school-attendance/lib/function/device_checkout_ledger_controller.dart

// 📋 선생님용 "스마트기기 반출 대장" 화면의 기능(서버 통신/상태) 담당 컨트롤러.
import 'dart:async';
import 'dart:convert';
import 'package:flutter/foundation.dart';
import 'package:http/http.dart' as http;
import '../config.dart';

class DeviceCheckoutLedgerController extends ChangeNotifier {
  List<dynamic> _requests = [];
  bool _isLoading = true;
  bool _isWorking = false;
  Timer? _timer;
  bool _disposed = false;

  List<dynamic> get requests => _requests;
  bool get isLoading => _isLoading;
  bool get isWorking => _isWorking;

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

  void init() {
    fetchAll();
    _timer = Timer.periodic(const Duration(seconds: 5), (_) => fetchAll());
  }

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

  Future<void> fetchAll() async {
    try {
      final response = await http.get(
        Uri.parse('$baseUrl/api/device-checkout/list'),
      );
      if (response.statusCode == 200) {
        final data = jsonDecode(utf8.decode(response.bodyBytes));
        _requests = data['requests'] ?? [];
      }
    } catch (_) {
      // 새로고침 실패는 조용히 무시하고 마지막으로 받아온 목록을 유지한다.
    } finally {
      _isLoading = false;
      _safeNotify();
    }
  }

  // ✅ 승인 시 승인한 선생님 계정을 함께 보낸다 (대장에 "OOO 선생님이 허용했습니다" 표시 +
  // 미반납 알림을 그 선생님에게만 보내기 위함).
  Future<(bool success, String message)> approve(
    int requestId, {
    required String teacherId,
    required String teacherName,
  }) async {
    return _postAction('/api/device-checkout/approve', {
      "requestId": requestId,
      "teacherId": teacherId,
      "teacherName": teacherName,
    });
  }

  Future<(bool success, String message)> reject(int requestId) async {
    return _postAction('/api/device-checkout/reject', {"requestId": requestId});
  }

  Future<(bool success, String message)> _postAction(
    String path,
    Map<String, dynamic> body,
  ) async {
    _isWorking = true;
    _safeNotify();
    try {
      final response = await http.post(
        Uri.parse('$baseUrl$path'),
        headers: {"Content-Type": "application/json"},
        body: jsonEncode(body),
      );
      final result = jsonDecode(utf8.decode(response.bodyBytes));
      if (response.statusCode == 200 && result['status'] == 'success') {
        await fetchAll();
        return (true, '✅ ${result['message'] ?? '처리되었습니다.'}');
      }
      return (false, '❌ ${result['message'] ?? '처리 실패'}');
    } catch (e) {
      return (false, '🚨 네트워크 에러: $e');
    } finally {
      _isWorking = false;
      _safeNotify();
    }
  }
}