import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:lba/res/colors.dart';
import 'package:lba/utils/sharedPreferencesKey.dart';
import 'package:lba/utils/sharedPreferencesManger.dart';

class ThemeManager extends ChangeNotifier with WidgetsBindingObserver {
  late SharedPreferencesManager _prefs;
  bool _isDarkMode = false;
  bool _isThemeTransitioning = false;
  bool _hasManualOverride = false;

  ThemeManager() {
    _prefs = SharedPreferencesManager();
    _loadTheme();
    WidgetsBinding.instance.addObserver(this);
  }

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    super.dispose();
  }

  bool get isDarkMode => _isDarkMode;
  bool get isThemeTransitioning => _isThemeTransitioning;

  ThemeData get lightTheme => ThemeData(
        fontFamily: 'Roboto',
        brightness: Brightness.light,
        scaffoldBackgroundColor: LightAppColors.scaffoldBackground,
        primaryColor: LightAppColors.inputBorder,
        buttonTheme: ButtonThemeData(
          buttonColor: LightAppColors.inputBorder,
        ),
        appBarTheme: AppBarTheme(
          backgroundColor: LightAppColors.surface,
          foregroundColor: LightAppColors.textPrimary,
          surfaceTintColor: LightAppColors.surface,
          systemOverlayStyle: SystemUiOverlayStyle(
            statusBarColor: Colors.transparent,
            statusBarIconBrightness: Brightness.dark,
            statusBarBrightness: Brightness.light,
          ),
          titleTextStyle: TextStyle(
            color: LightAppColors.textPrimary,
            fontSize: 20,
            fontWeight: FontWeight.w600,
          ),
        ),
        bottomNavigationBarTheme: BottomNavigationBarThemeData(
          backgroundColor: LightAppColors.surface,
          selectedItemColor: LightAppColors.primary,
          unselectedItemColor: LightAppColors.textSecondary,
        ),
        dialogTheme: DialogTheme(
          backgroundColor: LightAppColors.surface,
          titleTextStyle: TextStyle(color: LightAppColors.textPrimary),
          contentTextStyle: TextStyle(color: LightAppColors.textSecondary),
        ),
        dropdownMenuTheme: DropdownMenuThemeData(
          menuStyle: MenuStyle(
            backgroundColor: MaterialStatePropertyAll(LightAppColors.surface),
          ),
        ),
        inputDecorationTheme: InputDecorationTheme(
          labelStyle: TextStyle(color: LightAppColors.textPrimary),
          hintStyle: TextStyle(color: LightAppColors.hint),
          enabledBorder: OutlineInputBorder(
            borderSide: BorderSide(color: LightAppColors.divider),
          ),
          focusedBorder: OutlineInputBorder(
            borderSide: BorderSide(
              color: LightAppColors.inputBorder,
              width: 2,
            ),
          ),
        ),
        pageTransitionsTheme: const PageTransitionsTheme(
          builders: {
            TargetPlatform.android: CupertinoPageTransitionsBuilder(),
            TargetPlatform.iOS: CupertinoPageTransitionsBuilder(),
          },
        ),
        textTheme: TextTheme(
          bodyLarge: TextStyle(color: LightAppColors.textPrimary),
          bodyMedium: TextStyle(color: LightAppColors.textPrimary),
          bodySmall: TextStyle(color: LightAppColors.textSecondary),
          headlineLarge: TextStyle(color: LightAppColors.textPrimary),
          headlineMedium: TextStyle(color: LightAppColors.textPrimary),
          headlineSmall: TextStyle(color: LightAppColors.textPrimary),
          titleLarge: TextStyle(color: LightAppColors.textPrimary),
          titleMedium: TextStyle(color: LightAppColors.textPrimary),
          titleSmall: TextStyle(color: LightAppColors.textPrimary),
        ),
      );

