/// 일정 화면
library;

import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import '../../core/constants.dart';
import '../../models/schedule.dart';
import '../../services/schedules_service.dart';

/// HTML 엔티티 디코딩
String decodeHtmlEntities(String text) {
  return text
      .replaceAll('&', '&')
      .replaceAll('&lt;', '<')
      .replaceAll('&gt;', '>')
      .replaceAll('&quot;', '"')
      .replaceAll('&#39;', "'")
      .replaceAll('&nbsp;', ' ');
}

class ScheduleView extends StatefulWidget {
  const ScheduleView({super.key});

  @override
  State<ScheduleView> createState() => _ScheduleViewState();
}

class _ScheduleViewState extends State<ScheduleView> {
  DateTime _selectedDate = DateTime.now();
  List<Schedule> _schedules = [];
  bool _isLoading = true;
  final ScrollController _dateScrollController = ScrollController();
  final ScrollController _contentScrollController = ScrollController();

  @override
  void initState() {
    super.initState();
    _loadSchedules();
  }

  @override
  void dispose() {
    _dateScrollController.dispose();
    _contentScrollController.dispose();
    super.dispose();
  }

  /// 월별 일정 로드
  Future<void> _loadSchedules() async {
    setState(() => _isLoading = true);
    try {
      final schedules = await getSchedules(
        _selectedDate.year,
        _selectedDate.month,
      );
      setState(() {
        _schedules = schedules;
        _isLoading = false;
      });
      // 선택된 날짜로 스크롤
      WidgetsBinding.instance.addPostFrameCallback((_) {
        _scrollToSelectedDate();
      });
    } catch (e) {
      setState(() => _isLoading = false);
    }
  }

  /// 선택된 날짜로 스크롤
  void _scrollToSelectedDate() {
    if (!_dateScrollController.hasClients) return;

    final dayIndex = _selectedDate.day - 1;
    const itemWidth = 52.0; // 44 + 8 (gap)
    final targetOffset = (dayIndex * itemWidth) -
        (MediaQuery.of(context).size.width / 2) + (itemWidth / 2);
    _dateScrollController.animateTo(
      targetOffset.clamp(0, _dateScrollController.position.maxScrollExtent),
      duration: const Duration(milliseconds: 150),
      curve: Curves.easeOut,
    );
  }

  /// 월 변경
  void _changeMonth(int delta) {
    final newDate = DateTime(_selectedDate.year, _selectedDate.month + delta, 1);
    final today = DateTime.now();

    // 이번 달이면 오늘 날짜, 다른 달이면 1일 선택
    final selectedDay = (newDate.year == today.year && newDate.month == today.month)
        ? today.day
        : 1;

    setState(() {
      _selectedDate = DateTime(newDate.year, newDate.month, selectedDay);
    });
    _loadSchedules();
  }

  /// 날짜 선택
  void _selectDate(DateTime date) {
    // 일정 목록 맨 위로 즉시 이동 (애니메이션과 겹치지 않도록)
    if (_contentScrollController.hasClients) {
      _contentScrollController.jumpTo(0);
    }
    setState(() => _selectedDate = date);
    // 선택된 날짜 중앙으로 스크롤
    _scrollToSelectedDate();
  }

  /// 해당 달의 모든 날짜 배열
  List<DateTime> get _daysInMonth {
    final year = _selectedDate.year;
    final month = _selectedDate.month;
    final lastDay = DateTime(year, month + 1, 0).day;
    return List.generate(lastDay, (i) => DateTime(year, month, i + 1));
  }

  /// 선택된 날짜의 일정
  List<Schedule> get _selectedDateSchedules {
    final dateStr = DateFormat('yyyy-MM-dd').format(_selectedDate);
    return _schedules.where((s) => s.date.split('T')[0] == dateStr).toList();
  }

  /// 특정 날짜의 일정 (점 표시용)
  List<Schedule> _getDaySchedules(DateTime date) {
    final dateStr = DateFormat('yyyy-MM-dd').format(date);
    return _schedules.where((s) => s.date.split('T')[0] == dateStr).take(3).toList();
  }

  /// 요일 이름
  String _getDayName(DateTime date) {
    const days = ['일', '월', '화', '수', '목', '금', '토'];
    return days[date.weekday % 7];
  }

