"""FastAPI 应用入口。"""

import logging
import os
from contextlib import asynccontextmanager

from fastapi import FastAPI
from fastapi.responses import JSONResponse
from fastapi.staticfiles import StaticFiles
from starlette.middleware.sessions import SessionMiddleware

from app.config import settings
from app.exceptions import (
    AppError,
    ConflictError,
    ExternalAPIError,
    NotFoundError,
    PdfProcessError,
    ValidationError,
)
from app.database import engine, init_db
from app.routes.admin import router as admin_router
from app.routes.compare import router as compare_router
from app.routes.pages import router as pages_router
from app.routes.search import router as search_router
from app.routes.trends import router as trends_router
from app.routes.user import router as user_router

logging.basicConfig(
    level=logging.DEBUG if settings.APP_DEBUG else logging.INFO,
    format="%(asctime)s [%(levelname)s] %(name)s: %(message)s",
)
logger = logging.getLogger(__name__)


@asynccontextmanager
async def lifespan(app: FastAPI):
    """应用生命周期管理：启动与关闭。"""
    # ── startup ──
    from app.services.scheduler import start_scheduler
    from app.services.embedder import init_chroma
    from app.services.jobs import recover_stale_jobs
    from app.database import SessionLocal

    db = SessionLocal()
    try:
        recover_stale_jobs(db)
    finally:
        db.close()
    start_scheduler()
    init_chroma()

    yield

    # ── shutdown ──
    from app.services.scheduler import stop_scheduler
    from app.services.pdf_downloader import close_http_session

    stop_scheduler()
    close_http_session()


def create_app() -> FastAPI:
    app = FastAPI(
        title="HF Daily Papers",
        description="HuggingFace Daily Papers — 中文论文导览站",
        version="0.1.0",
        lifespan=lifespan,
    )

    # 确保数据目录存在
    os.makedirs(settings.db_path.parent, exist_ok=True)

    # 初始化数据库
    init_db(engine)
    logger.info("Database initialized at %s", settings.db_path)

    # Session 中间件
    app.add_middleware(SessionMiddleware, secret_key=settings.SECRET_KEY)

    # ── 统一业务异常处理 ──
    @app.exception_handler(NotFoundError)
    async def _not_found_handler(request, exc):
        return JSONResponse(status_code=404, content={"error": exc.message})

    @app.exception_handler(ValidationError)
    async def _validation_handler(request, exc):
        return JSONResponse(status_code=400, content={"error": exc.message})

    @app.exception_handler(ExternalAPIError)
    async def _external_api_handler(request, exc):
        return JSONResponse(status_code=502, content={"error": exc.message})

    @app.exception_handler(PdfProcessError)
    async def _pdf_process_handler(request, exc):
        return JSONResponse(status_code=500, content={"error": exc.message})

    @app.exception_handler(ConflictError)
    async def _conflict_handler(request, exc):
        return JSONResponse(status_code=409, content={"error": exc.message})

    @app.exception_handler(AppError)
    async def _app_error_handler(request, exc):
        return JSONResponse(status_code=500, content={"error": exc.message})

    # 安全警告
    if settings.SECRET_KEY == "change-me":
        logger.warning(
            "⚠️  SECRET_KEY is the default value 'change-me'. Please change it in .env!"
        )
    if not settings.ADMIN_PASSWORD:
        logger.warning("⚠️  ADMIN_PASSWORD is empty. Please set it in .env!")

    # 静态文件
    app.mount("/static", StaticFiles(directory="app/static"), name="static")

    # 论文图片静态服务
    papers_images_dir = os.path.join("data", "papers")
    os.makedirs(papers_images_dir, exist_ok=True)
    app.mount("/papers", StaticFiles(directory=papers_images_dir), name="papers")

    # 路由
    app.include_router(pages_router)
    app.include_router(admin_router)
    app.include_router(search_router)
    app.include_router(user_router)
    app.include_router(trends_router)
    app.include_router(compare_router)

    return app


app = create_app()


if __name__ == "__main__":
    import uvicorn

    uvicorn.run(
        "app.main:app",
        host=settings.APP_HOST,
        port=settings.APP_PORT,
        reload=settings.APP_DEBUG,
    )