import os

import numpy as np
import pytest


@pytest.mark.slow
def test_vnormal_longrun_no_outlier_jumps(sensor_factory, available_backends):
    preferred = os.getenv("ORISYS_LONGRUN_BACKEND", "cupy")
    backend = preferred if preferred in available_backends else "cpu"

    frames = int(os.getenv("ORISYS_LONGRUN_FRAMES", "1200"))
    ratio_limit = float(os.getenv("ORISYS_LONGRUN_MAX_P99_P95_RATIO", "6.0"))

    sensor = sensor_factory(backend=backend)
    deltas = []
    prev = None
    try:
        for _ in range(frames):
            img = sensor.get_img()
            assert img is not None
            sensor.compute_deformation(check_motion=False)
            (vnormal,) = sensor.read_info(sensor.info.VNORMAL)
            assert np.isfinite(vnormal).all()

            if prev is not None:
                deltas.append(float(np.mean(np.abs(vnormal - prev))))
            prev = vnormal.copy()
    finally:
        sensor.disconnect()

    if len(deltas) < 30:
        pytest.skip("Not enough frames to evaluate stability.")

    p95 = float(np.percentile(deltas, 95))
    p99 = float(np.percentile(deltas, 99))
    ratio = p99 / (p95 + 1e-9)
    assert ratio < ratio_limit, (
        f"Long-run jump risk detected on {backend}: p99/p95={ratio:.3f} "
        f"(limit={ratio_limit})."
    )