import json
import os

class ConfigManager:
    def __init__(self, config_path: str = "config/config.json"):
        self.config_path = config_path
        self.config = self._load()

    def _load(self):
        if not os.path.exists(self.config_path):
            raise FileNotFoundError(f"Config file not found: {self.config_path}")
        with open(self.config_path, "r", encoding="utf-8") as f:
            return json.load(f)

    def get(self, key, default=None):
        """Return a top-level config key, e.g. 'Font' or 'Mode'."""
        return self.config.get(key, default)

    def save(self):
        """Write any changes back to disk."""
        with open(self.config_path, "w", encoding="utf-8") as f:
            json.dump(self.config, f, indent=2)