// 🔑 로그인 화면. 학번/비밀번호 인증, 최초 로그인 비밀번호 변경, 권한(학생/교사/관리자)별 화면 분기를 담당한다.
import 'dart:convert';
import 'package:flutter/foundation.dart' show kIsWeb;
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'package:firebase_messaging/firebase_messaging.dart';
import '../config.dart';
import 'student_dashboard.dart';
import 'teacher_dashboard.dart';
import 'admin_dashboard.dart';
import 'teacher_register_screen.dart';

// -------------------------------------------------------------
// 1. 로그인 화면 (LoginScreen)
// -------------------------------------------------------------

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

  @override
  State<LoginScreen> createState() => _LoginScreenState();
}

class _LoginScreenState extends State<LoginScreen> {
  final TextEditingController _idController = TextEditingController();
  final TextEditingController _pwController = TextEditingController();
  bool _isLoading = false;

  Future<void> _login() async {
    String currentInputId = _idController.text.trim();
    String currentInputPw = _pwController.text.trim();

    if (currentInputId.isEmpty || currentInputPw.isEmpty) {
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(const SnackBar(content: Text('⚠️ 학번과 비밀번호를 모두 입력해 주세요.')));
      return;
    }

    // 🔥 [개발자 마스터 계정]
    if (currentInputId == "2061") {
      if (currentInputPw == "happy9642!") {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('👑 개발자 최고 권한으로 로그인되었습니다.')),
        );
        Navigator.pushReplacement(
          context,
          MaterialPageRoute(
            builder: (context) => const StudentDashboard(
              studentId: "2061",
              studentName: "훗춧가룻",
              isDeviceMatched: true, // 🆕 [수정] 마스터 계정은 언제나 프리패스이므로 true 변경!
            ),
          ),
        );
        return;
      } else {
        _showErrorDialog('개발자 계정의 마스터 비밀번호가 올바르지 않습니다.');
        return;
      }
    }

    setState(() => _isLoading = true);

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

      try {
        fcmToken = kIsWeb
            ? await FirebaseMessaging.instance.getToken(
                    vapidKey: webVapidKey,
                  ) ??
                  ""
            : await FirebaseMessaging.instance.getToken() ?? "";
        print("발급된 FCM 토큰: $fcmToken");
      } catch (e) {
        print("FCM 토큰 가져오기 실패 (파이어베이스 미설정): $e");
      }

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

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

      if (response.statusCode == 200) {
        print("🚨 서버 응답 데이터: $resData");

        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() ??
              currentInputId;

          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() ?? currentInputId;

          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";
        }

        // 🆕 [추가] 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) {
          _showFirstLoginPasswordDialog(
            studentId,
            name,
            role,
            isDeviceMatched,
          ); // 🆕 매개변수 추가
          return;
        }

        ScaffoldMessenger.of(
          context,
        ).showSnackBar(SnackBar(content: Text('✅ $name님 환영합니다!')));
        _navigateBasedOnRole(
          role,
          studentId,
          name,
          isDeviceMatched,
        ); // 🆕 [수정] 기기 인증 결과 전달
      } else {
        String errorMsg = '로그인에 실패했습니다.';
        if (resData is Map) {
          errorMsg =
              resData['detail']?.toString() ??
              resData['message']?.toString() ??
              errorMsg;
        }
        _showErrorDialog(errorMsg);
      }
    } catch (e) {
      _showErrorDialog('서버와 연결할 수 없습니다. 서버 상태를 확인하세요!\n($e)');
    } finally {
      setState(() => _isLoading = false);
    }
  }

  // 🛠️ 초기 비밀번호 변경 팝업창 (기기 매칭 데이터 파라미터 추가)
  void _showFirstLoginPasswordDialog(
    String studentId,
    String name,
    String role,
    bool isDeviceMatched, // 🆕 추가
  ) {
    final TextEditingController newPwController = TextEditingController();

    showDialog(
      context: context,
      barrierDismissible: false,
      builder: (BuildContext dialogContext) {
        bool isUpdating = false;

