from hermes_vision.detect import Face
from hermes_vision.tracking import FaceTracker


def f(x, y=100, w=80, h=80):
    return Face(x, y, w, h, 0.9)


def test_a_face_keeps_its_track_id_and_age_grows():
    tr = FaceTracker()
    ids = []
    for i in range(8):
        (t,) = tr.update([f(100 + 3 * i)], i * 0.25)
        ids.append(t.id)
    assert ids == [1] * 8 and abs(t.age(1.75) - 1.75) < 1e-9


def test_two_people_get_two_ids_and_keep_them_when_they_swap_order():
    tr = FaceTracker()
    a, b = tr.update([f(100), f(500)], 0.0)
    b2, a2 = tr.update([f(502), f(102)], 0.25)             # reported in the other order
    assert (a.id, b.id) == (a2.id, b2.id) and a.id != b.id


def test_a_track_survives_a_short_gap_but_not_a_long_one():
    tr = FaceTracker(max_age_s=1.5)
    (t,) = tr.update([f(100)], 0.0)
    tr.update([], 1.0)                                      # nobody for a second
    (t2,) = tr.update([f(100)], 1.2)
    assert t2.id == t.id
    tr.update([], 1.3)
    tr.update([], 3.5)                                      # gone for over max_age
    (t3,) = tr.update([f(100)], 3.6)
    assert t3.id != t.id


def test_identity_is_resolved_for_new_tracks_and_rechecked_once_a_second():
    calls = []
    tr = FaceTracker(recheck_s=1.0)
    ident = lambda face: (calls.append(face), ('Kyle', 0.8))[1]
    for i in range(8):                                      # 4 Hz for two seconds
        (t,) = tr.update([f(100 + i)], i * 0.25, ident)
    assert t.name == 'Kyle' and t.similarity == 0.8
    assert len(calls) == 2                                  # at t=0 and again at t=1.0


def test_a_stranger_is_unknown_not_named():
    tr = FaceTracker()
    (t,) = tr.update([f(100)], 0.0, lambda face: ('', 0.12))
    assert t.name == '' and t.similarity == 0.12


def test_without_an_identifier_nothing_is_named():
    (t,) = FaceTracker().update([f(100)], 0.0)
    assert t.name == '' and t.id == 1


def test_iou():
    from hermes_vision.recognize import 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