import unittest

from django.core.exceptions import ImproperlyConfigured

from django.db import ProgrammingError

try:

    from django.contrib.gis.db.backends.postgis.operations import PostGISOperations

    HAS_POSTGRES = True

except ImportError:

    HAS_POSTGRES = False

if HAS_POSTGRES:

    class FakeConnection:

        def __init__(self):

            self.settings_dict = {

                "NAME": "test",

            }

    class FakePostGISOperations(PostGISOperations):

        def __init__(self, version=None):

            self.version = version

            self.connection = FakeConnection()

        def _get_postgis_func(self, func):

            if func == "postgis_lib_version":

                if self.version is None:

                    raise ProgrammingError

                else:

                    return self.version

            elif func == "version":

                pass

            else:

                raise NotImplementedError("This function was not expected to be called")

@unittest.skipUnless(HAS_POSTGRES, "The psycopg2 driver is needed for these tests")

class TestPostGISVersionCheck(unittest.TestCase):

    """

    The PostGIS version check parses correctly the version numbers

    """

    def test_get_version(self):

        expect = "1.0.0"

        ops = FakePostGISOperations(expect)

        actual = ops.postgis_lib_version()

        self.assertEqual(expect, actual)

    def test_version_classic_tuple(self):

        expect = ("1.2.3", 1, 2, 3)

        ops = FakePostGISOperations(expect[0])

        actual = ops.postgis_version_tuple()

        self.assertEqual(expect, actual)

    def test_version_dev_tuple(self):

        expect = ("1.2.3dev", 1, 2, 3)

        ops = FakePostGISOperations(expect[0])

        actual = ops.postgis_version_tuple()

        self.assertEqual(expect, actual)

    def test_version_loose_tuple(self):

        expect = ("1.2.3b1.dev0", 1, 2, 3)

        ops = FakePostGISOperations(expect[0])

        actual = ops.postgis_version_tuple()

        self.assertEqual(expect, actual)

    def test_valid_version_numbers(self):

        versions = [

            ("1.3.0", 1, 3, 0),

            ("2.1.1", 2, 1, 1),

            ("2.2.0dev", 2, 2, 0),

        ]

        for version in versions:

            with self.subTest(version=version):

                ops = FakePostGISOperations(version[0])

                actual = ops.spatial_version

                self.assertEqual(version[1:], actual)

    def test_no_version_number(self):

        ops = FakePostGISOperations()

        with self.assertRaises(ImproperlyConfigured):

            ops.spatial_version