import logging
import os

from redis import Redis
from rq import pop_connection, push_connection

import unittest


def find_empty_redis_database(ssl=False):
    """Tries to connect to a random Redis database (starting from 4), and
    will use/connect it when no keys are in there.
    """
    for dbnum in range(4, 17):
        connection_kwargs = {'db': dbnum}
        if ssl:
            connection_kwargs['port'] = 9736
            connection_kwargs['ssl'] = True
            connection_kwargs['ssl_cert_reqs'] = None  # disable certificate validation
        testconn = Redis(**connection_kwargs)
        empty = testconn.dbsize() == 0
        if empty:
            return testconn
    assert False, 'No empty Redis database found to run tests in.'


def slow(f):
    return unittest.skipUnless(os.environ.get('RUN_SLOW_TESTS_TOO'), "Slow tests disabled")(f)


def ssl_test(f):
    return unittest.skipUnless(os.environ.get('RUN_SSL_TESTS'), "SSL tests disabled")(f)


class RQTestCase(unittest.TestCase):
    """Base class to inherit test cases from for RQ.

    It sets up the Redis connection (available via self.testconn), turns off
    logging to the terminal and flushes the Redis database before and after
    running each test.

    Also offers assertQueueContains(queue, that_func) assertion method.
    """

    @classmethod
    def setUpClass(cls):
        # Set up connection to Redis
        testconn = find_empty_redis_database()
        push_connection(testconn)

        # Store the connection (for sanity checking)
        cls.testconn = testconn
        cls.connection = testconn

        # Shut up logging
        logging.disable(logging.ERROR)

    def setUp(self):
        # Flush beforewards (we like our hygiene)
        self.testconn.flushdb()

    def tearDown(self):
        # Flush afterwards
        self.testconn.flushdb()

    # Implement assertIsNotNone for Python runtimes < 2.7 or < 3.1
    if not hasattr(unittest.TestCase, 'assertIsNotNone'):
        def assertIsNotNone(self, value, *args):  # noqa
            self.assertNotEqual(value, None, *args)

    @classmethod
    def tearDownClass(cls):
        logging.disable(logging.NOTSET)

        # Pop the connection to Redis
        testconn = pop_connection()
        assert testconn == cls.testconn, \
            'Wow, something really nasty happened to the Redis connection stack. Check your setup.'