"""Phase 3.5 fix3: re-gate Tier 0 — synthesis 자체 실패 처리.

`_detect_synthesis_failure()` 단위 테스트.

기존 버그:
  synthesis LLM self-refuse (`sr.refused=True, status="completed"`) 또는
  timeout/parse_failed/llm_error 시 grounding/verifier flag 0건 → re-gate else clean
  분기로 빠져 `completeness="full"` 초기값이 남아 `full + refused=True` 모순.
  baseline v1-400char 에서 24/223 (10.8%) 해당.

Tier 0 판정:
  - LLM self-refuse (completed + refused) → "synthesis_self_refuse"
  - mechanical fail (timeout/parse_failed/llm_error) → "synthesis_failed({status})"
  - answer 공백 → "synthesis_failed({status})"
  - 유효 답변 → None (기존 tier 1~7 경로)
"""

from __future__ import annotations

import os
import sys

sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "app"))

from api.search import _detect_synthesis_failure
from services.search.synthesis_service import SynthesisResult


def _sr(
    status: str = "completed",
    answer: str | None = "ok",
    refused: bool = False,
    refuse_reason: str | None = None,
) -> SynthesisResult:
    return SynthesisResult(
        status=status,  # type: ignore[arg-type]
        answer=answer,
        used_citations=[],
        confidence="low",
        refused=refused,
        refuse_reason=refuse_reason,
        elapsed_ms=100.0,
        cache_hit=False,
    )


# ─── self-refuse 케이스 ──────────────────────────────────


def test_llm_self_refuse_completed():
    """LLM 이 JSON 에 refused=true 반환 → synthesis_self_refuse."""
    sr = _sr(status="completed", answer=None, refused=True, refuse_reason="범위 밖")
    assert _detect_synthesis_failure(sr) == "synthesis_self_refuse"


def test_llm_self_refuse_with_answer_still_refused():
    """refused=True 면 answer 있어도 Tier 0 처리 (일관성)."""
    sr = _sr(status="completed", answer="왜 답변함", refused=True)
    assert _detect_synthesis_failure(sr) == "synthesis_self_refuse"


# ─── mechanical failure 케이스 ──────────────────────────


def test_timeout():
    sr = _sr(status="timeout", answer=None, refused=False)
    assert _detect_synthesis_failure(sr) == "synthesis_failed(timeout)"


def test_parse_failed():
    sr = _sr(status="parse_failed", answer=None, refused=False)
    assert _detect_synthesis_failure(sr) == "synthesis_failed(parse_failed)"


def test_llm_error():
    sr = _sr(status="llm_error", answer=None, refused=False)
    assert _detect_synthesis_failure(sr) == "synthesis_failed(llm_error)"


def test_refused_with_mechanical_fail_propagates_status():
    """refused=True + status!=completed → synthesis_failed({status}) 형식."""
    sr = _sr(status="timeout", answer=None, refused=True)
    assert _detect_synthesis_failure(sr) == "synthesis_failed(timeout)"


# ─── empty answer 케이스 ───────────────────────────────


def test_empty_answer_completed():
    """status=completed 인데 answer 공백 → synthesis_failed(completed)."""
    sr = _sr(status="completed", answer="", refused=False)
    assert _detect_synthesis_failure(sr) == "synthesis_failed(completed)"


def test_whitespace_only_answer():
    """공백/탭/개행만 있어도 empty 로 간주."""
    sr = _sr(status="completed", answer="   \n\t  ", refused=False)
    assert _detect_synthesis_failure(sr) == "synthesis_failed(completed)"


def test_none_answer_completed():
    """answer=None + status=completed → failed."""
    sr = _sr(status="completed", answer=None, refused=False)
    assert _detect_synthesis_failure(sr) == "synthesis_failed(completed)"


# ─── 유효 답변 케이스 (None 반환) ──────────────────────


def test_valid_answer_returns_none():
    """status=completed + answer 있고 refused=False → Tier 0 통과 (None)."""
    sr = _sr(status="completed", answer="교육 시간은 매년 6시간 이상이다 [1].", refused=False)
    assert _detect_synthesis_failure(sr) is None


def test_skipped_status_with_answer_passes():
    """status=skipped 는 Tier 0 대상 아님 — 초기 refusal gate 에서 이미 early-return 처리됨.

    (skipped 는 여기까지 도달하지 않는다는 전제. 만약 도달하더라도 refused 가 True 일 것.)
    """
    sr = _sr(status="skipped", answer="abc", refused=False)
    # 이 경우 Tier 0 미발동 (answer 있고 refused 아님) — 정상 경로로 나감.
    assert _detect_synthesis_failure(sr) is None