#!/usr/bin/python3

from os import environ
from os.path import exists
from json import load
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker


def import_config():
    try:
        path = environ['BOT_CONFIG_PATH']
    except:
        path = 'config/config.json'
    if(exists(path)):
        try:
            with open(path) as config_file:
                config_dict = load(config_file)
        except Exception as e:
            print(f'There was some issue opening and loading the config.\n{e}')
            exit(1)
    else:
        print('Didn\'t find the config file.')
        exit(1)
    return config_dict


def get_engine():
    config_data = import_config()
    try:
        with open(config_data['postgres_pass']) as pgdb_pass:
            engine = create_engine(
                f"postgresql+psycopg2://{config_data['postgres_user']}:{pgdb_pass.readline().strip()}@{config_data['postgres_host']}:{config_data['postgres_port']}/{config_data['postgres_db']}")
            return engine
    except Exception as e:
        print(
            f'There was an issue opening the config file for the postgres password.\n{e}')
        exit(1)


def create_session(Base):
    try:
        engine = get_engine()
        Base.metadata.bind = engine
        covidDataSession = sessionmaker(bind=engine)
    except Exception as e:
        print(
            f'There was an issue creating a session for the database.\n{e}')
        exit(1)
    return covidDataSession()