import uvicorn
from fastapi import FastAPI, Request
from fastapi.staticfiles import StaticFiles
from fastapi.responses import Response
from file_cleaner import FileCleaner
from settings import settings
import asyncio
import os

app = FastAPI(
    title="www",
    description="公共静态资源访问服务",
    version="1.0.0"
)

# 添加中间件，为静态文件响应添加 CORS 响应头和下载头
@app.middleware("http")
async def add_cors_headers(request: Request, call_next):
    # 只处理 /files 路径的请求，提前返回提高效率
    if not request.url.path.startswith("/files"):
        return await call_next(request)
    
    # 处理 OPTIONS 预检请求
    if request.method == "OPTIONS":
        return Response(
            headers={
                "Access-Control-Allow-Origin": "*",
                "Access-Control-Allow-Methods": "GET, OPTIONS",
                "Access-Control-Expose-Headers": "Content-Disposition"
            }
        )
    
    # 处理 GET 请求
    response = await call_next(request)
    
    # 添加 CORS 响应头
    response.headers["Access-Control-Allow-Origin"] = "*"
    response.headers["Access-Control-Allow-Methods"] = "GET, OPTIONS"
    response.headers["Access-Control-Expose-Headers"] = "Content-Disposition"
    
    # 添加 Content-Disposition 头，让浏览器下载而不是打开
    if "Content-Disposition" not in response.headers:
        filename = os.path.basename(request.url.path)
        if filename:
            response.headers["Content-Disposition"] = f'attachment; filename="{filename}"'
    
    return response

# 挂载静态文件目录
app.mount("/files", StaticFiles(directory="files"), name="files")


# 注册文件定时清理任务
save_dir = "files"
retention_hours = settings.file_retention_hours
cleanup_interval = settings.cleanup_interval_seconds
cleaner = FileCleaner(save_dir, retention_hours, cleanup_interval)

@app.on_event("startup")
async def startup_event():
    asyncio.create_task(cleaner.periodic_cleanup())

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(
        "app:app",
        host=settings.host,
        port=settings.port,
        reload=settings.debug
    )