from __future__ import annotations

import logging
import hmac
from contextlib import asynccontextmanager
from pathlib import Path

from fastapi import FastAPI
from fastapi import Request
from fastapi.responses import JSONResponse
from fastapi.responses import FileResponse
from fastapi.staticfiles import StaticFiles

from app.api.routes import router as api_router
from app.core.config import get_settings
from app.engine.detector import PlagiarismDetector
from app.jobs.store import JobStore

logging.basicConfig(level=logging.INFO, format="%(asctime)s %(levelname)s %(name)s: %(message)s")


@asynccontextmanager
async def lifespan(app: FastAPI):
    settings = get_settings()
    if not settings.api_key.strip():
        logging.critical(
            "API_KEY is empty: all /v1 endpoints are unauthenticated. "
            "Do not expose unpublished manuscripts publicly until client key rollout is complete."
        )
    app.state.settings = settings
    app.state.detector = PlagiarismDetector(settings=settings)
    app.state.job_store = JobStore()
    import threading
    app.state.detector_lock = threading.Lock()
    logging.info(
        "Engine ready: version=%s, corpus_size=%d",
        settings.engine_version,
        app.state.detector.corpus_size,
    )
    yield


def rebuild_detector(app: FastAPI) -> int:
    """코퍼스 변경 후 인덱스 재빌드. 호출 시점에 lock으로 보호."""
    settings = app.state.settings
    with app.state.detector_lock:
        app.state.detector = PlagiarismDetector(settings=settings)
        return app.state.detector.corpus_size


_settings = get_settings()

app = FastAPI(
    title="O2O 저작권 침해 여부 탐지 API",
    description=(
        "오투오 1단계 산출물 - 콘텐츠 표절 여부 AI 탐지 모듈. "
        "본 응답 스키마는 커뮤니케이션북스(아카이빙) 및 바이칼AI(분석 보고서) 통합 기준."
    ),
    version="1.0.0",
    lifespan=lifespan,
    root_path=_settings.root_path,
)

app.include_router(api_router)


@app.middleware("http")
async def optional_api_key_auth(request: Request, call_next):
    """API_KEY가 설정된 운영 환경에서만 API 인증을 강제한다."""
    configured = _settings.api_key.strip()
    public_paths = {"/", "/v1/health", "/docs", "/openapi.json", "/redoc"}
    if configured and request.url.path not in public_paths and request.url.path.startswith("/v1"):
        supplied = request.headers.get("x-api-key", "")
        if not hmac.compare_digest(configured, supplied):
            return JSONResponse(status_code=401, content={"detail": "Invalid or missing API key"})
    return await call_next(request)

_STATIC_DIR = Path(__file__).resolve().parent / "static"
if _STATIC_DIR.exists():
    app.mount("/static", StaticFiles(directory=str(_STATIC_DIR)), name="static")


@app.get("/", include_in_schema=False)
async def root() -> FileResponse:
    """검토 콘솔 페이지 — 컴북스 측이 브라우저에서 직접 엔진 성능 확인."""
    index = _STATIC_DIR / "index.html"
    if index.exists():
        return FileResponse(str(index))
    from fastapi.responses import JSONResponse
    return JSONResponse({"service": "o2o-plagiarism-api", "docs": "/docs"})


def main() -> None:
    """`.env` 의 HOST/PORT/LOG_LEVEL/RELOAD 를 읽어 서버 기동.

    사용법:
      python -m app.main          # .env 따라 실행
      PORT=9000 python -m app.main  # 환경변수 override
    """
    import uvicorn

    settings = get_settings()
    uvicorn.run(
        "app.main:app",
        host=settings.host,
        port=settings.port,
        log_level=settings.log_level,
        reload=settings.reload,
        root_path=settings.root_path,
        forwarded_allow_ips="*",  # 리버스 프록시(Apache) 헤더 신뢰
        proxy_headers=True,
    )


if __name__ == "__main__":
    main()