import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';
import '../l10n/app_localizations.dart';
import '../theme/app_colors.dart';
import '../theme/app_text_styles.dart';

/// Settings Screen - MVP version with duration presets
class SettingsScreen extends StatefulWidget {
  const SettingsScreen({super.key});

  /// Get the saved default duration (for use in other screens)
  static Future<int> getDefaultDuration() async {
    final prefs = await SharedPreferences.getInstance();
    return prefs.getInt(_durationKey) ?? 25;
  }

  /// Get the saved locale
  static Future<String?> getSavedLocale() async {
    final prefs = await SharedPreferences.getInstance();
    return prefs.getString(_localeKey);
  }

  /// Save the locale
  static Future<void> saveLocale(String localeCode) async {
    final prefs = await SharedPreferences.getInstance();
    await prefs.setString(_localeKey, localeCode);
  }

  static const String _durationKey = 'default_duration';
  static const String _localeKey = 'app_locale';

  @override
  State<SettingsScreen> createState() => _SettingsScreenState();
}

class _SettingsScreenState extends State<SettingsScreen> {
  int _selectedDuration = 25; // Default
  String _selectedLocale = 'en'; // Default

  final List<int> _durationOptions = [15, 25, 45];

  @override
  void initState() {
    super.initState();
    _loadSavedDuration();
    _loadSavedLocale();
  }

  Future<void> _loadSavedDuration() async {
    final prefs = await SharedPreferences.getInstance();
    setState(() {
      _selectedDuration = prefs.getInt(SettingsScreen._durationKey) ?? 25;
    });
  }

  Future<void> _loadSavedLocale() async {
    final prefs = await SharedPreferences.getInstance();
    setState(() {
      _selectedLocale = prefs.getString(SettingsScreen._localeKey) ?? 'en';
    });
  }

  Future<void> _saveDuration(int duration) async {
    final prefs = await SharedPreferences.getInstance();
    await prefs.setInt(SettingsScreen._durationKey, duration);
    setState(() {
      _selectedDuration = duration;
    });
  }

  Future<void> _saveLocale(String localeCode) async {
    await SettingsScreen.saveLocale(localeCode);
    setState(() {
      _selectedLocale = localeCode;
    });

    // Show snackbar to inform user to restart
    if (!mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text(AppLocalizations.of(context)!.onboardingReset),
        duration: const Duration(seconds: 2),
      ),
    );
  }

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

    return Scaffold(
      backgroundColor: AppColors.background,
      appBar: AppBar(
        title: Text(l10n.settings),
        backgroundColor: AppColors.background,
      ),
      body: ListView(
        padding: const EdgeInsets.all(24),
        children: [
          // Focus Duration Section
          _buildSection(
            title: l10n.focusSettings,
            children: [
              Padding(
                padding: const EdgeInsets.only(bottom: 16),
                child: Text(
                  l10n.defaultFocusDuration,
                  style: AppTextStyles.bodyText,
                ),
              ),
              ..._durationOptions.map((duration) {
                return _buildDurationOption(l10n, duration);
              }),
            ],
          ),

          const SizedBox(height: 32),

          // Language Section
          _buildSection(
            title: l10n.language,
            children: [
              _buildLanguageOption(l10n, 'en', l10n.english),
              const Divider(color: AppColors.divider),
              _buildLanguageOption(l10n, 'zh', l10n.chinese),
            ],
          ),

          const SizedBox(height: 32),

          // About Section
          _buildSection(
            title: l10n.about,
            children: [
              ListTile(
                contentPadding: EdgeInsets.zero,
                title: Text(
                  l10n.privacyPolicy,
                  style: AppTextStyles.bodyText,
                ),
                trailing: const Icon(
                  Icons.arrow_forward_ios,
                  size: 16,
                  color: AppColors.textSecondary,
                ),
                onTap: () {
                  _showPrivacyPolicy();
                },
              ),
              const Divider(color: AppColors.divider),
              ListTile(
                contentPadding: EdgeInsets.zero,
                title: Text(
                  l10n.aboutFocusBuddy,
                  style: AppTextStyles.bodyText,
                ),
                trailing: const Icon(
                  Icons.arrow_forward_ios,
                  size: 16,
                  color: AppColors.textSecondary,
                ),
                onTap: () {
                  _showAboutDialog();
                },
              ),
              const Divider(color: AppColors.divider),
              ListTile(
                contentPadding: EdgeInsets.zero,
                title: Text(
                  l10n.resetOnboarding,
                  style: AppTextStyles.bodyText.copyWith(
                    color: AppColors.textSecondary,
                  ),
                ),
                trailing: const Icon(
                  Icons.refresh,
                  size: 16,
                  color: AppColors.textSecondary,
                ),
                onTap: () {
                  _resetOnboarding();
                },
              ),
            ],
          ),

          const SizedBox(height: 32),

          // Version info
          Center(
            child: Text(
              l10n.version,
              style: AppTextStyles.helperText.copyWith(fontSize: 12),
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildSection({
    required String title,
    required List<Widget> children,
  }) {
    return Container(
      padding: const EdgeInsets.all(20),
      decoration: BoxDecoration(
        color: AppColors.white,
        borderRadius: BorderRadius.circular(16),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(
            title,
            style: const TextStyle(
              fontFamily: 'Nunito',
              fontSize: 18,
              fontWeight: FontWeight.w600,
              color: AppColors.textPrimary,
            ),
          ),
          const SizedBox(height: 16),
          ...children,
        ],
      ),
    );
  }

