import os
import time
import uuid
import aiofiles
from fastapi import UploadFile
from app.core.config import settings


async def save_upload_file(file: UploadFile) -> str:
    """
    保存上传的文件，返回文件名。
    文件名格式: timestamp_uuid.ext
    """
    # 1. 确保目录存在
    if not os.path.exists(settings.UPLOAD_PATH):
        os.makedirs(settings.UPLOAD_PATH)

    # 2. 生成唯一文件名
    # 获取扩展名 (如 .jpg)
    filename = file.filename
    ext = os.path.splitext(filename)[1] if filename else ".jpg"

    # 使用 时间戳 + UUID 防止重名
    unique_name = f"{int(time.time())}_{uuid.uuid4().hex[:8]}{ext}"
    file_path = os.path.join(settings.UPLOAD_PATH, unique_name)

    # 3. 异步写入磁盘
    async with aiofiles.open(file_path, 'wb') as out_file:
        # 即使是 UploadFile，读取 content 也是异步流
        content = await file.read()
        await out_file.write(content)

    return unique_name


def delete_file(filename: str) -> bool:
    """删除指定文件"""
    file_path = os.path.join(settings.UPLOAD_PATH, filename)
    if os.path.exists(file_path):
        os.remove(file_path)
        return True
    return False