"""Tests for orthogonal routing and crossing detection (pure geometry)."""
import math

from pipeline_editor.view.routing import (
    orthogonal_route, polyline_segments, segment_crossings,
)


def _is_orthogonal(points):
    for (x0, y0), (x1, y1) in zip(points, points[1:]):
        if not (math.isclose(x0, x1) or math.isclose(y0, y1)):
            return False
    return True


def test_route_is_orthogonal_horizontal_ports():
    # source outlet facing right -> pump inlet facing left
    pts = orthogonal_route((0, 0), (1, 0), (200, 80), (-1, 0), grid=20)
    assert pts[0] == (0, 0)
    assert pts[-1] == (200, 80)
    assert _is_orthogonal(pts)
    assert len(pts) >= 2


def test_route_is_orthogonal_vertical_ports():
    pts = orthogonal_route((50, 0), (0, -1), (130, 200), (0, 1), grid=20)
    assert pts[0] == (50, 0) and pts[-1] == (130, 200)
    assert _is_orthogonal(pts)


def test_route_straight_line_collapses():
    # aligned ports facing each other -> essentially a straight run
    pts = orthogonal_route((0, 40), (1, 0), (200, 40), (-1, 0), grid=20)
    assert _is_orthogonal(pts)
    assert all(math.isclose(p[1], 40) for p in pts)


def test_bends_snapped_to_grid():
    pts = orthogonal_route((0, 0), (1, 0), (207, 83), (-1, 0), grid=20)
    for x, y in pts[1:-1]:
        assert math.isclose(x % 20, 0) or math.isclose(x % 20, 20)


def test_perpendicular_crossing_detected():
    horiz = polyline_segments([(0, 50), (100, 50)])
    vert = polyline_segments([(50, 0), (50, 100)])
    cx = segment_crossings(horiz, vert)
    assert cx == [(50, 50)]


def test_shared_endpoint_is_not_a_crossing():
    # a T-junction where the vertical touches the horizontal endpoint
    horiz = polyline_segments([(0, 50), (50, 50)])
    vert = polyline_segments([(50, 50), (50, 100)])
    assert segment_crossings(horiz, vert) == []


def test_parallel_segments_no_crossing():
    a = polyline_segments([(0, 50), (100, 50)])
    b = polyline_segments([(0, 70), (100, 70)])
    assert segment_crossings(a, b) == []