school-attendance/lib/function/group_controller.dart

// 👥 백품타 그룹 스터디(목록/생성/초대) 화면의 기능(서버 통신/상태) 담당 컨트롤러.
import 'dart:convert';
import 'package:flutter/foundation.dart';
import 'package:http/http.dart' as http;
import '../config.dart';

class GroupController extends ChangeNotifier {
  final String studentId;
  final String studentName;

  GroupController({required this.studentId, required this.studentName});

  bool _isLoading = true;
  bool _isBusy = false;
  List<dynamic> _groups = [];
  List<dynamic> _invites = [];
  bool _disposed = false;

  bool get isLoading => _isLoading;
  bool get isBusy => _isBusy;
  List<dynamic> get groups => _groups;
  List<dynamic> get invites => _invites;

  void _safeNotify() {
    if (!_disposed) notifyListeners();
  }

  @override
  void dispose() {
    _disposed = true;
    super.dispose();
  }

  Future<void> init() => refresh();

  Future<void> refresh() async {
    _isLoading = true;
    _safeNotify();
    await Future.wait([_fetchGroups(), _fetchInvites()]);
    _isLoading = false;
    _safeNotify();
  }

  Future<void> _fetchGroups() async {
    try {
      final response = await http.get(
        Uri.parse('$baseUrl/api/groups/mine?studentId=$studentId'),
      );
      if (response.statusCode == 200) {
        final data = jsonDecode(utf8.decode(response.bodyBytes));
        _groups = data['groups'] ?? [];
      }
    } catch (_) {
      // 조용히 무시
    }
  }

  Future<void> _fetchInvites() async {
    try {
      final response = await http.get(
        Uri.parse('$baseUrl/api/groups/invites?studentId=$studentId'),
      );
      if (response.statusCode == 200) {
        final data = jsonDecode(utf8.decode(response.bodyBytes));
        _invites = data['invites'] ?? [];
      }
    } catch (_) {
      // 조용히 무시
    }
  }

  Future<(bool success, String message)> createGroup(String name) async {
    _isBusy = true;
    _safeNotify();
    try {
      final response = await http.post(
        Uri.parse('$baseUrl/api/groups'),
        headers: {"Content-Type": "application/json"},
        body: jsonEncode({
          "ownerId": studentId,
          "ownerName": studentName,
          "name": name.trim(),
        }),
      );
      final result = jsonDecode(utf8.decode(response.bodyBytes));
      if (response.statusCode == 200 && result['status'] == 'success') {
        await _fetchGroups();
        return (true, '${result['message'] ?? '그룹을 만들었습니다.'}');
      }
      return (false, '${result['message'] ?? '그룹 생성 실패'}');
    } catch (e) {
      return (false, '네트워크 에러: $e');
    } finally {
      _isBusy = false;
      _safeNotify();
    }
  }

  Future<(bool success, String message)> respondInvite(
    int inviteId,
    bool accept,
  ) async {
    _isBusy = true;
    _safeNotify();
    try {
      final response = await http.post(
        Uri.parse('$baseUrl/api/groups/invites/$inviteId/respond'),
        headers: {"Content-Type": "application/json"},
        body: jsonEncode({"responderId": studentId, "accept": accept}),
      );
      final result = jsonDecode(utf8.decode(response.bodyBytes));
      if (response.statusCode == 200 && result['status'] == 'success') {
        await refresh();
        return (true, '${result['message'] ?? '처리했습니다.'}');
      }
      return (false, '${result['message'] ?? '처리 실패'}');
    } catch (e) {
      return (false, '네트워크 에러: $e');
    } finally {
      _isBusy = false;
      _safeNotify();
    }
  }
}