"""Spike D tests — non-tautological top-K retrieval (B2).

The true match shares the *structured* similarity fields with the query but uses different
description text; the decoys share surface description text but differ structurally. A
text-matching retriever would be fooled by the decoys — a structural one is not.
Pattern: tests/test_reference_domain.py.
"""

import pytest

from spikes.d_verdictstore import (
    ExpeLContextProvider,
    ProposalFeatures,
    Verdict,
    VerdictStore,
    seed_store,
)

_QUERY = ProposalFeatures(
    affected_codes=frozenset({"05.2", "03.1"}),
    measure_type="scope_reduction",
    claimed_saving_nok=220_000,  # bucket [100k, 500k)
    description="asphalt base course reduction near school",
)


def _store_with_true_match_and_decoys() -> tuple[VerdictStore, str]:
    true_match = Verdict(
        id="TRUE",
        proposal_features=ProposalFeatures(
            affected_codes=frozenset({"05.2", "03.1"}),  # same codes
            measure_type="scope_reduction",  # same measure type
            claimed_saving_nok=200_000,  # same magnitude bucket
            description="zzz totally unrelated wording alpha beta",  # DIFFERENT text
        ),
        decision="approved",
        rationale="prior scope reduction on the same codes was approved",
    )
    # Decoys share the query's SURFACE text but differ structurally (disjoint codes,
    # different measure type, different magnitude bucket).
    decoy_low = Verdict(
        id="DECOY-LOW",
        proposal_features=ProposalFeatures(
            affected_codes=frozenset({"09.1"}),
            measure_type="rate_renegotiation",
            claimed_saving_nok=50_000,  # bucket [0, 100k)
            description="asphalt base course reduction near school",  # same words as query
        ),
        decision="rejected",
        rationale="surface-text decoy",
    )
    decoy_high = Verdict(
        id="DECOY-HIGH",
        proposal_features=ProposalFeatures(
            affected_codes=frozenset({"21.2"}),
            measure_type="material_substitution",
            claimed_saving_nok=700_000,  # bucket [500k, 1M)
            description="asphalt base course reduction extra words",
        ),
        decision="rejected",
        rationale="surface-text decoy",
    )
    # Order deliberately not putting the true match first.
    return VerdictStore(verdicts=[decoy_low, true_match, decoy_high]), "TRUE"


def test_retrieve_finds_structural_match_over_text_decoys() -> None:
    store, true_id = _store_with_true_match_and_decoys()
    hits = store.retrieve(_QUERY, k=3)
    assert hits[0].id == true_id  # structural match ranks #1 despite different wording
    assert true_id in {h.id for h in hits[:1]}  # within top-K (top-1 here)


def test_retrieve_is_deterministic() -> None:
    store, _ = _store_with_true_match_and_decoys()
    assert [h.id for h in store.retrieve(_QUERY, k=3)] == [
        h.id for h in store.retrieve(_QUERY, k=3)
    ]


def test_retrieve_rejects_non_positive_k() -> None:
    store, _ = _store_with_true_match_and_decoys()
    with pytest.raises(ValueError):
        store.retrieve(_QUERY, k=0)


def test_seed_store_has_10_to_20_verdicts() -> None:
    store = seed_store()
    assert 10 <= len(store.verdicts) <= 20


class _RecordingContext:
    """Duck-typed stand-in for SessionContext — records injected instructions without
    depending on the (private) SessionContext internals."""

    def __init__(self) -> None:
        self.instructions: list[str] = []

    def extend_instructions(self, items: list[str]) -> None:
        self.instructions.extend(items)


async def test_expel_provider_injects_retrieved_fewshot() -> None:
    store, true_id = _store_with_true_match_and_decoys()
    provider = ExpeLContextProvider(store, _QUERY, k=2)
    # The deterministic deliverable: the few-shot text carries the retrieved true match.
    assert true_id in provider.format_fewshot()
    # The injection hook (real ContextProvider.before_run signature) extends instructions.
    ctx = _RecordingContext()
    await provider.before_run(agent=None, session=None, context=ctx, state={})
    assert len(ctx.instructions) == 1
    assert true_id in ctx.instructions[0]