"""TDD for spaceutil.cards.top_k_with_matrix.

The local fast-path must rank identically to the upstream `top_k` from
optcg_cards.search on the same inputs - that's the load-bearing
invariant. The only difference is that top_k_with_matrix takes a
pre-stacked matrix to avoid the per-call _vectors_to_array restack.
"""

from __future__ import annotations

import numpy as np
from optcg_cards.search import SearchHit, top_k


def _matrix_from_cards(cards: list[dict]) -> np.ndarray:
    return np.stack(
        [np.asarray(c["embedding"], dtype=np.float32) for c in cards],
        axis=0,
    )


def test_top_k_with_matrix_matches_upstream(synthetic_cards):
    from spaceutil.cards import top_k_with_matrix

    matrix = _matrix_from_cards(synthetic_cards)
    cards_no_emb = [{k: v for k, v in c.items() if k != "embedding"} for c in synthetic_cards]
    query = matrix[3]

    upstream = top_k(query, synthetic_cards, k=5)
    local = top_k_with_matrix(query, matrix, cards_no_emb, k=5)

    assert [h.card_id for h in local] == [h.card_id for h in upstream]
    np.testing.assert_allclose(
        [h.score for h in local], [h.score for h in upstream], atol=1e-6
    )


def test_top_k_with_matrix_returns_searchhit(synthetic_cards):
    from spaceutil.cards import top_k_with_matrix

    matrix = _matrix_from_cards(synthetic_cards)
    cards_no_emb = [{k: v for k, v in c.items() if k != "embedding"} for c in synthetic_cards]

    hits = top_k_with_matrix(matrix[0], matrix, cards_no_emb, k=3)
    assert all(isinstance(h, SearchHit) for h in hits)
    assert len(hits) == 3
    assert all(h.rank == i + 1 for i, h in enumerate(hits))


def test_exclude_idx_removes_query_card(synthetic_cards):
    from spaceutil.cards import top_k_with_matrix

    matrix = _matrix_from_cards(synthetic_cards)
    cards_no_emb = [{k: v for k, v in c.items() if k != "embedding"} for c in synthetic_cards]

    hits = top_k_with_matrix(matrix[7], matrix, cards_no_emb, k=5, exclude_idx=7)
    assert all(h.card_id != cards_no_emb[7]["id"] for h in hits)


def test_k_larger_than_corpus_clamped(synthetic_cards):
    from spaceutil.cards import top_k_with_matrix

    matrix = _matrix_from_cards(synthetic_cards)
    cards_no_emb = [{k: v for k, v in c.items() if k != "embedding"} for c in synthetic_cards]

    hits = top_k_with_matrix(matrix[0], matrix, cards_no_emb, k=100)
    assert len(hits) == 20


def test_empty_corpus_returns_empty(synthetic_cards):
    from spaceutil.cards import top_k_with_matrix

    matrix = np.empty((0, 1024), dtype=np.float32)
    query = np.zeros(1024, dtype=np.float32)
    hits = top_k_with_matrix(query, matrix, [], k=10)
    assert hits == []


def test_scores_ordered_descending(synthetic_cards):
    from spaceutil.cards import top_k_with_matrix

    matrix = _matrix_from_cards(synthetic_cards)
    cards_no_emb = [{k: v for k, v in c.items() if k != "embedding"} for c in synthetic_cards]

    hits = top_k_with_matrix(matrix[0], matrix, cards_no_emb, k=10)
    scores = [h.score for h in hits]
    assert scores == sorted(scores, reverse=True)