import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

import '../../app/app_controller.dart';
import '../../app/app_theme.dart';
import '../../domain/app_settings.dart';
import '../../domain/semester.dart';
import '../../services/notification_service.dart';

class SettingsPage extends StatefulWidget {
  const SettingsPage({
    super.key,
    required this.controller,
    this.focusSemester = false,
  });
  final AppController controller;
  final bool focusSemester;
  @override
  State<SettingsPage> createState() => _SettingsPageState();
}

class _SettingsPageState extends State<SettingsPage> {
  late TextEditingController _weeks;
  DateTime? _start;
  double? _courseHeightDraft;
  bool _savingHeight = false;
  String? _weeksError, _dateError;
  final _scroll = ScrollController();
  @override
  void initState() {
    super.initState();
    _start = widget.controller.snapshot.settings.semester?.startDate;
    _weeks = TextEditingController(
      text: '${widget.controller.snapshot.settings.semester?.totalWeeks ?? 20}',
    );
    if (widget.focusSemester) {
      WidgetsBinding.instance.addPostFrameCallback((_) {
        if (mounted && _scroll.hasClients) {
          _scroll.jumpTo(_scroll.position.maxScrollExtent);
        }
      });
    }
  }

  @override
  void dispose() {
    _weeks.dispose();
    _scroll.dispose();
    super.dispose();
  }

  Future<void> _calendar(bool enabled) async {
    try {
      await _calendarAction(enabled);
    } catch (_) {
      if (mounted) {
        _notice('日历暂时不可用，请检查权限后重试');
      }
    }
  }

  Future<void> _calendarAction(bool enabled) async {
    final c = widget.controller;
    if (enabled) {
      if (!await c.calendar.requestAccess()) {
        if (mounted) _notice('请允许日历访问后重试');
        return;
      }
      final calendars = await c.calendar.listWritableCalendars();
      if (!mounted) return;
      if (calendars.isEmpty) {
        _notice('手机中没有可写入的日历，请先在日历应用中添加日历');
        return;
      }
      final id = await showDialog<String>(
        context: context,
        builder: (context) => SimpleDialog(
          title: const Text('选择手机日历'),
          children: calendars
              .map(
                (cal) => SimpleDialogOption(
                  onPressed: () => Navigator.pop(context, cal.id),
                  child: Text(cal.name),
                ),
              )
              .toList(),
        ),
      );
      if (id != null) {
        await c.enableCalendarFromUserAction(id);
      }
    } else {
      final delete = await showDialog<bool>(
        context: context,
        builder: (context) => AlertDialog(
          title: const Text('关闭日历同步'),
          content: const Text('是否删除 TPSchedule 创建的课程日程？其他日程不会受影响。'),
          actions: [
            TextButton(
              onPressed: () => Navigator.pop(context, false),
              child: const Text('保留日程'),
            ),
            TextButton(
              onPressed: () => Navigator.pop(context, true),
              child: const Text('删除课程日程'),
            ),
          ],
        ),
      );
      if (delete != null) {
        await c.disableCalendar(deleteEvents: delete);
      }
    }
    if (mounted && c.calendarSyncError != null) {
      _notice(c.calendarSyncError!);
    }
  }

  Future<void> _saveCourseHeight(double value) async {
    setState(() => _savingHeight = true);
    await widget.controller.updateSettings(
      (current) => current.copyWith(courseHeightScale: value),
    );
    if (!mounted) return;
    setState(() {
      _courseHeightDraft = null;
      _savingHeight = false;
    });
    if (widget.controller.lastError != null) {
      _notice(widget.controller.lastError!);
    }
  }

