core/src/Shipping/Concerns/CachesLivePricing.php

<?php

namespace Modules\Core\Shipping\Concerns;

use Closure;
use Illuminate\Support\Facades\Cache;
use Lunar\DataTypes\ShippingOption;
use Lunar\Models\Cart;
use Lunar\Shipping\Models\ShippingRate;

/**
 * Shared by any Modules\Core\Shipping\Contracts\SupportsLivePricing driver —
 * a live carrier price quote is a real, billed API call, but stable from
 * one fetch to the next within a single checkout attempt. Keyed by rate id
 * + cart id, so two different live-priced rates (e.g. ACS and a future
 * carrier) never collide — each is its own ShippingRate row. Not shared
 * across carts: the quote depends on cart-specific weight/quantity/
 * destination (see docs/checkout.md).
 *
 * Invalidated by Modules\Core\Shipping\Listeners\FlushLivePricingCache on
 * the only two things that can change what this cart's quote should be: a
 * cart line changing (add/update/remove/clear) or the shipping address
 * changing. Deliberately NOT invalidated on order placement — the price
 * the shopper was quoted must still be there if anything re-reads it after
 * the order exists; Cart::createOrder() persists the resolved price onto
 * the order anyway, so nothing should be re-querying the live driver for
 * that cart again regardless of cache state.
 */
trait CachesLivePricing
{
    private function cached(ShippingRate $shippingRate, Cart $cart, Closure $resolve): ?ShippingOption
    {
        return Cache::remember(
            "shipping.live_price.{$shippingRate->id}.{$cart->id}",
            now()->addMinutes(30),
            $resolve,
        );
    }
}