"""Slack connector."""

from typing import Optional

from slack_sdk import WebClient

from notifications.config import BULK_APP_SLACK_CHANNEL_ID, BULK_APP_SLACK_TOKEN


def get_slack_client(token: str) -> WebClient:
    """Return a Slack WebClient instance."""
    return WebClient(token=token)


def send_message(
    *, channel_id: str, token: str, body: str, color: str, thread_ts: Optional[str] = None
) -> str:
    """Send a message to a Slack channel.

    Returns:
        The timestamp of the sent message, which is used as a unique identifier.

    Raises:
        ValueError: If no timestamp is returned from the Slack API.

    """
    client = get_slack_client(token)
    response = client.chat_postMessage(
        channel=channel_id,
        unfurl_links=False,
        unfurl_media=False,
        thread_ts=thread_ts,
        attachments=[{'color': color, 'text': body}],
    )
    ts = response.get('ts')
    if not ts:
        raise ValueError('No timestamp returned from Slack API')
    return ts


def send_bulk_message(*, body: str, color: str, thread_ts: Optional[str] = None) -> str:
    """Send a message to the bulk app Slack channel."""
    return send_message(
        channel_id=BULK_APP_SLACK_CHANNEL_ID,
        body=body,
        token=BULK_APP_SLACK_TOKEN,
        color=color,
        thread_ts=thread_ts,
    )