"""翻译后端抽象。"""
from __future__ import annotations

from abc import ABC, abstractmethod
from dataclasses import dataclass


@dataclass
class TranslationResult:
    text: str
    engine: str
    chars: int
    cached: bool = False


class BaseTranslator(ABC):
    name: str = "base"

    @abstractmethod
    async def translate(self, text: str, source: str = "auto", target: str = "zh") -> TranslationResult:
        """同步调用,失败抛异常。"""


def count_chars(s: str) -> int:
    """近似的字符计数(Unicode 码点)。腾讯 TMT 按字符数计费。"""
    return len(s)