import numpy as np
import pytest
from merlin.features.blink import BlinkDetector, BlinkEvent, eye_aspect_ratio

LEFT_EYE = [33, 160, 158, 133, 153, 144]
RIGHT_EYE = [362, 385, 387, 263, 373, 380]


def _face(n: int = 478) -> np.ndarray:
    return np.zeros((n, 3), dtype=np.float32)


def _set_eye_open(face: np.ndarray, indices: list[int]) -> None:
    """Set 6 EAR landmarks so EAR = ~0.35 (open eye)."""
    p1, p2, p3, p4, p5, p6 = indices
    face[p1] = [0.0, 0.0, 0.0]
    face[p4] = [1.0, 0.0, 0.0]
    face[p2] = [0.25, 0.2, 0.0]
    face[p6] = [0.25, -0.2, 0.0]
    face[p3] = [0.75, 0.2, 0.0]
    face[p5] = [0.75, -0.2, 0.0]


def _set_eye_closed(face: np.ndarray, indices: list[int]) -> None:
    """Set 6 EAR landmarks so EAR ≈ 0 (closed)."""
    for i in indices:
        face[i] = [0.0, 0.0, 0.0]


def test_ear_open_eye():
    face = _face()
    _set_eye_open(face, LEFT_EYE)
    ear = eye_aspect_ratio(face, LEFT_EYE)
    assert ear > 0.20


def test_ear_closed_eye():
    face = _face()
    _set_eye_closed(face, LEFT_EYE)
    ear = eye_aspect_ratio(face, LEFT_EYE)
    assert ear < 0.05


def test_no_blink_when_both_open():
    detector = BlinkDetector(threshold=0.20)
    face = _face()
    _set_eye_open(face, LEFT_EYE)
    _set_eye_open(face, RIGHT_EYE)
    assert detector.detect(face) is None


def test_left_blink_detected():
    detector = BlinkDetector(threshold=0.20)
    face = _face()
    _set_eye_closed(face, LEFT_EYE)
    _set_eye_open(face, RIGHT_EYE)
    assert detector.detect(face) == BlinkEvent.LEFT


def test_right_blink_detected():
    detector = BlinkDetector(threshold=0.20)
    face = _face()
    _set_eye_open(face, LEFT_EYE)
    _set_eye_closed(face, RIGHT_EYE)
    assert detector.detect(face) == BlinkEvent.RIGHT


def test_both_blink_detected():
    detector = BlinkDetector(threshold=0.20)
    face = _face()
    _set_eye_closed(face, LEFT_EYE)
    _set_eye_closed(face, RIGHT_EYE)
    assert detector.detect(face) == BlinkEvent.BOTH