"""Phase 2Q Diagnose Phase 1B — query_rewriter scaffold + dispatcher 단위 테스트.

가드레일 (plan v6 §5 + §7 Phase 1):
  1. `_resolve_rewrite_backend` — slug resolve, unknown ValueError, baseline → None
  2. `_cache_key` — deterministic + NFKC normalize + backend slug 분리
  3. `_extract_variants` — valid shape / wrong count / type mismatch / empty / non-list
  4. cache set/get/TTL (LRU evict 시뮬레이션)
  5. `allowed_slugs` — LLM_BACKEND_MAP keys 1:1
"""

from __future__ import annotations

import asyncio
import logging
import os
import sys
import time

import pytest

# logs/llm_gate.log 가 root 소유 (운영 fastapi daemon write) → pytest 가 hyungi user 로
# import 시 PermissionError. 본 test 한정 FileHandler safe-wrap (다른 test 영향 0).
_orig_file_handler = logging.FileHandler

def _safe_file_handler(filename, *args, **kwargs):  # type: ignore
    try:
        return _orig_file_handler(filename, *args, **kwargs)
    except PermissionError:
        return logging.NullHandler()

logging.FileHandler = _safe_file_handler  # type: ignore[assignment]

# Phase 2 test (search_pipeline import) 는 api.search → SQLAlchemy engine init 트리거.
# DATABASE_URL 미설정 시 ArgumentError 로 collection 실패. dummy URL 주입 (실제 connect X).
os.environ.setdefault("DATABASE_URL", "postgresql+asyncpg://test:test@localhost:5432/test")

# tests/ → 프로젝트 루트 → app/
sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "app"))

from services.search import query_rewriter
from services.search.query_rewriter import (
    EXPECTED_N_VARIANTS,
    LLM_BACKEND_MAP,
    PROMPT_VERSION,
    _cache_key,
    _extract_variants,
    _resolve_rewrite_backend,
    allowed_slugs,
)


# ─── 1. _resolve_rewrite_backend ──────────────────────────


def test_resolve_baseline_returns_none():
    assert _resolve_rewrite_backend(None) is None
    assert _resolve_rewrite_backend("baseline") is None


def test_resolve_known_slugs():
    cfg = _resolve_rewrite_backend("cand_multi_query_macmini")
    assert cfg is not None
    assert "endpoint" in cfg and "model" in cfg and "sampling" in cfg
    assert cfg["model"] == "gemma-4-26b-a4b-it-8bit"

    cfg = _resolve_rewrite_backend("cand_multi_query_macbook")
    assert cfg is not None
    assert cfg["model"] == "mlx-community/Qwen3.6-27B-8bit"
    # qwen sampling 에 response_format 없음 (Phase 0 inspect 9 박제)
    assert "response_format" not in cfg["sampling"]


def test_resolve_unknown_slug_raises():
    with pytest.raises(ValueError, match="unknown_rewrite_backend"):
        _resolve_rewrite_backend("cand_bogus")
    with pytest.raises(ValueError):
        _resolve_rewrite_backend("cand_multi_query_other")


def test_allowed_slugs_matches_map():
    assert allowed_slugs() == list(LLM_BACKEND_MAP.keys())
    assert "baseline" in allowed_slugs()
    assert "cand_multi_query_macmini" in allowed_slugs()
    assert "cand_multi_query_macbook" in allowed_slugs()


# ─── 2. _cache_key ────────────────────────────────────────


def test_cache_key_deterministic():
    k1 = _cache_key("산업안전보건법 제6장", "cand_multi_query_macmini")
    k2 = _cache_key("산업안전보건법 제6장", "cand_multi_query_macmini")
    assert k1 == k2
    assert len(k1) == 32  # sha256[:32]


def test_cache_key_nfkc_normalize_and_strip_lower():
    # whitespace + uppercase → 동일 key
    base = _cache_key("ASME Section VIII", "cand_multi_query_macmini")
    assert _cache_key("  asme section viii  ", "cand_multi_query_macmini") == base
    assert _cache_key("ASME SECTION VIII", "cand_multi_query_macmini") == base


def test_cache_key_differs_by_backend_slug():
    k_a = _cache_key("query", "cand_multi_query_macmini")
    k_b = _cache_key("query", "cand_multi_query_macbook")
    assert k_a != k_b


def test_cache_key_includes_prompt_version():
    # PROMPT_VERSION 변경 시 cache 분리 — 직접 test 어렵지만 raw 구성 확인
    assert PROMPT_VERSION == "v1"
    k = _cache_key("query", "cand_multi_query_macmini")
    assert len(k) == 32


