// 📋 실시간 출석 현황 화면 (UI 전용). 위젯 빌드/레이아웃/스타일만 담당하고,
// 서버 통신·상태·파생 로직은 lib/function/teacher_attendance_controller.dart가 담당한다.
import 'package:flutter/material.dart';
import '../function/teacher_attendance_controller.dart';
import '../theme/app_palette.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();
}

class _TeacherAttendancePageState extends State<TeacherAttendancePage> {
  final TeacherAttendanceController _controller = TeacherAttendanceController();

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

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

  /// 컨트롤러 액션을 실행하고, 결과 메시지를 스낵바로 보여준다.
  Future<void> _runAction(Future<String> Function() action) async {
    final message = await action();
    if (!mounted) return;
    ScaffoldMessenger.of(
      context,
    ).showSnackBar(SnackBar(content: Text(message)));
  }

  Future<void> _showAttendanceTimeDialog() async {
    final String? current = _controller.attendanceTime;
    final TimeOfDay initial = current != null
        ? TimeOfDay(
            hour: int.parse(current.split(':')[0]),
            minute: int.parse(current.split(':')[1]),
          )
        : const TimeOfDay(hour: 19, minute: 0);

    final TimeOfDay? picked = await showTimePicker(
      context: context,
      initialTime: initial,
      helpText: '자습실 출석시간 지정',
    );
    if (picked == null) return;

    final String formatted =
        '${picked.hour.toString().padLeft(2, '0')}:${picked.minute.toString().padLeft(2, '0')}';
    await _runAction(() => _controller.setAttendanceTime(formatted));
  }

  void _showTestResetConfirmDialog() {
    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('테스트용 허용시간 초기화'),
        content: const Text(
          '하교 처리나 반출 허용 시간 설정으로 켜져 있는 모든 허용 시간대를 지금 즉시 해제합니다.\n'
          '(무단반출 감지 테스트할 때만 사용하세요)',
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: const Text('취소'),
          ),
          ElevatedButton(
            onPressed: () {
              Navigator.pop(context);
              _runAction(() => _controller.resetTestPermissions());
            },
            style: ElevatedButton.styleFrom(
              backgroundColor: Colors.grey[700],
              foregroundColor: Colors.white,
            ),
            child: const Text('초기화'),
          ),
        ],
      ),
    );
  }

  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);
              _runAction(() => _controller.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);
              _runAction(() => _controller.setPermissionWindow(minutes));
            },
            child: const Text('설정하기'),
          ),
        ],
      ),
    );
  }

  /// 🏫 하교 처리: 시간 입력 없이 바로 전체 학생의 반출을 (사실상 무기한) 허용한다.
  void _showDismissalConfirmDialog() {
    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('하교 처리'),
        content: const Text(
          '지금부터 모든 학생의 반출이 자동으로 허용되며, 더 이상 무단반출 경고가 뜨지 않습니다.\n하교 처리하시겠습니까?',
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: const Text('취소'),
          ),
          ElevatedButton(
            onPressed: () {
              Navigator.pop(context);
              _runAction(() => _controller.dismissAll());
            },
            child: const Text('하교 처리'),
          ),
        ],
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return ListenableBuilder(
      listenable: _controller,
      builder: (context, _) {
        final all = _controller.combinedStudentStatus;
        final int totalCount = all.length;
        final int checkedInCount = all
            .where((s) => s['isAttendanceComplete'] == true)
            .length;
        final int absentCount = totalCount - checkedInCount;

