// 👥 교사용 학생 계정 관리 화면 (UI 전용). 신규 학생 계정 추가 폼과 강제 삭제 다이얼로그를 그린다.
// 서버 통신/상태는 lib/function/teacher_student_management_controller.dart가 담당한다.
import 'dart:typed_data';
import 'package:desktop_drop/desktop_drop.dart';
import 'package:flutter/material.dart';
import '../function/excel_file_picker.dart';
import '../function/teacher_student_management_controller.dart';

// -----------------------------------------------------------------------------
// 👥 [서브 화면 2] 학생 계정 관리 란 (추가 양식 폼 + 강제 삭제 다이얼로그 완전 내장)
// -----------------------------------------------------------------------------
class TeacherStudentManagementPage extends StatefulWidget {
  const TeacherStudentManagementPage({super.key});

  @override
  State<TeacherStudentManagementPage> createState() =>
      _TeacherStudentManagementPageState();
}

class _TeacherStudentManagementPageState
    extends State<TeacherStudentManagementPage> {
  final TeacherStudentManagementController _controller =
      TeacherStudentManagementController();
  final TextEditingController _addIdController = TextEditingController();
  final TextEditingController _addNameController = TextEditingController();
  final TextEditingController _addPwController = TextEditingController();
  int? _selectedGrade;
  bool _isDragging = false;

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

  // ➕ [학생 추가 버튼 동작]
  Future<void> _addStudentAccount() async {
    final sId = _addIdController.text.trim();
    final sName = _addNameController.text.trim();
    final sPw = _addPwController.text.trim();

    if (sId.isEmpty || sName.isEmpty || sPw.isEmpty) {
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(const SnackBar(content: Text('⚠️ 모든 입력란을 채워주세요.')));
      return;
    }

    final (success, message) = await _controller.addStudentAccount(
      studentId: sId,
      name: sName,
      password: sPw,
      grade: _selectedGrade,
    );
    if (!mounted) return;
    if (success) {
      _addIdController.clear();
      _addNameController.clear();
      _addPwController.clear();
      setState(() => _selectedGrade = null);
    }
    ScaffoldMessenger.of(
      context,
    ).showSnackBar(SnackBar(content: Text(message)));
  }

  // 📄 [파일 선택 버튼 동작] "파일 선택"으로 엑셀 고르기
  Future<void> _pickExcelFile() async {
    final bytes = await pickExcelFileBytes();
    if (bytes == null) return;
    if (!mounted) return;
    await _handleExcelBytes(bytes);
  }

  // 📄 엑셀 바이트를 파싱해서 미리보기 다이얼로그를 띄운다 (드래그/파일선택 공용).
  Future<void> _handleExcelBytes(Uint8List bytes) async {
    List<BulkStudentRow> rows;
    try {
      rows = _controller.parseExcelBytes(bytes);
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(SnackBar(content: Text('❌ 엑셀 파일을 읽는 데 실패했습니다: $e')));
      return;
    }
    if (rows.isEmpty) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(
          content: Text('⚠️ 유효한 학생 데이터를 찾지 못했습니다. (1행은 머리글로 건너뜁니다)'),
        ),
      );
      return;
    }
    _showBulkPreviewDialog(rows);
  }

  // 📋 [일괄 등록 확인 팝업] 엑셀에서 뽑아낸 명단을 미리 보여주고 확정받는다.
  void _showBulkPreviewDialog(List<BulkStudentRow> rows) {
    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(24)),
        title: Text('📄 ${rows.length}명 확인됨'),
        content: SizedBox(
          width: 400,
          child: Column(
            mainAxisSize: MainAxisSize.min,
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              const Text(
                '아래 명단으로 계정을 일괄 생성합니다 (초기 비밀번호: 1234).',
                style: TextStyle(color: Colors.black54, fontSize: 13),
              ),
              const SizedBox(height: 12),
              ConstrainedBox(
                constraints: const BoxConstraints(maxHeight: 300),
                child: ListView.builder(
                  shrinkWrap: true,
                  itemCount: rows.length,
                  itemBuilder: (context, i) {
                    final row = rows[i];
                    return ListTile(
                      dense: true,
                      leading: CircleAvatar(
                        radius: 14,
                        child: Text(
                          '${i + 1}',
                          style: const TextStyle(fontSize: 11),
                        ),
                      ),
                      title: Text('${row.name} (${row.studentId})'),
                      trailing: Text(
                        row.grade != null ? '${row.grade}학년' : '미배정',
                        style: TextStyle(color: Colors.grey[600]),
                      ),
                    );
                  },
                ),
              ),
            ],
          ),
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: const Text('취소', style: TextStyle(color: Colors.grey)),
          ),
          ElevatedButton(
            onPressed: () {
              Navigator.pop(context);
              _runBulkImport(rows);
            },
            style: ElevatedButton.styleFrom(
              backgroundColor: Colors.orange,
              foregroundColor: Colors.white,
              shape: RoundedRectangleBorder(
                borderRadius: BorderRadius.circular(12),
              ),
            ),
            child: Text('${rows.length}명 일괄 등록'),
          ),
        ],
      ),
    );
  }

