import re

from django.db import connection
from django.test import TestCase, skipUnlessDBFeature
from django.utils.functional import cached_property

test_srs = (
    {
        "srid": 4326,
        "auth_name": ("EPSG", True),
        "auth_srid": 4326,
        # Only the beginning, because there are differences depending on installed libs
        "srtext": 'GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84"',
        # +ellps=WGS84 has been removed in the 4326 proj string in proj-4.8
        "proj_re": (
            r"\+proj=longlat (\+ellps=WGS84 )?(\+datum=WGS84 |\+towgs84=0,0,0,0,0,0,0 )"
            r"\+no_defs ?"
        ),
        "spheroid": "WGS 84",
        "name": "WGS 84",
        "geographic": True,
        "projected": False,
        "spatialite": True,
        # From proj's "cs2cs -le" and Wikipedia (semi-minor only)
        "ellipsoid": (6378137.0, 6356752.3, 298.257223563),
        "eprec": (1, 1, 9),
        "wkt": re.sub(
            r"[\s+]",
            "",
            """
        GEOGCS["WGS 84",
    DATUM["WGS_1984",
        SPHEROID["WGS 84",6378137,298.257223563,
            AUTHORITY["EPSG","7030"]],
        AUTHORITY["EPSG","6326"]],
    PRIMEM["Greenwich",0,
        AUTHORITY["EPSG","8901"]],
    UNIT["degree",0.01745329251994328,
        AUTHORITY["EPSG","9122"]],
    AUTHORITY["EPSG","4326"]]
    """,
        ),
    },
    {
        "srid": 32140,
        "auth_name": ("EPSG", False),
        "auth_srid": 32140,
        "srtext": (
            'PROJCS["NAD83 / Texas South Central",GEOGCS["NAD83",'
            'DATUM["North_American_Datum_1983",SPHEROID["GRS 1980"'
        ),
        "proj_re": (
            r"\+proj=lcc (\+lat_1=30.28333333333333? |\+lat_2=28.38333333333333? "
            r"|\+lat_0=27.83333333333333? |"
            r"\+lon_0=-99 ){4}\+x_0=600000 \+y_0=4000000 (\+ellps=GRS80 )?"
            r"(\+datum=NAD83 |\+towgs84=0,0,0,0,0,0,0 )?\+units=m \+no_defs ?"
        ),
        "spheroid": "GRS 1980",
        "name": "NAD83 / Texas South Central",
        "geographic": False,
        "projected": True,
        "spatialite": False,
        # From proj's "cs2cs -le" and Wikipedia (semi-minor only)
        "ellipsoid": (6378137.0, 6356752.31414, 298.257222101),
        "eprec": (1, 5, 10),
    },
)


@skipUnlessDBFeature("has_spatialrefsys_table")
class SpatialRefSysTest(TestCase):
    @cached_property
    def SpatialRefSys(self):
        return connection.ops.connection.ops.spatial_ref_sys()

    def test_get_units(self):
        epsg_4326 = next(f for f in test_srs if f["srid"] == 4326)
        unit, unit_name = self.SpatialRefSys().get_units(epsg_4326["wkt"])
        self.assertEqual(unit_name, "degree")
        self.assertAlmostEqual(unit, 0.01745329251994328)

    def test_retrieve(self):
        """
        Test retrieval of SpatialRefSys model objects.
        """
        for sd in test_srs:
            srs = self.SpatialRefSys.objects.get(srid=sd["srid"])
            self.assertEqual(sd["srid"], srs.srid)

            # Some of the authority names are borked on Oracle, e.g., SRID=32140.
            #  also, Oracle Spatial seems to add extraneous info to fields, hence the
            #  the testing with the 'startswith' flag.
            auth_name, oracle_flag = sd["auth_name"]
            # Compare case-insensitively because srs.auth_name is lowercase
            # ("epsg") on Spatialite.
            if not connection.ops.oracle or oracle_flag:
                self.assertIs(srs.auth_name.upper().startswith(auth_name), True)

            self.assertEqual(sd["auth_srid"], srs.auth_srid)

            # No PROJ and different srtext on Oracle.
            if not connection.ops.oracle:
                self.assertTrue(srs.wkt.startswith(sd["srtext"]))
                self.assertRegex(srs.proj4text, sd["proj_re"])

    def test_osr(self):
        """
        Test getting OSR objects from SpatialRefSys model objects.
        """
        for sd in test_srs:
            sr = self.SpatialRefSys.objects.get(srid=sd["srid"])
            self.assertTrue(sr.spheroid.startswith(sd["spheroid"]))
            self.assertEqual(sd["geographic"], sr.geographic)
            self.assertEqual(sd["projected"], sr.projected)
            self.assertIs(sr.name.startswith(sd["name"]), True)
            # Testing the SpatialReference object directly.
            if not connection.ops.oracle:
                srs = sr.srs
                self.assertRegex(srs.proj, sd["proj_re"])
                self.assertTrue(srs.wkt.startswith(sd["srtext"]))

    def test_ellipsoid(self):
        """
        Test the ellipsoid property.
        """
        for sd in test_srs:
            # Getting the ellipsoid and precision parameters.
            ellps1 = sd["ellipsoid"]
            prec = sd["eprec"]

            # Getting our spatial reference and its ellipsoid
            srs = self.SpatialRefSys.objects.get(srid=sd["srid"])
            ellps2 = srs.ellipsoid

            for i in range(3):
                self.assertAlmostEqual(ellps1[i], ellps2[i], prec[i])

    @skipUnlessDBFeature("supports_add_srs_entry")
    def test_add_entry(self):
        """
        Test adding a new entry in the SpatialRefSys model using the
        add_srs_entry utility.
        """
        from django.contrib.gis.utils import add_srs_entry

        add_srs_entry(3857)
        self.assertTrue(self.SpatialRefSys.objects.filter(srid=3857).exists())
        srs = self.SpatialRefSys.objects.get(srid=3857)
        self.assertTrue(
            self.SpatialRefSys.get_spheroid(srs.wkt).startswith("SPHEROID[")
        )