"""db.py.

Database level utility class for testing against the assets related tebles.
1. asset
2. asset_location
3. asset_location_detail
"""

from functools import wraps
import sys

from assets import config
from assets.connectors.mysql import dd_db_session


DROP_TABLE_ASSET = """
DROP TABLE IF EXISTS asset;
"""


DROP_TABLE_ASSET_LOCATION = """
DROP TABLE IF EXISTS asset_location;
"""


DROP_TABLE_ASSET_LOCATION_DETAIL = """
DROP TABLE IF EXISTS asset_location_detail;
"""


CREATE_TABLE_ASSET = """
CREATE TABLE asset (
  asset_id int(10),
  upc bigint(20));
"""


CREATE_TABLE_ASSET_LOCATION = """
CREATE TABLE asset_location (
  asset_location_id int(11),
  asset_id int(10));
"""


CREATE_TABLE_ASSET_LOCATION_DETAIL = """
CREATE TABLE asset_location_detail (
  asset_location_detail_id int(11),
  asset_location_id int(11),
  bits_per_sample tinyint(3));
"""


INSERT_INTO_ASSET = """
INSERT INTO asset(asset_id,upc)
VALUES('1','191018729677'),
('2','191018729678');
"""


INSERT_INTO_ASSET_LOCATION = """
INSERT INTO asset_location(asset_location_id,asset_id)
VALUES('1','1'),
('2','1'),
('3','1'),
('4','2'),
('5','2'),
('6','2');
"""


INSERT_INTO_ASSET_LOCATION_DETAIL = """
INSERT INTO asset_location_detail
(asset_location_detail_id,asset_location_id,bits_per_sample)
VALUES
('1','1','64'),
('2','2','64'),
('3','3','64'),
('4','4','64'),
('5','5','64'),
('6','6','16');
"""


def drop_asset_table():
    """DROP command for asset table."""
    with dd_db_session() as session:
        _exit_if_not_test_environment(session)
        session.execute(DROP_TABLE_ASSET)


def drop_asset_location_table():
    """DROP command for asset_location table."""
    with dd_db_session() as session:
        _exit_if_not_test_environment(session)
        session.execute(DROP_TABLE_ASSET_LOCATION)


def drop_asset_location_detail_table():
    """DROP command for asset_location_detail table."""
    with dd_db_session() as session:
        _exit_if_not_test_environment(session)
        session.execute(DROP_TABLE_ASSET_LOCATION_DETAIL)


def create_and_insert_into_asset():
    """Create and Insert into asset table."""
    with dd_db_session() as session:
        _exit_if_not_test_environment(session)
        session.execute(DROP_TABLE_ASSET)
        session.execute(CREATE_TABLE_ASSET)
        session.execute(INSERT_INTO_ASSET)


def create_and_insert_into_asset_location():
    """Create and Insert into asset_location table."""
    with dd_db_session() as session:
        session.execute(DROP_TABLE_ASSET_LOCATION)
        session.execute(CREATE_TABLE_ASSET_LOCATION)
        session.execute(INSERT_INTO_ASSET_LOCATION)


def create_and_insert_into_asset_location_detail():
    """Create and Insert into asset_location_detail table."""
    with dd_db_session() as session:
        session.execute(DROP_TABLE_ASSET_LOCATION_DETAIL)
        session.execute(CREATE_TABLE_ASSET_LOCATION_DETAIL)
        session.execute(INSERT_INTO_ASSET_LOCATION_DETAIL)


def _exit_if_not_test_environment(session):
    """For safety, only run tests in test environment pointed to sqlite.

    Exit immediately if not in test environment or not pointed to sqlite.
    """
    if config.ENVIRONMENT != config.TEST_ENVIRONMENT:
        sys.exit('Environment must be set to {}.'.format(
            config.TEST_ENVIRONMENT))
    if 'sqlite' not in session.bind.url.drivername:
        sys.exit('Tests must point to sqlite database.')


def test_schema(function):
    """Create and tear down the test DB schema around a function call.

    This just creates the schema and seed data.

    Args:
        function (callable): the function to be called after creating the test
        schema.

    Returns:
        function (callable): The decorated function.
    """
    @wraps(function)
    def call_function_within_db_context(*args, **kwargs):
        create_and_insert_into_asset()
        create_and_insert_into_asset_location()
        create_and_insert_into_asset_location_detail()

        try:
            function_return = function(*args, **kwargs)
        finally:
            drop_asset_location_detail_table()
            drop_asset_location_table()
            drop_asset_table()

        return function_return
    return call_function_within_db_context