  // 🚀 실제 일괄 등록 실행 + 진행 상황 표시 + 결과 요약 팝업.
  Future<void> _runBulkImport(List<BulkStudentRow> rows) async {
    showDialog(
      context: context,
      barrierDismissible: false,
      builder: (context) => ListenableBuilder(
        listenable: _controller,
        builder: (context, _) => AlertDialog(
          shape: RoundedRectangleBorder(
            borderRadius: BorderRadius.circular(24),
          ),
          content: Row(
            children: [
              const CircularProgressIndicator(),
              const SizedBox(width: 20),
              Text(
                '등록 중... (${_controller.bulkDone}/${_controller.bulkTotal})',
              ),
            ],
          ),
        ),
      ),
    );

    final result = await _controller.bulkAddStudents(rows);

    if (!mounted) return;
    Navigator.pop(context); // 진행 팝업 닫기

    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(24)),
        title: Text(
          result.failures.isEmpty ? '✅ 일괄 등록 완료' : '⚠️ 일괄 등록 완료 (일부 실패)',
        ),
        content: SizedBox(
          width: 400,
          child: Column(
            mainAxisSize: MainAxisSize.min,
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                '성공 ${result.successCount}명 / 실패 ${result.failures.length}명',
              ),
              if (result.failures.isNotEmpty) ...[
                const SizedBox(height: 12),
                const Text(
                  '실패 목록',
                  style: TextStyle(fontWeight: FontWeight.bold),
                ),
                const SizedBox(height: 6),
                ConstrainedBox(
                  constraints: const BoxConstraints(maxHeight: 200),
                  child: SingleChildScrollView(
                    child: Text(
                      result.failures.join('\n'),
                      style: const TextStyle(fontSize: 12, color: Colors.red),
                    ),
                  ),
                ),
              ],
            ],
          ),
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: const Text('확인'),
          ),
        ],
      ),
    );
  }

  // 🏫 [기존 학생 학년 지정/변경 다이얼로그]
  void _showUpdateGradeDialog() {
    final TextEditingController idController = TextEditingController();
    int? grade;

    showDialog(
      context: context,
      builder: (context) {
        return StatefulBuilder(
          builder: (context, setDialogState) {
            return AlertDialog(
              shape: RoundedRectangleBorder(
                borderRadius: BorderRadius.circular(24),
              ),
              title: const Text(
                '🏫 학년 지정/변경',
                style: TextStyle(fontWeight: FontWeight.bold, fontSize: 18),
              ),
              content: Column(
                mainAxisSize: MainAxisSize.min,
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  const Text(
                    '이미 만들어진 학생 계정의 학년을 지정하거나 바꿉니다.',
                    style: TextStyle(color: Colors.black54, fontSize: 13),
                  ),
                  const SizedBox(height: 16),
                  TextField(
                    controller: idController,
                    keyboardType: TextInputType.number,
                    decoration: const InputDecoration(
                      labelText: '학번',
                      border: OutlineInputBorder(),
                      prefixIcon: Icon(Icons.badge),
                    ),
                  ),
                  const SizedBox(height: 12),
                  DropdownButtonFormField<int?>(
                    initialValue: grade,
                    decoration: const InputDecoration(
                      labelText: '학년',
                      border: OutlineInputBorder(),
                      prefixIcon: Icon(Icons.class_),
                    ),
                    items: const [
                      DropdownMenuItem(value: null, child: Text('미배정')),
                      DropdownMenuItem(value: 1, child: Text('1학년')),
                      DropdownMenuItem(value: 2, child: Text('2학년')),
                      DropdownMenuItem(value: 3, child: Text('3학년')),
                    ],
                    onChanged: (value) => setDialogState(() => grade = value),
                  ),
                ],
              ),
              actions: [
                TextButton(
                  onPressed: () => Navigator.pop(context),
                  child: const Text('취소', style: TextStyle(color: Colors.grey)),
                ),
                ElevatedButton(
                  onPressed: () async {
                    final inputId = idController.text.trim();
                    if (inputId.isEmpty) return;
                    Navigator.pop(context);
                    final (_, message) = await _controller.updateStudentGrade(
                      studentId: inputId,
                      grade: grade,
                    );
                    if (!mounted) return;
                    ScaffoldMessenger.of(
                      context,
                    ).showSnackBar(SnackBar(content: Text(message)));
                  },
                  style: ElevatedButton.styleFrom(
                    backgroundColor: Colors.blue,
                    foregroundColor: Colors.white,
                    shape: RoundedRectangleBorder(
                      borderRadius: BorderRadius.circular(12),
                    ),
                  ),
                  child: const Text(
                    '적용',
                    style: TextStyle(fontWeight: FontWeight.bold),
                  ),
                ),
              ],
            );
          },
        );
      },
    );
  }

