// 📋 실시간 출석 현황 화면. 전체 학생 명단(/api/users)과 출석 로그(/api/logs)를
// 합쳐서 출석/미출석 요약 카드 및 필터링된 목록을 3초마다 갱신해 보여준다.
import 'dart:async';
import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import '../config.dart';

// -----------------------------------------------------------------------------
// 📅 [서브 화면 1] 실시간 출석 확인 란 (StudentDashboard 카드 스타일 리스트화)
// -----------------------------------------------------------------------------
class TeacherAttendancePage extends StatefulWidget {
  const TeacherAttendancePage({super.key});

  @override
  State<TeacherAttendancePage> createState() => _TeacherAttendancePageState();
}

// 로그의 'name' 컬럼은 백엔드에서 "학생이름 (주머니정보)" 형태로 합쳐져 저장되어 있어서
// 이름과 주머니 번호를 분리해서 보여주려면 클라이언트에서 파싱해야 한다.
final RegExp _logNamePattern = RegExp(r'^(.*?)\s*\(([^)]*)\)$');

class _TeacherAttendancePageState extends State<TeacherAttendancePage> {
  List<dynamic> _roster = []; // 전체 학생 명단 (/api/users)
  List<dynamic> _logs = []; // 출석 로그 (/api/logs)
  Map<String, dynamic> _activeViolationsByStudentId = {}; // 무단반출 중인 학생 (/api/violations/active)
  Timer? _timer;
  bool _isLoading = true;
  bool _isRefreshing = false; // 새로고침 버튼 클릭 시 잠깐 도는 표시용
  String _filterType = "ALL"; // "ALL", "CHECKED_IN", "ABSENT"

  @override
  void initState() {
    super.initState();
    _fetchAll();
    _timer = Timer.periodic(const Duration(seconds: 3), (timer) => _fetchAll());
  }

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

  Future<void> _manualRefresh() async {
    setState(() => _isRefreshing = true);
    await _fetchAll();
    if (mounted) setState(() => _isRefreshing = false);
  }

  Future<void> _fetchAll() async {
    try {
      final results = await Future.wait([
        http.get(Uri.parse('$baseUrl/api/users')),
        http.get(Uri.parse('$baseUrl/api/logs')),
        http.get(Uri.parse('$baseUrl/api/violations/active')),
      ]);

      final usersRes = results[0];
      final logsRes = results[1];
      final violationsRes = results[2];

      if (usersRes.statusCode == 200 && logsRes.statusCode == 200) {
        final usersData = jsonDecode(utf8.decode(usersRes.bodyBytes));
        final logsData = jsonDecode(utf8.decode(logsRes.bodyBytes));

        Map<String, dynamic> activeViolations = {};
        if (violationsRes.statusCode == 200) {
          final violationsData = jsonDecode(utf8.decode(violationsRes.bodyBytes));
          for (final v in (violationsData['violations'] ?? [])) {
            activeViolations[v['student_id'].toString()] = v;
          }
        }

        setState(() {
          _roster = usersData['users'] ?? [];
          _logs = logsData['logs'] ?? [];
          _activeViolationsByStudentId = activeViolations;
          _isLoading = false;
        });
      } else {
        setState(() => _isLoading = false);
      }
    } catch (e) {
      setState(() => _isLoading = false);
    }
  }

  /// 🚨 선생님이 특정 학생에게 지금부터 N분간 반출을 허용한다.
  Future<void> _allowRemoval(String studentId, int minutes) async {
    try {
      final response = await http.post(
        Uri.parse('$baseUrl/api/violations/allow'),
        headers: {"Content-Type": "application/json"},
        body: jsonEncode({"studentId": studentId, "minutes": minutes}),
      );
      final result = jsonDecode(utf8.decode(response.bodyBytes));
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text(result['message'] ?? '처리되었습니다.')),
      );
      _fetchAll();
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('❌ 반출 허용 실패: $e')),
      );
    }
  }

