import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:table_calendar/table_calendar.dart';
import '../../../core/constants/app_colors.dart';
import '../../../core/constants/app_typography.dart';
import '../../../domain/entities/visit_record.dart';
import '../../providers/visit_provider.dart';
import 'widgets/visit_record_card.dart';
import 'widgets/visit_statistics.dart';

class CalendarScreen extends ConsumerStatefulWidget {
  const CalendarScreen({super.key});

  @override
  ConsumerState<CalendarScreen> createState() => _CalendarScreenState();
}

class _CalendarScreenState extends ConsumerState<CalendarScreen>
    with SingleTickerProviderStateMixin {
  late DateTime _selectedDay;
  late DateTime _focusedDay;
  CalendarFormat _calendarFormat = CalendarFormat.month;
  late TabController _tabController;
  Map<DateTime, List<VisitRecord>> _visitRecordEvents = {};

  @override
  void initState() {
    super.initState();
    _selectedDay = DateTime.now();
    _focusedDay = DateTime.now();
    _tabController = TabController(length: 2, vsync: this);
  }

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

  List<VisitRecord> _getEventsForDay(DateTime day) {
    final normalizedDay = DateTime(day.year, day.month, day.day);
    return _visitRecordEvents[normalizedDay] ?? [];
  }

  @override
  Widget build(BuildContext context) {
    final isDark = Theme.of(context).brightness == Brightness.dark;

    return Scaffold(
      backgroundColor: isDark
          ? AppColors.darkBackground
          : AppColors.lightBackground,
      appBar: AppBar(
        title: const Text('방문 기록'),
        backgroundColor: isDark
            ? AppColors.darkPrimary
            : AppColors.lightPrimary,
        foregroundColor: Colors.white,
        elevation: 0,
        bottom: TabBar(
          controller: _tabController,
          indicatorColor: Colors.white,
          indicatorWeight: 3,
          tabs: const [
            Tab(text: '캘린더'),
            Tab(text: '통계'),
          ],
        ),
      ),
      body: TabBarView(
        controller: _tabController,
        children: [
          // 캘린더 탭
          _buildCalendarTab(isDark),
          // 통계 탭
          VisitStatistics(selectedMonth: _focusedDay),
        ],
      ),
    );
  }

  Widget _buildCalendarTab(bool isDark) {
    return Consumer(
      builder: (context, ref, child) {
        final visitRecordsAsync = ref.watch(visitRecordsProvider);

        // 방문 기록을 날짜별로 그룹화
        visitRecordsAsync.whenData((records) {
          _visitRecordEvents = {};
          for (final record in records) {
            final normalizedDate = DateTime(
              record.visitDate.year,
              record.visitDate.month,
              record.visitDate.day,
            );
            _visitRecordEvents[normalizedDate] = [
              ...(_visitRecordEvents[normalizedDate] ?? []),
              record,
            ];
          }
        });

        return Column(
          children: [
            // 캘린더
            Card(
              margin: const EdgeInsets.all(16),
              color: isDark ? AppColors.darkSurface : AppColors.lightSurface,
              elevation: 2,
              shape: RoundedRectangleBorder(
                borderRadius: BorderRadius.circular(12),
              ),
              child: TableCalendar(
                firstDay: DateTime.utc(2025, 1, 1),
                lastDay: DateTime.utc(2030, 12, 31),
                focusedDay: _focusedDay,
                calendarFormat: _calendarFormat,
                selectedDayPredicate: (day) => isSameDay(_selectedDay, day),
                onDaySelected: (selectedDay, focusedDay) {
                  setState(() {
                    _selectedDay = selectedDay;
                    _focusedDay = focusedDay;
                  });
                },
                onFormatChanged: (format) {
                  setState(() {
                    _calendarFormat = format;
                  });
                },
                eventLoader: _getEventsForDay,
                calendarBuilders: CalendarBuilders(
                  markerBuilder: (context, day, events) {
                    if (events.isEmpty) return null;

                    final visitRecords = events.cast<VisitRecord>();
                    final confirmedCount = visitRecords
                        .where((r) => r.isConfirmed)
                        .length;
                    final unconfirmedCount =
                        visitRecords.length - confirmedCount;

