from hermes_vision.detect import Face
from hermes_vision.recognize import IdentityCache, iou


def test_iou():
    a = Face(0, 0, 100, 100)
    assert iou(a, a) == 1.0
    assert iou(a, Face(200, 200, 50, 50)) == 0.0
    assert 0.3 < iou(a, Face(50, 0, 100, 100)) < 0.4


def test_a_tracked_face_is_identified_once_per_period():
    calls = []
    cache = IdentityCache(period_s=1.0)
    ident = lambda f: (calls.append(f), 'kyle')[1]
    assert cache.update([Face(100, 100, 80, 80)], 0.0, ident) == ['kyle']
    for i in range(1, 8):                                  # the face drifts a little, 4 times a second
        assert cache.update([Face(100 + i, 100, 80, 80)], i * 0.125, ident) == ['kyle']
    assert len(calls) == 1
    cache.update([Face(108, 100, 80, 80)], 1.1, ident)     # stale: rechecked
    assert len(calls) == 2


def test_a_new_face_is_identified_immediately_and_unknown_is_cached_too():
    calls = []
    cache = IdentityCache()
    ident = lambda f: (calls.append(f), '' if f.x > 400 else 'kyle')[1]
    names = cache.update([Face(100, 100, 80, 80), Face(500, 100, 80, 80)], 0.0, ident)
    assert names == ['kyle', ''] and len(calls) == 2
    assert cache.update([Face(101, 100, 80, 80), Face(501, 100, 80, 80)], 0.3, ident) == ['kyle', '']
    assert len(calls) == 2                                  # the stranger is not re-embedded every frame


def test_a_face_that_jumps_is_a_different_face():
    calls = []
    cache = IdentityCache()
    ident = lambda f: (calls.append(f), 'kyle')[1]
    cache.update([Face(100, 100, 80, 80)], 0.0, ident)
    cache.update([Face(600, 300, 80, 80)], 0.1, ident)
    assert len(calls) == 2