  /// ⏰ 지금부터 N분간 전체 학생의 반출을 자동으로 허용한다 (쉬는시간 등).
  Future<void> _setPermissionWindow(int minutes) async {
    try {
      final response = await http.post(
        Uri.parse('$baseUrl/api/permissions/window'),
        headers: {"Content-Type": "application/json"},
        body: jsonEncode({"minutes": minutes}),
      );
      final result = jsonDecode(utf8.decode(response.bodyBytes));
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text(result['message'] ?? '처리되었습니다.')),
      );
      _fetchAll();
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('❌ 설정 실패: $e')),
      );
    }
  }

  void _showAllowDialog(String studentId, String studentName) {
    final controller = TextEditingController(text: "5");
    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: Text('$studentName 학생 반출 허용'),
        content: TextField(
          controller: controller,
          keyboardType: TextInputType.number,
          decoration: const InputDecoration(
            labelText: '허용 시간 (분)',
            border: OutlineInputBorder(),
          ),
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: const Text('취소'),
          ),
          ElevatedButton(
            onPressed: () {
              final minutes = int.tryParse(controller.text.trim()) ?? 5;
              Navigator.pop(context);
              _allowRemoval(studentId, minutes);
            },
            child: const Text('허용하기'),
          ),
        ],
      ),
    );
  }

  void _showPermissionWindowDialog() {
    final controller = TextEditingController(text: "10");
    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('⏰ 전체 학생 반출 허용 시간 설정'),
        content: Column(
          mainAxisSize: MainAxisSize.min,
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            const Text(
              '쉬는시간처럼 지금부터 일정 시간 동안 모든 학생의 반출을 자동으로 허용합니다.',
              style: TextStyle(fontSize: 13, color: Colors.grey),
            ),
            const SizedBox(height: 16),
            TextField(
              controller: controller,
              keyboardType: TextInputType.number,
              decoration: const InputDecoration(
                labelText: '지금부터 허용 시간 (분)',
                border: OutlineInputBorder(),
              ),
            ),
          ],
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: const Text('취소'),
          ),
          ElevatedButton(
            onPressed: () {
              final minutes = int.tryParse(controller.text.trim()) ?? 10;
              Navigator.pop(context);
              _setPermissionWindow(minutes);
            },
            child: const Text('설정하기'),
          ),
        ],
      ),
    );
  }

  /// 오늘 날짜 기준으로 학번별 "가장 최근 출석 기록"만 남긴 맵을 만든다.
  Map<String, Map<String, String>> get _todaysCheckInsByStudentId {
    final String todayPrefix = DateTime.now().toIso8601String().substring(
      0,
      10,
    ); // "YYYY-MM-DD"
    final Map<String, Map<String, String>> result = {};

    for (final log in _logs) {
      final String time = log['time']?.toString() ?? '';
      if (!time.startsWith(todayPrefix)) continue; // 오늘 기록이 아니면 무시

      final String studentId = log['student_id']?.toString() ?? '';
      if (studentId.isEmpty) continue;

      // 이미 더 최신 기록을 찾았다면(로그는 최신순 정렬) 건너뛴다.
      if (result.containsKey(studentId)) continue;

      final String rawName = log['name']?.toString() ?? '';
      final match = _logNamePattern.firstMatch(rawName);
      result[studentId] = {
        'name': match != null ? match.group(1)! : rawName,
        'pocketNumber': match != null ? match.group(2)! : '주머니 미지정',
        'time': time,
      };
    }
    return result;
  }

  List<Map<String, dynamic>> get _combinedStudentStatus {
    final checkIns = _todaysCheckInsByStudentId;
    return _roster.map((u) {
      final String id = u['id']?.toString() ?? '';
      final checkIn = checkIns[id];
      final violation = _activeViolationsByStudentId[id];
      return {
        'studentId': id,
        'studentName': u['name']?.toString() ?? '',
        'isCheckedIn': checkIn != null,
        'pocketNumber': checkIn?['pocketNumber'],
        'checkInTime': checkIn?['time'],
        'hasActiveViolation': violation != null,
        'violationPocket': violation?['pocket_number'],
        'violationTime': violation?['time'],
      };
    }).toList();
  }

