import pytest

from src.fps_counter import FPSCounter


def test_initial_and_tick_and_average(monkeypatch: pytest.MonkeyPatch) -> None:
    times = iter([1.0, 1.5, 1.75])
    monkeypatch.setattr("src.fps_counter.time.perf_counter", lambda: next(times))
    counter = FPSCounter(2)
    assert counter.current_fps == counter.average_fps == 0.0
    assert counter.tick() == 0.0
    assert counter.tick() == pytest.approx(2.0)
    assert counter.tick() == pytest.approx(4.0)
    assert counter.average_fps == pytest.approx(3.0)


def test_reset(monkeypatch: pytest.MonkeyPatch) -> None:
    times = iter([1.0, 2.0])
    monkeypatch.setattr("src.fps_counter.time.perf_counter", lambda: next(times))
    counter = FPSCounter(3)
    counter.tick()
    counter.tick()
    counter.reset()
    assert counter.current_fps == counter.average_fps == 0.0
    assert counter.sample_count == 0


def test_invalid_window() -> None:
    with pytest.raises(ValueError):
        FPSCounter(0)