import psycopg2

from config import read_db_config
from log_setup import logger


class DBConnectionManager:
    def __init__(self):
        self._conn = None

    def connect(self):
        config = read_db_config()
        logger.debug("Establishing database connection.")
        self._conn = psycopg2.connect("dbname='{}' user='{}' password='{}' host='localhost'".format(
            config.db_name, config.db_user, config.db_pass
        ))
        logger.debug("Established database connection.")

    def get_connection(self):
        """
        Get the database connection.
        If not already connected, this reads the database config file and connects to the DB.
        Otherwise, the already active connection is returned.
        """
        if self._conn is None:
            self.connect()
        return self._conn


# Global instance that will hold our DB connection
conn_manager = DBConnectionManager()