  List<Map<String, dynamic>> get _filteredStudents {
    final all = _combinedStudentStatus;
    if (_filterType == "CHECKED_IN") {
      return all.where((s) => s['isCheckedIn'] == true).toList();
    } else if (_filterType == "ABSENT") {
      return all.where((s) => s['isCheckedIn'] == false).toList();
    }
    return all;
  }

  @override
  Widget build(BuildContext context) {
    final all = _combinedStudentStatus;
    final int totalCount = all.length;
    final int checkedInCount = all.where((s) => s['isCheckedIn'] == true).length;
    final int absentCount = totalCount - checkedInCount;

    return Scaffold(
      backgroundColor: Colors.grey[100],
      appBar: AppBar(
        title: const Text(
          '📋 실시간 출석 현황',
          style: TextStyle(fontWeight: FontWeight.bold),
        ),
        backgroundColor: Colors.blue,
        foregroundColor: Colors.white,
        elevation: 0,
        actions: [
          IconButton(
            onPressed: (_isLoading || _isRefreshing) ? null : _manualRefresh,
            icon: _isRefreshing
                ? const SizedBox(
                    width: 20,
                    height: 20,
                    child: CircularProgressIndicator(
                      strokeWidth: 2,
                      color: Colors.white,
                    ),
                  )
                : const Icon(Icons.refresh_rounded),
            tooltip: '새로고침',
          ),
          TextButton.icon(
            onPressed: _showPermissionWindowDialog,
            icon: const Icon(Icons.timer_outlined, color: Colors.white),
            label: const Text(
              '반출 허용 시간 설정',
              style: TextStyle(color: Colors.white),
            ),
          ),
          const SizedBox(width: 8),
        ],
      ),
      body: _isLoading
          ? const Center(child: CircularProgressIndicator())
          : LayoutBuilder(
              builder: (context, constraints) {
                final bool isWide = constraints.maxWidth >= 800;
                return isWide
                    ? _buildDesktopBody(totalCount, checkedInCount, absentCount)
                    : _buildMobileBody(totalCount, checkedInCount, absentCount);
              },
            ),
    );
  }

