"""IMP-33 u5 — AI fallback validator tests.

Scope (Stage 2 plan, u5):
  - schema re-validation (defence-in-depth)
  - builder whitelist (BUILDER_OPTIONS_PATCH)
  - dropped-slot guard (PARTIAL_OVERRIDES / SLOT_MAPPING_PROPOSAL must keep
    every declared sub_zone slot present)
  - frame-swap guard (no payload.frame_id mutation; V4 rank-1 protected)
  - Internal Region containment (payload.region_id must match declared id)
"""
from __future__ import annotations

import pytest

from src.phase_z2_ai_fallback import AiFallbackProposal, ProposalKind
from src.phase_z2_ai_fallback.validate import (
    AiFallbackValidationError,
    validate_proposal,
)


_FRAME_CONTRACT = {
    "frame_id": 1171281190,
    "sub_zones": [
        {"id": "pillar_1", "accepts": ["text_block"]},
        {"id": "pillar_2", "accepts": ["text_block"]},
        {"id": "pillar_3", "accepts": ["text_block"]},
    ],
    "payload": {
        "builder_options": {
            "item_parser": "pillar_item",
            "array_root": "pillars",
            "role_field": "color_class",
        },
    },
}

_REGION = {"id": "zone_top.region_a"}


def _make(kind: ProposalKind, payload: dict) -> AiFallbackProposal:
    return AiFallbackProposal(proposal_kind=kind, payload=payload)


def test_builder_options_patch_accepts_whitelisted_keys() -> None:
    proposal = _make(
        ProposalKind.BUILDER_OPTIONS_PATCH,
        {"item_parser": "alt_pillar_item"},
    )
    validate_proposal(proposal, frame_contract=_FRAME_CONTRACT)


def test_builder_options_patch_rejects_unknown_key() -> None:
    proposal = _make(
        ProposalKind.BUILDER_OPTIONS_PATCH,
        {"item_parser": "x", "padding_px": 10},
    )
    with pytest.raises(AiFallbackValidationError, match="builder whitelist"):
        validate_proposal(proposal, frame_contract=_FRAME_CONTRACT)


def test_partial_overrides_requires_all_declared_slots() -> None:
    proposal = _make(
        ProposalKind.PARTIAL_OVERRIDES,
        {"slots": {"pillar_1": "a", "pillar_2": "b"}},
    )
    with pytest.raises(AiFallbackValidationError, match="dropped-slot guard"):
        validate_proposal(proposal, frame_contract=_FRAME_CONTRACT)


def test_partial_overrides_with_all_slots_passes() -> None:
    proposal = _make(
        ProposalKind.PARTIAL_OVERRIDES,
        {"slots": {"pillar_1": "a", "pillar_2": "b", "pillar_3": "c"}},
    )
    validate_proposal(proposal, frame_contract=_FRAME_CONTRACT)


def test_slot_mapping_proposal_requires_slots_dict() -> None:
    proposal = _make(ProposalKind.SLOT_MAPPING_PROPOSAL, {"slots": []})
    with pytest.raises(AiFallbackValidationError, match="dropped-slot guard"):
        validate_proposal(proposal, frame_contract=_FRAME_CONTRACT)


def test_frame_swap_guard_rejects_mismatched_frame_id() -> None:
    proposal = _make(
        ProposalKind.BUILDER_OPTIONS_PATCH,
        {"frame_id": 9999, "item_parser": "x"},
    )
    with pytest.raises(AiFallbackValidationError, match="frame-swap guard"):
        validate_proposal(proposal, frame_contract=_FRAME_CONTRACT)


def test_frame_swap_guard_accepts_matching_frame_id() -> None:
    proposal = _make(
        ProposalKind.PARTIAL_OVERRIDES,
        {
            "frame_id": 1171281190,
            "slots": {"pillar_1": "a", "pillar_2": "b", "pillar_3": "c"},
        },
    )
    validate_proposal(proposal, frame_contract=_FRAME_CONTRACT)


def test_internal_region_containment_rejects_mismatch() -> None:
    proposal = _make(
        ProposalKind.PARTIAL_OVERRIDES,
        {
            "slots": {"pillar_1": "a", "pillar_2": "b", "pillar_3": "c"},
            "region_id": "zone_bottom.region_x",
        },
    )
    with pytest.raises(AiFallbackValidationError, match="Internal Region"):
        validate_proposal(
            proposal,
            frame_contract=_FRAME_CONTRACT,
            internal_region=_REGION,
        )


def test_internal_region_containment_accepts_match() -> None:
    proposal = _make(
        ProposalKind.PARTIAL_OVERRIDES,
        {
            "slots": {"pillar_1": "a", "pillar_2": "b", "pillar_3": "c"},
            "region_id": "zone_top.region_a",
        },
    )
    validate_proposal(
        proposal,
        frame_contract=_FRAME_CONTRACT,
        internal_region=_REGION,
    )


def test_internal_region_check_skipped_when_no_region_supplied() -> None:
    proposal = _make(
        ProposalKind.PARTIAL_OVERRIDES,
        {
            "slots": {"pillar_1": "a", "pillar_2": "b", "pillar_3": "c"},
            "region_id": "zone_top.region_a",
        },
    )
    validate_proposal(proposal, frame_contract=_FRAME_CONTRACT)