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

import '../../providers/auth_provider.dart';
import '../../providers/locale_provider.dart';
import '../../providers/theme_provider.dart';
import '../../providers/display_provider.dart';
import '../../services/api_client.dart';
import '../../services/sys_service.dart';
import '../../utils/constants.dart';
import '../../utils/i10n.dart';
import '../../utils/app_update.dart';
import 'package:package_info_plus/package_info_plus.dart';

/// 设置页（底部导航第 3 个 tab）：主题切换 / 语言占位 / 关于 / 退出登录。
class SettingsPage extends ConsumerWidget {
  const SettingsPage({super.key});

  Future<void> _showChangePasswordDialog(BuildContext context, WidgetRef ref) async {
    final t = AppLocalizations.of(context);
    final oldCtrl = TextEditingController();
    final newCtrl = TextEditingController();
    final confirmCtrl = TextEditingController();
    bool saving = false;

    await showDialog<void>(
      context: context,
      builder: (ctx) => StatefulBuilder(
        builder: (ctx, setState) => AlertDialog(
          title: Text(t.passwordDialogTitle),
          content: SingleChildScrollView(
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                TextField(
                  controller: oldCtrl,
                  obscureText: true,
                  decoration: InputDecoration(
                    labelText: t.oldPassword,
                    border: const OutlineInputBorder(),
                  ),
                ),
                const SizedBox(height: 12),
                TextField(
                  controller: newCtrl,
                  obscureText: true,
                  decoration: InputDecoration(
                    labelText: t.newPassword,
                    border: const OutlineInputBorder(),
                  ),
                ),
                const SizedBox(height: 12),
                TextField(
                  controller: confirmCtrl,
                  obscureText: true,
                  decoration: InputDecoration(
                    labelText: t.confirmNewPassword,
                    border: const OutlineInputBorder(),
                  ),
                ),
              ],
            ),
          ),
          actions: [
            TextButton(
              onPressed: saving ? null : () => Navigator.pop(ctx),
              child: Text(t.cancel),
            ),
            FilledButton(
              onPressed: saving
                  ? null
                  : () async {
                      final oldPwd = oldCtrl.text.trim();
                      final newPwd = newCtrl.text.trim();
                      final confirmPwd = confirmCtrl.text.trim();
                      if (oldPwd.isEmpty || newPwd.isEmpty) {
                        ScaffoldMessenger.of(ctx).showSnackBar(
                          SnackBar(content: Text(t.pleaseFillPassword)),
                        );
                        return;
                      }
                      if (newPwd != confirmPwd) {
                        ScaffoldMessenger.of(ctx).showSnackBar(
                          SnackBar(content: Text(t.passwordsDoNotMatch)),
                        );
                        return;
                      }
                      setState(() => saving = true);
                      try {
                        await SystemService().updatePassword(oldPwd, newPwd);
                        if (!ctx.mounted) return;
                        Navigator.pop(ctx);
                        ScaffoldMessenger.of(context).showSnackBar(
                          SnackBar(content: Text(t.passwordChangeSuccess)),
                        );
                        // 修改成功后安全登出，要求用新密码重新登录。
                        Future.delayed(const Duration(seconds: 1), () {
                          if (context.mounted) {
                            ref.read(authProvider.notifier).logout();
                          }
                        });
                      } on ApiException catch (e) {
                        setState(() => saving = false);
                        ScaffoldMessenger.of(ctx).showSnackBar(
                          SnackBar(content: Text(e.message)),
                        );
                      } catch (e) {
                        setState(() => saving = false);
                        ScaffoldMessenger.of(ctx).showSnackBar(
                          SnackBar(content: Text(t.passwordChangeFailed(formatApiError(e)))),
                        );
                      }
                    },
              child: saving
                  ? const SizedBox(
                      height: 18,
                      width: 18,
                      child: CircularProgressIndicator(strokeWidth: 2),
                    )
                  : Text(t.save),
            ),
          ],
        ),
      ),
    );

    oldCtrl.dispose();
    newCtrl.dispose();
    confirmCtrl.dispose();
  }

  String _themeModeLabel(ThemeMode mode, AppLocalizations t) {
    switch (mode) {
      case ThemeMode.dark:
        return t.themeDark;
      case ThemeMode.light:
        return t.themeLight;
      case ThemeMode.system:
        return t.themeSystem;
    }
  }