  /// 오늘 여부
  bool _isToday(DateTime date) {
    final today = DateTime.now();
    return date.year == today.year &&
           date.month == today.month &&
           date.day == today.day;
  }

  /// 선택된 날짜 여부
  bool _isSelected(DateTime date) {
    return date.year == _selectedDate.year &&
           date.month == _selectedDate.month &&
           date.day == _selectedDate.day;
  }

  /// 카테고리 색상 파싱
  Color _parseColor(String? colorStr) {
    if (colorStr == null || colorStr.isEmpty) return AppColors.textTertiary;
    try {
      final hex = colorStr.replaceFirst('#', '');
      return Color(int.parse('FF$hex', radix: 16));
    } catch (_) {
      return AppColors.textTertiary;
    }
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        // 자체 툴바
        _buildToolbar(),
        // 날짜 선택기
        _buildDateSelector(),
        // 일정 목록
        Expanded(
          child: _buildScheduleList(),
        ),
      ],
    );
  }

  /// 툴바 빌드
  Widget _buildToolbar() {
    return Container(
      color: Colors.white,
      child: SafeArea(
        bottom: false,
        child: Container(
          height: 56,
          padding: const EdgeInsets.symmetric(horizontal: 4),
          child: Row(
            children: [
              // 달력 아이콘 (2단계에서 구현)
              IconButton(
                onPressed: () {
                  // TODO: 달력 팝업
                },
                icon: const Icon(Icons.calendar_today_outlined, size: 20),
                color: AppColors.textSecondary,
              ),
              // 이전 월
              IconButton(
                onPressed: () => _changeMonth(-1),
                icon: const Icon(Icons.chevron_left, size: 24),
                color: AppColors.textPrimary,
              ),
              // 년월 표시
              Expanded(
                child: Center(
                  child: Text(
                    '${_selectedDate.year}년 ${_selectedDate.month}월',
                    style: const TextStyle(
                      fontSize: 16,
                      fontWeight: FontWeight.bold,
                      color: AppColors.textPrimary,
                    ),
                  ),
                ),
              ),
              // 다음 월
              IconButton(
                onPressed: () => _changeMonth(1),
                icon: const Icon(Icons.chevron_right, size: 24),
                color: AppColors.textPrimary,
              ),
              // 검색 아이콘 (3단계에서 구현)
              IconButton(
                onPressed: () {
                  // TODO: 검색 모드
                },
                icon: const Icon(Icons.search, size: 20),
                color: AppColors.textSecondary,
              ),
            ],
          ),
        ),
      ),
    );
  }

  /// 날짜 선택기 빌드
  Widget _buildDateSelector() {
    return Container(
      color: Colors.white,
      child: Container(
        height: 80,
        decoration: BoxDecoration(
          color: Colors.white,
          boxShadow: [
            BoxShadow(
              color: Colors.black.withValues(alpha: 0.05),
              blurRadius: 4,
              offset: const Offset(0, 1),
            ),
          ],
        ),
        child: ListView.builder(
          controller: _dateScrollController,
          scrollDirection: Axis.horizontal,
          padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 8),
          itemCount: _daysInMonth.length,
          itemBuilder: (context, index) {
            final date = _daysInMonth[index];
            final isSelected = _isSelected(date);
            final isToday = _isToday(date);
            final dayOfWeek = date.weekday;
            final daySchedules = _getDaySchedules(date);