        return Scaffold(
          backgroundColor: AppPalette.mist,
          appBar: AppBar(
            title: const Text(
              '실시간 출석 현황',
              style: TextStyle(fontWeight: FontWeight.bold),
            ),
            backgroundColor: AppPalette.ink,
            foregroundColor: Colors.white,
            elevation: 0,
            actions: [
              IconButton(
                onPressed: (_controller.isLoading || _controller.isRefreshing)
                    ? null
                    : _controller.manualRefresh,
                icon: _controller.isRefreshing
                    ? const SizedBox(
                        width: 20,
                        height: 20,
                        child: CircularProgressIndicator(
                          strokeWidth: 2,
                          color: Colors.white,
                        ),
                      )
                    : const Icon(Icons.refresh_rounded),
                tooltip: '새로고침',
              ),
              TextButton.icon(
                onPressed: _showAttendanceTimeDialog,
                icon: const Icon(
                  Icons.access_time_rounded,
                  color: Colors.white,
                ),
                label: Text(
                  _controller.attendanceTime != null
                      ? '출석시간 ${_controller.attendanceTime}'
                      : '자습실 출석시간 설정',
                  style: const TextStyle(color: Colors.white),
                ),
              ),
              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),
                ),
              ),
              TextButton.icon(
                onPressed: _showDismissalConfirmDialog,
                icon: const Icon(Icons.school_rounded, color: Colors.white),
                label: const Text('하교', style: TextStyle(color: Colors.white)),
              ),
              IconButton(
                onPressed: _showTestResetConfirmDialog,
                icon: const Icon(
                  Icons.bug_report_outlined,
                  color: Colors.white70,
                ),
                tooltip: '테스트용: 허용시간 초기화',
              ),
              const SizedBox(width: 8),
            ],
          ),
          body: _controller.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) {
    final groups = _controller.studentsByGrade;
    return Column(
      children: [
        _buildSummaryCards(total, checkedIn, absent),
        _buildPermissionBanner(),
        _buildFilterChips(),
        Expanded(
          child: groups.isEmpty
              ? const Center(
                  child: Text(
                    '해당하는 학생이 없습니다.',
                    style: TextStyle(color: Colors.grey),
                  ),
                )
              : _buildGradeGroupedList(
                  groups,
                  padding: const EdgeInsets.fromLTRB(16, 12, 16, 16),
                ),
        ),
      ],
    );
  }

  /// 🏫 학년별로 섹션 제목을 붙여 그리드를 이어붙인 목록. 모바일/데스크톱 공용.
  Widget _buildGradeGroupedList(
    List<MapEntry<String, List<Map<String, dynamic>>>> groups, {
    required EdgeInsets padding,
  }) {
    return ListView.builder(
      padding: padding,
      itemCount: groups.length,
      itemBuilder: (context, index) {
        final group = groups[index];
        return Padding(
          padding: EdgeInsets.only(bottom: index == groups.length - 1 ? 0 : 24),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Row(
                children: [
                  Container(
                    width: 4,
                    height: 16,
                    decoration: BoxDecoration(
                      color: AppPalette.ink,
                      borderRadius: BorderRadius.circular(2),
                    ),
                  ),
                  const SizedBox(width: 8),
                  Text(
                    group.key,
                    style: const TextStyle(
                      fontSize: 16,
                      fontWeight: FontWeight.bold,
                      color: AppPalette.ink,
                    ),
                  ),
                  const SizedBox(width: 6),
                  Text(
                    '${group.value.length}명',
                    style: TextStyle(fontSize: 13, color: Colors.grey[500]),
                  ),
                ],
              ),
              const SizedBox(height: 10),
              GridView.builder(
                shrinkWrap: true,
                physics: const NeverScrollableScrollPhysics(),
                gridDelegate: const SliverGridDelegateWithMaxCrossAxisExtent(
                  maxCrossAxisExtent: 220,
                  mainAxisSpacing: 12,
                  crossAxisSpacing: 12,
                  mainAxisExtent: 148,
                ),
                itemCount: group.value.length,
                itemBuilder: (context, i) => _buildStudentTile(group.value[i]),
              ),
            ],
          ),
        );
      },
    );
  }

