"""
Unit tests for haversine distance calculations.
"""

import sys
import os
import numpy as np

sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', '..'))

from app.geometry.haversine import haversine_distance, haversine_batch, points_to_local_coords


class TestHaversineDistance:
    def test_same_point_is_zero(self):
        d = haversine_distance(50.45, 30.52, 50.45, 30.52)
        assert abs(d) < 1.0

    def test_known_distance(self):
        # Kyiv to Kharkiv ≈ 410 km
        d = haversine_distance(50.45, 30.52, 49.99, 36.23)
        assert 400000 < d < 420000

    def test_short_distance(self):
        # ~111m for 0.001 degree lat
        d = haversine_distance(50.0, 30.0, 50.001, 30.0)
        assert 100 < d < 120


class TestHaversineBatch:
    def test_single_point(self):
        lats = np.array([50.001])
        lons = np.array([30.0])
        distances = haversine_batch(50.0, 30.0, lats, lons)
        assert len(distances) == 1
        assert 100 < distances[0] < 120

    def test_multiple_points(self):
        lats = np.array([50.001, 50.01, 50.1])
        lons = np.array([30.0, 30.0, 30.0])
        distances = haversine_batch(50.0, 30.0, lats, lons)
        assert len(distances) == 3
        # Should be monotonically increasing
        assert distances[0] < distances[1] < distances[2]


class TestLocalCoords:
    def test_same_point_is_origin(self):
        x, y = points_to_local_coords(50.0, 30.0, np.array([50.0]), np.array([30.0]))
        assert abs(x[0]) < 1.0
        assert abs(y[0]) < 1.0

    def test_north_is_positive_y(self):
        x, y = points_to_local_coords(50.0, 30.0, np.array([50.001]), np.array([30.0]))
        assert y[0] > 0
        assert abs(x[0]) < 1.0

    def test_east_is_positive_x(self):
        x, y = points_to_local_coords(50.0, 30.0, np.array([50.0]), np.array([30.001]))
        assert x[0] > 0
        assert abs(y[0]) < 1.0


if __name__ == "__main__":
    for cls in [TestHaversineDistance, TestHaversineBatch, TestLocalCoords]:
        instance = cls()
        for method_name in [m for m in dir(instance) if m.startswith("test_")]:
            try:
                getattr(instance, method_name)()
                print(f"  PASS  {cls.__name__}.{method_name}")
            except Exception as e:
                print(f"  FAIL  {cls.__name__}.{method_name}: {e}")

    print("\nAll tests completed.")