// lib/screens/group_manager_screen.dart
import 'package:flutter/material.dart';
import '../services/api_service.dart';
import '../models/group.dart';

class GroupManagerScreen extends StatefulWidget {
  const GroupManagerScreen({super.key});

  @override
  State<GroupManagerScreen> createState() => _GroupManagerScreenState();
}

class _GroupManagerScreenState extends State<GroupManagerScreen> {
  List<Group> _groups = [];
  bool _isLoading = true;
  final _newGroupController = TextEditingController();

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

  Future<void> _loadGroups() async {
    setState(() => _isLoading = true);
    try {
      final apiService = ApiService();
      final groups = await apiService.getGroups();
      setState(() {
        _groups = groups;
        _isLoading = false;
      });
    } catch (e) {
      setState(() => _isLoading = false);
      _showError('Gruppen konnten nicht geladen werden');
    }
  }

  Future<void> _addGroup() async {
    if (_newGroupController.text.trim().isEmpty) {
      _showError('Bitte geben Sie einen Namen ein');
      return;
    }

    try {
      final apiService = ApiService();
      final success = await apiService.createGroup(_newGroupController.text.trim());
      if (success) {
        _newGroupController.clear();
        await _loadGroups();
      } else {
        _showError('Erstellen fehlgeschlagen');
      }
    } catch (e) {
      _showError('Fehler: $e');
    }
  }

  Future<void> _deleteGroup(Group group) async {
    final confirm = await showDialog<bool>(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('Gruppe löschen'),
        content: Text('Möchten Sie "${group.name}" wirklich löschen?'),
        actions: [
          TextButton(onPressed: () => Navigator.pop(context, false), child: const Text('Abbrechen')),
          TextButton(onPressed: () => Navigator.pop(context, true), child: const Text('Löschen')),
        ],
      ),
    );
    
    if (confirm == true) {
      try {
        final apiService = ApiService();
        final success = await apiService.deleteGroup(group.gruppeID);
        if (success) {
          await _loadGroups();
        } else {
          _showError('Löschen fehlgeschlagen');
        }
      } catch (e) {
        _showError('Fehler: $e');
      }
    }
  }

  void _showError(String message) {
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(content: Text(message), backgroundColor: Colors.red),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Gruppenverwaltung'),
        actions: [
          IconButton(
            icon: const Icon(Icons.refresh),
            onPressed: _loadGroups,
          ),
        ],
      ),
      body: Column(
        children: [
          Padding(
            padding: const EdgeInsets.all(16),
            child: Row(
              children: [
                Expanded(
                  child: TextField(
                    controller: _newGroupController,
                    decoration: const InputDecoration(
                      hintText: 'Neue Gruppe...',
                      border: OutlineInputBorder(),
                    ),
                  ),
                ),
                const SizedBox(width: 8),
                ElevatedButton(
                  onPressed: _addGroup,
                  child: const Text('Hinzufügen'),
                ),
              ],
            ),
          ),
          Expanded(
            child: _isLoading
                ? const Center(child: CircularProgressIndicator())
                : _groups.isEmpty
                    ? const Center(child: Text('Keine Gruppen vorhanden'))
                    : ListView.builder(
                        itemCount: _groups.length,
                        itemBuilder: (context, index) {
                          final group = _groups[index];
                          return Card(
                            margin: const EdgeInsets.symmetric(horizontal: 16, vertical: 4),
                            child: ListTile(
                              title: Text(group.name),
                              trailing: IconButton(
                                icon: const Icon(Icons.delete, color: Colors.red),
                                onPressed: () => _deleteGroup(group),
                              ),
                            ),
                          );
                        },
                      ),
          ),
        ],
      ),
    );
  }
}