drb-core-client/app/config.py

import os
import json

class Config:
    """
    Manages application configuration stored in a JSON file.

    Provides attribute-style access to configuration values.
    """
    def __init__(self, file_path='/data/config.json'):
        """
        Initializes the Config manager.

        Loads configuration from the JSON file. Creates the file with an
        empty JSON object if it doesn't exist.

        Args:
            file_path (str): The path to the JSON configuration file.
        """
        self.file_path = file_path
        self._config_data = {} # Internal dictionary to hold config data
        self._load_config()

    def _load_config(self):
        """Loads configuration key-value pairs from the JSON file."""
        # Check if the file exists. If not, create it with an empty JSON object.
        if not os.path.exists(self.file_path):
            self._save_config() # Create the file with empty data

        try:
            with open(self.file_path, 'r') as f:
                # Load data from the file. Handle empty file case.
                content = f.read()
                if content:
                    self._config_data = json.loads(content)
                else:
                    self._config_data = {} # Initialize as empty if file is empty
        except (FileNotFoundError, json.JSONDecodeError) as e:
            print(f"Error loading config file {self.file_path}: {e}")
            # If there's an error loading, initialize with empty data
            self._config_data = {}
            # Optionally, you might want to back up the problematic file
            # or log the error more severely in a real application.

    def _save_config(self):
        """Saves the current configuration data to the JSON file."""
        try:
            with open(self.file_path, 'w') as f:
                json.dump(self._config_data, f, indent=4) # Use indent for readability
        except IOError as e:
            print(f"Error saving config file {self.file_path}: {e}")
        except TypeError as e:
            print(f"Error serializing config data to JSON: {e}. Ensure all values are JSON serializable.")

    def get(self, key, default=None):
        """
        Retrieves a configuration value by key.

        Args:
            key (str): The configuration key.
            default: The value to return if the key is not found.

        Returns:
            The configuration value or the default value if not found.
        """
        return self._config_data.get(key, default)

    def set(self, key, value):
        """
        Sets or updates a configuration value in memory and saves to the file.

        Args:
            key (str): The configuration key.
            value: The configuration value. Must be JSON serializable.
        """
        self._config_data[key] = value
        self._save_config()

    def delete(self, key):
        """
        Deletes a configuration key-value pair from memory and saves to the file.

        Args:
            key (str): The configuration key to delete.
        """
        if key in self._config_data:
            del self._config_data[key]
            self._save_config()
        else:
            print(f"Warning: Key '{key}' not found in config.")

    def __str__(self):
        """
        Returns a neat, formatted string representation of all configuration
        key-value pairs. This method is automatically called when the object
        is converted to a string (e.g., by print()).
        """
        if not self._config_data:
            return "\n--- Configuration is Empty ---\n"

        output = ["\n--- Current Configuration ---"]
        max_key_len = max(len(key) for key in self._config_data)
        for key, value in self._config_data.items():
            output.append(f"{key.ljust(max_key_len)} : {json.dumps(value, indent=None)}")
        output.append("-----------------------------\n")
        return "\n".join(output)

    def __getattr__(self, name):
        """
        Allows accessing configuration values using attribute notation (e.g., config.my_key).

        Args:
            name (str): The attribute name (configuration key).

        Returns:
            The configuration value associated with the key.

        Raises:
            AttributeError: If the key is not found in the configuration.
        """
        if name in self._config_data:
            return self._config_data[name]
        # Fallback for standard attributes if not found in config data
        try:
            return self.__getattribute__(name)
        except AttributeError:
            raise AttributeError(f"'Config' object has no attribute '{name}' and key '{name}' not found in config.")

    def __setattr__(self, name, value):
        """
        Allows setting configuration values using attribute notation (e.g., config.my_key = value).

        Args:
            name (str): The attribute name (configuration key).
            value: The value to set. Must be JSON serializable.
        """
        # Handle setting internal attributes like file_path or _config_data
        if name in ('file_path', '_config_data'):
            super().__setattr__(name, value)
        else:
            # Treat other attribute assignments as setting config values
            self.set(name, value)

    def __delattr__(self, name):
        """
        Allows deleting configuration values using attribute notation (e.g., del config.my_key).

        Args:
            name (str): The attribute name (configuration key) to delete.
        """
        if name in self._config_data:
            self.delete(name)
        else:
            # Fallback for standard attributes
            super().__delattr__(name)