// Shopify Storefront API access, backed by `@shopify/hydrogen` (preview build).
//
// The package supplies the transport (`createStorefrontClient`) and the typed
// query documents (`gql`, see graphql/*.ts). `shopifyFetch` keeps the call
// shape the rest of the app already uses — `{ query, variables }` in, `{ data }`
// out, throwing on GraphQL errors — but now infers `data` from the document.
import {
  createShopifyRequestContext,
  createStorefrontClient,
  StorefrontApiError,
  type AnyStorefrontQueryString,
  type StorefrontApi,
} from '@shopify/hydrogen';

const SHOPIFY_STORE_DOMAIN = process.env.NEXT_PUBLIC_SHOPIFY_DOMAIN;
const SHOPIFY_STOREFRONT_ACCESS_TOKEN =
  process.env.NEXT_PUBLIC_SHOPIFY_STOREFRONT_ACCESS_TOKEN;
const SHOPIFY_API_VERSION =
  process.env.NEXT_PUBLIC_SHOPIFY_API_VERSION || '2025-07';
const SHOPIFY_STOREFRONT_API_URL = `https://${SHOPIFY_STORE_DOMAIN}/api/${SHOPIFY_API_VERSION}/graphql.json`;

// No incoming request and no buyer context: these clients are module-scoped and
// serve both server rendering and the browser-side hooks, so they must not close
// over per-request state. `$country`/`$language` are injected from this i18n.
const requestContext = createShopifyRequestContext({
  request: { headers: new Headers() },
  i18n: { country: 'US', language: 'EN' },
});

// Hydrogen calls `fetch(url, init, cacheOptions)`; Next's caching hints ride
// along on `init`, which is how the two ways of caching get to coexist.
const fetchWith = (overrides: RequestInit): typeof globalThis.fetch =>
  ((url, init) =>
    globalThis.fetch(url, { ...init, ...overrides })) as typeof globalThis.fetch;

const config = {
  storeDomain: SHOPIFY_STORE_DOMAIN!,
  apiVersion: SHOPIFY_API_VERSION,
  // `mock.shop` and other tokenless storefronts leave this unset.
  publicStorefrontToken: SHOPIFY_STOREFRONT_ACCESS_TOKEN,
};

/**
 * Default client. Uncached, because carts and customer reads must never serve a
 * stale response.
 */
export const storefront = createStorefrontClient({
  type: 'public',
  requestContext,
  config: { ...config, fetch: fetchWith({ cache: 'no-store' }) },
});

/**
 * Client for catalogue data that changes rarely (shop policies, and anything
 * else safe to serve from Next's data cache for an hour).
 */
export const cachedStorefront = createStorefrontClient({
  type: 'public',
  requestContext,
  config: { ...config, fetch: fetchWith({ next: { revalidate: 3600 } }) },
});

interface ShopifyFetchArgs<TDoc extends AnyStorefrontQueryString> {
  query: TDoc;
  variables?: StorefrontApi.VariablesOf<TDoc>;
  /** Serve from Next's data cache instead of hitting Shopify every time. */
  cache?: boolean;
}

/**
 * Runs a `gql()` document and returns its data.
 *
 * Hydrogen returns GraphQL errors rather than throwing them (a 200 with partial
 * data is still a valid response), so this re-raises them to preserve the
 * fail-loudly behaviour the callers were written against. Transport failures
 * already throw as `StorefrontApiError`.
 */
export async function shopifyFetch<TDoc extends AnyStorefrontQueryString>({
  query,
  variables,
  cache = false,
}: ShopifyFetchArgs<TDoc>): Promise<{
  data: StorefrontApi.ResultOf<TDoc>;
}> {
  const client = cache ? cachedStorefront : storefront;

  try {
    const { data, errors } = await client.graphql(query, {
      variables,
    } as never);

    if (errors?.length) {
      console.error('Shopify API errors:', errors);
      throw new Error(`Shopify GraphQL errors: ${JSON.stringify(errors)}`);
    }

    return { data: data as StorefrontApi.ResultOf<TDoc> };
  } catch (error) {
    if (error instanceof StorefrontApiError) {
      console.error('Shopify fetch error:', error.toJSON());
    } else {
      console.error('Shopify fetch error:', error);
    }
    throw error;
  }
}

export { SHOPIFY_STORE_DOMAIN, SHOPIFY_STOREFRONT_API_URL };