import 'package:flutter/material.dart';

import '../app_info.dart';

/// 设置页，按 Android 系统设置的分组列表组织。
class SettingsPage extends StatefulWidget {
  const SettingsPage({super.key});

  @override
  State<SettingsPage> createState() => _SettingsPageState();
}

class _SettingsPageState extends State<SettingsPage> {
  bool _requeueOnWrong = true;
  bool _readAloud = true;
  bool _autoSync = true;
  bool _wifiOnly = true;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('设置')),
      body: ListView(
        padding: const EdgeInsets.only(bottom: 32),
        children: <Widget>[
          const _SectionHeader('学习'),
          _ValueTile(
            icon: Icons.school_outlined,
            title: '每日新识记上限',
            value: '35 条',
            onTap: () => _pending('每日新识记上限'),
          ),
          _ValueTile(
            icon: Icons.replay_rounded,
            title: '每日复习上限',
            value: '200 条',
            onTap: () => _pending('每日复习上限'),
          ),
          _ValueTile(
            icon: Icons.schedule_rounded,
            title: '学习时段',
            value: '08:00–23:00',
            onTap: () => _pending('学习时段'),
          ),
          _SwitchTile(
            icon: Icons.restart_alt_rounded,
            title: '答错后重新排队',
            subtitle: '同一轮里再出现一次',
            value: _requeueOnWrong,
            onChanged: (bool value) => setState(() => _requeueOnWrong = value),
          ),

          const _SectionHeader('测验'),
          _ValueTile(
            icon: Icons.quiz_outlined,
            title: '默认谜题类型',
            value: '完形填空',
            onTap: () => _pending('默认谜题类型'),
          ),
          _SwitchTile(
            icon: Icons.volume_up_outlined,
            title: '自动朗读',
            subtitle: '进入谜题时播放语音',
            value: _readAloud,
            onChanged: (bool value) => setState(() => _readAloud = value),
          ),

          const _SectionHeader('外观'),
          _ValueTile(
            icon: Icons.dark_mode_outlined,
            title: '主题',
            value: '跟随系统',
            onTap: () => _pending('主题'),
          ),
          _ValueTile(
            icon: Icons.text_fields_rounded,
            title: '字号',
            value: '标准',
            onTap: () => _pending('字号'),
          ),

          const _SectionHeader('同步'),
          _SwitchTile(
            icon: Icons.cloud_sync_outlined,
            title: '自动同步',
            subtitle: '学完一轮后自动上传',
            value: _autoSync,
            onChanged: (bool value) => setState(() => _autoSync = value),
          ),
          _SwitchTile(
            icon: Icons.wifi_rounded,
            title: '仅在 Wi-Fi 下同步',
            value: _wifiOnly,
            onChanged: (bool value) => setState(() => _wifiOnly = value),
          ),
          _ValueTile(
            icon: Icons.sync_rounded,
            title: '立即同步',
            onTap: () => _pending('立即同步'),
          ),

          const _SectionHeader('关于'),
          _ValueTile(
            icon: Icons.info_outline_rounded,
            title: '版本',
            value: appVersion,
          ),
          _ValueTile(
            icon: Icons.description_outlined,
            title: '开源许可',
            onTap: () => _pending('开源许可'),
          ),
        ],
      ),
    );
  }

  void _pending(String feature) {
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text('$feature 尚未接入内核'),
        behavior: SnackBarBehavior.floating,
      ),
    );
  }
}

class _SectionHeader extends StatelessWidget {
  const _SectionHeader(this.title);

  final String title;

  @override
  Widget build(BuildContext context) {
    final ThemeData theme = Theme.of(context);
    return Padding(
      padding: const EdgeInsets.fromLTRB(16, 20, 16, 6),
      child: Text(
        title,
        style: theme.textTheme.labelLarge?.copyWith(
          color: theme.colorScheme.primary,
          fontWeight: FontWeight.w600,
        ),
      ),
    );
  }
}

class _ValueTile extends StatelessWidget {
  const _ValueTile({
    required this.icon,
    required this.title,
    this.value,
    this.onTap,
  });

  final IconData icon;
  final String title;
  final String? value;
  final VoidCallback? onTap;

  @override
  Widget build(BuildContext context) {
    final ColorScheme colors = Theme.of(context).colorScheme;
    final String? value = this.value;

    return ListTile(
      leading: Icon(icon, color: colors.onSurfaceVariant),
      title: Text(title),
      trailing: Row(
        mainAxisSize: MainAxisSize.min,
        children: <Widget>[
          if (value != null)
            Text(
              value,
              style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                color: colors.onSurfaceVariant,
              ),
            ),
          if (onTap != null) ...<Widget>[
            const SizedBox(width: 4),
            Icon(
              Icons.chevron_right_rounded,
              size: 20,
              color: colors.onSurfaceVariant,
            ),
          ],
        ],
      ),
      onTap: onTap,
    );
  }
}

class _SwitchTile extends StatelessWidget {
  const _SwitchTile({
    required this.icon,
    required this.title,
    required this.value,
    required this.onChanged,
    this.subtitle,
  });

  final IconData icon;
  final String title;
  final String? subtitle;
  final bool value;
  final ValueChanged<bool> onChanged;

  @override
  Widget build(BuildContext context) {
    final ColorScheme colors = Theme.of(context).colorScheme;
    return SwitchListTile(
      secondary: Icon(icon, color: colors.onSurfaceVariant),
      title: Text(title),
      subtitle: subtitle == null ? null : Text(subtitle!),
      value: value,
      onChanged: onChanged,
    );
  }
}