"""IMP-47B u12 — Initial plan_composition allow_provisional_fill for mixed direct+reject.

Scope (this slice):
  The u12 glue inserted in ``run_phase_z2_mvp1`` (src/phase_z2_pipeline.py,
  right after the initial plan_composition + telemetry build, before the
  Step 7-A layout override block) detects the mixed direct+reject case
  (initial plan_composition returns a viable layout but some sections
  remain uncovered) and re-runs plan_composition with:

    * a lookup_fn that passes ``allow_provisional=True`` (so chain_exhausted
      sections synthesize a provisional rank-1 V4Match), and
    * ``allow_provisional_fill=True`` (so uncovered sections receive a
      last-resort provisional candidate fill in select_composition_units).

  This admits the mixed direct+reject case to the AI repair path
  (IMP-47B u4/u5) on first render — the reject section becomes a
  provisional unit (``provisional=True`` + ``label="reject"``) which Step
  12's reject route gather (u4) routes to AI fallback.

Gate predicates (mirrored from src/phase_z2_pipeline.py u12 block):
  * units non-empty  (all-reject case is handled by IMP-30 u4 retry below)
  * layout_preset is not None
  * not override_section_assignments  (operator override bypasses the gate)
  * at least one section_id is uncovered after initial pass

Guardrails proven by these tests:
  * MDX 원문 100% 보존 — every section_id covered after mixed admission
    (no silent drop).
  * 자동 frame swap 금지 — mixed admission only re-runs plan_composition
    with provisional flags; rank-1 reject judgment is preserved as the
    provisional V4Match (no template_id swap to a different rank).
  * Normal-path AI=0 — the mixed admission still emits the reject label;
    AI activation is gated separately in router (config.py:19 default OFF).
  * All-direct slides are a no-op — gate skips when no uncovered sections.

This test file exercises ``plan_composition`` directly with synthetic
stub V4 matches + a stub lookup_fn that mirrors the u12 retry seam.
Stub naming follows the IMP-30 u3 convention (MOCK_ prefix mandatory,
no real catalog template_id / frame_id leakage).
"""
from __future__ import annotations

from dataclasses import dataclass
from typing import Optional

from src.phase_z2_composition import plan_composition


# ─── Synthetic V4Match duck-type (mirrors IMP-30 _StubV4Match) ───────────

@dataclass
class _StubV4Match:
    template_id: str
    frame_id: str
    frame_number: int
    confidence: float
    label: str
    v4_rank: Optional[int] = None
    selection_path: str = "rank_1"
    fallback_reason: Optional[str] = None
    provisional: bool = False


@dataclass
class _StubSection:
    section_id: str
    title: str = ""
    raw_content: str = ""


_LABEL_TO_STATUS = {
    "use_as_is": "matched_zone",
    "light_edit": "adapt_matched_zone",
    "restructure": "extract_matched_zone",
    "reject": "fallback_candidate",
}

_ALLOWED_STATUSES = {"matched_zone", "adapt_matched_zone"}


def _make_normal_lookup(matches_by_section: dict[str, _StubV4Match]):
    """Lookup_fn that returns the synthetic rank-1 match (no provisional path).

    Mirrors the pipeline initial ``lookup_fn`` at
    src/phase_z2_pipeline.py:3456-3465 (no ``allow_provisional`` kwarg).
    """
    def _fn(section_id: str):
        return matches_by_section.get(section_id)
    return _fn


def _make_provisional_lookup(matches_by_section: dict[str, _StubV4Match]):
    """Lookup_fn that flags reject rank-1 matches provisional.

