/**
 * Crew employee-number generator. Format: CRW-<id>, e.g. CRW-1000.
 *
 * Sequential, floored at 1000, scanning existing CrewMember.employeeId values.
 * Assigned at onboarding (Phase 3c). Call inside the onboarding transaction to
 * minimise the race window (the unique constraint is the backstop).
 */

import { db } from "@/lib/db";
import type { Prisma } from "@prisma/client";

const PREFIX = "CRW-";
const FLOOR = 999; // first generated id is 1000

export async function generateEmployeeId(
  client: Prisma.TransactionClient | typeof db = db
): Promise<string> {
  const rows = await client.crewMember.findMany({
    where: { employeeId: { startsWith: PREFIX } },
    select: { employeeId: true },
  });
  let maxId = FLOOR;
  for (const { employeeId } of rows) {
    if (!employeeId) continue;
    const n = parseInt(employeeId.slice(PREFIX.length), 10);
    if (!isNaN(n) && n > maxId) maxId = n;
  }
  return `${PREFIX}${maxId + 1}`;
}