schon/storefront/app/composables/wishlist/useWishlistSync.ts

import { useWishlistOverwrite } from '@composables/wishlist/useWishlistOverwrite';

export function useWishlistSync() {
	const wishlistStore = useWishlistStore();
	const userStore = useUserStore();
	const { $appHelpers } = useNuxtApp();

	const { overwriteWishlist } = useWishlistOverwrite();

	const isAuthenticated = computed(() => userStore.isAuthenticated);
	const wishlistUuid = computed(() => wishlistStore.wishlist?.uuid);

	const cookieWishlist = useCookie($appHelpers.COOKIES_WISHLIST_KEY, {
		default: () => [],
		path: '/',
	});

	async function syncWishlist() {
		if (!isAuthenticated.value || !wishlistUuid.value) {
			return;
		}

		const cookieProducts = cookieWishlist.value || [];

		if (cookieProducts.length === 0) {
			return;
		}

		const apiProductUuids = wishlistStore.wishlist?.products?.edges.map((e) => e.node.uuid) || [];

		const productsToAdd = cookieProducts.filter((product) => !apiProductUuids.includes(product));

		if (productsToAdd.length === 0) {
			cookieWishlist.value = [];
			return;
		}

		try {
			await overwriteWishlist({
				type: 'bulk',
				bulkAction: 'add',
				isBulkSync: true,
				products: productsToAdd.map(uuid => ({ uuid }))
			});

			if (bulkResult?.data?.bulkWishlistAction?.wishlist) {
				wishlistStore.setWishlist(bulkResult.data.bulkWishlistAction.wishlist);

				cookieWishlist.value = [];
			}
		} catch (err) {
			console.error('useWishlistSync error:', err);
		}
	}

	return {
		syncWishlist,
	};
}