  String _orientationLabel(DisplayOrientation mode, AppLocalizations t) {
    switch (mode) {
      case DisplayOrientation.system:
        return t.orientationSystem;
      case DisplayOrientation.portrait:
        return t.orientationPortrait;
      case DisplayOrientation.landscape:
        return t.orientationLandscape;
    }
  }

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final themeMode = ref.watch(themeModeProvider);
    final appLocale = ref.watch(localeProvider);
    final displayOrientation = ref.watch(displayOrientationProvider);
    final authState = ref.watch(authProvider);
    final t = AppLocalizations.of(context);

    return Scaffold(
      appBar: AppBar(title: Text(t.settings)),
      body: ListView(
        children: [
          if (authState.user != null)
            ListTile(
              leading: const CircleAvatar(child: Icon(Icons.person)),
              title: Text(authState.user!.displayName),
              subtitle: Text(
                authState.user!.role.isEmpty
                    ? '${t.account}：${authState.user!.account}'
                    : authState.user!.role,
              ),
            ),
          const Divider(),
          // 主题切换：深色 / 浅色 / 跟随系统
          _AppSettingsTile(
            leading: const Icon(Icons.dark_mode_outlined),
            title: t.themeMode,
            subtitle: _themeModeLabel(themeMode, t),
            control: SegmentedButton<ThemeMode>(
              segments: [
                ButtonSegment(
                  value: ThemeMode.dark,
                  icon: const Icon(Icons.dark_mode),
                  label: Text(t.themeDark),
                ),
                ButtonSegment(
                  value: ThemeMode.light,
                  icon: const Icon(Icons.light_mode),
                  label: Text(t.themeLight),
                ),
                ButtonSegment(
                  value: ThemeMode.system,
                  icon: const Icon(Icons.settings_suggest),
                  label: Text(t.themeSystem),
                ),
              ],
              selected: {themeMode},
              onSelectionChanged: (selection) => ref
                  .read(themeModeProvider.notifier)
                  .setThemeMode(selection.first),
            ),
          ),
          // 语言切换：简体中文 / English
          _AppSettingsTile(
            leading: const Icon(Icons.language_outlined),
            title: t.language,
            subtitle: appLocale.label,
            control: SegmentedButton<AppLocale>(
              segments: const [
                ButtonSegment(value: AppLocale.zh, label: Text('中文')),
                ButtonSegment(value: AppLocale.en, label: Text('EN')),
              ],
              selected: {appLocale},
              onSelectionChanged: (selection) {
                try {
                  ref.read(localeProvider.notifier).setLocale(selection.first);
                } catch (e) {
                  if (!context.mounted) return;
                  ScaffoldMessenger.of(context).showSnackBar(
                    SnackBar(content: Text('语言切换失败：$e')),
                  );
                }
              },
            ),
          ),
          const Divider(),
          // 显示方向：跟随系统 / 竖屏 / 横屏（手动切换屏幕方向，布局自动适配）。
          _AppSettingsTile(
            leading: const Icon(Icons.screen_rotation_outlined),
            title: t.orientationMode,
            subtitle: _orientationLabel(displayOrientation, t),
            control: SegmentedButton<DisplayOrientation>(
              segments: [
                ButtonSegment(
                  value: DisplayOrientation.system,
                  icon: const Icon(Icons.screen_rotation),
                  label: Text(t.orientationSystem),
                ),
                ButtonSegment(
                  value: DisplayOrientation.portrait,
                  icon: const Icon(Icons.stay_current_portrait),
                  label: Text(t.orientationPortrait),
                ),
                ButtonSegment(
                  value: DisplayOrientation.landscape,
                  icon: const Icon(Icons.stay_current_landscape),
                  label: Text(t.orientationLandscape),
                ),
              ],
              selected: {displayOrientation},
              onSelectionChanged: (selection) => ref
                  .read(displayOrientationProvider.notifier)
                  .set(selection.first),
            ),
          ),
          const Divider(),
          // 修改密码
          ListTile(
            leading: const Icon(Icons.lock_outline),
            title: Text(t.changePassword),
            onTap: () => _showChangePasswordDialog(context, ref),
          ),
          const Divider(),
          // 检查更新
          ListTile(
            leading: const Icon(Icons.system_update_alt_outlined),
            title: Text(t.checkUpdate),
            subtitle: _VersionSubtitle(t: t),
            onTap: () => checkAndPromptUpdate(
              context,
              silentIfNoUpdate: false,
              orgId: ref.read(authProvider).user?.orgId,
            ),
          ),
          const Divider(),
          // 关于
          ListTile(
            leading: const Icon(Icons.info_outline),
            title: Text(t.about),
            subtitle: _VersionSubtitle(t: t, includeName: true),
            onTap: () async {
              final pkg = await currentPackageInfo;
              if (!context.mounted) return;
              showAboutDialog(
                context: context,
                applicationName: AppConstants.appName,
                applicationVersion: '${pkg.version} (${pkg.buildNumber})',
                applicationIcon: Image.asset(
                  'assets/images/logo.png',
                  width: 64,
                  height: 64,
                ),
                applicationLegalese: 'Device/system operation admin mobile demo',
              );
            },
          ),
          const Divider(),
          // 退出登录
          ListTile(
            leading: Icon(
              Icons.logout,
              color: Theme.of(context).colorScheme.error,
            ),
            title: Text(
              t.logout,
              style: TextStyle(color: Theme.of(context).colorScheme.error),
            ),
            onTap: () async {
              final confirmed = await showDialog<bool>(
                context: context,
                builder: (ctx) => AlertDialog(
                  title: Text(t.logout),
                  content: const Text('确定要退出当前账号吗？'),
                  actions: [
                    TextButton(
                      onPressed: () => Navigator.pop(ctx, false),
                      child: Text(t.cancel),
                    ),
                    FilledButton(
                      style: FilledButton.styleFrom(
                        backgroundColor: Theme.of(context).colorScheme.error,
                        foregroundColor: Theme.of(context).colorScheme.onError,
                      ),
                      onPressed: () => Navigator.pop(ctx, true),
                      child: Text(t.logout),
                    ),
                  ],
                ),
              );
              if (confirmed == true && context.mounted) {
                ref.read(authProvider.notifier).logout();
              }
            },
          ),
        ],
      ),
    );
  }
}

