import configparser
import os
from typing import Dict

class ConfigManager:
    """Manages the application's INI configuration file."""

    _SECTION_NAME = 'Settings'
    _LAST_DIR_KEY = 'last_directory'
    _LAST_CMAP_KEY = 'last_colormap'

    def __init__(self, config_file: str):
        """
        Initializes the ConfigManager.

        Args:
            config_file: The path to the configuration file.
        """
        self.config_file = config_file
        self.config = configparser.ConfigParser()

    def load_config(self) -> Dict[str, str]:
        """
        Loads the configuration from the file.

        If the file does not exist, it returns default values.

        Returns:
            A dictionary containing the configuration settings.
        """
        if os.path.exists(self.config_file):
            self.config.read(self.config_file)
        
        # Use .get with fallback for safety, even if file exists
        last_directory = self.config.get(
            self._SECTION_NAME, self._LAST_DIR_KEY, fallback='.'
        )
        last_colormap = self.config.get(
            self._SECTION_NAME, self._LAST_CMAP_KEY, fallback='viridis'
        )

        return {
            'last_directory': last_directory,
            'last_colormap': last_colormap
        }

    def save_config(self, settings: Dict[str, str]) -> None:
        """
        Saves the given settings to the configuration file.

        Args:
            settings: A dictionary of settings to save.
        """
        self.config[self._SECTION_NAME] = settings
        with open(self.config_file, 'w') as configfile:
            self.config.write(configfile)