import contextlib
import os
import unittest

from flask_env import MetaFlaskEnv


class TestFlaskEnv(unittest.TestCase):
    @contextlib.contextmanager
    def with_env(self, **kwargs):
        """Context manager to set temporary environment variables and then remove when done"""
        # Set environment variables
        os.environ.update(kwargs)

        # Yield to caller
        yield

        # Delete set variables
        for key in kwargs.keys():
            if key in os.environ:
                del os.environ[key]

    def _get_test_configuration(self, env_prefix='', env_load_all=False, **kwargs):
        """Helper to define a new configuration class using our MetaFlaskEnv"""
        return MetaFlaskEnv('TestConfiguration', (object, ), dict(
            ENV_PREFIX=env_prefix,
            ENV_LOAD_ALL=env_load_all,
            **kwargs
        ))

    def test_default_env_load_all(self):
        """A test to ensure that we load all environment variables by default"""
        # Configure an environment variable not defined on the configuration class
        with self.with_env(TEST_SETTING='true', DEFAULT_SETTING='set_by_env'):
            # Create our configuration object
            TestConfiguration = MetaFlaskEnv('TestConfiguration', (object, ), dict(
                DEFAULT_SETTING='set_in_class',
            ))

        # Assert that we only loaded defined settings from environment
        self.assertFalse(hasattr(TestConfiguration, 'TEST_SETTING'))
        self.assertEqual(TestConfiguration.DEFAULT_SETTING, 'set_by_env')


    def test_default_settings(self):
        """A test to ensure that if no environment variable is set, we get the default value that is set"""
        TestConfiguration = self._get_test_configuration(DEFAULT_SETTING='default_value')
        self.assertEqual(TestConfiguration.DEFAULT_SETTING, 'default_value')

    def test_override_from_env(self):
        """A test to ensure that an environment variable will override the default setting"""
        with self.with_env(DEFAULT_SETTING='set_by_env'):
            TestConfiguration = self._get_test_configuration(DEFAULT_SETTING='default_value')
            self.assertEqual(TestConfiguration.DEFAULT_SETTING, 'set_by_env')

    def test_only_set_on_env(self):
        """A test to ensure that a setting only defined by an environment variable is still available"""
        with self.with_env(NEW_SETTING='set_by_env'):
            # When configured to load all environment variables
            TestConfiguration = self._get_test_configuration(env_load_all=True)
            self.assertEqual(TestConfiguration.NEW_SETTING, 'set_by_env')

            # When configured to not load all environment variables
            TestConfiguration = self._get_test_configuration(env_load_all=False)
            self.assertFalse(hasattr(TestConfiguration, 'NEW_SETTING'))

    def test_env_prefix(self):
        """A test to ensure that the ENV_PREFIX setting functions as needed"""
        with self.with_env(TEST_DEFAULT_SETTING='set_by_env'):
            TestConfiguration = self._get_test_configuration(env_prefix='TEST_', DEFAULT_SETTING='default_value')
            self.assertEqual(TestConfiguration.DEFAULT_SETTING, 'set_by_env')

    def test_env_prefix_non_matching(self):
        """A test to ensure that the ENV_PREFIX setting does not allow non-matching settings in"""
        with self.with_env(DEFAULT_SETTING='set_by_env'):
            TestConfiguration = self._get_test_configuration(env_prefix='MYAPP_', DEFAULT_SETTING='default_value')
            self.assertEqual(TestConfiguration.DEFAULT_SETTING, 'default_value')

    def test_parsing_boolean(self):
        """A test to ensure that we properly parse booleans"""
        # DEV: We have to set the environment variable first, since they get loaded into the class on definition
        env = dict(
            IS_TRUE='true',
            IS_NOT_TRUE='true-ish',
            IS_FALSE='FALSE',
            IS_WACKY_FALSE='FaLSe',
        )
        with self.with_env(**env):
            # DEV: Set `env_load_all=True` to keep from having to make default values for each variable
            TestConfiguration = self._get_test_configuration(env_load_all=True)
            self.assertEqual(TestConfiguration.IS_TRUE, True)
            self.assertEqual(TestConfiguration.IS_NOT_TRUE, 'true-ish')
            self.assertEqual(TestConfiguration.IS_FALSE, False)
            self.assertEqual(TestConfiguration.IS_WACKY_FALSE, False)

    def test_parsing_float(self):
        """A test to ensure that we properly parse floats"""
        env = dict(
            IS_FLOAT='12.5',
            TRAILING_DOT='12.',
            LEADING_DOT='.12',
            IS_NOT_FLOAT='This is 6.5',
        )
        with self.with_env(**env):
            # DEV: Set `env_load_all=True` to keep from having to make default values for each variable
            TestConfiguration = self._get_test_configuration(env_load_all=True)
            self.assertEqual(TestConfiguration.IS_FLOAT, 12.5)
            self.assertEqual(TestConfiguration.TRAILING_DOT, 12.0)
            self.assertEqual(TestConfiguration.LEADING_DOT, 0.12)
            self.assertEqual(TestConfiguration.IS_NOT_FLOAT, 'This is 6.5')

    def test_parsing_int(self):
        """A test to ensure that we properly parse integers"""
        env = dict(
            IS_INT='12',
            IS_ZERO='0',
            IS_NOT_INT='12fa',
        )
        with self.with_env(**env):
            # DEV: Set `env_load_all=True` to keep from having to make default values for each variable
            TestConfiguration = self._get_test_configuration(env_load_all=True)
            self.assertEqual(TestConfiguration.IS_INT, 12)
            self.assertEqual(TestConfiguration.IS_ZERO, 0)
            self.assertEqual(TestConfiguration.IS_NOT_INT, '12fa')


if __name__ == '__main__':
    unittest.main()