import shutil

import yaml
import platformdirs
from pathlib import Path

import constants
from log_setup import logger


class DBConfig:
    def __init__(self, db_name: str, db_user: str, db_pass: str):
        self.db_name = db_name
        self.db_user = db_user
        self.db_pass = db_pass


def get_db_config_path() -> Path:
    config_dir = Path(platformdirs.user_config_dir(constants.APP_NAME, ensure_exists=True))
    config_path = config_dir / constants.DB_CONFIG_FILE_NAME
    return config_path


def read_db_config() -> DBConfig:
    """
    Reads the DB connection parameters from the config file.
    """
    config_path = get_db_config_path()
    logger.verbose("DB Configuration read from file {}".format(config_path))

    if config_path.exists():
        with open(config_path, "r") as f:
            config = yaml.safe_load(f)
        db_name = config.get('dbname', None)
        db_user = config.get('dbuser', None)
        db_pass = config.get('dbpass', None)

        if db_name is None:
            logger.debug("Falling back to default DB name {}".format(constants.DEFAULT_DB_NAME))
            db_name = constants.DEFAULT_DB_NAME
        if db_user is None:
            logger.debug("Falling back to default DB user {}".format(constants.DEFAULT_DB_USER))
            db_user = constants.DEFAULT_DB_USER
        if db_pass is None:
            logger.debug("Falling back to default DB pass {}".format(constants.DEFAULT_DB_PASS))
            db_pass = constants.DEFAULT_DB_PASS

        logger.debug("Read config values (dbname={}, dbuser={}, dbpass={})".format(db_name, db_user, db_pass))

        return DBConfig(db_name, db_user, db_pass)
    else:
        logger.info(
            "No configuration file for database connection found, falling back to default values "
            "(dbname={}, dbuser={}, dbpass={}).".format(
                constants.DEFAULT_DB_NAME, constants.DEFAULT_DB_USER, constants.DEFAULT_DB_PASS
            )
        )
        logger.info(
            "Note: To turn off this message, create a config file at {}".format(config_path)
        )
        return DBConfig(constants.DEFAULT_DB_NAME, constants.DEFAULT_DB_USER, constants.DEFAULT_DB_PASS)


def create_db_config() -> None:
    """
    Creates a default DB config file at the config location
    """
    config_path = get_db_config_path()
    if not config_path.exists():
        shutil.copy(constants.DEFAULT_DB_CONFIG_PATH, config_path)
        logger.info("Created default DB config file at {}".format(config_path))
    else:
        logger.info("DB config file at {} already exists".format(config_path))