  Widget _buildDurationOption(AppLocalizations l10n, int duration) {
    final isSelected = _selectedDuration == duration;

    return GestureDetector(
      onTap: () => _saveDuration(duration),
      child: Container(
        margin: const EdgeInsets.only(bottom: 12),
        padding: const EdgeInsets.all(16),
        decoration: BoxDecoration(
          color: isSelected
              ? AppColors.primary.withValues(alpha: 0.1)
              : AppColors.background,
          border: Border.all(
            color: isSelected ? AppColors.primary : AppColors.divider,
            width: isSelected ? 2 : 1,
          ),
          borderRadius: BorderRadius.circular(12),
        ),
        child: Row(
          children: [
            // Radio button
            Container(
              width: 20,
              height: 20,
              decoration: BoxDecoration(
                shape: BoxShape.circle,
                border: Border.all(
                  color: isSelected ? AppColors.primary : AppColors.textSecondary,
                  width: 2,
                ),
                color: isSelected ? AppColors.primary : Colors.transparent,
              ),
              child: isSelected
                  ? const Center(
                      child: Icon(
                        Icons.check,
                        size: 12,
                        color: AppColors.white,
                      ),
                    )
                  : null,
            ),

            const SizedBox(width: 16),

            // Duration text
            Expanded(
              child: Text(
                l10n.minutesValue(duration, l10n.minutes(duration)),
                style: TextStyle(
                  fontFamily: 'Nunito',
                  fontSize: 16,
                  fontWeight: isSelected ? FontWeight.w600 : FontWeight.w400,
                  color: isSelected
                      ? AppColors.primary
                      : AppColors.textPrimary,
                ),
              ),
            ),

            // Description
            if (duration == 25)
              Container(
                padding: const EdgeInsets.symmetric(
                  horizontal: 8,
                  vertical: 4,
                ),
                decoration: BoxDecoration(
                  color: AppColors.success.withValues(alpha: 0.1),
                  borderRadius: BorderRadius.circular(8),
                ),
                child: Text(
                  l10n.defaultLabel,
                  style: const TextStyle(
                    fontFamily: 'Nunito',
                    fontSize: 12,
                    fontWeight: FontWeight.w600,
                    color: AppColors.success,
                  ),
                ),
              ),
          ],
        ),
      ),
    );
  }

  Widget _buildLanguageOption(AppLocalizations l10n, String localeCode, String label) {
    final isSelected = _selectedLocale == localeCode;

    return ListTile(
      contentPadding: EdgeInsets.zero,
      title: Text(
        label,
        style: TextStyle(
          fontFamily: 'Nunito',
          fontSize: 16,
          fontWeight: isSelected ? FontWeight.w600 : FontWeight.w400,
          color: isSelected ? AppColors.primary : AppColors.textPrimary,
        ),
      ),
      trailing: isSelected
          ? const Icon(
              Icons.check_circle,
              color: AppColors.primary,
            )
          : null,
      onTap: () => _saveLocale(localeCode),
    );
  }

  void _showPrivacyPolicy() {
    final l10n = AppLocalizations.of(context)!;

    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: Text(l10n.privacyPolicyTitle),
        content: SingleChildScrollView(
          child: Text(
            l10n.privacyPolicyContent,
            style: AppTextStyles.bodyText,
          ),
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: Text(l10n.close),
          ),
        ],
      ),
    );
  }

  void _showAboutDialog() {
    final l10n = AppLocalizations.of(context)!;

    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: Text(l10n.aboutTitle),
        content: SingleChildScrollView(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                l10n.appTitle,
                style: const TextStyle(
                  fontFamily: 'Nunito',
                  fontSize: 20,
                  fontWeight: FontWeight.w700,
                  color: AppColors.primary,
                ),
              ),
              const SizedBox(height: 8),
              Text(
                l10n.aboutSubtitle,
                style: AppTextStyles.bodyText,
              ),
              const SizedBox(height: 16),
              Text(
                l10n.aboutQuote,
                style: AppTextStyles.encouragementQuote,
              ),
              const SizedBox(height: 16),
              Text(
                l10n.aboutFeatures,
                style: AppTextStyles.bodyText,
              ),
            ],
          ),
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: Text(l10n.close),
          ),
        ],
      ),
    );
  }

  void _resetOnboarding() async {
    final l10n = AppLocalizations.of(context)!;

    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: Text(l10n.resetOnboardingTitle),
        content: Text(
          l10n.resetOnboardingMessage,
          style: AppTextStyles.bodyText,
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: Text(l10n.cancel),
          ),
          TextButton(
            onPressed: () async {
              final prefs = await SharedPreferences.getInstance();
              await prefs.remove('onboarding_completed');

              if (!context.mounted) return;

              Navigator.pop(context);
              ScaffoldMessenger.of(context).showSnackBar(
                SnackBar(
                  content: Text(l10n.onboardingReset),
                  duration: const Duration(seconds: 3),
                ),
              );
            },
            child: Text(l10n.reset),
          ),
        ],
      ),
    );
  }
}