from typing import Optional
from PyQt6.QtWidgets import QApplication
from .theme import Theme, StyleSheet

class ThemeManager:
    _instance: Optional['ThemeManager'] = None
    _current_theme = Theme.DARK

    def __new__(cls):
        if cls._instance is None:
            cls._instance = super(ThemeManager, cls).__new__(cls)
        return cls._instance

    @classmethod
    def get_instance(cls) -> 'ThemeManager':
        if cls._instance is None:
            cls._instance = cls()
        return cls._instance

    @property
    def current_theme(self) -> Theme:
        return self._current_theme

    def switch_theme(self, theme: Theme):
        """Переключение темы приложения"""
        self._current_theme = theme
        self.apply_theme()

    def toggle_theme(self):
        """Переключение между светлой и темной темой"""
        new_theme = Theme.LIGHT if self._current_theme == Theme.DARK else Theme.DARK
        self.switch_theme(new_theme)

    def apply_theme(self):
        """Применение текущей темы ко всему приложению"""
        if not QApplication.instance():
            return

        # Применяем базовые стили
        QApplication.instance().setStyleSheet(
            StyleSheet.get_base_styles(self._current_theme)
        )

    def get_style(self, style_name: str) -> str:
        """Получение конкретного стиля"""
        return StyleSheet.get_base_styles(self._current_theme)