"""TTSProvider port — 文字转语音能力契约。"""

from typing import Protocol, runtime_checkable


@runtime_checkable
class TTSProvider(Protocol):
    async def synthesize(
        self, text: str, voice: str = "alloy", *, language: str = "zh"
    ) -> bytes:
        """Convert text to speech audio bytes.

        language: 'zh' or 'en' — 调用方应使用用户语言偏好（与正文语种无关）；各 adapter 按自身能力解释。
        """
        ...