import 'package:flutter/material.dart';

import '../../../../l10n/app_localizations.dart';
import '../../../../shared/theme/design_tokens.dart';
import '../widgets/settings_section_widgets.dart';

class LanguageSettingsScreen extends StatelessWidget {
  const LanguageSettingsScreen({super.key, required this.selectedLanguageTag});

  final String selectedLanguageTag;

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    final colors = Theme.of(context).colorScheme;

    final options = _buildLanguageOptions(l10n);

    return Scaffold(
      backgroundColor: colors.surfaceContainerLow,
      appBar: AppBar(
        title: Text(l10n.language),
        centerTitle: true,
        backgroundColor: colors.surfaceContainerLow,
        surfaceTintColor: colors.surfaceContainerLow,
      ),
      body: ListView(
        padding: const EdgeInsets.all(AppSpacing.lg),
        children: [
          SectionLabel(text: l10n.settingsLanguageSection),
          SettingsGroupCard(
            children: [
              for (int i = 0; i < options.length; i++)
                SettingsMenuTile(
                  icon: Icons.language_rounded,
                  title: options[i].label,
                  subtitle: options[i].tag,
                  tint: colors.primary,
                  background: colors.surfaceContainerHighest,
                  showDivider: i != options.length - 1,
                  showChevron: false,
                  trailing: selectedLanguageTag == options[i].tag
                      ? Icon(Icons.check_rounded, color: colors.primary)
                      : null,
                  onTap: () => Navigator.of(context).pop(options[i].tag),
                ),
            ],
          ),
        ],
      ),
    );
  }

  List<({String tag, String label})> _buildLanguageOptions(
    AppLocalizations l10n,
  ) {
    final supportedLocales = AppLocalizations.supportedLocales;
    return supportedLocales.map((locale) {
      final tag = _localeToTag(locale);
      final label = _getLocaleLabel(locale, l10n);
      return (tag: tag, label: label);
    }).toList();
  }

  String _localeToTag(Locale locale) {
    final lang = locale.languageCode;
    final script = locale.scriptCode;
    final country = locale.countryCode;
    if (script != null && country != null) {
      return '$lang-$script-$country';
    } else if (country != null) {
      return '$lang-$country';
    }
    return _mapToBackendTag(lang);
  }

  String _mapToBackendTag(String flutterTag) {
    const mapping = {'zh': 'zh-CN', 'en': 'en-US'};
    return mapping[flutterTag] ?? flutterTag;
  }

  String _getLocaleLabel(Locale locale, AppLocalizations l10n) {
    if (locale.languageCode == 'zh') {
      return l10n.chinese;
    } else if (locale.languageCode == 'en') {
      return l10n.english;
    }
    return locale.languageCode;
  }
}