import os
from huggingface_hub import HfApi, create_bucket, list_bucket_tree
from datetime import datetime

HF_TOKEN = os.environ.get("HF_TOKEN")  # 在 Space Secrets 中设置
BUCKET_ID = os.environ.get("HF_BUCKET_ID", "your-username/learning-platform-data")

api = HfApi(token=HF_TOKEN)

def ensure_bucket():
    """确保 Bucket 存在"""
    try:
        create_bucket(BUCKET_ID, private=True)
    except Exception:
        pass  # 已存在

def upload_file(file_bytes: bytes, filename: str, username: str, content_type: str) -> str:
    """上传文件到 Bucket，返回存储路径"""
    timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
    safe_name = f"{timestamp}_{filename}"
    bucket_path = f"users/{username}/{safe_name}"

    from huggingface_hub import batch_bucket_files
    import tempfile

    with tempfile.NamedTemporaryFile(delete=False, suffix=f"_{filename}") as tmp:
        tmp.write(file_bytes)
        tmp_path = tmp.name

    batch_bucket_files(
        BUCKET_ID,
        add=[(tmp_path, bucket_path)]
    )
    os.unlink(tmp_path)
    return bucket_path

def list_user_files(username: str) -> list:
    """列出用户的所有文件"""
    try:
        tree = list_bucket_tree(BUCKET_ID, prefix=f"users/{username}/")
        return [item.rfilename for item in tree if hasattr(item, 'rfilename')]
    except Exception:
        return []

def download_file(bucket_path: str) -> str:
    """下载文件到本地临时路径，返回本地路径"""
    from huggingface_hub import hf_hub_download
    return hf_hub_download(
        repo_id=BUCKET_ID.replace("/", "_"),
        filename=bucket_path,
        repo_type="bucket"
    )

def get_file_url(bucket_path: str) -> str:
    """获取文件的下载 URL"""
    return f"https://huggingface.co/buckets/{BUCKET_ID}/resolve/main/{bucket_path}"