  // ❌ [학생 삭제 버튼 동작]
  Future<void> _deleteStudentAccount(String studentId) async {
    final (_, message) = await _controller.deleteStudentAccount(studentId);
    if (!mounted) return;
    ScaffoldMessenger.of(
      context,
    ).showSnackBar(SnackBar(content: Text(message)));
  }

  // 🚨 계정 삭제 확인 팝업창 모달
  void _showDeleteDialog() {
    final TextEditingController deleteIdController = TextEditingController();
    showDialog(
      context: context,
      builder: (context) {
        return AlertDialog(
          shape: RoundedRectangleBorder(
            borderRadius: BorderRadius.circular(24),
          ),
          title: Row(
            children: [
              Icon(Icons.warning_amber_rounded, color: Colors.orange[700]),
              const SizedBox(width: 10),
              const Text(
                '학생 계정 강제 삭제',
                style: TextStyle(fontWeight: FontWeight.bold, fontSize: 18),
              ),
            ],
          ),
          content: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              const Text(
                '영구 삭제할 학생의 학번을 정확하게 입력하세요.',
                style: TextStyle(color: Colors.black54, fontSize: 13),
              ),
              const SizedBox(height: 16),
              TextField(
                controller: deleteIdController,
                keyboardType: TextInputType.number,
                decoration: InputDecoration(
                  labelText: '학번 입력',
                  labelStyle: TextStyle(color: Colors.orange[700]),
                  focusedBorder: OutlineInputBorder(
                    borderRadius: BorderRadius.circular(16),
                    borderSide: BorderSide(
                      color: Colors.orange[700]!,
                      width: 2,
                    ),
                  ),
                  border: OutlineInputBorder(
                    borderRadius: BorderRadius.circular(16),
                  ),
                  prefixIcon: const Icon(Icons.no_accounts_rounded),
                ),
              ),
            ],
          ),
          actions: [
            TextButton(
              onPressed: () => Navigator.pop(context),
              child: const Text('취소', style: TextStyle(color: Colors.grey)),
            ),
            ElevatedButton(
              onPressed: () {
                final inputId = deleteIdController.text.trim();
                if (inputId.isNotEmpty) {
                  Navigator.pop(context);
                  _deleteStudentAccount(inputId);
                }
              },
              style: ElevatedButton.styleFrom(
                backgroundColor: Colors.orange[700],
                foregroundColor: Colors.white,
                shape: RoundedRectangleBorder(
                  borderRadius: BorderRadius.circular(12),
                ),
              ),
              child: const Text(
                '삭제 확정',
                style: TextStyle(fontWeight: FontWeight.bold),
              ),
            ),
          ],
        );
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    return ListenableBuilder(
      listenable: _controller,
      builder: (context, _) {
        return Scaffold(
          backgroundColor: Colors.grey[100],
          appBar: AppBar(
            title: const Text(
              '⚙️ 학생 통합 관리 센터',
              style: TextStyle(fontWeight: FontWeight.bold),
            ),
            backgroundColor: Colors.orange,
            foregroundColor: Colors.white,
            elevation: 0,
          ),
          body: SingleChildScrollView(
            padding: const EdgeInsets.all(24.0),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                // 🏷️ 인디케이터 바 1 (추가 메뉴)
                Row(
                  children: [
                    Container(
                      width: 4,
                      height: 16,
                      decoration: BoxDecoration(
                        color: Colors.orange,
                        borderRadius: BorderRadius.circular(2),
                      ),
                    ),
                    const SizedBox(width: 8),
                    const Text(
                      '신규 학생 계정 추가',
                      style: TextStyle(
                        fontSize: 18,
                        fontWeight: FontWeight.bold,
                      ),
                    ),
                  ],
                ),
                const SizedBox(height: 16),

