import json
import os
import secrets
import logging

class Settings:
    _instance = None

    def __new__(cls, config_file=None):
        if cls._instance is None:
            cls._instance = super(Settings, cls).__new__(cls)
            if config_file is None:
                config_file = os.path.join(os.path.dirname(__file__), '..', 'appsettings.json')
            cls._instance.config_file = config_file
            cls._instance.load_settings()
        return cls._instance

    def load_settings(self):
        """Load settings from the JSON file, providing defaults if necessary, and save them."""
        try:
            if os.path.exists(self.config_file):
                with open(self.config_file, 'r') as file:
                    self.settings = json.load(file)
            else:
                self.settings = {}
            self.validate_settings()
            self.save_settings()
        except Exception as e:
            logging.error(f"Failed to load settings: {e}")
            self.settings = {}
            self.validate_settings()
            self.save_settings()

    def validate_settings(self):
        """Ensure all necessary settings are present, set defaults if not."""
        default_values = {
            'host': 'localhost',
            'port': 8000,
            'reload': False,
            'api_key': None  # Default API key is None which will trigger generation
        }

        # Check for presence and validity of each setting
        for key, default in default_values.items():
            if key == 'api_key':  # Special handling for API key
                if key not in self.settings or not self.is_valid_api_key(self.settings[key]):
                    self.settings[key] = self.generate_api_key()
            else:
                if key not in self.settings:
                    logging.info(key)
                    self.settings[key] = default
        self.save_settings()

    def is_valid_api_key(self, api_key):
        """Check if the API key is valid."""
        if api_key is None or not isinstance(api_key, str) or len(api_key) < 20:
            return False
        return True

    def generate_api_key(self):
        """Generate a new API key."""
        return secrets.token_urlsafe(32)

    def save_settings(self):
        """Save the current settings back to the JSON file."""
        try:
            with open(self.config_file, 'w') as file:
                json.dump(self.settings, file, indent=4)
            logging.info("Settings saved successfully.")
        except Exception as e:
            logging.error(f"Failed to save settings: {e}")

    def get_api_key(self):
        """Retrieve or generate an API key."""
        api_key = self.settings.get('api_key')
        if not self.is_valid_api_key(api_key):
            logging.error("Invalid API key found, generating a new one.")
            api_key = self.generate_api_key()
            self.settings['api_key'] = api_key
            self.save_settings()
        return api_key

    def generate_api_key(self):
        """Generate a new API key."""
        return secrets.token_urlsafe(32)

    def is_valid_api_key(self, api_key):
        """Check if the API key is valid."""
        if not api_key or not isinstance(api_key, str) or len(api_key) < 20:
            return False
        return True

# Initialize logging
logging.basicConfig(level=logging.INFO)
settings = Settings()