"""A section must be served in the order it was written.

Found 2026-08-05 by reading a real answer in the UI rather than a test:
`liều dùng paracetamol` opened mid-sentence on `5 - 12 tuổi:` and buried
`Liều lượng: Người lớn:` seven hundred words down. Qdrant scrolls in point-id
order and point ids are `uuid5(chunk_id)`, so PARACETAMOL's five dosing parts
came back **3, 4, 1, 2, 0**.

This is a clinical defect, not a cosmetic one: a reader who stops partway
through stops in the middle of a different population's dose.
"""
from __future__ import annotations

from adapters.qdrant import QdrantRetriever


class _ScrambledClient:
    """Returns parts out of order, the way a real scroll did."""

    def __init__(self, part_indices: list[int], include_index: bool = True) -> None:
        self._payloads = [
            {
                "chunk_id": f"paracetamol__lieu__{index}",
                "drug_id": "paracetamol",
                "section_key": "lieu_luong_va_cach_dung",
                "chunk_kind": "prose",
                "text": f"part {index}",
                "source_refs": [{"physical_page": 1120, "precision": "page"}],
                **({"part_index": index} if include_index else {}),
            }
            for index in part_indices
        ]

    def scroll(self, **kwargs):
        points = [type("P", (), {"payload": payload})() for payload in self._payloads]
        return points, None


class _Embedder:
    dimensions = 4

    def embed_query(self, text: str) -> list[float]:  # never used by this route
        raise AssertionError("find_by_section must not embed anything")


def _hits(part_indices: list[int], include_index: bool = True) -> list[str]:
    retriever = QdrantRetriever(
        _ScrambledClient(part_indices, include_index), "duocthu_v1", _Embedder()
    )
    return [
        hit.document.text
        for hit in retriever.find_by_section("paracetamol", "lieu_luong_va_cach_dung")
    ]


def test_the_exact_scramble_observed_against_the_real_collection():
    assert _hits([3, 4, 1, 2, 0]) == [
        "part 0",
        "part 1",
        "part 2",
        "part 3",
        "part 4",
    ]


def test_an_already_ordered_section_is_left_alone():
    assert _hits([0, 1, 2, 3]) == ["part 0", "part 1", "part 2", "part 3"]


def test_a_part_missing_its_index_is_kept_and_sorted_last():
    """Dropping it would silently shorten a dose list, which is the one
    outcome worse than showing it out of order."""
    texts = _hits([1, 0], include_index=False)

    assert len(texts) == 2
    assert set(texts) == {"part 0", "part 1"}