  void _notice(String text) =>
      ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(text)));
  @override
  Widget build(BuildContext context) => AnimatedBuilder(
    animation: widget.controller,
    builder: (context, _) {
      final c = widget.controller, s = c.snapshot.settings;
      return Scaffold(
        appBar: AppBar(
          title: const Text(
            '课表设置',
            style: TextStyle(fontSize: 21, fontWeight: FontWeight.w700),
          ),
        ),
        body: ListView(
          controller: _scroll,
          padding: const EdgeInsets.fromLTRB(20, 12, 20, 40),
          children: [
            if (c.isDemo)
              const Padding(
                padding: EdgeInsets.only(bottom: 18),
                child: Text(
                  '示例模式中，提醒与日历功能不会应用到示例课程。',
                  style: TextStyle(fontSize: 12, color: river),
                ),
              ),
            _heading('课表配色'),
            SurfaceCard(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Wrap(
                    spacing: 10,
                    runSpacing: 8,
                    children: [
                      ChoiceChip(
                        label: const Text('多彩'),
                        selected: s.colorMode == ColorMode.multicolor,
                        onSelected: (_) => c.updateSettings(
                          (current) =>
                              current.copyWith(colorMode: ColorMode.multicolor),
                        ),
                      ),
                      ChoiceChip(
                        label: const Text('单色'),
                        selected: s.colorMode == ColorMode.single,
                        onSelected: (_) => c.updateSettings(
                          (current) =>
                              current.copyWith(colorMode: ColorMode.single),
                        ),
                      ),
                    ],
                  ),
                  const SizedBox(height: 15),
                  Wrap(
                    spacing: 14,
                    runSpacing: 12,
                    children: [
                      for (final color in [
                        0xFF348F91,
                        0xFF6E83B1,
                        0xFFB18A6E,
                        0xFF8C789E,
                      ])
                        Semantics(
                          label: '选择课表颜色',
                          button: true,
                          child: InkWell(
                            onTap: () => c.updateSettings(
                              (current) => current.copyWith(
                                singleColorArgb: color,
                                colorMode: ColorMode.single,
                              ),
                            ),
                            borderRadius: BorderRadius.circular(30),
                            child: Container(
                              width: 36,
                              height: 36,
                              decoration: BoxDecoration(
                                color: Color(color),
                                shape: BoxShape.circle,
                                border: Border.all(
                                  color: s.singleColorArgb == color
                                      ? ink
                                      : Colors.transparent,
                                  width: 2,
                                ),
                              ),
                              child: s.singleColorArgb == color
                                  ? const Icon(
                                      Icons.check_rounded,
                                      color: Colors.white,
                                      size: 20,
                                    )
                                  : null,
                            ),
                          ),
                        ),
                    ],
                  ),
                ],
              ),
            ),
            const SizedBox(height: 22),
            _heading('课程条长度'),
            SurfaceCard(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Row(
                    children: [
                      Expanded(
                        child: Text(
                          '${((_courseHeightDraft ?? s.courseHeightScale) * 100).round()}%',
                          style: const TextStyle(
                            fontSize: 18,
                            fontWeight: FontWeight.w700,
                            color: river,
                          ),
                        ),
                      ),
                      TextButton(
                        onPressed: _savingHeight
                            ? null
                            : () => _saveCourseHeight(
                                AppSettings.defaultCourseHeightScale,
                              ),
                        child: const Text('恢复默认'),
                      ),
                    ],
                  ),
                  Slider(
                    key: const Key('course-height-slider'),
                    value: _courseHeightDraft ?? s.courseHeightScale,
                    min: AppSettings.minCourseHeightScale,
                    max: AppSettings.maxCourseHeightScale,
                    divisions: 24,
                    label:
                        '${((_courseHeightDraft ?? s.courseHeightScale) * 100).round()}%',
                    semanticFormatterCallback: (value) =>
                        '${(value * 100).round()}%',
                    onChanged: _savingHeight
                        ? null
                        : (value) => setState(() => _courseHeightDraft = value),
                    onChangeEnd: _saveCourseHeight,
                  ),
                  const Row(
                    mainAxisAlignment: MainAxisAlignment.spaceBetween,
                    children: [
                      Text('较短', style: TextStyle(fontSize: 11)),
                      Text('较长', style: TextStyle(fontSize: 11)),
                    ],
                  ),
                  const SizedBox(height: 10),
                  Text(
                    '统一调整课程条长度，老师和教室始终完整显示。',
                    style: TextStyle(
                      fontSize: 11,
                      height: 1.6,
                      color: ink.withValues(alpha: 0.55),
                    ),
                  ),
                ],
              ),
            ),
            const SizedBox(height: 22),
            _heading('课前提醒'),
            SurfaceCard(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  SwitchListTile.adaptive(
                    contentPadding: EdgeInsets.zero,
                    title: const Text('提醒我去上课', style: TextStyle(fontSize: 15)),
                    value: s.remindersEnabled,
                    onChanged: c.isDemo
                        ? null
                        : (v) async {
                            if (v) {
                              await c.enableRemindersFromUserAction();
                            } else {
                              await c.updateSettings(
                                (current) =>
                                    current.copyWith(remindersEnabled: false),
                              );
                            }
                          },
                  ),
                  const SizedBox(height: 5),
                  Wrap(
