"""MySQL connector."""

from contextlib import contextmanager

from sqlalchemy import create_engine
from sqlalchemy.orm import declarative_base, scoped_session, sessionmaker

from sales_goals import config

BaseModel = declarative_base()


_sales_goals_engine = create_engine(
    config.SG_DB_CONNECTION_STRING, poolclass=config.DB_POOLCLASS)

_sales_goals_factory = sessionmaker(
    bind=_sales_goals_engine, expire_on_commit=False)

Session = scoped_session(_sales_goals_factory)


@contextmanager
def sales_goals_session_scope():
    """Provide a transactional scope around a series of operations.

    Taken from http://docs.sqlalchemy.org/en/latest/orm/session_basics.html.
    This handles rollback and closing of session, so there is no need
    to do that throughout the code. Usage:
    with sales_goals_session_scope() as session:
        session.execute(query)
    """
    session = Session()
    try:
        yield session
        session.commit()
    except Exception:
        session.rollback()
        raise
    finally:
        session.close()


_art_relations_engine = create_engine(
    config.AR_DB_CONNECTION_STRING, poolclass=config.DB_POOLCLASS)

_art_relations_factory = sessionmaker(
    bind=_art_relations_engine, expire_on_commit=False)

ARSession = scoped_session(_art_relations_factory)


@contextmanager
def art_relations_session_scope():
    """Provide a transactional scope around a series of operations.

    Taken from http://docs.sqlalchemy.org/en/latest/orm/session_basics.html.
    This handles rollback and closing of session, so there is no need
    to do that throughout the code. Usage:
    with sales_goals_session_scope() as session:
        session.execute(query)
    """
    session = ARSession()
    try:
        yield session
        session.commit()
    except Exception:
        session.rollback()
        raise
    finally:
        session.close()