"""db.py.

Database level utility class for testing against the track_info schema.
"""

from functools import wraps

import sys

from product_film import config
from product_film.connectors.mysql import db_session


DROP_TABLE_TRACK_CROP_INFO = """
DROP TABLE IF EXISTS track_crop_info;
"""

CREATE_TABLE_TRACK_CROP_INFO = """
CREATE TABLE `track_crop_info` (
  `track_id` INT(10),
  `crop_left` INT(10),
  `crop_right` INT(10),
  `crop_top` INT(10),
  `crop_bottom` INT(10),
  `orchard_user_id` INT(10),
  `created_timestamp` TIMESTAMP NULL DEFAULT CURRENT_TIMESTAMP,
  `updated_timestamp` TIMESTAMP NULL DEFAULT CURRENT_TIMESTAMP
)
"""

INSERT_TRACK_CROP_INFO_DATA = """
INSERT INTO `track_crop_info`(
    track_id,
    crop_left,
    crop_right,
    crop_top,
    crop_bottom,
    orchard_user_id,
    created_timestamp,
    updated_timestamp
)
VALUES
    (1, 10, 11, 10, 11, 1, '2018-04-02 03:32:34', '2018-04-02 03:32:34'),
    (2, 20, 20, 20, 20, 1, '2018-04-02 03:32:34', '2018-04-02 03:32:34'),
    (3, 21, 21, 21, 21, 2, '2018-04-02 03:32:34', '2018-04-02 03:32:34')
"""


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(f'Environment must be set to {config.TEST_ENVIRONMENT!r}.')
    if 'sqlite' not in session.bind.url.drivername:
        sys.exit('Tests must point to sqlite database.')


def drop_track_crop_info_table():
    """DROP `track_crop_info`."""
    with db_session() as session:
        _exit_if_not_test_environment(session)
        session.execute(DROP_TABLE_TRACK_CROP_INFO)


def create_track_crop_info_table():
    """Create `track_crop_info` table, which is actually a SQL view."""
    with db_session() as session:
        _exit_if_not_test_environment(session)
        drop_track_crop_info_table()
        session.execute(CREATE_TABLE_TRACK_CROP_INFO)


def insert_track_crop_info_data():
    """Insert data into track_crop_info table."""
    with db_session() as session:
        _exit_if_not_test_environment(session)
        session.execute(INSERT_TRACK_CROP_INFO_DATA)


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

    This just creates the schema and does not seed data. Indvidual test cases
    can use factories to seed data as needed.

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

    Returns:
        Function: The decorated function.
    """
    @wraps(function)
    def call_function_within_db_context(*args, **kwargs):
        create_track_crop_info_table()

        try:
            function_return = function(*args, **kwargs)
            return function_return
        finally:
            drop_track_crop_info_table()

    return call_function_within_db_context