# ─── 3. _extract_variants ─────────────────────────────────


def test_extract_variants_valid_shape():
    raw = '{"variants": ["원본", "한국어 변형", "english"]}'
    out = _extract_variants(raw, expected_n=3)
    assert out == ["원본", "한국어 변형", "english"]


def test_extract_variants_strips_whitespace():
    raw = '{"variants": ["  원본  ", "한국어\\n", " english "]}'
    out = _extract_variants(raw, expected_n=3)
    assert out == ["원본", "한국어", "english"]


def test_extract_variants_wrong_count_returns_none():
    raw = '{"variants": ["only_one"]}'
    assert _extract_variants(raw, expected_n=3) is None
    raw = '{"variants": ["a", "b", "c", "d"]}'
    assert _extract_variants(raw, expected_n=3) is None


def test_extract_variants_missing_key_returns_none():
    raw = '{"queries": ["a", "b", "c"]}'
    assert _extract_variants(raw, expected_n=3) is None


def test_extract_variants_non_list_returns_none():
    raw = '{"variants": "single string"}'
    assert _extract_variants(raw, expected_n=3) is None


def test_extract_variants_empty_string_returns_none():
    raw = '{"variants": ["a", "", "c"]}'
    assert _extract_variants(raw, expected_n=3) is None


def test_extract_variants_non_string_element_returns_none():
    raw = '{"variants": ["a", 123, "c"]}'
    assert _extract_variants(raw, expected_n=3) is None


def test_extract_variants_invalid_json_returns_none():
    raw = "not json at all"
    assert _extract_variants(raw, expected_n=3) is None


def test_extract_variants_markdown_fence_fallback():
    # parse_json_response 가 ```json fenced 블록 내부 추출 — production parser 재사용 검증
    raw = '```json\n{"variants": ["a", "b", "c"]}\n```'
    out = _extract_variants(raw, expected_n=3)
    assert out == ["a", "b", "c"]


# ─── 4. cache set / get ───────────────────────────────────


@pytest.mark.asyncio
async def test_cache_set_get_roundtrip():
    # 격리: 전역 _CACHE 초기화 (다른 테스트와 격리)
    query_rewriter._CACHE.clear()
    key = _cache_key("__test_unique_key__", "cand_multi_query_macmini")
    assert await query_rewriter._get_cached(key) is None
    await query_rewriter._set_cached(key, ["v0", "v1", "v2"])
    out = await query_rewriter._get_cached(key)
    assert out == ["v0", "v1", "v2"]


@pytest.mark.asyncio
async def test_cache_ttl_expiry():
    query_rewriter._CACHE.clear()
    key = "ttl_test_key"
    # manual entry with past expire_at
    query_rewriter._CACHE[key] = (time.time() - 1.0, ["a", "b", "c"])
    assert await query_rewriter._get_cached(key) is None
    # lazy delete verify
    assert key not in query_rewriter._CACHE


@pytest.mark.asyncio
async def test_cache_returns_copy_not_reference():
    """_get_cached 반환 list 를 외부에서 수정해도 internal cache 안전."""
    query_rewriter._CACHE.clear()
    key = "copy_test_key"
    await query_rewriter._set_cached(key, ["a", "b", "c"])
    out = await query_rewriter._get_cached(key)
    out.append("mutated")
    out2 = await query_rewriter._get_cached(key)
    assert out2 == ["a", "b", "c"]


# ─── 5. constants ─────────────────────────────────────────


def test_constants_match_plan_v6():
    assert PROMPT_VERSION == "v1"
    assert EXPECTED_N_VARIANTS == 3
    assert query_rewriter.LLM_REWRITE_TIMEOUT_MS == 15000
    assert query_rewriter.CACHE_TTL == 86400
    assert query_rewriter.CACHE_MAXSIZE == 1000


