import pytest

from pygui.backend.visualization.chart_geometry import index_to_pixel, value_to_pixel


def test_value_to_pixel_min_maps_to_bottom():
    assert value_to_pixel(0.0, 0.0, 100.0, pixel_start=10.0, pixel_span=200.0) == pytest.approx(210.0)


def test_value_to_pixel_max_maps_to_top():
    assert value_to_pixel(100.0, 0.0, 100.0, pixel_start=10.0, pixel_span=200.0) == pytest.approx(10.0)


def test_value_to_pixel_midpoint():
    assert value_to_pixel(50.0, 0.0, 100.0, pixel_start=0.0, pixel_span=200.0) == pytest.approx(100.0)


def test_value_to_pixel_degenerate_range_centers():
    assert value_to_pixel(5.0, 5.0, 5.0, pixel_start=0.0, pixel_span=200.0) == pytest.approx(100.0)


def test_index_to_pixel_first_and_last():
    assert index_to_pixel(0, 5, pixel_start=0.0, pixel_span=100.0) == pytest.approx(0.0)
    assert index_to_pixel(4, 5, pixel_start=0.0, pixel_span=100.0) == pytest.approx(100.0)


def test_index_to_pixel_single_point_centers():
    assert index_to_pixel(0, 1, pixel_start=0.0, pixel_span=100.0) == pytest.approx(50.0)