Function handleMemberJoinedChannel

server/src/slack/events.ts:341–378

(event: SlackMemberJoinedChannelEvent)

 * Also auto-adds users to working groups (chapters/events) when they join linked Slack channels
 */
export async function handleMemberJoinedChannel(event: SlackMemberJoinedChannelEvent): Promise<void> {
  logger.debug(
    { userId: event.user, channel: event.channel },
    'User joined channel'
  );

  try {
    // Get user's org mapping if they're linked
    const mapping = await slackDb.getBySlackUserId(event.user);
    let organizationId: string | undefined;

    if (mapping?.workos_user_id) {
      // Note: Would need to lookup org from WorkOS - for now just record without org
      // This could be enhanced with a cache or join table
    }

    await slackDb.recordActivity({
      slack_user_id: event.user,
      activity_type: 'channel_join',
      channel_id: event.channel,
      activity_timestamp: new Date(),
      organization_id: organizationId,
      metadata: {
        channel_type: event.channel_type,
        inviter: event.inviter,
      },
    });

    // Check if this channel is linked to a working group (chapter or event)
    // and auto-add the user if they have a WorkOS mapping
    if (mapping?.workos_user_id) {
      const isPrivateChannel = event.channel_type === 'G';
      await autoAddToWorkingGroup(event.channel, mapping.workos_user_id, mapping, isPrivateChannel);
    }
  } catch (error) {
    logger.error({ error, userId: event.user }, 'Failed to record channel join activity');
  }
}

/**
 * Auto-add user to a working group when they join its Slack channel