                // 📝 학생 추가 컨테이너 폼
                Container(
                  padding: const EdgeInsets.all(20),
                  decoration: BoxDecoration(
                    color: Colors.white,
                    borderRadius: BorderRadius.circular(24),
                    boxShadow: [
                      BoxShadow(
                        color: Colors.black.withValues(alpha: 0.04),
                        blurRadius: 16,
                      ),
                    ],
                  ),
                  child: Column(
                    children: [
                      TextField(
                        controller: _addIdController,
                        keyboardType: TextInputType.number,
                        decoration: const InputDecoration(
                          labelText: '학번',
                          prefixIcon: Icon(Icons.badge),
                        ),
                      ),
                      const SizedBox(height: 12),
                      TextField(
                        controller: _addNameController,
                        decoration: const InputDecoration(
                          labelText: '이름',
                          prefixIcon: Icon(Icons.person),
                        ),
                      ),
                      const SizedBox(height: 12),
                      TextField(
                        controller: _addPwController,
                        obscureText: true,
                        decoration: const InputDecoration(
                          labelText: '초기 비밀번호',
                          prefixIcon: Icon(Icons.lock),
                        ),
                      ),
                      const SizedBox(height: 12),
                      DropdownButtonFormField<int>(
                        initialValue: _selectedGrade,
                        decoration: const InputDecoration(
                          labelText: '학년 (선택)',
                          prefixIcon: Icon(Icons.class_),
                        ),
                        items: const [
                          DropdownMenuItem(value: 1, child: Text('1학년')),
                          DropdownMenuItem(value: 2, child: Text('2학년')),
                          DropdownMenuItem(value: 3, child: Text('3학년')),
                        ],
                        onChanged: (value) =>
                            setState(() => _selectedGrade = value),
                      ),
                      const SizedBox(height: 20),
                      SizedBox(
                        width: double.infinity,
                        height: 50,
                        child: ElevatedButton(
                          onPressed: _controller.isWorking
                              ? null
                              : _addStudentAccount,
                          style: ElevatedButton.styleFrom(
                            backgroundColor: Colors.orange,
                            foregroundColor: Colors.white,
                            shape: RoundedRectangleBorder(
                              borderRadius: BorderRadius.circular(12),
                            ),
                          ),
                          child: _controller.isWorking
                              ? const CircularProgressIndicator(
                                  color: Colors.white,
                                )
                              : const Text(
                                  '학생 등록 완료',
                                  style: TextStyle(
                                    fontWeight: FontWeight.bold,
                                    fontSize: 15,
                                  ),
                                ),
                        ),
                      ),
                    ],
                  ),
                ),
                const SizedBox(height: 36),

                // 🏷️ 인디케이터 바 (엑셀 일괄 등록)
                Row(
                  children: [
                    Container(
                      width: 4,
                      height: 16,
                      decoration: BoxDecoration(
                        color: Colors.orange,
                        borderRadius: BorderRadius.circular(2),
                      ),
                    ),
                    const SizedBox(width: 8),
                    const Text(
                      '엑셀로 한번에 추가 (신입생 등)',
                      style: TextStyle(
                        fontSize: 18,
                        fontWeight: FontWeight.bold,
                      ),
                    ),
                  ],
                ),
                const SizedBox(height: 16),

                DropTarget(
                  onDragEntered: (_) => setState(() => _isDragging = true),
                  onDragExited: (_) => setState(() => _isDragging = false),
                  onDragDone: (details) async {
                    setState(() => _isDragging = false);
                    if (details.files.isEmpty) return;
                    final bytes = await details.files.first.readAsBytes();
                    if (!mounted) return;
                    await _handleExcelBytes(bytes);
                  },
                  child: InkWell(
                    onTap: _pickExcelFile,
                    borderRadius: BorderRadius.circular(24),
                    child: Container(
                      width: double.infinity,
                      padding: const EdgeInsets.symmetric(vertical: 28),
                      decoration: BoxDecoration(
                        color: _isDragging ? Colors.orange[50] : Colors.white,
                        borderRadius: BorderRadius.circular(24),
                        border: Border.all(
                          color: _isDragging
                              ? Colors.orange
                              : Colors.grey.shade300,
                          width: _isDragging ? 2 : 1,
                        ),
                      ),
                      child: Column(
                        children: [
                          Icon(
                            Icons.upload_file_rounded,
                            size: 40,
                            color: _isDragging
                                ? Colors.orange
                                : Colors.grey[400],
                          ),
                          const SizedBox(height: 12),
                          Text(
                            _isDragging ? '여기에 놓으세요' : '엑셀 파일을 드래그하거나 눌러서 선택',
                            style: TextStyle(
                              fontWeight: FontWeight.bold,
                              color: _isDragging
                                  ? Colors.orange[800]
                                  : Colors.black87,
                            ),
                          ),
                          const SizedBox(height: 4),
                          Text(
                            '.xlsx · 1행은 머리글, A열=학번 B열=이름 C열=학년(선택)',
                            style: TextStyle(
                              fontSize: 12,
                              color: Colors.grey[500],
                            ),
                            textAlign: TextAlign.center,
                          ),
                        ],
                      ),
                    ),
                  ),
                ),
                const SizedBox(height: 36),

