"""A1 — sift: rank-fusion math + graceful degradation when the vibe-engineer is unavailable.
(Offline — no network; the embedding path is exercised in the cached e2e verification.)"""
from app.engine import sift as S


def test_ranks_normalization():
    r = S._ranks({"a": 0.9, "b": 0.5, "c": 0.1})
    assert r["a"] == 1.0 and r["c"] == 0.0 and 0.0 < r["b"] < 1.0
    assert S._ranks({"x": 0.5}) == {"x": 1.0}                 # single item → top


def test_sift_degrades_to_whitebox_when_no_vibe(monkeypatch):
    monkeypatch.setattr(S._embed, "vibe_scores", lambda *a, **k: None)   # embeddings unavailable
    jobs = [{"id": str(i), "title": "Product Manager", "organization": "X",
             "location_city": "New Delhi", "location_country": "India",
             "details": {"description": "product manager roadmap"}} for i in range(30)]
    prefs = {"title": "Product Manager", "location": ["New Delhi · India"]}
    top, dbg = S.sift(prefs, None, jobs, k=18)
    assert dbg["mode"] == "whitebox-only" and len(top) == 18
    assert all("match" in j for j in top)                    # white-box match block rides along


def test_sift_empty_input():
    top, dbg = S.sift({"title": "PM"}, None, [], k=18)
    assert top == [] and dbg["mode"] == "empty"