            return GestureDetector(
              onTap: () => _selectDate(date),
              child: Container(
                width: 44,
                margin: const EdgeInsets.symmetric(horizontal: 4),
                decoration: BoxDecoration(
                  color: isSelected ? AppColors.primary : Colors.transparent,
                  borderRadius: BorderRadius.circular(12),
                ),
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    // 요일
                    Text(
                      _getDayName(date),
                      style: TextStyle(
                        fontSize: 10,
                        fontWeight: FontWeight.w500,
                        color: isSelected
                            ? Colors.white.withValues(alpha: 0.8)
                            : dayOfWeek == 7
                                ? Colors.red.shade400
                                : dayOfWeek == 6
                                    ? Colors.blue.shade400
                                    : AppColors.textTertiary,
                      ),
                    ),
                    const SizedBox(height: 4),
                    // 날짜
                    Text(
                      '${date.day}',
                      style: TextStyle(
                        fontSize: 14,
                        fontWeight: FontWeight.w600,
                        color: isSelected
                            ? Colors.white
                            : isToday
                                ? AppColors.primary
                                : AppColors.textPrimary,
                      ),
                    ),
                    const SizedBox(height: 4),
                    // 일정 점 (최대 3개)
                    SizedBox(
                      height: 6,
                      child: !isSelected && daySchedules.isNotEmpty
                          ? Row(
                              mainAxisAlignment: MainAxisAlignment.center,
                              children: daySchedules.map((schedule) {
                                return Container(
                                  width: 4,
                                  height: 4,
                                  margin: const EdgeInsets.symmetric(horizontal: 1),
                                  decoration: BoxDecoration(
                                    color: _parseColor(schedule.categoryColor),
                                    shape: BoxShape.circle,
                                  ),
                                );
                              }).toList(),
                            )
                          : const SizedBox.shrink(),
                    ),
                  ],
                ),
              ),
            );
          },
        ),
      ),
    );
  }

  /// 일정 목록 빌드
  Widget _buildScheduleList() {
    if (_isLoading) {
      return const Center(
        child: CircularProgressIndicator(color: AppColors.primary),
      );
    }

    if (_selectedDateSchedules.isEmpty) {
      return Center(
        child: Text(
          '${_selectedDate.month}월 ${_selectedDate.day}일 일정이 없습니다',
          style: const TextStyle(
            fontSize: 14,
            color: AppColors.textTertiary,
          ),
        ),
      );
    }

    return ListView.builder(
      controller: _contentScrollController,
      padding: const EdgeInsets.all(16),
      itemCount: _selectedDateSchedules.length,
      itemBuilder: (context, index) {
        final schedule = _selectedDateSchedules[index];
        return Padding(
          padding: EdgeInsets.only(bottom: index < _selectedDateSchedules.length - 1 ? 12 : 0),
          child: _AnimatedScheduleCard(
            key: ValueKey('${schedule.id}_${_selectedDate.toString()}'),
            index: index,
            schedule: schedule,
            categoryColor: _parseColor(schedule.categoryColor),
          ),
        );
      },
    );
  }
}

/// 애니메이션이 적용된 일정 카드 래퍼
class _AnimatedScheduleCard extends StatefulWidget {
  final int index;
  final Schedule schedule;
  final Color categoryColor;

  const _AnimatedScheduleCard({
    super.key,
    required this.index,
    required this.schedule,
    required this.categoryColor,
  });

  @override
  State<_AnimatedScheduleCard> createState() => _AnimatedScheduleCardState();
}

class _AnimatedScheduleCardState extends State<_AnimatedScheduleCard>
    with SingleTickerProviderStateMixin {
  late AnimationController _controller;
  late Animation<double> _fadeAnimation;
  late Animation<double> _slideAnimation;

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(
      duration: const Duration(milliseconds: 300),
      vsync: this,
    );

    _fadeAnimation = Tween<double>(begin: 0.0, end: 1.0).animate(
      CurvedAnimation(parent: _controller, curve: Curves.easeOut),
    );

    // 웹과 동일: x: -10px 에서 0으로 (spring 효과)
    _slideAnimation = Tween<double>(begin: -10.0, end: 0.0).animate(
      CurvedAnimation(parent: _controller, curve: Curves.easeOutCubic),
    );

    // 순차적 애니메이션 (index * 30ms 딜레이) - 더 빠르게
    Future.delayed(Duration(milliseconds: widget.index * 30), () {
      if (mounted) _controller.forward();
    });
  }

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

  @override
  Widget build(BuildContext context) {
    return AnimatedBuilder(
      animation: _controller,
      builder: (context, child) {
        return Opacity(
          opacity: _fadeAnimation.value,
          child: Transform.translate(
            offset: Offset(_slideAnimation.value, 0),
            child: child,
          ),
        );
      },
      child: _ScheduleCard(
        schedule: widget.schedule,
        categoryColor: widget.categoryColor,
      ),
    );
  }
}