    Mirrors the pipeline u12 retry ``_lookup_fn_mixed_admission`` at the
    inserted block — for reject judgments, returns a provisional=True
    rank-1 V4Match-shaped stub so plan_composition's last-resort fill
    pool can see it (provisional candidates are otherwise filtered out
    of the normal greedy pass).
    """
    def _fn(section_id: str):
        m = matches_by_section.get(section_id)
        if m is not None and m.label == "reject":
            # Synthesize the provisional shape that
            # lookup_v4_match_with_fallback returns when allow_provisional
            # is True: provisional=True + selection_path="provisional_rank_1".
            return _StubV4Match(
                template_id=m.template_id,
                frame_id=m.frame_id,
                frame_number=m.frame_number,
                confidence=m.confidence,
                label=m.label,
                v4_rank=1,
                selection_path="provisional_rank_1",
                provisional=True,
            )
        return m
    return _fn


def _make_candidates_lookup_empty():
    def _fn(section_id: str):
        return []
    return _fn


# ─── u12 case 1 : mechanic — mixed admission via provisional lookup + fill ────


def test_u12_mechanic_mixed_admission_covers_reject_section_via_provisional_fill():
    """Positive proof. Mixed direct+reject (S1=use_as_is, S2=reject).

    Without u12 (initial path: normal lookup + allow_provisional_fill=False),
    plan_composition returns only the S1 unit and S2 is silently dropped.

    With u12 (retry: provisional lookup + allow_provisional_fill=True),
    plan_composition returns both units; S2 is a provisional unit with
    label="reject" — ready to be picked up by Step 12's reject route
    gather (IMP-47B u4).
    """
    sections = [_StubSection("S1"), _StubSection("S2")]
    matches = {
        "S1": _StubV4Match(
            template_id="MOCK_template_direct_a",
            frame_id="MOCK_frame_001",
            frame_number=1,
            confidence=0.92,
            label="use_as_is",
            v4_rank=1,
        ),
        "S2": _StubV4Match(
            template_id="MOCK_template_reject_a",
            frame_id="MOCK_frame_002",
            frame_number=2,
            confidence=0.30,
            label="reject",
            v4_rank=1,
        ),
    }

    # Pre-u12 baseline — normal lookup, no provisional fill.
    units_pre, preset_pre, _ = plan_composition(
        sections,
        _make_normal_lookup(matches),
        _LABEL_TO_STATUS,
        _ALLOWED_STATUSES,
        v4_candidates_lookup_fn=_make_candidates_lookup_empty(),
    )
    covered_pre = {sid for u in units_pre for sid in u.source_section_ids}
    assert "S1" in covered_pre, "S1 (use_as_is) must cover pre-u12"
    assert "S2" not in covered_pre, (
        "Pre-u12 baseline regression: reject S2 should be uncovered (no provisional fill)"
    )

    # u12 mixed-admission retry — provisional lookup + allow_provisional_fill=True.
    units_post, preset_post, _ = plan_composition(
        sections,
        _make_provisional_lookup(matches),
        _LABEL_TO_STATUS,
        _ALLOWED_STATUSES,
        v4_candidates_lookup_fn=_make_candidates_lookup_empty(),
        allow_provisional_fill=True,
    )
    covered_post = {sid for u in units_post for sid in u.source_section_ids}
    assert covered_post == {"S1", "S2"}, (
        "u12 mixed admission must cover every section (no text loss)"
    )
    assert preset_post is not None
    # The S2 unit must be marked provisional so the reject route gather
    # (src/phase_z2_ai_fallback/step12.py:133-136) admits it.
    s2_unit = next(u for u in units_post if "S2" in u.source_section_ids)
    assert s2_unit.provisional is True, (
        "Reject S2 unit must be provisional so Step 12 reject route admits it"
    )
    assert s2_unit.label == "reject"
    # Frame template id is preserved — no auto frame swap.
    assert s2_unit.frame_template_id == "MOCK_template_reject_a"