  /// 🀄 학생 한 명을 "한눈에 보기" 타일로 그린다. 모바일/데스크톱 그리드에서 공용으로 쓴다.
  Widget _buildStudentTile(Map<String, dynamic> student) {
    final bool isCheckedIn = student['isCheckedIn'];
    final bool hasViolation = student['hasActiveViolation'] == true;
    final bool isPending = student['attendanceStatus'] == 'PENDING';
    final bool isComplete = student['attendanceStatus'] == 'COMPLETE';
    final Color statusColor = hasViolation
        ? Colors.red
        : (isPending ? Colors.orange : (isComplete ? Colors.blue : Colors.red));
    final String statusLine = hasViolation
        ? '무단반출 (${student['violationTime']})'
        : (isPending
              ? '미완료 (${student['checkInTime']})'
              : (isComplete
                    ? '${student['checkInTime']}'
                    : (student['hasEverCheckedIn'] == true ? '미제출' : '미등록')));

    return Container(
      padding: const EdgeInsets.all(14),
      decoration: BoxDecoration(
        color: hasViolation ? Colors.red[50] : AppPalette.paper,
        borderRadius: BorderRadius.circular(20),
        border: Border.all(
          color: hasViolation ? Colors.red[300]! : AppPalette.sage,
          width: hasViolation ? 1.5 : 1,
        ),
        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(8),
                decoration: BoxDecoration(
                  color: statusColor.withValues(alpha: 0.1),
                  shape: BoxShape.circle,
                ),
                child: Icon(
                  hasViolation
                      ? Icons.warning_amber_rounded
                      : (isPending
                            ? Icons.hourglass_bottom_rounded
                            : (isComplete
                                  ? Icons.check_circle_rounded
                                  : Icons.error_rounded)),
                  color: statusColor,
                  size: 18,
                ),
              ),
              const Spacer(),
              if (isCheckedIn && student['pocketNumber'] != null)
                Container(
                  padding: const EdgeInsets.symmetric(
                    horizontal: 8,
                    vertical: 3,
                  ),
                  decoration: BoxDecoration(
                    color: AppPalette.linen,
                    borderRadius: BorderRadius.circular(20),
                    border: Border.all(color: AppPalette.sage),
                  ),
                  child: Text(
                    student['pocketNumber'],
                    style: const TextStyle(
                      fontWeight: FontWeight.bold,
                      color: AppPalette.ink,
                      fontSize: 11,
                    ),
                  ),
                ),
            ],
          ),
          const SizedBox(height: 8),
          Text(
            '${student['studentName']}',
            maxLines: 1,
            overflow: TextOverflow.ellipsis,
            style: const TextStyle(fontWeight: FontWeight.bold, fontSize: 15),
          ),
          Text(
            '학번 ${student['studentId']}',
            style: TextStyle(color: Colors.grey[500], fontSize: 11),
          ),
          const SizedBox(height: 4),
          Text(
            statusLine,
            maxLines: 2,
            overflow: TextOverflow.ellipsis,
            style: TextStyle(
              color: hasViolation
                  ? Colors.red[700]
                  : (isPending
                        ? Colors.orange[800]
                        : (isComplete ? Colors.grey[600] : Colors.red[400])),
              fontSize: 11.5,
              fontWeight: hasViolation ? FontWeight.bold : FontWeight.normal,
            ),
          ),
          if (hasViolation) ...[
            const Spacer(),
            SizedBox(
              width: double.infinity,
              height: 30,
              child: ElevatedButton(
                onPressed: () => _showAllowDialog(
                  student['studentId'],
                  student['studentName'],
                ),
                style: ElevatedButton.styleFrom(
                  backgroundColor: Colors.red[600],
                  foregroundColor: Colors.white,
                  padding: EdgeInsets.zero,
                ),
                child: const Text('반출 허용', style: TextStyle(fontSize: 12)),
              ),
            ),
          ],
        ],
      ),
    );
  }