  // -----------------------------------------------------------------------
  // 📱 모바일 레이아웃 (기존 카드 리스트)
  // -----------------------------------------------------------------------
  Widget _buildMobileBody(int total, int checkedIn, int absent) {
    return Column(
      children: [
        _buildSummaryCards(total, checkedIn, absent),
        _buildFilterChips(),
        Expanded(
          child: _filteredStudents.isEmpty
              ? const Center(
                  child: Text(
                    '해당하는 학생이 없습니다.',
                    style: TextStyle(color: Colors.grey),
                  ),
                )
              : ListView.builder(
                  padding: const EdgeInsets.symmetric(vertical: 12),
                  itemCount: _filteredStudents.length,
                  itemBuilder: (context, index) {
                    final student = _filteredStudents[index];
                    final bool isCheckedIn = student['isCheckedIn'];
                    final bool hasViolation = student['hasActiveViolation'] == true;
                    return Container(
                      margin: const EdgeInsets.symmetric(
                        horizontal: 24,
                        vertical: 8,
                      ),
                      padding: const EdgeInsets.all(18),
                      decoration: BoxDecoration(
                        color: hasViolation ? Colors.red[50] : Colors.white,
                        borderRadius: BorderRadius.circular(20),
                        border: hasViolation
                            ? Border.all(color: Colors.red[300]!, width: 1.5)
                            : null,
                        boxShadow: [
                          BoxShadow(
                            color: Colors.black.withValues(alpha: 0.03),
                            blurRadius: 12,
                            offset: const Offset(0, 4),
                          ),
                        ],
                      ),
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          Row(
                            children: [
                              Container(
                                padding: const EdgeInsets.all(10),
                                decoration: BoxDecoration(
                                  color: (hasViolation
                                          ? Colors.red
                                          : (isCheckedIn ? Colors.blue : Colors.red))
                                      .withValues(alpha: 0.1),
                                  shape: BoxShape.circle,
                                ),
                                child: Icon(
                                  hasViolation
                                      ? Icons.warning_amber_rounded
                                      : (isCheckedIn
                                          ? Icons.check_circle_rounded
                                          : Icons.error_rounded),
                                  color: hasViolation
                                      ? Colors.red
                                      : (isCheckedIn ? Colors.blue : Colors.red),
                                  size: 24,
                                ),
                              ),
                              const SizedBox(width: 16),
                              Expanded(
                                child: Column(
                                  crossAxisAlignment: CrossAxisAlignment.start,
                                  children: [
                                    Text(
                                      '${student['studentName']} 학생',
                                      style: const TextStyle(
                                        fontWeight: FontWeight.bold,
                                        fontSize: 16,
                                      ),
                                    ),
                                    const SizedBox(height: 4),
                                    Text(
                                      hasViolation
                                          ? '🚨 무단반출 감지! (${student['violationTime']})'
                                          : (isCheckedIn
                                              ? '학번: ${student['studentId']} | 제출시간: ${student['checkInTime']}'
                                              : '학번: ${student['studentId']} | 미제출'),
                                      style: TextStyle(
                                        color: hasViolation
                                            ? Colors.red[700]
                                            : (isCheckedIn
                                                ? Colors.grey[600]
                                                : Colors.red[400]),
                                        fontSize: 12,
                                        fontWeight: hasViolation
                                            ? FontWeight.bold
                                            : FontWeight.normal,
                                      ),
                                    ),
                                  ],
                                ),
                              ),
                              if (isCheckedIn && student['pocketNumber'] != null)
                                Container(
                                  padding: const EdgeInsets.symmetric(
                                    horizontal: 12,
                                    vertical: 6,
                                  ),
                                  decoration: BoxDecoration(
                                    color: Colors.blue.shade50,
                                    borderRadius: BorderRadius.circular(20),
                                    border:
                                        Border.all(color: Colors.blue.shade200),
                                  ),
                                  child: Text(
                                    student['pocketNumber'],
                                    style: const TextStyle(
                                      fontWeight: FontWeight.bold,
                                      color: Colors.blueAccent,
                                      fontSize: 12,
                                    ),
                                  ),
                                ),
                            ],
                          ),
                          if (hasViolation)
                            Padding(
                              padding: const EdgeInsets.only(top: 12),
                              child: SizedBox(
                                width: double.infinity,
                                child: ElevatedButton.icon(
                                  onPressed: () => _showAllowDialog(
                                    student['studentId'],
                                    student['studentName'],
                                  ),
                                  icon: const Icon(Icons.check, size: 18),
                                  label: const Text('반출 허용'),
                                  style: ElevatedButton.styleFrom(
                                    backgroundColor: Colors.red[600],
                                    foregroundColor: Colors.white,
                                  ),
                                ),
                              ),
                            ),
                        ],
                      ),
                    );
                  },
                ),
        ),
      ],
    );
  }