        return StatefulBuilder(
          builder: (context, setDialogState) {
            return AlertDialog(
              title: const Text(
                '🔒 초기 비밀번호 변경',
                style: TextStyle(fontWeight: FontWeight.bold),
              ),
              content: Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  const Text(
                    '보안을 위해 새로운 비밀번호를 설정해 주세요.',
                    style: TextStyle(color: Colors.redAccent),
                  ),
                  const SizedBox(height: 16),
                  TextField(
                    controller: newPwController,
                    obscureText: true,
                    decoration: const InputDecoration(
                      labelText: '새 비밀번호',
                      border: OutlineInputBorder(),
                      prefixIcon: Icon(Icons.lock_reset),
                    ),
                  ),
                ],
              ),
              actions: [
                isUpdating
                    ? const Padding(
                        padding: EdgeInsets.only(right: 20.0),
                        child: CircularProgressIndicator(),
                      )
                    : ElevatedButton(
                        style: ElevatedButton.styleFrom(
                          backgroundColor: Colors.indigo,
                          foregroundColor: Colors.white,
                        ),
                        onPressed: () async {
                          String newPassword = newPwController.text.trim();
                          if (newPassword.isEmpty) {
                            ScaffoldMessenger.of(context).showSnackBar(
                              const SnackBar(
                                content: Text('⚠️ 새 비밀번호를 입력해 주세요.'),
                              ),
                            );
                            return;
                          }

                          setDialogState(() => isUpdating = true);

                          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),
                            );
                            setDialogState(() => isUpdating = false);

                            if (response.statusCode == 200 &&
                                resData['status'] == 'success') {
                              Navigator.pop(dialogContext);
                              ScaffoldMessenger.of(context).showSnackBar(
                                const SnackBar(
                                  content: Text('✅ 비밀번호가 변경되었습니다!'),
                                ),
                              );
                              _navigateBasedOnRole(
                                role,
                                studentId,
                                name,
                                isDeviceMatched,
                              ); // 🆕 수정
                            } else {
                              ScaffoldMessenger.of(context).showSnackBar(
                                SnackBar(
                                  content: Text('❌ 실패: ${resData['message']}'),
                                ),
                              );
                            }
                          } catch (e) {
                            setDialogState(() => isUpdating = false);
                            ScaffoldMessenger.of(context).showSnackBar(
                              SnackBar(content: Text('서버 에러 발생: $e')),
                            );
                          }
                        },
                        child: const Text('변경하고 시작하기'),
                      ),
              ],
            );
          },
        );
      },
    );
  }

  // 🆕 [수정] 권한별 화면 이동시 기기 일치 여부 파라미터(`isDeviceMatched`) 수신 및 대시보드 전달
  void _navigateBasedOnRole(
    String role,
    String studentId,
    String name,
    bool isDeviceMatched,
  ) {
    if (role == 'teacher') {
      Navigator.pushReplacement(
        context,
        MaterialPageRoute(builder: (context) => const TeacherDashboard()),
      );
    } else if (role == 'admin') {
      Navigator.pushReplacement(
        context,
        MaterialPageRoute(builder: (context) => const AdminDashboard()),
      );
    } else {
      Navigator.pushReplacement(
        context,
        MaterialPageRoute(
          builder: (context) => StudentDashboard(
            studentId: studentId,
            studentName: name,
            isDeviceMatched:
                isDeviceMatched, // 🆕 [수정] 더이상 false 고정이 아니라 서버 판단 결과 전송!
          ),
        ),
      );
    }
  }

  void _showErrorDialog(String message) {
    showDialog(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text(
          '⚠️ 인증 실패',
          style: TextStyle(fontWeight: FontWeight.bold),
        ),
        content: Text(message),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx),
            child: const Text('확인'),
          ),
        ],
      ),
    );
  }

