"""Tests that the location classes in :mod:`pyrate.plan.geometry.location` work correctly."""

# Python standard math
from math import isclose

# Typing
from typing import cast

# Generic testing
from unittest import TestCase

# Geometry
from shapely.geometry import Point

# Hypothesis testing
from hypothesis import given
from hypothesis import HealthCheck
from hypothesis import settings
import hypothesis.strategies as st

# Package under test
from pyrate.plan.geometry import CartesianLocation
from pyrate.plan.geometry import PolarLocation

# Test helpers
from pyrate.common.testing.strategies.geometry import cartesian_locations
from pyrate.common.testing.strategies.geometry import geo_bearings
from pyrate.common.testing.strategies.geometry import polar_locations

# Local test helpers
from . import is_near_special_point
from . import simple_property_only_few_examples


class TestLocationConversion(TestCase):
    """Test for correct runtime behaviour in :mod:`pyrate.plan` location and shape primitives."""

    @given(cartesian_locations(origin=polar_locations()))
    @settings(max_examples=20, suppress_health_check=(HealthCheck.data_too_large,))  # this is a slow test
    def test_projection_and_back_projection_origin_in_route(
        self, cartesian_location: CartesianLocation
    ) -> None:
        """Test the projection with an origin already being present in the geometry."""
        recreated = cartesian_location.to_polar().to_cartesian(cast(PolarLocation, cartesian_location.origin))
        self.assertTrue(recreated.equals_exact(recreated, tolerance=1e-6))

    @given(cartesian_locations(origin=st.none()), polar_locations())
    @simple_property_only_few_examples  # this only checks very simple additional logic
    def test_projection_and_back_projection_origin_given_extra(
        self, cartesian_location: CartesianLocation, origin: PolarLocation
    ) -> None:
        """Test the projection with an origin being provided."""
        recreated = cartesian_location.to_polar(origin).to_cartesian(origin)
        self.assertTrue(recreated.equals_exact(recreated, tolerance=1e-6))

    @given(cartesian_locations(origin=st.none()))
    @simple_property_only_few_examples  # this only checks very simple additional logic
    def test_projection_and_back_projection_origin_not_given(
        self, cartesian_location: CartesianLocation
    ) -> None:
        """Test the projection with no origin being given."""
        with self.assertRaises(ValueError):
            cartesian_location.to_polar()

    @given(cartesian_locations(origin=polar_locations()), polar_locations())
    @simple_property_only_few_examples  # this only checks very simple additional logic
    def test_projection_and_back_projection_origin_given_twice(
        self, cartesian_location: CartesianLocation, origin: PolarLocation
    ) -> None:
        """Test the projection with ambiguous origin being provided."""
        with self.assertRaises(ValueError):
            cartesian_location.to_polar(origin)

    def test_distance_measuring_specific(self) -> None:
        """Tests a specific input/output pair."""

        location_a = PolarLocation(latitude=55.6544, longitude=139.74477)
        location_b = PolarLocation(latitude=21.4225, longitude=39.8261)
        distance = location_a.distance(location_b, approximate=False)
        self.assertAlmostEqual(distance, 8_665_850.116876071)

    @given(
        polar_locations(),
        geo_bearings(),
        st.floats(min_value=1.0, max_value=100_000.0, allow_nan=False, allow_infinity=False),
    )
    def test_translation_is_invertible(
        self, original: PolarLocation, direction: float, distance: float
    ) -> None:
        """Tests that translation is invertible and a valid bearing is returned.

        Warning:
            Only tests in-depth in the case where latitudes and longitudes are not near the poles.
        """

        # translate
        translated, back_direction = original.translate(direction, distance)
        self.assertGreaterEqual(back_direction, 0.0)
        self.assertLess(back_direction, 360.0)

        # translate back
        translated_translated, back_back_direction = translated.translate(back_direction, distance)
        self.assertGreaterEqual(back_back_direction, 0.0)
        self.assertLess(back_back_direction, 360.0)

        # the method seems to have problems at poles
        if not is_near_special_point(original) and not is_near_special_point(translated):
            # the method is rather rough, so we want to add larger tolerances than usual while checking
            self.assertTrue(isclose(direction, back_back_direction, abs_tol=1e-6))
            self.assertTrue(original.equals_exact(translated_translated, 1e-6))

    @given(cartesian_locations())
    def test_from_shapely_conversion(self, cartesian_location: CartesianLocation) -> None:
        """Test that :meth:`pyrate.plan.geometry.location.CartesianLocation.from_shapely` works."""

        # we only want to compare the coordinates, so create a new instance without the identifier, name, etc.
        bare = CartesianLocation(cartesian_location.x, cartesian_location.y)
        bare_shapely = Point(cartesian_location.x, cartesian_location.y)
        recreated = CartesianLocation.from_shapely(bare_shapely)
        self.assertEqual(recreated, bare)


class TestPolarLocationDistanceIsAMetric(TestCase):
    """Makes sure that :meth:`~pyrate.plan.geometry.location.PolarLocation.distance` is a metric.

    This should always succeed since we use a very stable external library for this.

    See `Wikipedia <https://en.wikipedia.org/wiki/Metric_(mathematics)#Definition>`__ for the axioms.
    """

    @given(polar_locations(), polar_locations(), st.booleans())
    def test_distance_measuring_commutes_and_sanity_checks(
        self, location_a: PolarLocation, location_b: PolarLocation, approximate: bool
    ) -> None:
        """Assures flipping the sides when calculating distances does not make a significant difference."""

        distance_1 = location_a.distance(location_b, approximate)
        distance_2 = location_b.distance(location_a, approximate)

        # make sure it commutes
        self.assertAlmostEqual(distance_1, distance_2)

        # make sure the distance is always positive
        self.assertGreaterEqual(distance_1, 0.0)
        self.assertGreaterEqual(distance_2, 0.0)

    @given(polar_locations(), polar_locations(), polar_locations(), st.booleans())
    def test_distance_measuring_triangle_inequality(
        self,
        location_a: PolarLocation,
        location_b: PolarLocation,
        location_c: PolarLocation,
        approximate: bool,
    ) -> None:
        """Assures flipping the sides when calculating distances does not make a significant difference."""

        distance_a_b = location_a.distance(location_b, approximate)
        distance_b_c = location_b.distance(location_c, approximate)
        distance_a_c = location_a.distance(location_c, approximate)

        # allow for floating point errors
        abs_tolerance = 1e-6  # 1 micro meter
        self.assertGreaterEqual(distance_a_b + distance_b_c + abs_tolerance, distance_a_c)

    @given(polar_locations(), st.booleans())
    def test_distance_measuring_to_itself_is_zero(self, location: PolarLocation, approximate: bool) -> None:
        """Assures flipping the sides when calculating distances does not make a significant difference."""

        distance = location.distance(location, approximate)

        # make sure the distance is always positive and very close to zero
        self.assertGreaterEqual(distance, 0.0)
        self.assertAlmostEqual(distance, 0.0)