import os, tarfile, tempfile
from datetime import datetime, timezone
from huggingface_hub import HfApi

def env_int(name, default):
    try:
        return int(os.getenv(name, str(default)))
    except Exception:
        return default

def make_tar(src_dir: str, out_path: str):
    with tarfile.open(out_path, "w:gz") as tar:
        tar.add(src_dir, arcname=os.path.basename(src_dir))

def main():
    if os.getenv("BACKUP_ENABLE", "0") != "1":
        return

    token = os.getenv("HF_TOKEN") or os.getenv("HUGGINGFACE_HUB_TOKEN")
    if not token:
        print("HF_TOKEN 未设置，跳过备份")
        return

    dataset_repo = os.getenv("BACKUP_DATASET_REPO", "").strip()
    if not dataset_repo:
        print("BACKUP_DATASET_REPO 未设置，跳过备份")
        return

    src_dir = os.getenv("BACKUP_SRC_DIR", "/home/user/work")
    keep_last = env_int("BACKUP_KEEP_LAST", 10)

    api = HfApi(token=token)
    api.create_repo(repo_id=dataset_repo, repo_type="dataset", exist_ok=True)

    ts = datetime.now(timezone.utc).strftime("%Y%m%d-%H%M%S")
    backup_name = f"backups/work-{ts}.tar.gz"

    with tempfile.TemporaryDirectory() as tmp:
        local_path = os.path.join(tmp, f"work-{ts}.tar.gz")
        make_tar(src_dir, local_path)
        api.upload_file(
            path_or_fileobj=local_path,
            path_in_repo=backup_name,
            repo_id=dataset_repo,
            repo_type="dataset",
            commit_message=f"backup: {backup_name}",
        )
        print(f"Uploaded: {backup_name}")

    files = api.list_repo_files(repo_id=dataset_repo, repo_type="dataset")
    backups = sorted([f for f in files if f.startswith("backups/work-") and f.endswith(".tar.gz")])

    if keep_last > 0 and len(backups) > keep_last:
        for f in backups[:-keep_last]:
            api.delete_file(
                path_in_repo=f,
                repo_id=dataset_repo,
                repo_type="dataset",
                commit_message=f"prune: {f}",
            )
            print(f"Deleted old backup: {f}")

if __name__ == "__main__":
    main()