// 🔑 로그인 화면의 기능(서버 통신/인증 분기 로직) 담당 컨트롤러.
// 위젯/BuildContext/다이얼로그 코드는 없다 — 전부 UI 파일(lib/screens/login_screen.dart) 몫.
import 'dart:convert';
import 'package:flutter/foundation.dart' show ChangeNotifier, kIsWeb;
import 'package:http/http.dart' as http;
import 'package:firebase_messaging/firebase_messaging.dart';
import '../config.dart';

enum LoginOutcome { masterSuccess, needsPasswordChange, success, error }

/// 로그인 시도 결과. UI는 [outcome]만 보고 어떤 화면/다이얼로그를 띄울지 분기한다.
class LoginResult {
  final LoginOutcome outcome;
  final String? role;
  final String? studentId;
  final String? name;
  final bool isDeviceMatched;
  final String? errorMessage;

  const LoginResult.masterSuccess({
    required this.studentId,
    required this.name,
  }) : outcome = LoginOutcome.masterSuccess,
       role = null,
       isDeviceMatched = true,
       errorMessage = null;

  const LoginResult.needsPasswordChange({
    required this.studentId,
    required this.name,
    required this.role,
    required this.isDeviceMatched,
  }) : outcome = LoginOutcome.needsPasswordChange,
       errorMessage = null;

  const LoginResult.success({
    required this.role,
    required this.studentId,
    required this.name,
    required this.isDeviceMatched,
  }) : outcome = LoginOutcome.success,
       errorMessage = null;

  const LoginResult.error(this.errorMessage)
    : outcome = LoginOutcome.error,
      role = null,
      studentId = null,
      name = null,
      isDeviceMatched = false;
}

class LoginController extends ChangeNotifier {
  bool _isLoading = false;
  bool get isLoading => _isLoading;

  Future<LoginResult> login(String id, String password) async {
    if (id.isEmpty || password.isEmpty) {
      return const LoginResult.error('⚠️ 학번과 비밀번호를 모두 입력해 주세요.');
    }

    // 🔥 [개발자 마스터 계정]
    if (id == "2061") {
      if (password == "happy9642!") {
        return const LoginResult.masterSuccess(
          studentId: "2061",
          name: "훗춧가룻",
        );
      } else {
        return const LoginResult.error('개발자 계정의 마스터 비밀번호가 올바르지 않습니다.');
      }
    }

    _isLoading = true;
    notifyListeners();

    try {
      String deviceUuid = await getDeviceUuid();
      String fcmToken = "";

      try {
        fcmToken = kIsWeb
            ? await FirebaseMessaging.instance.getToken(
                    vapidKey: webVapidKey,
                  ) ??
                  ""
            : await FirebaseMessaging.instance.getToken() ?? "";
      } catch (e) {
        // 파이어베이스 미설정 등 - 로그인 자체는 계속 진행
      }

      final response = await http.post(
        Uri.parse('$baseUrl/login'),
        headers: {"Content-Type": "application/json"},
        body: jsonEncode({
          "studentId": id,
          "password": password,
          "deviceUuid": deviceUuid,
          "fcmToken": fcmToken,
        }),
      );

      final resData = jsonDecode(utf8.decode(response.bodyBytes));

      if (response.statusCode == 200) {
        String role = '';
        String name = '';
        String studentId = '';
        int isFirstLogin = 0;

        var userObj = resData['user'];
        if (userObj != null) {
          role = userObj['role']?.toString() ?? '';
          name =
              userObj['name']?.toString() ??
              userObj['studentName']?.toString() ??
              userObj['student_name']?.toString() ??
              '';
          studentId =
              userObj['studentId']?.toString() ??
              userObj['student_id']?.toString() ??
              id;

          var rawFirst = userObj['isFirstLogin'] ?? userObj['is_first_login'];
          isFirstLogin = (rawFirst is bool)
              ? (rawFirst ? 1 : 0)
              : (int.tryParse(rawFirst.toString()) ?? 0);
        } else {
          role = resData['role']?.toString() ?? '';
          name =
              resData['name']?.toString() ??
              resData['studentName']?.toString() ??
              '';
          studentId = resData['studentId']?.toString() ?? id;

          var rawFirst = resData['isFirstLogin'] ?? resData['is_first_login'];
          isFirstLogin = (rawFirst is bool)
              ? (rawFirst ? 1 : 0)
              : (int.tryParse(rawFirst.toString()) ?? 0);
        }

        if (name.trim().isEmpty) {
          name = "알수없음";
        }

        // 🆕 서버 응답 데이터에서 기기 일치 여부 추출하기
        // (서버가 주는 Key 이름에 맞춰서 데이터를 가져옵니다. 아래 항목 중 맞는 게 알아서 들어감)
        bool isDeviceMatched =
            resData['isDeviceMatched'] ??
            resData['isUuidMatched'] ??
            resData['is_matched'] ??
            (userObj != null
                ? (userObj['isDeviceMatched'] ?? userObj['is_matched'] ?? false)
                : false);

        if (isFirstLogin == 1) {
          return LoginResult.needsPasswordChange(
            studentId: studentId,
            name: name,
            role: role,
            isDeviceMatched: isDeviceMatched,
          );
        }

        return LoginResult.success(
          role: role,
          studentId: studentId,
          name: name,
          isDeviceMatched: isDeviceMatched,
        );
      } else {
        String errorMsg = '로그인에 실패했습니다.';
        if (resData is Map) {
          errorMsg =
              resData['detail']?.toString() ??
              resData['message']?.toString() ??
              errorMsg;
        }
        return LoginResult.error(errorMsg);
      }
    } catch (e) {
      return LoginResult.error('서버와 연결할 수 없습니다. 서버 상태를 확인하세요!\n($e)');
    } finally {
      _isLoading = false;
      notifyListeners();
    }
  }

  /// 🛠️ 초기 비밀번호 변경. (성공여부, 메시지)를 반환한다.
  Future<(bool success, String message)> changePassword({
    required String studentId,
    required String newPassword,
  }) async {
    try {
      final response = await http.post(
        Uri.parse('$baseUrl/api/users/change-password'),
        headers: {"Content-Type": "application/json"},
        body: jsonEncode({"studentId": studentId, "newPassword": newPassword}),
      );

      final resData = jsonDecode(utf8.decode(response.bodyBytes));

      if (response.statusCode == 200 && resData['status'] == 'success') {
        return (true, '✅ 비밀번호가 변경되었습니다!');
      } else {
        return (false, '❌ 실패: ${resData['message']}');
      }
    } catch (e) {
      return (false, '서버 에러 발생: $e');
    }
  }
}