// 🔐 (마스터 계정용) 학생 계정 및 기기 관리 화면 (UI 전용). 기기 UUID 초기화/계정 삭제/생성 다이얼로그를 그린다.
// 서버 통신/상태는 lib/function/student_management_controller.dart가 담당한다.
import 'package:flutter/material.dart';
import '../function/student_management_controller.dart';

// ==========================================
// 🔐 6. 학생 계정 및 기기 관리 화면 (기기 리셋 + 계정 삭제 완본)
// ==========================================
class StudentManagementScreen extends StatefulWidget {
  const StudentManagementScreen({super.key});

  @override
  State<StudentManagementScreen> createState() =>
      _StudentManagementScreenState();
}

class _StudentManagementScreenState extends State<StudentManagementScreen> {
  final StudentManagementController _controller =
      StudentManagementController();

  @override
  void initState() {
    super.initState();
    _controller.init();
  }

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  Future<void> _fetchStudents() async {
    final error = await _controller.fetchStudents();
    if (error != null && mounted) {
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(SnackBar(content: Text(error)));
    }
  }

  // 🌐 서버로 기기 초기화(리셋) 명령 보내기
  void _resetDevice(String studentId, String studentName) {
    showDialog(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text(
          '⚠️ 기기 잠금 해제',
          style: TextStyle(fontWeight: FontWeight.bold, color: Colors.purple),
        ),
        content: Text('$studentName 학생의 스마트폰 기기 등록을 초기화하시겠습니까?'),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx),
            child: const Text('취소', style: TextStyle(color: Colors.grey)),
          ),
          ElevatedButton(
            style: ElevatedButton.styleFrom(
              backgroundColor: Colors.purple,
              foregroundColor: Colors.white,
            ),
            onPressed: () async {
              Navigator.pop(ctx);
              final (_, message) = await _controller.resetDevice(
                studentId,
                studentName,
              );
              if (!mounted) return;
              ScaffoldMessenger.of(
                context,
              ).showSnackBar(SnackBar(content: Text(message)));
            },
            child: const Text('초기화 승인'),
          ),
        ],
      ),
    );
  }

  // 🌐 [새 기능] 서버로 계정 완전 삭제 명령 보내기
  void _deleteUser(String studentId, String studentName) {
    showDialog(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text(
          '🚨 계정 완전 삭제 경고',
          style: TextStyle(fontWeight: FontWeight.bold, color: Colors.red),
        ),
        content: Text(
          '정말로 $studentName ($studentId) 학생의 계정을 시스템에서 탈퇴(삭제)시키겠습니까?\n\n이 작업은 되돌릴 수 없으며, 해당 학생은 다시 회원가입을 진행해야 합니다.',
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx),
            child: const Text('취소', style: TextStyle(color: Colors.grey)),
          ),
          ElevatedButton(
            style: ElevatedButton.styleFrom(
              backgroundColor: Colors.red,
              foregroundColor: Colors.white,
            ),
            onPressed: () async {
              Navigator.pop(ctx);
              final (_, message) = await _controller.deleteUser(
                studentId,
                studentName,
              );
              if (!mounted) return;
              ScaffoldMessenger.of(
                context,
              ).showSnackBar(SnackBar(content: Text(message)));
            },
            child: const Text('영구 삭제'),
          ),
        ],
      ),
    );
  }

  void _showCreateUserDialog() {
    final idController = TextEditingController();
    final nameController = TextEditingController();

    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('👤 신규 학생 계정 추가'),
        content: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            TextField(
              controller: idController,
              decoration: const InputDecoration(labelText: '학번 입력 (예: 20101)'),
              keyboardType: TextInputType.number,
            ),
            const SizedBox(height: 8),
            TextField(
              controller: nameController,
              decoration: const InputDecoration(labelText: '학생 이름 입력'),
            ),
          ],
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: const Text('취소'),
          ),
          ElevatedButton(
            onPressed: () async {
              String studentId = idController.text.trim();
              String name = nameController.text.trim();

              if (studentId.isEmpty || name.isEmpty) {
                ScaffoldMessenger.of(context).showSnackBar(
                  const SnackBar(content: Text('⚠️ 학번과 이름을 모두 입력하세요.')),
                );
                return;
              }

