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

enum AppThemeVariant { redDark, redLight, greenDark, greenLight }

const _themeKey = 'themeVariant';

/// Colour scheme (red/green) × brightness (dark/light), persisted.
class ThemeNotifier extends StateNotifier<AppThemeVariant> {
  ThemeNotifier() : super(AppThemeVariant.redDark) {
    _load();
  }

  Future<void> _load() async {
    try {
      final prefs = await SharedPreferences.getInstance();
      final saved = prefs.getString(_themeKey);
      for (final v in AppThemeVariant.values) {
        if (v.name == saved && mounted) state = v;
      }
    } catch (_) {
      // Keep the default if preferences can't be read.
    }
  }

  void set(AppThemeVariant v) {
    state = v;
    SharedPreferences.getInstance()
        .then((prefs) => prefs.setString(_themeKey, v.name))
        .catchError((Object _) => false);
  }
}

final themeProvider =
    StateNotifierProvider<ThemeNotifier, AppThemeVariant>(
  (ref) => ThemeNotifier(),
);

/// Returns the accent color for the current theme variant.
extension AppThemeVariantX on AppThemeVariant {
  Color get accentColor {
    switch (this) {
      case AppThemeVariant.redDark:
      case AppThemeVariant.redLight:
        return const Color(0xFFFF4444);
      case AppThemeVariant.greenDark:
      case AppThemeVariant.greenLight:
        return const Color(0xFF00E676);
    }
  }

  bool get isDark =>
      this == AppThemeVariant.redDark || this == AppThemeVariant.greenDark;
}