/// 设置项：图标 + 标题 + 副标题在上，控件整行铺满在下。
///
/// 用于 [SegmentedButton] 等较宽的控件，避免塞进 [ListTile.trailing]
/// 在窄屏溢出。
class _AppSettingsTile extends StatelessWidget {
  const _AppSettingsTile({
    required this.title,
    required this.control,
    this.subtitle,
    this.leading,
  });

  final String title;
  final Widget control;
  final String? subtitle;
  final Widget? leading;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 10),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            children: [
              if (leading != null) ...[
                leading!,
                const SizedBox(width: 12),
              ],
              Expanded(
                child: Text(
                  title,
                  style: theme.textTheme.titleMedium
                      ?.copyWith(fontWeight: FontWeight.w600),
                ),
              ),
            ],
          ),
          if (subtitle != null) ...[
            const SizedBox(height: 2),
            Padding(
              padding: EdgeInsets.only(left: leading != null ? 32 : 0),
              child: Text(
                subtitle!,
                style: theme.textTheme.bodySmall?.copyWith(
                  color: theme.colorScheme.onSurfaceVariant,
                ),
              ),
            ),
          ],
          const SizedBox(height: 12),
          SizedBox(width: double.infinity, child: control),
        ],
      ),
    );
  }
}

/// 当前 App 版本副标题：异步读取 [PackageInfo] 展示版本名与构建号。
///
/// [includeName]=true 时前缀应用名（用于「关于」项）。
class _VersionSubtitle extends StatelessWidget {
  const _VersionSubtitle({required this.t, this.includeName = false});

  final AppLocalizations t;
  final bool includeName;

  @override
  Widget build(BuildContext context) {
    return FutureBuilder<PackageInfo>(
      future: currentPackageInfo,
      builder: (ctx, snap) {
        final info = snap.data;
        if (includeName) {
          // 「关于」项：副标题只展示应用名，版本详情交由「关于」弹窗承载，
          // 避免与应用名 + 版本号 + 构建号叠加成冗余且暴露内部构建号的文案。
          return const Text(AppConstants.appName);
        }
        // 「检查更新」项：展示当前已安装版本名（不暴露内部构建号）。
        final version = info != null ? info.version : t.loading;
        return Text('${t.currentVersion} $version');
      },
    );
  }
}