from typing import Protocol, runtime_checkable


@runtime_checkable
class ChannelAdapter(Protocol):
    """Protocol for channel-specific message delivery."""

    def send(self, text: str) -> str:
        """Send a message. Returns message_id if available."""
        ...

    def send_typing(self) -> None:
        """Send a typing indicator (best-effort)."""
        ...

    def edit(self, message_id: str, text: str) -> None:
        """Edit an existing message in-place."""
        ...