"""External notification tool (#168) — Discord, Telegram, SMTP, webhook.

``notify_external`` is WRITE (external side effect → confirmation card in the
UI, propose/apply over MCP). Delivery itself lives in :mod:`backend.notify`.
"""

from __future__ import annotations

from typing import Any

from backend import notify as _notify
from backend.tools.context import ToolContext, ToolError, ToolRisk
from backend.tools.registry import tool
from backend.tools.schemas import NotifyExternalInput


@tool(
    name="notify_external",
    description="Send a notification through external channels (Discord, Telegram, SMTP, webhook).",
    input_model=NotifyExternalInput,
    risk=ToolRisk.WRITE,
)
def notify_external(ctx: ToolContext, params: NotifyExternalInput) -> dict[str, Any]:
    """Broadcast to the trigger scope, or target a single channel id."""
    try:
        if params.channel_id:
            channel = next(
                (c for c in _notify._read_channels() if c.get("id") == params.channel_id),
                None,
            )
            if channel is None:
                raise ToolError(f"Unknown channel: {params.channel_id}", code="not_found")
            if not channel.get("enabled", True):
                raise ToolError(f"Channel disabled: {params.channel_id}", code="invalid_arguments")
            _notify.send_via_channel(channel, params.title, params.message, params.trigger)
            return {"ok": True, "channel_id": params.channel_id}
        results = _notify.broadcast(params.trigger, params.title, params.message)
        return {"ok": True, "deliveries": results}
    except ToolError:
        raise
    except Exception as e:
        raise ToolError(f"Notification failed: {e}", code="notify_failed") from e