"""Messaging tool — channel-adapter-backed send_message for the agent."""
from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from channels.adapter import ChannelAdapter

# Injected by main.py before each invocation
_adapter: 'ChannelAdapter | None' = None


def set_adapter(adapter: 'ChannelAdapter') -> None:
    global _adapter
    _adapter = adapter


def send(text: str) -> str:
    """Send a message to the user via the active channel adapter."""
    if _adapter is None:
        return 'No channel adapter configured.'
    msg_id = _adapter.send(text)
    return f"Sent (id={msg_id})" if msg_id else 'Sent'