/**
 * The gate every order-scoped route handler stands behind.
 *
 * Signed in, and the order is one this user has claimed. Both checks belong
 * here rather than in each handler because a route handler is reachable
 * directly, and an ownership check that only three of four routes perform is
 * the one an attacker uses.
 *
 * Refusals are deliberately indistinguishable: an order that does not exist
 * and an order belonging to somebody else both answer 404, so the route cannot
 * be used to find out which order ids are real.
 */
import { auth } from "@clerk/nextjs/server";
import { NextResponse } from "next/server";
import { userOwnsOrder } from "@/lib/checkout-order-claim";
import type { OrderLookupError } from "@/vendor/carrier/client";

export type OrderRouteGuard =
  | { ok: true; userId: string; orderId: string }
  | { ok: false; response: NextResponse };

export async function guardOrderRoute(
  params: Promise<{ orderId: string }>,
): Promise<OrderRouteGuard> {
  const { userId } = await auth();
  if (!userId) {
    return { ok: false, response: NextResponse.json({ error: "Unauthorized" }, { status: 401 }) };
  }

  const { orderId } = await params;
  if (!orderId) {
    return {
      ok: false,
      response: NextResponse.json({ error: "orderId is required" }, { status: 400 }),
    };
  }

  if (!(await userOwnsOrder(userId, orderId))) {
    return {
      ok: false,
      response: NextResponse.json({ error: "Order not found" }, { status: 404 }),
    };
  }

  return { ok: true, userId, orderId };
}

/**
 * One fulfilment failure, as customer copy plus a status.
 *
 * `action` names the thing that did not happen ("read your usage", "cancel
 * this plan"), because "something went wrong" tells the reader nothing about
 * whether their eSIM is still working.
 */
export function fulfilmentFailureResponse(
  reason: OrderLookupError,
  action: string,
  orderId: string,
): NextResponse {
  if (reason === "not-found") {
    return NextResponse.json({ error: "Order not found", code: "not_found" }, { status: 404 });
  }

  if (reason === "unconfigured") {
    console.error(
      `[orders] NEXT_PUBLIC_CARRIER_API_URL is unset — cannot ${action} for ${orderId}`,
    );
    return NextResponse.json(
      {
        error: `We can't ${action} yet. Please contact support with your order number.`,
        code: "fulfilment_unconfigured",
      },
      { status: 503 },
    );
  }

  console.error(`[orders] failed to ${action} for ${orderId}: ${reason}`);
  return NextResponse.json(
    {
      error: `We couldn't ${action} right now. Please try again in a moment.`,
      code: "fulfilment_unavailable",
    },
    { status: 502 },
  );
}