"""Shape hashing and equality — the contract cad/topology/geom_memo.py rests on.

Verified against the stock wheel before being replicated here: upstream binds
__hash__ (TShape + Location) and leaves __eq__ at Python's default identity
comparison.  That pairing is deliberate on our side too.  geom_memo buckets on
hash(face) and disambiguates with IsSame precisely because == cannot be
trusted; binding __eq__ to IsEqual would collapse entries that memo expects to
keep apart, changing behaviour while looking like an improvement.
"""

from __future__ import annotations

from OCP.gp import gp_Trsf, gp_Vec
from OCP.TopAbs import TopAbs_EDGE, TopAbs_FACE
from OCP.TopExp import TopExp
from OCP.TopLoc import TopLoc_Location
from OCP.TopTools import TopTools_IndexedMapOfShape


def _faces(shape):
    faces = TopTools_IndexedMapOfShape()
    TopExp.MapShapes_s(shape, TopAbs_FACE, faces)
    return faces


def test_re_extracted_face_hashes_equal_and_is_same(fixture_shapes):
    shape = fixture_shapes["box"]
    f1 = _faces(shape).FindKey(1)
    f2 = _faces(shape).FindKey(1)

    assert f1 is not f2  # separate extractions, separate wrappers
    assert hash(f1) == hash(f2)
    assert f1.IsSame(f2)
    assert f1.IsEqual(f2)


def test_eq_is_identity_not_isequal(fixture_shapes):
    shape = fixture_shapes["box"]
    f1 = _faces(shape).FindKey(1)
    f2 = _faces(shape).FindKey(1)

    # Matches the stock wheel: equal hashes, unequal objects.
    assert f1 != f2
    assert f1 == f1


def test_moved_copy_hashes_differently(fixture_shapes):
    trsf = gp_Trsf()
    trsf.SetTranslation(gp_Vec(1.0, 0.0, 0.0))

    face = _faces(fixture_shapes["box"]).FindKey(1)
    moved = face.Moved(TopLoc_Location(trsf))

    assert hash(moved) != hash(face)
    assert not face.IsSame(moved)


def test_orientation_is_not_part_of_the_hash(fixture_shapes):
    # Area and centre of mass are orientation-independent, which is why the
    # memo's key needs no orientation component.
    face = _faces(fixture_shapes["box"]).FindKey(1)
    reversed_face = face.Reversed()

    assert hash(reversed_face) == hash(face)
    assert face.IsSame(reversed_face)
    assert not face.IsEqual(reversed_face)


def test_subshapes_outlive_their_container(fixture_shapes):
    """The lifetime class that segfaulted a process-global face memo."""
    faces = _faces(fixture_shapes["fused"])
    picked = [faces.FindKey(i) for i in range(1, faces.Extent() + 1)]
    del faces

    # Every wrapper owns its own copy, so the map's death is irrelevant.
    assert all(not f.IsNull() for f in picked)
    assert len({hash(f) for f in picked}) == len(picked)


def test_explorer_results_outlive_the_explorer(fixture_shapes):
    from OCP.TopExp import TopExp_Explorer

    exp = TopExp_Explorer(fixture_shapes["box"], TopAbs_EDGE)
    edges = []
    while exp.More():
        edges.append(exp.Current())
        exp.Next()
    del exp

    assert len(edges) == 24  # a box: 12 edges, each shared by two faces
    assert all(not e.IsNull() for e in edges)


def test_indexed_map_contains_uses_is_same(fixture_shapes):
    shape = fixture_shapes["box"]
    faces = _faces(shape)
    other = _faces(shape).FindKey(3)

    assert faces.Contains(other)
    assert faces.FindIndex(other) == 3