# ─── u12 case 2 : gate — all-direct slides are a no-op ──────────────────────


def test_u12_gate_all_direct_yields_no_uncovered_sections():
    """No-op proof. When every section is auto-renderable (use_as_is or
    light_edit), the initial plan_composition covers everything — the
    u12 mixed-admission gate's ``_u12_uncovered_ids`` list is empty and
    the retry is skipped.
    """
    sections = [_StubSection("S1"), _StubSection("S2")]
    matches = {
        "S1": _StubV4Match(
            template_id="MOCK_template_direct_a",
            frame_id="MOCK_frame_001",
            frame_number=1,
            confidence=0.92,
            label="use_as_is",
            v4_rank=1,
        ),
        "S2": _StubV4Match(
            template_id="MOCK_template_direct_b",
            frame_id="MOCK_frame_002",
            frame_number=2,
            confidence=0.81,
            label="light_edit",
            v4_rank=1,
        ),
    }
    units, preset, _ = plan_composition(
        sections,
        _make_normal_lookup(matches),
        _LABEL_TO_STATUS,
        _ALLOWED_STATUSES,
        v4_candidates_lookup_fn=_make_candidates_lookup_empty(),
    )
    covered = {sid for u in units for sid in u.source_section_ids}
    assert covered == {"S1", "S2"}, "All-direct must cover every section pre-u12"
    # Predicate from src/phase_z2_pipeline.py u12 block:
    uncovered = [s.section_id for s in sections if s.section_id not in covered]
    assert uncovered == [], (
        "u12 gate must classify all-direct as no-op (uncovered list empty)"
    )
    assert preset is not None


# ─── u12 case 3 : gate — initial empty units bypass u12 (IMP-30 retry owns it) ──


def test_u12_gate_skips_when_initial_units_empty():
    """All-reject case is owned by IMP-30 u4 retry (units=[] guard at
    src/phase_z2_pipeline.py:3646). u12 mixed-admission must NOT compete
    with that path; the gate ``units and layout_preset is not None``
    short-circuits when the initial plan_composition returns nothing.
    """
    sections = [_StubSection("S1")]
    matches = {
        "S1": _StubV4Match(
            template_id="MOCK_template_reject_a",
            frame_id="MOCK_frame_002",
            frame_number=2,
            confidence=0.30,
            label="reject",
            v4_rank=1,
        ),
    }
    units, preset, _ = plan_composition(
        sections,
        _make_normal_lookup(matches),
        _LABEL_TO_STATUS,
        _ALLOWED_STATUSES,
        v4_candidates_lookup_fn=_make_candidates_lookup_empty(),
    )
    # All-reject initial pass: no auto-renderable units, no layout preset.
    assert units == [] and preset is None
    # u12 gate predicate would short-circuit on `units` truthiness:
    gate_active = bool(units) and preset is not None
    assert gate_active is False, (
        "u12 mixed-admission gate must skip the all-reject case (IMP-30 u4 owns it)"
    )


# ─── u12 case 4 : code-path anchor — pipeline source contains u12 marker ────


def test_u12_pipeline_source_contains_mixed_admission_marker():
    """Anchor test. Ensures the inserted u12 block in src/phase_z2_pipeline.py
    is reachable (not silently removed by a future refactor).

    Asserts on the marker comment + ``imp47b_u12_mixed_admission`` debug key
    + ``allow_provisional_fill=True`` invocation co-located in the file.
    Cheap structural guard — does not run the heavy pipeline.
    """
    from pathlib import Path
    src_path = Path(__file__).resolve().parent.parent / "src" / "phase_z2_pipeline.py"
    text = src_path.read_text(encoding="utf-8")
    assert "IMP-47B u12 — mixed direct+reject first-render admission" in text, (
        "u12 marker comment missing from pipeline — block may have been removed"
    )
    assert "imp47b_u12_mixed_admission" in text, (
        "u12 comp_debug telemetry key missing"
    )
    # The mixed-admission retry must pass allow_provisional_fill=True.
    # Anchor against the helper function name + the kwarg co-occurrence.
    assert "_lookup_fn_mixed_admission" in text
    assert "allow_provisional_fill=True" in text