                // 🏷️ 인디케이터 바 (기존 학생 학년 지정/변경)
                Row(
                  children: [
                    Container(
                      width: 4,
                      height: 16,
                      decoration: BoxDecoration(
                        color: Colors.blue,
                        borderRadius: BorderRadius.circular(2),
                      ),
                    ),
                    const SizedBox(width: 8),
                    const Text(
                      '기존 학생 학년 지정/변경',
                      style: TextStyle(
                        fontSize: 18,
                        fontWeight: FontWeight.bold,
                      ),
                    ),
                  ],
                ),
                const SizedBox(height: 16),

                InkWell(
                  onTap: _showUpdateGradeDialog,
                  borderRadius: BorderRadius.circular(24),
                  child: Container(
                    padding: const EdgeInsets.all(20),
                    decoration: BoxDecoration(
                      color: Colors.blue[50],
                      borderRadius: BorderRadius.circular(24),
                      border: Border.all(color: Colors.blue.shade200),
                    ),
                    child: const Row(
                      children: [
                        Icon(Icons.class_rounded, color: Colors.blue, size: 32),
                        SizedBox(width: 16),
                        Expanded(
                          child: Column(
                            crossAxisAlignment: CrossAxisAlignment.start,
                            children: [
                              Text(
                                '학번으로 학년 지정',
                                style: TextStyle(
                                  fontSize: 16,
                                  fontWeight: FontWeight.bold,
                                  color: Colors.blue,
                                ),
                              ),
                              SizedBox(height: 2),
                              Text(
                                '이미 만든 계정의 학년을 나중에 지정하거나 바꿀 때 사용',
                                style: TextStyle(
                                  fontSize: 12,
                                  color: Colors.blueAccent,
                                ),
                              ),
                            ],
                          ),
                        ),
                        Icon(
                          Icons.arrow_forward_ios_rounded,
                          color: Colors.blue,
                          size: 16,
                        ),
                      ],
                    ),
                  ),
                ),
                const SizedBox(height: 36),

                // 🏷️ 인디케이터 바 2 (삭제 권한 제어메뉴)
                Row(
                  children: [
                    Container(
                      width: 4,
                      height: 16,
                      decoration: BoxDecoration(
                        color: Colors.red,
                        borderRadius: BorderRadius.circular(2),
                      ),
                    ),
                    const SizedBox(width: 8),
                    const Text(
                      '위험 구역 (Account Reset)',
                      style: TextStyle(
                        fontSize: 18,
                        fontWeight: FontWeight.bold,
                        color: Colors.redAccent,
                      ),
                    ),
                  ],
                ),
                const SizedBox(height: 16),

                // 🚨 학생 삭제 트리거 카드
                InkWell(
                  onTap: _showDeleteDialog,
                  borderRadius: BorderRadius.circular(24),
                  child: Container(
                    padding: const EdgeInsets.all(20),
                    decoration: BoxDecoration(
                      color: Colors.red[50],
                      borderRadius: BorderRadius.circular(24),
                      border: Border.all(color: Colors.red.shade200),
                    ),
                    child: const Row(
                      children: [
                        Icon(
                          Icons.delete_sweep_rounded,
                          color: Colors.red,
                          size: 32,
                        ),
                        SizedBox(width: 16),
                        Expanded(
                          child: Column(
                            crossAxisAlignment: CrossAxisAlignment.start,
                            children: [
                              Text(
                                '학생 계정 강제 원격 삭제',
                                style: TextStyle(
                                  fontSize: 16,
                                  fontWeight: FontWeight.bold,
                                  color: Colors.red,
                                ),
                              ),
                              SizedBox(height: 2),
                              Text(
                                '인증 초기화 및 DB 제거용',
                                style: TextStyle(
                                  fontSize: 12,
                                  color: Colors.redAccent,
                                ),
                              ),
                            ],
                          ),
                        ),
                        Icon(
                          Icons.arrow_forward_ios_rounded,
                          color: Colors.red,
                          size: 16,
                        ),
                      ],
                    ),
                  ),
                ),
              ],
            ),
          ),
        );
      },
    );
  }
}