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


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 format_date(d: Optional[Union[date, datetime]]) -> str:
    """格式化日期为 YYYY-MM-DD"""
    if d is None:
        return ""
    if isinstance(d, datetime):
        d = d.date()
    return d.strftime("%Y-%m-%d")


def parse_date(date_str: str) -> Optional[date]:
    """解析 YYYY-MM-DD 日期"""
    if not date_str:
        return None
    try:
        s = str(date_str).strip()
        if not s:
            return None
        return datetime.fromisoformat(s[:10]).date()
    except (ValueError, AttributeError):
        return None


def optional_date(v: object) -> Optional[date]:
    """将字符串 / date / datetime 转为 date 或 None"""
    if v is None or v == "":
        return None
    if isinstance(v, datetime):
        return v.date()
    if isinstance(v, date):
        return v
    return parse_date(str(v))


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"