from __future__ import generator_stop
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, scoped_session
from .psiturk_config import PsiturkConfig
import sys

config = PsiturkConfig()
config.load_config()

DATABASE = config.get('Database Parameters', 'database_url')

if 'mysql://' in DATABASE.lower():
    try:
        __import__('imp').find_module('pymysql')
    except ImportError:
        print("To use a MySQL database you need to install "
              "the `pymysql` python package.  Try `pip install "
              "pymysql`.")
        sys.exit()
    # internally use `mysql+pymysql://` so sqlalchemy talks to
    # the pymysql package
    DATABASE = DATABASE.replace('mysql://', 'mysql+pymysql://')

engine = create_engine(DATABASE, echo=False, pool_recycle=3600)
db_session = scoped_session(sessionmaker(autocommit=False,
                                         autoflush=False,
                                         bind=engine))


def init_db():
    from .models import Base
    # print "Initializing db if necessary."
    Base.metadata.create_all(bind=engine)


def truncate_tables():
    from .models import Base
    for table in Base.metadata.sorted_tables:
        db_session.execute(table.delete(bind=engine))
    db_session.commit()