import type { LoaderFunctionArgs } from "@remix-run/node";
import { authenticate } from "../shopify.server";
import db from "../db.server";
import {
  resolveProductRuleConstraints,
  resolveProductRefs,
  productRefsFromCartLines,
} from "../services/product-rules.server";
import { parseCartLinesParam, parseProductIdsParam, parseGidListParam } from "../lib/cart-rule-params";
import { resolvePickupLocations } from "../services/pickup-locations.server";

// Standalone list of eligible pickup points (study §3.4 multi-pin pickup).
// The same data is also returned inline on `method=PICKUP` availability
// responses (`pickupLocations`) — this endpoint stays for callers that just
// want the list without asking for a specific location's calendar. Shared
// resolution logic lives in pickup-locations.server.ts so the two paths
// can't drift.
export const loader = async ({ request }: LoaderFunctionArgs) => {
  const { session, admin } = await authenticate.public.appProxy(request);
  if (!session) {
    return Response.json({ error: "Shop not found" }, { status: 404 });
  }

  const url = new URL(request.url);

  const productIds = parseProductIdsParam(url.searchParams.get("productIds"));
  const productRefs = admin && productIds.length > 0 ? await resolveProductRefs(admin, productIds) : [];
  const cartProductRefs = [
    ...productRefs,
    ...productRefsFromCartLines(parseCartLinesParam(url.searchParams.get("cartLines"))),
  ];

  const productRules = await db.productRule.findMany({ where: { shopDomain: session.shop, active: true } });
  const ruleConstraints = resolveProductRuleConstraints(productRules, cartProductRefs);

  // A rule that forbids PICKUP for this cart ⇒ no pickup points at all.
  if (ruleConstraints.allowedMethods != null && !ruleConstraints.allowedMethods.includes("PICKUP")) {
    return Response.json({ locations: [] });
  }

  const locations = await resolvePickupLocations(session.shop, {
    allowedLocationIds: ruleConstraints.allowedLocationIds,
    admin: admin ?? undefined,
    productVariantGids: parseGidListParam(url.searchParams.get("variantIds")),
  });

  return Response.json({ locations });
};