                    spacing: 6,
                    runSpacing: 7,
                    children: [
                      for (final minutes in AppSettings.allowedReminderMinutes)
                        FilterChip(
                          label: Text('$minutes 分钟'),
                          selected: s.reminderOffsets.contains(minutes),
                          onSelected: c.isDemo
                              ? null
                              : (selected) {
                                  if (!selected &&
                                      s.reminderOffsets.length == 1) {
                                    _notice('请至少保留一个提醒时间');
                                    return;
                                  }
                                  c.updateSettings(
                                    (current) => current.copyWith(
                                      reminderOffsets: [
                                        for (final value
                                            in current.reminderOffsets)
                                          if (value != minutes) value,
                                        if (selected) minutes,
                                      ],
                                    ),
                                  );
                                },
                        ),
                    ],
                  ),
                  const SizedBox(height: 10),
                  Text(
                    c.reminderResult.message.isNotEmpty
                        ? c.reminderResult.message
                        : c.reminderResult.status ==
                              ReminderStatus.permissionDenied
                        ? '尚未允许通知权限，点击下方按钮开启。'
                        : '可多选提前时间，连续课程按每个选中的时间提醒。',
                    style: TextStyle(
                      fontSize: 11,
                      height: 1.6,
                      color: ink.withValues(alpha: 0.5),
                    ),
                  ),
                  if (!c.isDemo && s.remindersEnabled)
                    TextButton(
                      onPressed: c.enableRemindersFromUserAction,
                      child: const Text('允许课前提醒'),
                    ),
                ],
              ),
            ),
            const SizedBox(height: 22),
            _heading('手机日历'),
            SurfaceCard(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  SwitchListTile.adaptive(
                    contentPadding: EdgeInsets.zero,
                    title: const Text('导入手机日历', style: TextStyle(fontSize: 15)),
                    subtitle: const Text(
                      '按实际上课周次同步，不重复提醒',
                      style: TextStyle(fontSize: 11),
                    ),
                    value: s.calendarEnabled,
                    onChanged: c.isDemo ? null : _calendar,
                  ),
                  if (c.calendarSyncError != null)
                    Text(
                      c.calendarSyncError!,
                      style: const TextStyle(
                        fontSize: 12,
                        color: Color(0xFFB45D54),
                      ),
                    ),
                  if (c.snapshot.calendarCleanupPending)
                    TextButton(
                      onPressed: c.retryCalendarCleanup,
                      child: const Text('重试清理课程日程'),
                    ),
                ],
              ),
            ),
            const SizedBox(height: 22),
            _heading('学期安排'),
            SurfaceCard(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  ListTile(
                    contentPadding: EdgeInsets.zero,
                    title: const Text('学期开始日', style: TextStyle(fontSize: 15)),
                    subtitle: Text(
                      _start == null
                          ? '请选择学校实际开学日期'
                          : '${_start!.year} 年 ${_start!.month} 月 ${_start!.day} 日',
                      style: const TextStyle(fontSize: 12),
                    ),
                    trailing: const Icon(
                      Icons.date_range_outlined,
                      color: river,
                    ),
                    onTap: () async {
                      final date = await showDatePicker(
                        context: context,
                        initialDate: _start ?? c.clock(),
                        firstDate: DateTime(2020),
                        lastDate: DateTime(2040),
                      );
                      if (date != null && mounted) {
                        setState(() => _start = date);
                      }
                    },
                  ),
                  if (_dateError != null)
                    Text(
                      _dateError!,
                      style: const TextStyle(
                        fontSize: 12,
                        color: Color(0xFFB45D54),
                      ),
                    ),
                  const SizedBox(height: 16),
                  TextField(
                    key: const Key('semester-weeks'),
                    controller: _weeks,
                    keyboardType: TextInputType.number,
                    inputFormatters: [
                      FilteringTextInputFormatter.digitsOnly,
                      LengthLimitingTextInputFormatter(2),
                    ],
                    decoration: InputDecoration(
                      labelText: '学期总周数',
                      hintText: '1–30',
                      errorText: _weeksError,
                    ),
                  ),
                  const SizedBox(height: 16),
                  SizedBox(
                    width: double.infinity,
                    child: FilledButton(
                      onPressed: () async {
                        final weeks = int.tryParse(_weeks.text);
                        setState(() {
                          _weeksError = weeks == null || weeks < 1 || weeks > 30
                              ? '周数应为 1–30'
                              : null;
                          _dateError = _start == null ? '请先选择学期开始日' : null;
                        });
                        if (_weeksError != null || _dateError != null) return;
                        await c.updateSettings(
                          (current) => current.copyWith(
                            semester: Semester(
                              startDate: _start!,
                              totalWeeks: weeks!,
                            ),
                          ),
                        );
                        if (mounted) {
                          _notice(c.lastError ?? '学期设置已保存');
                        }
                      },
                      child: const Text('保存学期设置'),
                    ),
                  ),
                  const SizedBox(height: 12),
                  Text(
                    '开始日所在的周一至周日为第 1 周。开始日前不会生成课程。',
                    style: TextStyle(
                      fontSize: 11,
                      height: 1.6,
                      color: ink.withValues(alpha: 0.45),
                    ),
                  ),
                ],
              ),
            ),
          ],
        ),
      );
    },
  );
  Widget _heading(String text) => Padding(
    padding: const EdgeInsets.only(left: 4, bottom: 10),
    child: Text(
      text,
      style: const TextStyle(fontSize: 13, fontWeight: FontWeight.w600),
    ),
  );
}