import type { User } from "@/lib/types";

const POCKETBASE_RECORD_ID = /^[a-z0-9]{15}$/i;

type RepUser = Pick<User, "id" | "name" | "email">;

export interface ResolveRepDisplayNameOptions {
  /** Expanded `customer.rep` record, when PocketBase returned it. */
  expandedCustomerRep?: Partial<RepUser> | null;
  /** Raw relation id stored in `customer.rep`. */
  customerRepId?: string | null;
  /** Legacy/free-text snapshot stored in `orders.rep`. */
  orderRep?: string | null;
  /** Admin-resolved users, keyed by PocketBase user id. */
  usersById?: ReadonlyMap<string, RepUser>;
}

function userLabel(user?: Partial<RepUser> | null): string {
  return (user?.name || user?.email || "").trim();
}

/**
 * Resolves the sales rep shown on order surfaces without ever leaking an
 * opaque PocketBase record id into the UI.
 *
 * Customer ownership is authoritative, so its expanded/user-map value wins.
 * `orders.rep` remains the fallback because company-only and older orders can
 * carry a manually entered name there. Some older rows stored a user id in
 * that text field; those ids are resolved through `usersById`, or hidden when
 * the related user no longer exists.
 */
export function resolveRepDisplayName({
  expandedCustomerRep,
  customerRepId,
  orderRep,
  usersById,
}: ResolveRepDisplayNameOptions): string {
  const expandedLabel = userLabel(expandedCustomerRep);
  if (expandedLabel) return expandedLabel;

  const customerRef = (customerRepId || "").trim();
  if (customerRef) {
    const customerUserLabel = userLabel(usersById?.get(customerRef));
    if (customerUserLabel) return customerUserLabel;
  }

  const orderValue = (orderRep || "").trim();
  if (!orderValue) return "";

  const orderUserLabel = userLabel(usersById?.get(orderValue));
  if (orderUserLabel) return orderUserLabel;

  // A free-text name is safe to show. An unresolved PB id is not useful to
  // an operator, so suppress it instead of regressing to the old ID display.
  return POCKETBASE_RECORD_ID.test(orderValue) ? "" : orderValue;
}