# ─── 6. Phase 2 — _rrf_fuse_variants 합성 알고리즘 ────────


def _mk_search_result(doc_id: int, score: float = 1.0, match_reason: str = "test"):
    """SearchResult 인스턴스 (api.search 의 BaseModel). file_format 은 str 필수."""
    from api.search import SearchResult
    return SearchResult(
        id=doc_id, title=f"doc-{doc_id}", ai_domain=None,
        ai_summary=None, file_format="pdf",
        score=score, snippet=None, match_reason=match_reason,
    )


def test_rrf_fuse_variants_single_variant_preserves_order():
    from services.search.search_pipeline import _rrf_fuse_variants
    docs = [_mk_search_result(i) for i in (10, 20, 30)]
    out = _rrf_fuse_variants([docs], k=60, limit=10)
    assert [r.id for r in out] == [10, 20, 30]
    # RRF score = 1/(60+1) > 1/(60+2) > 1/(60+3)
    assert out[0].score > out[1].score > out[2].score
    assert "multi_query_rrf" in out[0].match_reason


def test_rrf_fuse_variants_accumulates_overlapping_doc_ids():
    """같은 doc_id 가 여러 variant 에서 top rank 면 점수 누적 → 상위."""
    from services.search.search_pipeline import _rrf_fuse_variants
    v1 = [_mk_search_result(i) for i in (10, 20, 30)]
    v2 = [_mk_search_result(i) for i in (40, 10, 50)]  # 10 이 두 variant 모두 등장
    out = _rrf_fuse_variants([v1, v2], k=60, limit=10)
    # 10 = 1/61 + 1/62 (rank 1 + rank 2). 다른 doc 은 1 variant 만 → 단일 RRF score.
    ids = [r.id for r in out]
    assert ids[0] == 10  # 누적 점수 최상위
    # 40 (1/61) vs 20 (1/62) — variant 1 에서 rank 1 인 40 이 단일 등장 doc 중 최상위
    assert ids[1] == 40
    assert set(ids) == {10, 20, 30, 40, 50}


def test_rrf_fuse_variants_first_variant_representative():
    """같은 doc_id 가 여러 variant 에 있으면 첫 등장 variant 의 SearchResult 보존."""
    from services.search.search_pipeline import _rrf_fuse_variants
    v1 = [_mk_search_result(10, match_reason="from_v1")]
    v2 = [_mk_search_result(10, match_reason="from_v2")]
    out = _rrf_fuse_variants([v1, v2], k=60, limit=10)
    assert len(out) == 1
    assert out[0].id == 10
    assert "from_v1" in out[0].match_reason  # 첫 등장 보존
    assert "multi_query_rrf" in out[0].match_reason


def test_rrf_fuse_variants_respects_limit_cap():
    from services.search.search_pipeline import _rrf_fuse_variants
    v1 = [_mk_search_result(i) for i in range(100, 130)]  # 30 docs
    v2 = [_mk_search_result(i) for i in range(200, 230)]  # 30 docs, 모두 unique
    out = _rrf_fuse_variants([v1, v2], k=60, limit=5)
    assert len(out) == 5


def test_rrf_fuse_variants_empty_lists_returns_empty():
    from services.search.search_pipeline import _rrf_fuse_variants
    assert _rrf_fuse_variants([], k=60, limit=10) == []
    assert _rrf_fuse_variants([[], [], []], k=60, limit=10) == []


def test_rrf_fuse_variants_rank_position_matters():
    """variant 가 길어져도 RRF 공식이 rank 만 사용."""
    from services.search.search_pipeline import _rrf_fuse_variants
    v1 = [_mk_search_result(10)]  # rank 1
    v2 = [_mk_search_result(99), _mk_search_result(10)]  # 10 이 rank 2
    out = _rrf_fuse_variants([v1, v2], k=60, limit=10)
    # 10 = 1/61 + 1/62, 99 = 1/61. 둘 다 등장 doc 중 10 점수 높음.
    assert out[0].id == 10
    assert out[1].id == 99


# ─── 7. Phase 2 — search_pipeline import + run_search signature ───


def test_search_pipeline_imports_query_rewriter():
    """search_pipeline 이 query_rewriter 를 import 하는지 (dispatch 분기 활성)."""
    from services.search import search_pipeline
    assert hasattr(search_pipeline, "query_rewriter")
    assert hasattr(search_pipeline, "search_with_rewrite")
    assert hasattr(search_pipeline, "_rrf_fuse_variants")


def test_run_search_has_rewrite_backend_param():
    """run_search signature 에 rewrite_backend 가 추가됐는지."""
    import inspect
    from services.search.search_pipeline import run_search
    sig = inspect.signature(run_search)
    assert "rewrite_backend" in sig.parameters
    # default = None (baseline 회귀 0 invariant)
    assert sig.parameters["rewrite_backend"].default is None


