// 📋 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)
  Timer? _timer;
  bool _isLoading = true;
  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> _fetchAll() async {
    try {
      final results = await Future.wait([
        http.get(Uri.parse('$baseUrl/api/users')),
        http.get(Uri.parse('$baseUrl/api/logs')),
      ]);

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

      if (usersRes.statusCode == 200 && logsRes.statusCode == 200) {
        final usersData = jsonDecode(utf8.decode(usersRes.bodyBytes));
        final logsData = jsonDecode(utf8.decode(logsRes.bodyBytes));
        setState(() {
          _roster = usersData['users'] ?? [];
          _logs = logsData['logs'] ?? [];
          _isLoading = false;
        });
      } else {
        setState(() => _isLoading = false);
      }
    } catch (e) {
      setState(() => _isLoading = false);
    }
  }

  /// 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];
      return {
        'studentId': id,
        'studentName': u['name']?.toString() ?? '',
        'isCheckedIn': checkIn != null,
        'pocketNumber': checkIn?['pocketNumber'],
        'checkInTime': checkIn?['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,
      ),
      body: _isLoading
          ? const Center(child: CircularProgressIndicator())
          : Column(
              children: [
                _buildSummaryCards(totalCount, checkedInCount, absentCount),
                _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'];
                            return Container(
                              margin: const EdgeInsets.symmetric(
                                horizontal: 24,
                                vertical: 8,
                              ),
                              padding: const EdgeInsets.all(18),
                              decoration: BoxDecoration(
                                color: Colors.white,
                                borderRadius: BorderRadius.circular(20),
                                boxShadow: [
                                  BoxShadow(
                                    color: Colors.black.withValues(alpha: 0.03),
                                    blurRadius: 12,
                                    offset: const Offset(0, 4),
                                  ),
                                ],
                              ),
                              child: Row(
                                children: [
                                  Container(
                                    padding: const EdgeInsets.all(10),
                                    decoration: BoxDecoration(
                                      color: (isCheckedIn
                                              ? Colors.blue
                                              : Colors.red)
                                          .withValues(alpha: 0.1),
                                      shape: BoxShape.circle,
                                    ),
                                    child: Icon(
                                      isCheckedIn
                                          ? Icons.check_circle_rounded
                                          : Icons.error_rounded,
                                      color: 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(
                                          isCheckedIn
                                              ? '학번: ${student['studentId']} | 제출시간: ${student['checkInTime']}'
                                              : '학번: ${student['studentId']} | 미제출',
                                          style: TextStyle(
                                            color: isCheckedIn
                                                ? Colors.grey[600]
                                                : Colors.red[400],
                                            fontSize: 12,
                                          ),
                                        ),
                                      ],
                                    ),
                                  ),
                                  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,
                                        ),
                                      ),
                                    ),
                                ],
                              ),
                            );
                          },
                        ),
                ),
              ],
            ),
    );
  }

  /// 📊 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"),
          ),
        ],
      ),
    );
  }
}