  ThemeData get darkTheme => ThemeData(
        fontFamily: 'Roboto',
        brightness: Brightness.dark,
        scaffoldBackgroundColor: DarkAppColors.scaffoldBackground,
        primaryColor: DarkAppColors.inputBorder,
        buttonTheme: ButtonThemeData(
          buttonColor: DarkAppColors.inputBorder,
        ),
        appBarTheme: AppBarTheme(
          backgroundColor: DarkAppColors.surface,
          foregroundColor: DarkAppColors.textPrimary,
          surfaceTintColor: DarkAppColors.surface,
          systemOverlayStyle: SystemUiOverlayStyle(
            statusBarColor: Colors.transparent,
            statusBarIconBrightness: Brightness.light,
            statusBarBrightness: Brightness.dark,
          ),
          titleTextStyle: TextStyle(
            color: DarkAppColors.textPrimary,
            fontSize: 20,
            fontWeight: FontWeight.w600,
          ),
        ),
        bottomNavigationBarTheme: BottomNavigationBarThemeData(
          backgroundColor: DarkAppColors.surface,
          selectedItemColor: DarkAppColors.primary,
          unselectedItemColor: DarkAppColors.textSecondary,
        ),
        dialogTheme: DialogTheme(
          backgroundColor: DarkAppColors.surface,
          titleTextStyle: TextStyle(color: DarkAppColors.textPrimary),
          contentTextStyle: TextStyle(color: DarkAppColors.textSecondary),
        ),
        dropdownMenuTheme: DropdownMenuThemeData(
          menuStyle: MenuStyle(
            backgroundColor: MaterialStatePropertyAll(DarkAppColors.surface),
          ),
        ),
        inputDecorationTheme: InputDecorationTheme(
          labelStyle: TextStyle(color: DarkAppColors.textPrimary),
          hintStyle: TextStyle(color: DarkAppColors.hint),
          enabledBorder: OutlineInputBorder(
            borderSide: BorderSide(color: DarkAppColors.divider),
          ),
          focusedBorder: OutlineInputBorder(
            borderSide: BorderSide(
              color: DarkAppColors.inputBorder,
              width: 2,
            ),
          ),
        ),
        pageTransitionsTheme: const PageTransitionsTheme(
          builders: {
            TargetPlatform.android: CupertinoPageTransitionsBuilder(),
            TargetPlatform.iOS: CupertinoPageTransitionsBuilder(),
          },
        ),
        textTheme: TextTheme(
          bodyLarge: TextStyle(color: DarkAppColors.textPrimary),
          bodyMedium: TextStyle(color: DarkAppColors.textPrimary),
          bodySmall: TextStyle(color: DarkAppColors.textSecondary),
          headlineLarge: TextStyle(color: DarkAppColors.textPrimary),
          headlineMedium: TextStyle(color: DarkAppColors.textPrimary),
          headlineSmall: TextStyle(color: DarkAppColors.textPrimary),
          titleLarge: TextStyle(color: DarkAppColors.textPrimary),
          titleMedium: TextStyle(color: DarkAppColors.textPrimary),
          titleSmall: TextStyle(color: DarkAppColors.textSecondary),
        ),
      );

  ThemeData get currentTheme => _isDarkMode ? darkTheme : lightTheme;

  /// Returns the appropriate ThemeMode based on user preferences
  ThemeMode getThemeMode() {
    if (_hasManualOverride) {
      return _isDarkMode ? ThemeMode.dark : ThemeMode.light;
    } else {
      return ThemeMode.system;
    }
  }

  @override
  void didChangePlatformBrightness() {
    super.didChangePlatformBrightness();
    
    // Only respond to system theme changes if user hasn't manually overridden
    if (!_hasManualOverride) {
      bool systemIsDark = _getSystemTheme();
      if (_isDarkMode != systemIsDark) {
        _isDarkMode = systemIsDark;
        AppColors.setDarkMode(_isDarkMode);
        _updateSystemUIOverlay();
        notifyListeners();
      }
    }
  }

  Future<void> _loadTheme() async {
    await _prefs.init();
    _hasManualOverride = _prefs.getBool(SharedPreferencesKey.hasManualThemeOverride) ?? false;
    
    if (_hasManualOverride) {
      _isDarkMode = _prefs.getBool(SharedPreferencesKey.isDarkMode) ?? false;
    } else {
      _isDarkMode = _getSystemTheme();
    }
    
    AppColors.setDarkMode(_isDarkMode);
    _updateSystemUIOverlay();
    notifyListeners();
  }

  bool _getSystemTheme() {
    return WidgetsBinding.instance.platformDispatcher.platformBrightness == Brightness.dark;
  }

  void _updateSystemUIOverlay() {
    SystemChrome.setSystemUIOverlayStyle(
      SystemUiOverlayStyle(
        statusBarColor: Colors.transparent,
        statusBarIconBrightness: _isDarkMode ? Brightness.light : Brightness.dark,
        statusBarBrightness: _isDarkMode ? Brightness.dark : Brightness.light,
        systemNavigationBarColor: _isDarkMode 
            ? DarkAppColors.scaffoldBackground 
            : LightAppColors.scaffoldBackground,
        systemNavigationBarIconBrightness: _isDarkMode ? Brightness.light : Brightness.dark,
        systemNavigationBarDividerColor: _isDarkMode 
            ? DarkAppColors.divider 
            : LightAppColors.divider,
      ),
    );
  }

  Future<void> toggleTheme() async {
    _isDarkMode = !_isDarkMode;
    _hasManualOverride = true;
    AppColors.setDarkMode(_isDarkMode);
    _updateSystemUIOverlay();
    await _prefs.saveBool(SharedPreferencesKey.isDarkMode, _isDarkMode);
    await _prefs.saveBool(SharedPreferencesKey.hasManualThemeOverride, _hasManualOverride);
    notifyListeners();
  }

  Future<void> setTheme(bool isDark) async {
    if (_isDarkMode != isDark) {
      _isDarkMode = isDark;
      _hasManualOverride = true;
      AppColors.setDarkMode(_isDarkMode);
      _updateSystemUIOverlay();
      await _prefs.saveBool(SharedPreferencesKey.isDarkMode, _isDarkMode);
      await _prefs.saveBool(SharedPreferencesKey.hasManualThemeOverride, _hasManualOverride);
      notifyListeners();
    }
  }

  Future<void> resetToSystemTheme() async {
    _hasManualOverride = false;
    _isDarkMode = _getSystemTheme();
    AppColors.setDarkMode(_isDarkMode);
    _updateSystemUIOverlay();
    await _prefs.saveBool(SharedPreferencesKey.hasManualThemeOverride, _hasManualOverride);
    await _prefs.saveBool(SharedPreferencesKey.isDarkMode, _isDarkMode);
    notifyListeners();
  }
}