"""UUIDv7（36 字符形式），兼容 Python 3.10。"""

from __future__ import annotations

import os
import time
import uuid


def new_uuid7() -> str:
    if hasattr(uuid, "uuid7"):
        return str(uuid.uuid7())  # type: ignore[attr-defined]
    # RFC 9562 简化实现
    ts_ms = int(time.time() * 1000) & ((1 << 48) - 1)
    rand_a = int.from_bytes(os.urandom(2), "big") & 0x0FFF
    rand_b = int.from_bytes(os.urandom(8), "big") & ((1 << 62) - 1)
    value = (ts_ms << 80) | (0x7 << 76) | (rand_a << 64) | (0b10 << 62) | rand_b
    return str(uuid.UUID(int=value))