import os

import psycopg2


class DBConnection:

    def __init__(self):
        self.conn = DBConnection.create_conn()

    def table_exists(self, table_name, table_schema='public'):
        cur = self.conn.cursor()
        query = '''select exists (select 1 from information_schema.tables \
                    where table_name = %s and table_schema = %s)''' % (table_name, table_schema)

        cur.execute(query)
        try:
            row = cur.fetchone()
            if row is not None:
                return row[0]
            else:
                return None
        except Exception as e:
            print(f"An error occurred: {e}")
            return False

    @staticmethod
    def create_conn():
        """
        :return: psycopg2.connection
        """
        return psycopg2.connect(
            host=os.environ.get('POSTGRES_HOST'),
            database=os.environ.get('POSTGRES_DB'),
            user=os.environ.get('POSTGRES_USER'),
            password=os.environ.get('POSTGRES_PASS'),
            port=os.environ.get('POSTGRES_PORT')
        )

    def cursor(self):
        """
        :return: psycopg2.cursor
        """
        return self.conn.cursor()