              final (success, message) = await _controller.createUser(
                studentId,
                name,
              );
              if (!mounted) return;
              if (success) {
                Navigator.pop(context); // 팝업 닫기
              }
              ScaffoldMessenger.of(
                context,
              ).showSnackBar(SnackBar(content: Text(message)));
            },
            child: const Text('생성'),
          ),
        ],
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return ListenableBuilder(
      listenable: _controller,
      builder: (context, _) {
        final realStudents = _controller.students;
        return Scaffold(
          backgroundColor: Colors.grey[50],
          appBar: AppBar(
            title: const Text(
              '학생 계정 및 기기 관리',
              style: TextStyle(fontWeight: FontWeight.bold),
            ),
            backgroundColor: Colors.purple,
            foregroundColor: Colors.white,
            actions: [
              IconButton(
                icon: const Icon(Icons.person_add_alt_1_rounded),
                onPressed: () => _showCreateUserDialog(),
              ),
              IconButton(icon: const Icon(Icons.refresh), onPressed: _fetchStudents),
            ],
          ),
          body: _controller.isLoading
              ? const Center(
                  child: CircularProgressIndicator(color: Colors.purple),
                )
              : realStudents.isEmpty
              ? const Center(
                  child: Text(
                    '가입된 학생 계정이 없습니다.',
                    style: TextStyle(color: Colors.grey, fontSize: 16),
                  ),
                )
              : ListView.builder(
                  padding: const EdgeInsets.all(16),
                  itemCount: realStudents.length,
                  itemBuilder: (context, index) {
                    final student = realStudents[index];
                    final bool needsReset = student['device'] == "초기화 필요";

                    return Card(
                      elevation: 2,
                      margin: const EdgeInsets.only(bottom: 12),
                      shape: RoundedRectangleBorder(
                        borderRadius: BorderRadius.circular(16),
                      ),
                      child: ListTile(
                        contentPadding: const EdgeInsets.symmetric(
                          horizontal: 16,
                          vertical: 12,
                        ),
                        leading: CircleAvatar(
                          backgroundColor: needsReset
                              ? Colors.red[50]
                              : Colors.purple[50],
                          child: Icon(
                            needsReset ? Icons.lock_reset : Icons.person,
                            color: needsReset ? Colors.red : Colors.purple,
                          ),
                        ),
                        title: Text(
                          '${student['name']} (${student['id']})',
                          style: const TextStyle(
                            fontWeight: FontWeight.bold,
                            fontSize: 16,
                          ),
                        ),
                        subtitle: Text(
                          needsReset ? '기기 초기화 승인 대기중' : '정상 등록 상태',
                          style: TextStyle(
                            color: needsReset ? Colors.red : Colors.grey,
                            fontWeight: needsReset
                                ? FontWeight.bold
                                : FontWeight.normal,
                          ),
                        ),
                        // 🕹️ 오른쪽 끝에 [기기 리셋] 버튼과 [쓰레기통(삭제)] 버튼을 나란히 배치하는 Row 레이아웃 기획
                        trailing: Row(
                          mainAxisSize: MainAxisSize.min,
                          children: [
                            if (!needsReset)
                              OutlinedButton(
                                style: OutlinedButton.styleFrom(
                                  foregroundColor: Colors.purple,
                                  side: BorderSide(
                                    color: Colors.purple.withValues(
                                      alpha: 0.5,
                                    ),
                                  ),
                                  shape: RoundedRectangleBorder(
                                    borderRadius: BorderRadius.circular(8),
                                  ),
                                ),
                                onPressed: () => _resetDevice(
                                  student['id'],
                                  student['name'],
                                ),
                                child: const Text('기기 리셋'),
                              )
                            else
                              const Icon(
                                Icons.check_circle,
                                color: Colors.green,
                              ),

                            const SizedBox(width: 8),

                            // 🔴 [새 버튼] 최고권한 마스터 전용 계정 영구 삭제 쓰레기통 버튼!
                            IconButton(
                              icon: const Icon(
                                Icons.delete_forever_rounded,
                                color: Colors.redAccent,
                              ),
                              tooltip: '계정 영구 삭제',
                              onPressed: () =>
                                  _deleteUser(student['id'], student['name']),
                            ),
                          ],
                        ),
                      ),
                    );
                  },
                ),
        );
      },
    );
  }
}