def test_phase2q_constants():
    """plan v6 §5.5 박제값."""
    from services.search.search_pipeline import (
        PHASE2Q_PRODUCTION_TOPK,
        PHASE2Q_RRF_K,
        PHASE2Q_UNIFIED_CAP,
    )
    assert PHASE2Q_PRODUCTION_TOPK == 50
    assert PHASE2Q_RRF_K == 60
    assert PHASE2Q_UNIFIED_CAP == 60
    # per-variant K = 50 // 3 = 16 (A1 채택)
    assert PHASE2Q_PRODUCTION_TOPK // EXPECTED_N_VARIANTS == 16


# ─── 8. Phase 3 incident regression — fixture-first call shape ───
# Phase 3 cold 측정에서 NDCG 0.033 catastrophic 발견 → variants 가 query 무관 동일 응답.
# root cause = _call_llm 이 user 메시지 1개에 prompt template 전체 박음. fixture 의 정확한
# request_body 는 system=prompt / user=query 분리. fixture-first invariant 위반.
# 본 test 는 호출 형식이 fixture 와 일치하는지 verify (regression 방지).


@pytest.mark.asyncio
async def test_call_llm_uses_system_user_message_split(monkeypatch):
    """_call_llm 이 fixture 의 request_body 형식 (system=prompt / user=query) 으로 호출하는지."""
    captured = {}

    class _MockResponse:
        def raise_for_status(self):
            return None

        def json(self):
            return {"choices": [{"message": {"content": '{"variants": ["a", "b", "c"]}'}}]}

    class _MockClient:
        def __init__(self, *args, **kwargs):
            pass

        async def __aenter__(self):
            return self

        async def __aexit__(self, *args):
            return None

        async def post(self, url, json):
            captured["url"] = url
            captured["payload"] = json
            return _MockResponse()

    monkeypatch.setattr(query_rewriter.httpx, "AsyncClient", _MockClient)

    cfg = query_rewriter.LLM_BACKEND_MAP["cand_multi_query_macmini"]
    raw = await query_rewriter._call_llm(cfg, "LPG 저장탱크 안전거리")

    # raw 응답 정상
    assert "variants" in raw

    # endpoint = cfg endpoint 사용
    assert captured["url"] == cfg["endpoint"]

    payload = captured["payload"]
    # model = cfg model
    assert payload["model"] == cfg["model"]

    # messages = 2 entry, system + user 분리
    messages = payload["messages"]
    assert len(messages) == 2
    assert messages[0]["role"] == "system"
    assert messages[1]["role"] == "user"

    # user 메시지 = query verbatim (prompt template 안 박힘)
    assert messages[1]["content"] == "LPG 저장탱크 안전거리"

    # system 메시지 = prompt template (instruction). query 본문은 포함되지 않음.
    assert "LPG 저장탱크 안전거리" not in messages[0]["content"]
    assert "search query rewriter" in messages[0]["content"].lower()

    # sampling 박제 적용 (gemma → response_format json_object)
    assert payload["temperature"] == 0.3
    assert payload["max_tokens"] == 256
    assert payload.get("response_format") == {"type": "json_object"}


@pytest.mark.asyncio
async def test_call_llm_qwen_no_response_format(monkeypatch):
    """qwen backend = response_format 미사용 (mlx-vlm.server 미지원, Phase 0 inspect 9 박제)."""
    captured = {}

    class _MockResponse:
        def raise_for_status(self):
            return None
        def json(self):
            return {"choices": [{"message": {"content": '{"variants": ["a", "b", "c"]}'}}]}

    class _MockClient:
        def __init__(self, *args, **kwargs):
            pass
        async def __aenter__(self):
            return self
        async def __aexit__(self, *args):
            return None
        async def post(self, url, json):
            captured["payload"] = json
            return _MockResponse()

    monkeypatch.setattr(query_rewriter.httpx, "AsyncClient", _MockClient)

    cfg = query_rewriter.LLM_BACKEND_MAP["cand_multi_query_macbook"]
    await query_rewriter._call_llm(cfg, "ASME Section VIII")

    payload = captured["payload"]
    # qwen 은 response_format 박제 0 (prompt rule 만)
    assert "response_format" not in payload