  // -----------------------------------------------------------------------
  // 🖥️ 데스크톱 레이아웃 (선생님이 교실 컴퓨터 브라우저로 접속했을 때)
  // -----------------------------------------------------------------------
  Widget _buildDesktopBody(int total, int checkedIn, int absent) {
    return Center(
      child: ConstrainedBox(
        constraints: const BoxConstraints(maxWidth: 1100),
        child: Padding(
          padding: const EdgeInsets.all(24.0),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Row(
                children: [
                  Expanded(
                    child: _statTile(
                      "전체 학생",
                      "$total명",
                      Icons.groups_rounded,
                      Colors.blueGrey,
                    ),
                  ),
                  const SizedBox(width: 16),
                  Expanded(
                    child: _statTile(
                      "출석 완료",
                      "$checkedIn명",
                      Icons.check_circle_rounded,
                      Colors.green,
                    ),
                  ),
                  const SizedBox(width: 16),
                  Expanded(
                    child: _statTile(
                      "미출석",
                      "$absent명",
                      Icons.error_rounded,
                      Colors.red,
                    ),
                  ),
                ],
              ),
              const SizedBox(height: 20),
              _buildFilterChips(),
              const SizedBox(height: 12),
              Expanded(
                child: Container(
                  width: double.infinity,
                  decoration: BoxDecoration(
                    color: Colors.white,
                    borderRadius: BorderRadius.circular(16),
                    boxShadow: [
                      BoxShadow(
                        color: Colors.black.withValues(alpha: 0.04),
                        blurRadius: 16,
                        offset: const Offset(0, 4),
                      ),
                    ],
                  ),
                  child: _filteredStudents.isEmpty
                      ? const Center(
                          child: Text(
                            '해당하는 학생이 없습니다.',
                            style: TextStyle(color: Colors.grey),
                          ),
                        )
                      : SingleChildScrollView(
                          child: DataTable(
                            headingRowColor: WidgetStateProperty.all(
                              Colors.grey[50],
                            ),
                            columns: const [
                              DataColumn(label: Text('상태')),
                              DataColumn(label: Text('학번')),
                              DataColumn(label: Text('이름')),
                              DataColumn(label: Text('제출 시간')),
                              DataColumn(label: Text('주머니 번호')),
                              DataColumn(label: Text('작업')),
                            ],
                            rows: _filteredStudents.map((student) {
                              final bool isCheckedIn = student['isCheckedIn'];
                              final bool hasViolation =
                                  student['hasActiveViolation'] == true;
                              return DataRow(
                                color: hasViolation
                                    ? WidgetStateProperty.all(Colors.red[50])
                                    : null,
                                cells: [
                                  DataCell(
                                    Icon(
                                      hasViolation
                                          ? Icons.warning_amber_rounded
                                          : (isCheckedIn
                                              ? Icons.check_circle_rounded
                                              : Icons.error_rounded),
                                      color: hasViolation
                                          ? Colors.red
                                          : (isCheckedIn
                                              ? Colors.blue
                                              : Colors.red),
                                      size: 20,
                                    ),
                                  ),
                                  DataCell(Text('${student['studentId']}')),
                                  DataCell(
                                    Text(
                                      '${student['studentName']}',
                                      style: const TextStyle(
                                        fontWeight: FontWeight.bold,
                                      ),
                                    ),
                                  ),
                                  DataCell(
                                    Text(
                                      hasViolation
                                          ? '🚨 무단반출 (${student['violationTime']})'
                                          : (isCheckedIn
                                              ? '${student['checkInTime']}'
                                              : '미제출'),
                                      style: TextStyle(
                                        color: hasViolation
                                            ? Colors.red[700]
                                            : (isCheckedIn
                                                ? Colors.grey[700]
                                                : Colors.red[400]),
                                        fontWeight: hasViolation
                                            ? FontWeight.bold
                                            : FontWeight.normal,
                                      ),
                                    ),
                                  ),
                                  DataCell(
                                    isCheckedIn && student['pocketNumber'] != null
                                        ? Container(
                                            padding: const EdgeInsets.symmetric(
                                              horizontal: 10,
                                              vertical: 4,
                                            ),
                                            decoration: BoxDecoration(
                                              color: Colors.blue.shade50,
                                              borderRadius:
                                                  BorderRadius.circular(20),
                                              border: Border.all(
                                                color: Colors.blue.shade200,
                                              ),
                                            ),
                                            child: Text(
                                              student['pocketNumber'],
                                              style: const TextStyle(
                                                fontWeight: FontWeight.bold,
                                                color: Colors.blueAccent,
                                                fontSize: 12,
                                              ),
                                            ),
                                          )
                                        : const Text('-'),
                                  ),
                                  DataCell(
                                    hasViolation
                                        ? ElevatedButton.icon(
                                            onPressed: () => _showAllowDialog(
                                              student['studentId'],
                                              student['studentName'],
                                            ),
                                            icon: const Icon(
                                              Icons.check,
                                              size: 16,
                                            ),
                                            label: const Text('반출 허용'),
                                            style: ElevatedButton.styleFrom(
                                              backgroundColor: Colors.red[600],
                                              foregroundColor: Colors.white,
                                              padding:
                                                  const EdgeInsets.symmetric(
                                                horizontal: 12,
                                              ),
                                            ),
                                          )
                                        : const Text('-'),
                                  ),
                                ],
                              );
                            }).toList(),
                          ),
                        ),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }

