import json
from pathlib import Path
import logging

logger = logging.getLogger(__name__)

DB_NAME = 'iottb.db'

class IottbConfig:
    def __init__(self, cfg_file):
        self.cfg_file = cfg_file
        self.default_database = None
        self.default_path = None
        self.database_locations = {}
        self.load_config()

    def create_default_config(self):
        """Create default iottb config file."""
        logger.info(f'Creating default config file at {self.cfg_file}')
        self.default_database = DB_NAME
        self.default_path = str(Path.home() / DB_NAME)
        self.database_locations = {
            DB_NAME: self.default_path
        }

        defaults = {
            'DefaultDatabase': self.default_database,
            'DefaultDatabasePath': self.default_path,
            'DatabaseLocations': self.database_locations
        }

        try:
            self.cfg_file.parent.mkdir(parents=True, exist_ok=True)
            with self.cfg_file.open('w') as config_file:
                json.dump(defaults, config_file, indent=4)
        except IOError as e:
            logger.error(f"Failed to create default configuration file at {self.cfg_file}: {e}")
            raise RuntimeError(f"Failed to create configuration file: {e}") from e

    def load_config(self):
        """Loads or creates default configuration from given file path."""
        if not self.cfg_file.is_file():
            self.create_default_config()
        else:
            with self.cfg_file.open('r') as config_file:
                data = json.load(config_file)
                self.default_database = data.get('DefaultDatabase')
                self.default_path = data.get('DefaultDatabasePath')
                self.database_locations = data.get('DatabaseLocations', {})

    def save_config(self):
        """Save the current configuration to the config file."""
        data = {
            'DefaultDatabase': self.default_database,
            'DefaultDatabasePath': self.default_path,
            'DatabaseLocations': self.database_locations
        }
        try:
            with self.cfg_file.open('w') as config_file:
                json.dump(data, config_file, indent=4)
        except IOError as e:
            logger.error(f"Failed to save configuration file at {self.cfg_file}: {e}")
            raise RuntimeError(f"Failed to save configuration file: {e}") from e

    def set_default_database(self, name, path):
        """Set the default database and its path."""
        self.default_database = name
        self.default_path = path
        self.database_locations[name] = path

    def get_database_location(self, name):
        """Get the location of a specific database."""
        return self.database_locations.get(name)

    def set_database_location(self, name, path):
        """Set the location for a database."""
        self.database_locations[name] = path