/// 일정 카드 위젯
class _ScheduleCard extends StatelessWidget {
  final Schedule schedule;
  final Color categoryColor;

  const _ScheduleCard({
    required this.schedule,
    required this.categoryColor,
  });

  @override
  Widget build(BuildContext context) {
    final memberList = schedule.memberList;

    return Container(
      decoration: BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.circular(8),
        boxShadow: [
          BoxShadow(
            color: Colors.black.withValues(alpha: 0.04),
            blurRadius: 12,
            offset: const Offset(0, 2),
          ),
        ],
        border: Border.all(
          color: AppColors.border.withValues(alpha: 0.5),
          width: 1,
        ),
      ),
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            // 시간 및 카테고리 뱃지
            Row(
              children: [
                // 시간 뱃지
                if (schedule.formattedTime != null)
                  Container(
                    padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 3),
                    decoration: BoxDecoration(
                      color: categoryColor,
                      borderRadius: BorderRadius.circular(12),
                    ),
                    child: Row(
                      mainAxisSize: MainAxisSize.min,
                      children: [
                        const Icon(
                          Icons.access_time,
                          size: 10,
                          color: Colors.white,
                        ),
                        const SizedBox(width: 4),
                        Text(
                          schedule.formattedTime!,
                          style: const TextStyle(
                            fontSize: 11,
                            fontWeight: FontWeight.w500,
                            color: Colors.white,
                          ),
                        ),
                      ],
                    ),
                  ),
                if (schedule.formattedTime != null) const SizedBox(width: 6),
                // 카테고리 뱃지
                if (schedule.categoryName != null)
                  Container(
                    padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 3),
                    decoration: BoxDecoration(
                      color: categoryColor.withValues(alpha: 0.1),
                      borderRadius: BorderRadius.circular(12),
                    ),
                    child: Text(
                      schedule.categoryName!,
                      style: TextStyle(
                        fontSize: 11,
                        fontWeight: FontWeight.w500,
                        color: categoryColor,
                      ),
                    ),
                  ),
              ],
            ),
            const SizedBox(height: 10),
            // 제목
            Text(
              decodeHtmlEntities(schedule.title),
              style: const TextStyle(
                fontSize: 15,
                fontWeight: FontWeight.bold,
                color: AppColors.textPrimary,
                height: 1.4,
              ),
            ),
            // 출처
            if (schedule.sourceName != null) ...[
              const SizedBox(height: 6),
              Row(
                children: [
                  Icon(
                    Icons.link,
                    size: 11,
                    color: AppColors.textTertiary,
                  ),
                  const SizedBox(width: 4),
                  Text(
                    schedule.sourceName!,
                    style: const TextStyle(
                      fontSize: 11,
                      color: AppColors.textTertiary,
                    ),
                  ),
                ],
              ),
            ],
            // 멤버
            if (memberList.isNotEmpty) ...[
              const SizedBox(height: 12),
              Container(
                padding: const EdgeInsets.only(top: 12),
                decoration: const BoxDecoration(
                  border: Border(
                    top: BorderSide(color: AppColors.divider, width: 1),
                  ),
                ),
                child: Wrap(
                  spacing: 6,
                  runSpacing: 6,
                  children: memberList.length >= 5
                      ? [
                          _MemberChip(name: '프로미스나인'),
                        ]
                      : memberList.map((name) => _MemberChip(name: name)).toList(),
                ),
              ),
            ],
          ],
        ),
      ),
    );
  }
}

/// 멤버 칩 위젯
class _MemberChip extends StatelessWidget {
  final String name;

  const _MemberChip({required this.name});

  @override
  Widget build(BuildContext context) {
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 5),
      decoration: BoxDecoration(
        gradient: const LinearGradient(
          colors: [AppColors.primary, AppColors.primaryDark],
        ),
        borderRadius: BorderRadius.circular(8),
        boxShadow: [
          BoxShadow(
            color: AppColors.primary.withValues(alpha: 0.3),
            blurRadius: 4,
            offset: const Offset(0, 2),
          ),
        ],
      ),
      child: Text(
        name,
        style: const TextStyle(
          fontSize: 11,
          fontWeight: FontWeight.w600,
          color: Colors.white,
        ),
      ),
    );
  }
}