  // -----------------------------------------------------------------------
  // 🖥️ 데스크톱 레이아웃 (선생님이 교실 컴퓨터 브라우저로 접속했을 때)
  // -----------------------------------------------------------------------
  Widget _buildDesktopBody(int total, int checkedIn, int absent) {
    final groups = _controller.studentsByGrade;
    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),
              _buildPermissionBanner(),
              _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: groups.isEmpty
                      ? const Center(
                          child: Text(
                            '해당하는 학생이 없습니다.',
                            style: TextStyle(color: Colors.grey),
                          ),
                        )
                      : _buildGradeGroupedList(
                          groups,
                          padding: const EdgeInsets.all(20),
                        ),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }

  Widget _statTile(String label, String value, IconData icon, Color color) {
    return Container(
      padding: const EdgeInsets.all(20),
      decoration: BoxDecoration(
        color: AppPalette.paper,
        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: AppPalette.ink,
      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,
          ),
        ),
      ],
    );
  }

  /// 🔓 하교(12시간)/반출 허용 시간 설정으로 지금 전체 반출이 허용 중이면 눈에 띄게 배너로 알려준다.
  /// (허용 중일 땐 무단반출을 감지해도 대시보드에 뜨지 않기 때문에, 왜 안 뜨는지 헷갈리지 않게 하기 위함)
  Widget _buildPermissionBanner() {
    final String? until = _controller.globalPermissionUntil;
    if (until == null) return const SizedBox.shrink();

    return Container(
      width: double.infinity,
      margin: const EdgeInsets.fromLTRB(16, 8, 16, 0),
      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 10),
      decoration: BoxDecoration(
        color: Colors.amber[100],
        borderRadius: BorderRadius.circular(12),
        border: Border.all(color: Colors.amber[400]!),
      ),
      child: Row(
        children: [
          Icon(Icons.lock_open_rounded, color: Colors.amber[800], size: 20),
          const SizedBox(width: 8),
          Expanded(
            child: Text(
              '지금 전체 반출 허용 중입니다 ($until 까지) — 이 시간 동안은 무단반출 경고가 뜨지 않아요.',
              style: TextStyle(
                color: Colors.amber[900],
                fontWeight: FontWeight.bold,
                fontSize: 12.5,
              ),
            ),
          ),
        ],
      ),
    );
  }

  /// 🔘 필터 칩버튼 (전체 / 출석자 / 미출석자)
  Widget _buildFilterChips() {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 8, horizontal: 16),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Wrap(
            spacing: 8,
            runSpacing: 8,
            children: [
              FilterChip(
                label: const Text("전체"),
                selected: _controller.filterType == "ALL",
                onSelected: (_) => _controller.setFilter("ALL"),
              ),
              FilterChip(
                label: const Text("출석자"),
                selected: _controller.filterType == "CHECKED_IN",
                onSelected: (_) => _controller.setFilter("CHECKED_IN"),
              ),
              FilterChip(
                label: const Text("미출석자"),
                selected: _controller.filterType == "ABSENT",
                onSelected: (_) => _controller.setFilter("ABSENT"),
              ),
            ],
          ),
          const SizedBox(height: 8),
          Wrap(
            spacing: 8,
            runSpacing: 8,
            children: [
              ChoiceChip(
                label: const Text("학년 전체"),
                selected: _controller.gradeFilter == "ALL",
                onSelected: (_) => _controller.setGradeFilter("ALL"),
              ),
              ChoiceChip(
                label: const Text("1학년"),
                selected: _controller.gradeFilter == "1",
                onSelected: (_) => _controller.setGradeFilter("1"),
              ),
              ChoiceChip(
                label: const Text("2학년"),
                selected: _controller.gradeFilter == "2",
                onSelected: (_) => _controller.setGradeFilter("2"),
              ),
              ChoiceChip(
                label: const Text("3학년"),
                selected: _controller.gradeFilter == "3",
                onSelected: (_) => _controller.setGradeFilter("3"),
              ),
            ],
          ),
        ],
      ),
    );
  }
}