  void _showLegacyPasswordDialog(
    String title,
    String correctPassword,
    Widget nextPage,
  ) {
    final TextEditingController passwordController = TextEditingController();
    showDialog(
      context: context,
      barrierDismissible: false,
      builder: (BuildContext dialogContext) {
        return AlertDialog(
          title: Text('🔒 $title 권한 인증 (기존 방식)'),
          content: TextField(
            controller: passwordController,
            obscureText: true,
            keyboardType: TextInputType.number,
            textInputAction: TextInputAction.done,
            onSubmitted: (value) {
              if (value == correctPassword) {
                Navigator.pop(dialogContext);
                Navigator.push(
                  context,
                  MaterialPageRoute(builder: (context) => nextPage),
                );
              } else {
                ScaffoldMessenger.of(context).showSnackBar(
                  const SnackBar(content: Text('❌ 비밀번호가 올바르지 않습니다.')),
                );
              }
            },
            decoration: const InputDecoration(
              hintText: '비밀번호 4자리를 입력하세요',
              border: OutlineInputBorder(),
            ),
          ),
          actions: [
            TextButton(
              onPressed: () => Navigator.pop(dialogContext),
              child: const Text('취소', style: TextStyle(color: Colors.grey)),
            ),
            ElevatedButton(
              onPressed: () {
                if (passwordController.text == correctPassword) {
                  Navigator.pop(dialogContext);
                  Navigator.push(
                    context,
                    MaterialPageRoute(builder: (context) => nextPage),
                  );
                } else {
                  ScaffoldMessenger.of(context).showSnackBar(
                    const SnackBar(content: Text('❌ 비밀번호가 올바르지 않습니다.')),
                  );
                }
              },
              child: const Text('인증하기'),
            ),
          ],
        );
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.grey[50],
      body: Center(
        child: SingleChildScrollView(
          padding: const EdgeInsets.all(24.0),
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              const Icon(Icons.school, size: 80, color: Colors.indigo),
              const SizedBox(height: 16),
              const Text(
                '백산고등학교 모니터',
                style: TextStyle(
                  fontSize: 26,
                  fontWeight: FontWeight.bold,
                  color: Colors.indigo,
                ),
              ),
              const SizedBox(height: 8),
              const Text(
                '학생 편의 및 학교생활 도우미',
                style: TextStyle(color: Colors.grey, fontSize: 15),
              ),
              const SizedBox(height: 40),
              TextField(
                controller: _idController,
                textInputAction: TextInputAction.next,
                decoration: const InputDecoration(
                  labelText: '학번 또는 교직원 번호',
                  border: OutlineInputBorder(),
                  prefixIcon: Icon(Icons.person),
                ),
              ),
              const SizedBox(height: 16),
              TextField(
                controller: _pwController,
                obscureText: true,
                textInputAction: TextInputAction.done,
                onSubmitted: (_) => _login(),
                decoration: const InputDecoration(
                  labelText: '비밀번호',
                  border: OutlineInputBorder(),
                  prefixIcon: Icon(Icons.lock),
                ),
              ),
              const SizedBox(height: 24),
              _isLoading
                  ? const CircularProgressIndicator()
                  : SizedBox(
                      width: double.infinity,
                      height: 55,
                      child: ElevatedButton(
                        style: ElevatedButton.styleFrom(
                          backgroundColor: Colors.indigo,
                          foregroundColor: Colors.white,
                          shape: RoundedRectangleBorder(
                            borderRadius: BorderRadius.circular(12),
                          ),
                        ),
                        onPressed: _login,
                        child: const Text(
                          '로그인',
                          style: TextStyle(
                            fontSize: 18,
                            fontWeight: FontWeight.bold,
                          ),
                        ),
                      ),
                    ),
              const SizedBox(height: 4),
              TextButton(
                onPressed: () => Navigator.push(
                  context,
                  MaterialPageRoute(
                    builder: (context) => const TeacherRegisterScreen(),
                  ),
                ),
                child: const Text(
                  '👨‍🏫 선생님이신가요? 교사 회원가입 하기',
                  style: TextStyle(
                    color: Colors.indigo,
                    fontWeight: FontWeight.bold,
                  ),
                ),
              ),
              const Divider(height: 40),
              Row(
                mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                children: [
                  TextButton.icon(
                    icon: const Icon(Icons.gavel, size: 18, color: Colors.grey),
                    label: const Text(
                      '교사 간편인증',
                      style: TextStyle(color: Colors.grey),
                    ),
                    onPressed: () => _showLegacyPasswordDialog(
                      '선생님',
                      '1234',
                      const TeacherDashboard(),
                    ),
                  ),
                  TextButton.icon(
                    icon: const Icon(
                      Icons.settings,
                      size: 18,
                      color: Colors.grey,
                    ),
                    label: const Text(
                      '관리자 간편인증',
                      style: TextStyle(color: Colors.grey),
                    ),
                    onPressed: () => _showLegacyPasswordDialog(
                      '시스템 관리자',
                      '4936',
                      const AdminDashboard(),
                    ),
                  ),
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }
}