import 'package:flutter/material.dart';

import '../../app/app_controller.dart';
import '../../app/app_theme.dart';
import '../../domain/schedule_engine.dart';
import 'week_grid.dart';

class TimetablePage extends StatefulWidget {
  const TimetablePage({super.key, required this.controller});
  final AppController controller;
  @override
  State<TimetablePage> createState() => _TimetablePageState();
}

class _TimetablePageState extends State<TimetablePage> {
  int? _week;
  bool? _wasDemo;
  @override
  Widget build(BuildContext context) {
    final c = widget.controller, term = c.visibleSettings.semester;
    final today = ScheduleEngine.schoolDate(c.clock());
    if (_wasDemo != c.isDemo) {
      _week = null;
      _wasDemo = c.isDemo;
    }
    final current = term == null
        ? 1
        : (ScheduleEngine.weekNumber(term, today) ?? 1);
    final week = (_week ?? current).clamp(1, term?.totalWeeks ?? 1);
    final monday = term == null
        ? today.subtract(Duration(days: today.weekday - 1))
        : term.firstMonday.add(Duration(days: (week - 1) * 7));
    final sunday = monday.add(const Duration(days: 6));
    return ListView(
      key: const PageStorageKey('timetable-scroll'),
      padding: EdgeInsets.fromLTRB(
        8,
        10,
        8,
        140 + MediaQuery.paddingOf(context).bottom,
      ),
      children: [
        const Padding(
          padding: EdgeInsets.symmetric(horizontal: 14),
          child: Text(
            'RSchedule',
            style: TextStyle(fontSize: 22, fontWeight: FontWeight.w700),
          ),
        ),
        const SizedBox(height: 10),
        SurfaceCard(
          padding: const EdgeInsets.symmetric(horizontal: 4, vertical: 0),
          child: Row(
            children: [
              IconButton(
                onPressed: term != null && week > 1
                    ? () => setState(() => _week = week - 1)
                    : null,
                icon: const Icon(Icons.chevron_left_rounded),
              ),
              Expanded(
                child: Column(
                  children: [
                    Text(
                      term == null ? '本周' : '第 $week 周',
                      style: const TextStyle(
                        fontSize: 17,
                        fontWeight: FontWeight.w700,
                      ),
                    ),
                    const SizedBox(height: 4),
                    Text(
                      '${monday.month}.${monday.day.toString().padLeft(2, '0')} – ${sunday.month}.${sunday.day.toString().padLeft(2, '0')}',
                      style: TextStyle(
                        fontSize: 12,
                        color: ink.withValues(alpha: 0.5),
                      ),
                    ),
                  ],
                ),
              ),
              IconButton(
                onPressed: term != null && week < term.totalWeeks
                    ? () => setState(() => _week = week + 1)
                    : null,
                icon: const Icon(Icons.chevron_right_rounded),
              ),
              TextButton(
                onPressed: () => setState(() => _week = null),
                child: const Text('本周'),
              ),
            ],
          ),
        ),
        const SizedBox(height: 4),
        if (c.isDemo)
          Padding(
            padding: const EdgeInsets.only(bottom: 12),
            child: Wrap(
              crossAxisAlignment: WrapCrossAlignment.center,
              spacing: 8,
              children: [
                Container(
                  padding: const EdgeInsets.symmetric(
                    horizontal: 12,
                    vertical: 7,
                  ),
                  decoration: BoxDecoration(
                    color: const Color(0xFFE2EEFF),
                    borderRadius: BorderRadius.circular(10),
                  ),
                  child: const Text(
                    '示例课表',
                    style: TextStyle(
                      fontSize: 11,
                      color: Color(0xFF356AA8),
                      fontWeight: FontWeight.w600,
                    ),
                  ),
                ),
                const Text(
                  '不会生成提醒或日历事件',
                  style: TextStyle(fontSize: 10, color: Color(0xFF8193AB)),
                ),
                TextButton(onPressed: c.leaveDemo, child: const Text('退出示例')),
              ],
            ),
          ),
        if (term != null) ...[
          WeekGrid(
            events: ScheduleEngine.occurrences(
              c.visibleCourses,
              term,
            ).where((e) => e.week == week).toList(),
            monday: monday,
            today: today,
            settings: c.visibleSettings,
          ),
          const SizedBox(height: 12),
          Text(
            '点击课程查看完整信息',
            textAlign: TextAlign.center,
            style: TextStyle(fontSize: 11, color: ink.withValues(alpha: 0.35)),
          ),
        ] else ...[
          const SizedBox(height: 38),
          const Icon(
            Icons.calendar_month_outlined,
            size: 66,
            color: Color(0xFFB7CDF0),
          ),
          const SizedBox(height: 22),
          const Text(
            '让课表，陪你开启每一天',
            textAlign: TextAlign.center,
            style: TextStyle(fontSize: 18, fontWeight: FontWeight.w600),
          ),
          const SizedBox(height: 12),
          Text(
            '在「个人设置」设置学期并导入课程，\n或先看看示例课表。',
            textAlign: TextAlign.center,
            style: TextStyle(
              fontSize: 13,
              height: 1.8,
              color: ink.withValues(alpha: 0.5),
            ),
          ),
          const SizedBox(height: 25),
          Center(
            child: FilledButton.icon(
              onPressed: c.showDemo,
              icon: const Icon(Icons.auto_awesome_outlined, size: 18),
              label: const Text('体验示例课表'),
            ),
          ),
        ],
      ],
    );
  }
}