"""Merge endpoints over HTTP against a real gallery on a temp database.

The gallery here is real (SQLite + numpy index, no models) because the point
of these tests is the refusal contract the UI depends on: a refused merge must
come back as a 409 carrying the measured similarity, so the operator can be
shown what they are being asked to override.
"""
import threading

import numpy as np
import pytest

pytest.importorskip("httpx")

from fastapi.testclient import TestClient  # noqa: E402

from behavision.api import create_app  # noqa: E402
from behavision.cameras import CameraStore  # noqa: E402
from behavision.config import Config  # noqa: E402
from behavision.engine import Engine  # noqa: E402
from behavision.events import EventBus  # noqa: E402
from behavision.gallery import Gallery, IdentityStore, VectorIndex  # noqa: E402

DIM = 16


def _unit(seed):
    rng = np.random.default_rng(seed)
    v = rng.normal(size=DIM).astype(np.float32)
    return v / np.linalg.norm(v)


def _at_similarity(base, target, seed=99):
    other = _unit(seed)
    other -= (other @ base) * base
    other /= np.linalg.norm(other)
    v = target * base + np.sqrt(1 - target ** 2) * other
    return (v / np.linalg.norm(v)).astype(np.float32)


@pytest.fixture
def client(tmp_path):
    eng = object.__new__(Engine)
    eng.cfg = Config()
    eng.cfg.app.data_dir = tmp_path
    eng.cfg.api.username = eng.cfg.api.password = ""
    eng.cfg.recognition.sighting_cooldown_seconds = 0.0
    eng.store = IdentityStore(tmp_path / "api.db")
    eng.gallery = Gallery(eng.store, VectorIndex(DIM), eng.cfg.recognition)
    eng.bus = EventBus()
    eng.encoder = eng.attributes = None
    eng._lock = threading.RLock()
    eng.workers, eng.detectors = {}, {}
    eng.started_at, eng._running = 1.0, True
    eng.camera_store = CameraStore(tmp_path / "cameras.json")
    yield TestClient(create_app(eng)), eng
    eng.store.close()


def test_merge_succeeds_and_emits_an_audit_event(client):
    c, eng = client
    base = _unit(1)
    a = eng.gallery.enroll("Alice", [base])
    b = eng.gallery.enroll("Visitor 2", [_at_similarity(base, 0.50)])

    r = c.post(f"/api/identities/{b}/merge", json={"into": a})

    assert r.status_code == 200
    assert r.json()["ok"] is True
    assert r.json()["similarity"] == pytest.approx(0.50, abs=0.01)
    assert len(c.get("/api/identities").json()) == 1

    # Merging is destructive and irreversible; it has to leave a trace.
    types = [e["type"] for e in eng.bus.recent]
    assert "identity.merged" in types


def test_refusal_is_409_and_reports_the_similarity(client):
    """The UI needs the number, not just a failure — it is what justifies
    offering the force override to a human."""
    c, eng = client
    a = eng.gallery.enroll("Alice", [_unit(1)])
    b = eng.gallery.enroll("Bob", [_at_similarity(_unit(1), 0.05)])

    r = c.post(f"/api/identities/{b}/merge", json={"into": a})

    assert r.status_code == 409
    detail = r.json()["detail"]
    assert detail["ok"] is False
    assert detail["similarity"] == pytest.approx(0.05, abs=0.01)
    assert detail["threshold"] == eng.cfg.recognition.enroll_threshold
    assert len(c.get("/api/identities").json()) == 2


def test_force_is_not_the_default(client):
    c, eng = client
    a = eng.gallery.enroll("Alice", [_unit(1)])
    b = eng.gallery.enroll("Bob", [_at_similarity(_unit(1), 0.05)])

    assert c.post(f"/api/identities/{b}/merge",
                  json={"into": a}).status_code == 409
    r = c.post(f"/api/identities/{b}/merge", json={"into": a, "force": True})
    assert r.status_code == 200
    assert r.json()["forced"] is True


def test_missing_identity_is_404(client):
    c, eng = client
    a = eng.gallery.enroll("Alice", [_unit(1)])
    r = c.post(f"/api/identities/9999/merge", json={"into": a})
    assert r.status_code == 404


def test_self_merge_is_409(client):
    c, eng = client
    a = eng.gallery.enroll("Alice", [_unit(1)])
    assert c.post(f"/api/identities/{a}/merge",
                  json={"into": a}).status_code == 409


def test_duplicates_endpoint_lists_candidates(client):
    c, eng = client
    base = _unit(1)
    a = eng.gallery.enroll("Alice", [base])
    b = eng.gallery.enroll("Visitor 2", [_at_similarity(base, 0.50)])

    pairs = c.get("/api/identities/duplicates").json()

    assert len(pairs) == 1
    assert {pairs[0]["a"]["id"], pairs[0]["b"]["id"]} == {a, b}
    assert pairs[0]["confident"] is True  # 0.50 clears match_threshold


def test_duplicates_route_is_not_shadowed_by_the_id_routes(client):
    """`/api/identities/duplicates` sits under a path whose siblings take an
    int id; if it ever gets matched by one of those it returns 422, not a
    list."""
    c, _ = client
    r = c.get("/api/identities/duplicates")
    assert r.status_code == 200
    assert isinstance(r.json(), list)


def test_embedding_endpoint_returns_the_best_view(client):
    """The server needs a vector to match across sites, and the event bus
    deliberately does not carry one."""
    c, eng = client
    base = _unit(1)
    poor = _at_similarity(base, 0.60, seed=5)
    # enroll() defaults to quality 1.0, which would win regardless and make
    # the assertion below vacuous.
    ident = eng.gallery.enroll("Alice", [base], quality=0.50)
    eng.store.add_embedding(ident, poor, 0.20, eng.gallery.model_name)
    eng.store.add_embedding(ident, base, 0.91, eng.gallery.model_name)

    r = c.get(f"/api/identities/{ident}/embedding")

    assert r.status_code == 200
    body = r.json()
    assert body["quality"] == 0.91, "did not pick the best view"
    assert len(body["embedding"]) == DIM
    assert body["model"] == eng.gallery.model_name


def test_embedding_endpoint_404s_for_an_unknown_identity(client):
    c, _ = client
    assert c.get("/api/identities/9999/embedding").status_code == 404


def test_embedding_endpoint_404s_when_the_model_differs(client):
    """Vectors from another encoder are not comparable, so returning one would
    hand the server a template it must not use."""
    c, eng = client
    ident = eng.store.create_identity("Bob")
    eng.store.add_embedding(ident, _unit(3), 0.9, "some_other_model")
    assert c.get(f"/api/identities/{ident}/embedding").status_code == 404