            child: Center(child: CircularProgressIndicator()),
          );
        }
        if (snap.hasError) {
          return TextButton(onPressed: onRetry, child: Text('Fehler: ${snap.error}'));
        }
        final gemeinden = snap.data!;
        if (gemeinden.isEmpty) return const Text('Noch keine Gemeinden.');
        return Column(
          children: [
            for (final g in gemeinden)
              ListTile(
                dense: true,
                leading: const Icon(Icons.church),
                title: Text(g.name),
              ),
          ],
        );
      },
    );
  }
}

class _RequestList extends StatelessWidget {
  const _RequestList({required this.future, required this.onAction});
  final Future<List<OnboardingRequest>> future;
  final Future<void> Function(String id, bool approve) onAction;

  @override
  Widget build(BuildContext context) {
    return FutureBuilder<List<OnboardingRequest>>(
      future: future,
      builder: (context, snap) {
        if (snap.connectionState != ConnectionState.done) {
          return const Padding(
            padding: EdgeInsets.all(12),
            child: Center(child: CircularProgressIndicator()),
          );
        }
        if (snap.hasError) {
          return Text('Fehler: ${snap.error}');
        }
        final requests = snap.data!;
        if (requests.isEmpty) return const Text('Keine offenen Anfragen.');
        return Column(
          children: [
            for (final r in requests)
              Card(
                child: ListTile(
                  title: Text(r.userName.isEmpty ? r.userEmail : r.userName),
                  subtitle: Text('${r.userEmail}\nGemeinde: ${r.gemeindeName}'),
                  isThreeLine: true,
                  trailing: Row(
                    mainAxisSize: MainAxisSize.min,
                    children: [
                      IconButton(
                        tooltip: 'Genehmigen',
                        icon: const Icon(Icons.check, color: Colors.green),
                        onPressed: () => onAction(r.id, true),
                      ),
                      IconButton(
                        tooltip: 'Ablehnen',
                        icon: const Icon(Icons.close, color: Colors.red),
                        onPressed: () => onAction(r.id, false),
                      ),
                    ],
                  ),
                ),
              ),
          ],
        );
      },
    );
  }
}

Future<String?> _promptText(BuildContext context, String title, String label) {
  final controller = TextEditingController();
  return showDialog<String>(
    context: context,
    builder: (context) => AlertDialog(
      title: Text(title),
      content: TextField(
        controller: controller,
        autofocus: true,
        decoration: InputDecoration(labelText: label),
        onSubmitted: (v) => Navigator.of(context).pop(v.trim()),
      ),
      actions: [
        TextButton(
          onPressed: () => Navigator.of(context).pop(),
          child: const Text('Abbrechen'),
        ),
        FilledButton(
          onPressed: () => Navigator.of(context).pop(controller.text.trim()),
          child: const Text('OK'),
        ),
      ],
    ),
  );
}

void _toast(BuildContext context, String message) {
  ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(message)));
}