from zope.interface import implementer
from zope import component
from ceo_common.interfaces import IDatabaseService, IConfig
from ceo_common.errors import DatabaseConnectionError, DatabasePermissionError
from ceod.utils import gen_password
from ceod.db.utils import response_is_empty
from psycopg2 import connect, OperationalError, ProgrammingError
from psycopg2.extensions import ISOLATION_LEVEL_AUTOCOMMIT


@implementer(IDatabaseService)
class PostgreSQLService:
    def __init__(self):
        self.type = 'postgresql'
        config = component.getUtility(IConfig)
        self.auth_username = config.get('postgresql_username')
        self.auth_password = config.get('postgresql_password')

    def create_db(self, username: str) -> str:
        password = gen_password()
        search_for_user = f"SELECT FROM pg_roles WHERE rolname='{username}'"
        search_for_db = f"SELECT FROM pg_database WHERE datname='{username}'"
        create_user = f"CREATE USER {username} WITH PASSWORD %(password)s"
        reset_password = f"ALTER USER {username} WITH PASSWORD %(password)s)"
        create_database = f"""
        CREATE DATABASE {username} OWNER {username};
        REVOKE ALL ON DATABASE {username} FROM PUBLIC;
        """
        try:
            with connect(
                host='localhost',
                user=self.auth_username,
                password=self.auth_password,
            ) as con:
                con.set_isolation_level(ISOLATION_LEVEL_AUTOCOMMIT)
                with con.cursor() as cursor:
                    if response_is_empty(search_for_user, con):
                        cursor.execute(create_user, {'password': password})
                    else:
                        cursor.execute(reset_password, {'password': password})
                    if response_is_empty(search_for_db, con):
                        cursor.execute(create_database)
            return password
        except OperationalError:
            raise DatabaseConnectionError()
        except ProgrammingError:
            raise DatabasePermissionError()

    def delete_db(self, username: str):
        drop_user = f"DROP USER IF EXISTS {username}"
        drop_db = f"DROP DATABASE IF EXISTS {username}"
        try:
            with connect(
                    host='localhost',
                    user=self.auth_username,
                    password=self.auth_password,
            ) as con:
                con.set_isolation_level(ISOLATION_LEVEL_AUTOCOMMIT)
                with con.cursor() as cursor:
                    cursor.execute(drop_user)
                    cursor.execute(drop_db)
        except OperationalError:
            raise DatabaseConnectionError()
        except ProgrammingError:
            raise DatabasePermissionError()