brackt/app/lib/owner-map.ts

import { findUsersByIds, getUserDisplayName } from "~/models/user";

/**
 * Builds a map of teamId -> manager username (or displayName fallback).
 * Accepts any array of objects that have a `team` with `id` and `ownerId`.
 */
export async function buildOwnerMap(
  slots: Array<{ team: { id: string; ownerId: string | null } }>
): Promise<Record<string, string>> {
  const uniqueOwnerIds = [...new Set(
    slots.map((s) => s.team.ownerId).filter((id): id is string => id !== null)
  )];

  const userRows = await findUsersByIds(uniqueOwnerIds);
  const userById = new Map(
    userRows
      .map((u) => [u.id, getUserDisplayName(u)] as const)
      .filter((entry): entry is [string, string] => entry[1] !== null && entry[1] !== undefined)
  );

  const ownerMap: Record<string, string> = {};
  for (const slot of slots) {
    const name = slot.team.ownerId ? userById.get(slot.team.ownerId) : undefined;
    if (name) {
      ownerMap[slot.team.id] = name;
    }
  }
  return ownerMap;
}