  Widget _statTile(String label, String value, IconData icon, Color color) {
    return Container(
      padding: const EdgeInsets.all(20),
      decoration: BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.circular(16),
        boxShadow: [
          BoxShadow(
            color: Colors.black.withValues(alpha: 0.04),
            blurRadius: 12,
            offset: const Offset(0, 4),
          ),
        ],
      ),
      child: Row(
        children: [
          Container(
            padding: const EdgeInsets.all(12),
            decoration: BoxDecoration(
              color: color.withValues(alpha: 0.1),
              borderRadius: BorderRadius.circular(12),
            ),
            child: Icon(icon, color: color, size: 26),
          ),
          const SizedBox(width: 14),
          Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                label,
                style: TextStyle(color: Colors.grey[600], fontSize: 13),
              ),
              const SizedBox(height: 2),
              Text(
                value,
                style: TextStyle(
                  color: color,
                  fontSize: 22,
                  fontWeight: FontWeight.bold,
                ),
              ),
            ],
          ),
        ],
      ),
    );
  }

  /// 📊 상단 요약 카드 뷰 (전체 / 출석 완료 / 미출석)
  Widget _buildSummaryCards(int total, int checkedIn, int absent) {
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.all(16),
      color: const Color(0xFF1E293B),
      child: Row(
        mainAxisAlignment: MainAxisAlignment.spaceAround,
        children: [
          _summaryCard("전체", "$total명", Colors.white70),
          _summaryCard("출석 완료", "$checkedIn명", Colors.greenAccent),
          _summaryCard("미출석", "$absent명", Colors.redAccent),
        ],
      ),
    );
  }

  Widget _summaryCard(String title, String count, Color color) {
    return Column(
      children: [
        Text(title, style: const TextStyle(color: Colors.grey, fontSize: 12)),
        const SizedBox(height: 4),
        Text(
          count,
          style: TextStyle(
            color: color,
            fontSize: 20,
            fontWeight: FontWeight.bold,
          ),
        ),
      ],
    );
  }

  /// 🔘 필터 칩버튼 (전체 / 출석자 / 미출석자)
  Widget _buildFilterChips() {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 8, horizontal: 16),
      child: Row(
        children: [
          FilterChip(
            label: const Text("전체"),
            selected: _filterType == "ALL",
            onSelected: (_) => setState(() => _filterType = "ALL"),
          ),
          const SizedBox(width: 8),
          FilterChip(
            label: const Text("🟢 출석자"),
            selected: _filterType == "CHECKED_IN",
            onSelected: (_) => setState(() => _filterType = "CHECKED_IN"),
          ),
          const SizedBox(width: 8),
          FilterChip(
            label: const Text("🔴 미출석자"),
            selected: _filterType == "ABSENT",
            onSelected: (_) => setState(() => _filterType = "ABSENT"),
          ),
        ],
      ),
    );
  }
}