"""
Configuration Manager for the application.
Handles loading and saving of application settings to a JSON file.
"""
import json
from pathlib import Path
from typing import Dict, Any, Optional

from . import logger

log = logger.get_logger(__name__)


class ConfigManager:
    """Manages loading and saving configuration from/to a JSON file."""

    def __init__(self, config_path: Path):
        """
        Initializes the ConfigManager.

        Args:
            config_path: The path to the configuration file.
        """
        self.config_path: Path = config_path
        self.config: Dict[str, Any] = self._get_default_config()

    @staticmethod
    def _get_default_config() -> Dict[str, Any]:
        """Provides the default configuration structure."""
        return {
            "last_opened_file": ""
        }

    def load_config(self) -> None:
        """
        Loads the configuration from the JSON file.
        If the file does not exist, it starts with the default configuration.
        """
        log.info(f"Attempting to load configuration from: {self.config_path}")
        if self.config_path.is_file():
            try:
                with open(self.config_path, 'r', encoding='utf-8') as f:
                    loaded_data = json.load(f)
                    # Merge loaded data with defaults to ensure all keys exist
                    self.config.update(loaded_data)
                    log.info("Configuration loaded successfully.")
            except (json.JSONDecodeError, IOError) as e:
                log.error(f"Failed to load or parse config file: {e}. Using defaults.")
                self.config = self._get_default_config()
        else:
            log.warning("Configuration file not found. Using default settings.")
            self.config = self._get_default_config()

    def save_config(self) -> None:
        """Saves the current configuration to the JSON file."""
        log.info(f"Saving configuration to: {self.config_path}")
        try:
            # Ensure the parent directory exists
            self.config_path.parent.mkdir(parents=True, exist_ok=True)
            with open(self.config_path, 'w', encoding='utf-8') as f:
                json.dump(self.config, f, indent=4)
            log.info("Configuration saved successfully.")
        except IOError as e:
            log.error(f"Failed to save configuration file: {e}")

    def get(self, key: str, default: Optional[Any] = None) -> Any:
        """Gets a value from the configuration."""
        return self.config.get(key, default)

    def set(self, key: str, value: Any) -> None:
        """Sets a value in the configuration."""
        self.config[key] = value