"""세션 영속화 회귀 — 스냅샷/복원 + SQLite 저장소 + 라우터 재시작 복원.

핵심 회귀: 복원은 _enter()를 거치지 않는다 — 쇠약도/신뢰축이 재적용되면 결함.
"""

import pytest
from fastapi import HTTPException

from engine import router
from engine.repositories.content import ContentRepository
from engine.repositories.play_session import PlaySessionRepository
from engine.services.story import StoryEngine


@pytest.fixture(scope="module")
def repo():
    return ContentRepository("content")


def play_until(repo, stop_id: str | None, policy: str = "trust") -> StoryEngine:
    """stop_id 카드 도달(또는 None이면 엔딩)까지 진행."""
    engine = StoryEngine(repo)
    step = engine.start()
    while step.ending is None and engine.current_id != stop_id:
        if step.choices:
            idx = next((i for i, c in enumerate(step.choices) if c.axis == policy),
                       next((i for i, c in enumerate(step.choices)
                             if c.axis in (None, "neutral")), 0))
            _, step = engine.choose(idx)
        else:
            step = engine.advance()
    return engine


# ── 스냅샷/복원 (엔진) ──────────────────────────────────────
def test_snapshot_restore_roundtrip(repo):
    engine = play_until(repo, "E04-01")
    snap = engine.snapshot()
    restored = StoryEngine.restore(repo, snap)

    assert restored.snapshot() == snap  # 복원이 상태를 조금도 바꾸지 않는다
    assert restored.current_id == engine.current_id
    assert restored.visited == engine.visited
    step = restored.current_step()
    assert step.card.id == engine.current_id
    assert step.ending is None


def test_restore_does_not_reapply_enter_side_effects(repo):
    """핵심 회귀 — 복원 시 쇠약도·신뢰축이 재적용되면 안 된다 (_enter 우회 검증)."""
    engine = play_until(repo, None)  # 엔딩까지 = 쇠약도·축 이벤트 다수 누적
    assert engine.state.frailty > 0 and engine.state.trust_score > 0

    snap = engine.snapshot()
    restored = StoryEngine.restore(repo, snap)
    assert restored.state.frailty == engine.state.frailty
    assert restored.state.trust_score == engine.state.trust_score
    assert restored.state.doubt_score == engine.state.doubt_score
    assert restored.state.axis_log == engine.state.axis_log

    # 여러 번 복원해도 동일 (재적용이 있으면 여기서 어긋난다)
    again = StoryEngine.restore(repo, restored.snapshot())
    assert again.snapshot() == snap


def test_ending_session_restores_to_ending(repo):
    engine = play_until(repo, None, policy="trust")
    assert engine.ending is not None
    restored = StoryEngine.restore(repo, engine.snapshot())
    step = restored.current_step()
    assert step.ending is not None and step.ending.id == engine.ending.id


# ── SQLite 저장소 ───────────────────────────────────────────
def test_play_session_repo_save_load(tmp_path, repo):
    db = PlaySessionRepository(tmp_path / "sessions.db")
    engine = play_until(repo, "E02-01")
    db.save("sid1", engine.snapshot(), repo.content_version)

    loaded = db.load("sid1", repo.content_version)
    assert loaded == engine.snapshot()
    assert db.load("없는sid", repo.content_version) is None


def test_content_version_mismatch_invalidates(tmp_path, repo):
    db = PlaySessionRepository(tmp_path / "sessions.db")
    db.save("sid1", {"story": {}, "hidden": {}}, "구버전해시")
    assert db.load("sid1", repo.content_version) is None  # 콘텐츠 갱신 → 무효화


def test_purge_removes_stale_sessions(tmp_path):
    db = PlaySessionRepository(tmp_path / "sessions.db")
    db.save("sid1", {"story": {}, "hidden": {}}, "v")
    assert db.purge(days=30) == 0  # 방금 저장 — 남는다
    assert db.purge(days=0) == 1   # 즉시 만료 취급 — 지워진다


# ── 라우터 (재시작 모사) ────────────────────────────────────
@pytest.mark.asyncio
async def test_router_restores_after_restart(tmp_path, monkeypatch):
    monkeypatch.setattr(router, "_playdb", PlaySessionRepository(tmp_path / "s.db"))
    monkeypatch.setattr(router, "_sessions", {})

    data = await router.create_session()
    sid = data["session_id"]
    step = data["step"]
    while not step["choices"] and not step["ending"]:  # 첫 선택지까지 읽기
        step = (await router.advance(sid))["step"]
    step = (await router.choose(sid, router.ChooseBody(index=0)))["step"]
    current_card = step["card"]["id"]

    router._sessions.clear()  # 서버 재시작 모사 (인메모리 캐시 소실)
    got = await router.get_session(sid)
    assert got["step"]["card"]["id"] == current_card
    assert router._sessions[sid].pocket_sid is None  # 포켓은 비영속 — 닫힌 채 복원


@pytest.mark.asyncio
async def test_router_unknown_sid_404(tmp_path, monkeypatch):
    monkeypatch.setattr(router, "_playdb", PlaySessionRepository(tmp_path / "s.db"))
    monkeypatch.setattr(router, "_sessions", {})
    with pytest.raises(HTTPException) as exc:
        await router.get_session("없는세션")
    assert exc.value.status_code == 404