/**
 * PREREQUISITE: Before this code can run against a real PocketBase
 * instance, the operator must add two fields to the `orders`
 * collection in the PB admin UI (per the AGENTS.md convention — PB
 * schema is not self-service from code):
 *   - `order_number_duplicate`  (Relation → orders, single)
 *   - `order_number_duplicate_checked`  (Bool)
 * Without these fields, the `.update()` below will 500 in production.
 */

/**
 * order-number-duplicate-link-service — detects when an order's
 * `order_number` is reused by ANOTHER order (any status, no time
 * limit). Catches two cases that have bitten the operator:
 *  - internal ORD-number collisions from a partial intake race
 *  - operator not realising a PO was already entered
 *
 * Visibility only. Nothing downstream reads this to drive pricing,
 * supplier assignment, or processing — a wrong flag costs nothing, the
 * operator just ignores the pill. That's what justifies writing the
 * match automatically with no human confirmation step, unlike the
 * order↔quote matcher's deliberately conservative suggest-only policy
 * (see order-quote-link-service.ts) — that policy exists because a
 * wrong quote link puts wrong prices in front of a buyer.
 *
 * NOTE: customer PO refs (e.g. "PO-12345") and placeholders like
 * "NO-REF" are ALLOWED to repeat by design — one blanket customer PO
 * is often split into several partial-delivery orders. This matcher
 * flags any exact-string duplicate regardless of shape; the order
 * review collision check (orders-service.ts) is the only place that
 * gates on ORD-YYYY-MM-NNN shape.
 */

import { getAdminPocketBase } from "@/lib/server/pocketbase-admin";

const ORDER_COLLECTION = "orders";

export interface OrderNumberDuplicateResult {
  orderId: string;
  duplicateOrderId: string | null;
}

function esc(s: string): string {
  return (s || "").replace(/"/g, '\\"');
}

export async function suggestOrderNumberDuplicate(
  orderId: string,
): Promise<OrderNumberDuplicateResult> {
  const pb = await getAdminPocketBase();
  pb.autoCancellation(false);

  const order = await pb
    .collection(ORDER_COLLECTION)
    .getOne<{ id: string; order_number?: string }>(orderId);

  if (!order.order_number) {
    return { orderId, duplicateOrderId: null };
  }

  const others = await pb
    .collection(ORDER_COLLECTION)
    .getFullList<{ id: string; created: string }>({
      filter: `order_number = "${esc(order.order_number)}" && id != "${esc(orderId)}"`,
      fields: "id,created",
      sort: "created",
      batch: 500,
    });

  const duplicateOrderId = others.length > 0 ? others[0].id : null;

  await pb.collection(ORDER_COLLECTION).update(orderId, {
    order_number_duplicate: duplicateOrderId,
    order_number_duplicate_checked: true,
  });

  return { orderId, duplicateOrderId };
}