                    return Row(
                      mainAxisAlignment: MainAxisAlignment.center,
                      children: [
                        if (confirmedCount > 0)
                          Container(
                            width: 6,
                            height: 6,
                            margin: const EdgeInsets.symmetric(horizontal: 1),
                            decoration: const BoxDecoration(
                              color: AppColors.lightPrimary,
                              shape: BoxShape.circle,
                            ),
                          ),
                        if (unconfirmedCount > 0)
                          Container(
                            width: 6,
                            height: 6,
                            margin: const EdgeInsets.symmetric(horizontal: 1),
                            decoration: const BoxDecoration(
                              color: Colors.orange,
                              shape: BoxShape.circle,
                            ),
                          ),
                      ],
                    );
                  },
                ),
                calendarStyle: CalendarStyle(
                  outsideDaysVisible: false,
                  selectedDecoration: const BoxDecoration(
                    color: AppColors.lightPrimary,
                    shape: BoxShape.circle,
                  ),
                  todayDecoration: BoxDecoration(
                    color: AppColors.lightPrimary.withOpacity(0.5),
                    shape: BoxShape.circle,
                  ),
                  markersMaxCount: 2,
                  markerDecoration: const BoxDecoration(
                    color: AppColors.lightSecondary,
                    shape: BoxShape.circle,
                  ),
                  weekendTextStyle: const TextStyle(
                    color: AppColors.lightError,
                  ),
                ),
                headerStyle: HeaderStyle(
                  formatButtonVisible: true,
                  titleCentered: true,
                  formatButtonShowsNext: false,
                  formatButtonDecoration: BoxDecoration(
                    color: AppColors.lightPrimary.withOpacity(0.1),
                    borderRadius: BorderRadius.circular(12),
                  ),
                  formatButtonTextStyle: const TextStyle(
                    color: AppColors.lightPrimary,
                  ),
                ),
              ),
            ),

            // 범례
            Padding(
              padding: const EdgeInsets.symmetric(horizontal: 16),
              child: Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  _buildLegend('추천받음', Colors.orange, isDark),
                  const SizedBox(width: 24),
                  _buildLegend('방문완료', Colors.green, isDark),
                ],
              ),
            ),

            const SizedBox(height: 16),

            // 선택된 날짜의 기록
            Expanded(child: _buildDayRecords(_selectedDay, isDark)),
          ],
        );
      },
    );
  }

  Widget _buildLegend(String label, Color color, bool isDark) {
    return Row(
      children: [
        Container(
          width: 14,
          height: 14,
          decoration: BoxDecoration(color: color, shape: BoxShape.circle),
        ),
        const SizedBox(width: 6),
        Text(label, style: AppTypography.body2(isDark)),
      ],
    );
  }

  Widget _buildDayRecords(DateTime day, bool isDark) {
    final events = _getEventsForDay(day);

    if (events.isEmpty) {
      return Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(
              Icons.event_available,
              size: 48,
              color: isDark
                  ? AppColors.darkTextSecondary
                  : AppColors.lightTextSecondary,
            ),
            const SizedBox(height: 16),
            Text('이날의 기록이 없습니다', style: AppTypography.body2(isDark)),
          ],
        ),
      );
    }

    return Column(
      children: [
        Padding(
          padding: const EdgeInsets.all(16),
          child: Row(
            children: [
              Icon(
                Icons.calendar_today,
                size: 20,
                color: isDark
                    ? AppColors.darkTextSecondary
                    : AppColors.lightTextSecondary,
              ),
              const SizedBox(width: 8),
              Text(
                '${day.month}월 ${day.day}일 방문 기록',
                style: AppTypography.body1(
                  isDark,
                ).copyWith(fontWeight: FontWeight.bold),
              ),
              const Spacer(),
              Text(
                '${events.length}건',
                style: AppTypography.body2(isDark).copyWith(
                  color: AppColors.lightPrimary,
                  fontWeight: FontWeight.bold,
                ),
              ),
            ],
          ),
        ),
        Expanded(
          child: ListView.builder(
            itemCount: events.length,
            itemBuilder: (context, index) {
              final sortedEvents = events
                ..sort((a, b) => b.visitDate.compareTo(a.visitDate));
              return VisitRecordCard(
                visitRecord: sortedEvents[index],
                onTap: () {
                  // TODO: 맛집 상세 페이지로 이동
                },
              );
            },
          ),
        ),
      ],
    );
  }
}