"""统一工具函数"""
import uuid
import random
import string
from datetime import datetime
from typing import Optional


def generate_uuid() -> str:
    """生成UUID"""
    return str(uuid.uuid4()).replace("-", "").upper()


def generate_id(prefix: str = "") -> str:
    """生成带前缀的ID"""
    uid = str(uuid.uuid4()).replace("-", "").upper()
    return f"{prefix}{uid}" if prefix else uid


def generate_random_password(length: int = 8) -> str:
    """生成随机密码"""
    chars = string.ascii_letters + string.digits
    return ''.join(random.choice(chars) for _ in range(length))


def get_current_time() -> datetime:
    """获取当前时间"""
    return datetime.now()


def format_datetime(dt: Optional[datetime]) -> Optional[str]:
    """格式化时间为ISO 8601格式"""
    if dt is None:
        return None
    return dt.strftime("%Y-%m-%d %H:%M:%S")


def parse_datetime(dt_str: str) -> Optional[datetime]:
    """解析ISO 8601格式时间"""
    if not dt_str:
        return None
    try:
        return datetime.fromisoformat(dt_str.replace("Z", "+00:00"))
    except (ValueError, AttributeError):
        return None


def get_file_size_display(size_bytes: int) -> str:
    """将字节数转换为可读的文件大小"""
    if size_bytes is None:
        return "0 B"
    for unit in ['B', 'KB', 'MB', 'GB', 'TB']:
        if size_bytes < 1024.0:
            return f"{size_bytes:.2f} {unit}"
        size_bytes /= 1024.0
    return f"{size_bytes:.2f} PB"