"""IMP-33 u6 — AI fallback cache gate tests.

Verifies the IMP-46 gate contract:
  * ``read_proposal`` is a stub (returns None until IMP-46).
  * ``save_proposal`` enforces both gates before any write attempt.
  * Storage itself raises NotImplementedError (IMP-46 marker).
"""
from __future__ import annotations

import pytest

from src.phase_z2_ai_fallback.cache import (
    AiFallbackCacheGateError,
    read_proposal,
    save_proposal,
)
from src.phase_z2_ai_fallback.schema import AiFallbackProposal, ProposalKind


def _proposal() -> AiFallbackProposal:
    return AiFallbackProposal(
        proposal_kind=ProposalKind.BUILDER_OPTIONS_PATCH,
        payload={"item_parser": "bullet_v2"},
        rationale="u6-test",
    )


def test_read_proposal_returns_none_for_any_key():
    assert read_proposal("frame=foo|cardinality=3") is None


def test_read_proposal_rejects_empty_key():
    with pytest.raises(ValueError):
        read_proposal("")


def test_save_rejects_when_visual_check_failed():
    with pytest.raises(AiFallbackCacheGateError) as exc:
        save_proposal(
            "k", _proposal(), visual_check_passed=False, user_approved=True
        )
    assert "visual_check_passed" in str(exc.value)


def test_save_rejects_when_user_not_approved():
    with pytest.raises(AiFallbackCacheGateError) as exc:
        save_proposal(
            "k", _proposal(), visual_check_passed=True, user_approved=False
        )
    assert "user_approved" in str(exc.value)


def test_save_rejects_when_both_gates_false():
    with pytest.raises(AiFallbackCacheGateError):
        save_proposal(
            "k", _proposal(), visual_check_passed=False, user_approved=False
        )


def test_save_raises_not_implemented_when_both_gates_pass():
    with pytest.raises(NotImplementedError) as exc:
        save_proposal(
            "k", _proposal(), visual_check_passed=True, user_approved=True
        )
    assert "IMP-46" in str(exc.value)


def test_save_rejects_empty_key():
    with pytest.raises(ValueError):
        save_proposal(
            "", _proposal(), visual_check_passed=True, user_approved=True
        )


def test_save_rejects_non_proposal_object():
    with pytest.raises(TypeError):
        save_proposal(
            "k",
            {"proposal_kind": "builder_options_patch"},  # type: ignore[arg-type]
            visual_check_passed=True,
            user_approved=True,
        )


def test_gate_error_is_not_notimplementederror():
    with pytest.raises(AiFallbackCacheGateError):
        save_proposal(
            "k", _proposal(), visual_check_passed=False, user_approved=True
        )
    assert not issubclass(AiFallbackCacheGateError, NotImplementedError)