import json
from pathlib import Path
import logging

logger = logging.getLogger(__name__)

DB_NAME = 'iottb.db'


class IottbConfig:
    """ Class to handle operations on the testbed configuration.

       TODO: Add instead of overwrite Database locations when initializing if a location with valid db
        exists.
    """

    @staticmethod
    def warn():
        logger.warning(f'DatabaseLocations are DatabaseLocationMap in the class {__name__}')

    def __init__(self, cfg_file):
        logger.info('Initializing Config object')
        IottbConfig.warn()
        self.cfg_file = cfg_file
        self.default_database = None
        self.default_path = None
        self.DatabaseLocationMap = {}
        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.DatabaseLocationMap = {
            DB_NAME: self.default_path
        }

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

        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."""
        logger.info('Loading configuration file')
        if not self.cfg_file.is_file():
            logger.info('Config file does not exist.')
            self.create_default_config()
        else:
            logger.info('Config file exists, opening.')
            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.DatabaseLocationMap = 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.DatabaseLocationMap
        }
        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.DatabaseLocationMap[name] = path

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

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

    def get_known_databases(self):
        """Get the set of known databases"""
        logger.info(f'Getting known databases.')

        return self.DatabaseLocationMap.keys()


# TODO: Know issue:
class Database:
    pass