import type { LoaderFunctionArgs } from "@remix-run/node";
import type { Method } from "@prisma/client";
import { authenticate } from "../shopify.server";
import { resolveAvailabilityRequest } from "../services/availability-request.server";
import { resolveProductRefs } from "../services/product-rules.server";
import { parseCartLinesParam, parseProductIdsParam } from "../lib/cart-rule-params";

// Public endpoint, reachable only through Shopify's App Proxy (signature
// verified by authenticate.public.appProxy) — this is what the storefront
// Theme App Extension calls. Requests to https://{shop}/apps/scheduling/*
// forward here because shopify.app.toml's [app_proxy].url already includes
// the /apps/scheduling prefix, so this file's path (apps.scheduling.*)
// mirrors the shop-facing URL exactly. The actual resolution logic lives in
// services/availability-request.server.ts, shared with the POS route
// (pos.scheduling.availability.tsx) — same pool, same code, different auth.

const VALID_METHODS = new Set<Method>(["SHIPPING", "LOCAL_DELIVERY", "PICKUP"]);

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 methodParam = url.searchParams.get("method");
  if (!methodParam || !VALID_METHODS.has(methodParam as Method)) {
    return Response.json({ error: "Invalid or missing method" }, { status: 400 });
  }

  // ProductRule scoping (PRODUCT_STRATEGY.md §2): vendor/type come free from
  // the widget's own /cart.js read; product/collection/tag rules additionally
  // need one Admin API round trip to resolve productIds — skipped gracefully
  // if there's no admin client (shouldn't happen for an installed shop's app
  // proxy request, but this endpoint must not 500 over an optional feature).
  const productIds = parseProductIdsParam(url.searchParams.get("productIds"));
  const productRefs = admin && productIds.length > 0 ? await resolveProductRefs(admin, productIds) : [];

  const result = await resolveAvailabilityRequest(session.shop, {
    method: methodParam as Method,
    locationId: url.searchParams.get("locationId") || undefined,
    postalCode: url.searchParams.get("postalCode") || undefined,
    address: url.searchParams.get("address") || undefined,
    days: Number(url.searchParams.get("days")) || undefined,
    cartLines: parseCartLinesParam(url.searchParams.get("cartLines")),
    productRefs,
  });

  if (!result.locationId) {
    return Response.json(result, { status: result.error === "No active location configured" ? 404 : 200 });
  }

  return Response.json(result);
};