import {useMemo} from 'preact/hooks';

import type {
  AppMetafieldEntryTarget,
  Metafield,
  AppMetafieldEntry,
} from '../api/standard/standard';
import type {RenderExtensionTarget} from '../extension-targets';

import {CheckoutUIExtensionError} from './errors';
import {useApi} from './api';
import {useSubscription} from './subscription';

interface AppMetafieldFilters {
  id?: AppMetafieldEntryTarget['id'];
  type?: AppMetafieldEntryTarget['type'];
  /**
   * To filter for app owned metafields, use the `$app` format. The fully qualified reserved namespace format such as `app--{your-app-id}[--{optional-namespace}]` is not supported.
   *
   * See [app owned metafields](/docs/apps/build/custom-data/ownership#reserved-prefixes) for more information.
   */
  namespace?: Metafield['namespace'];
  key?: Metafield['key'];
}

type AppMetafieldFilterKeys = keyof AppMetafieldFilters;

/**
 * Returns the metafields configured with `shopify.extension.toml`.
 * @arg {AppMetafieldFilters} - filter the list of returned metafields
 */
export function useAppMetafields<
  Target extends RenderExtensionTarget = RenderExtensionTarget,
>(filters: AppMetafieldFilters = {}): AppMetafieldEntry[] {
  const appMetafields = useSubscription(useApi<Target>().appMetafields);

  return useMemo(() => {
    if (filters.key && !filters.namespace) {
      throw new CheckoutUIExtensionError(
        'You must pass in a namespace with a key',
      );
    }

    const filterKeys = Object.keys(filters) as AppMetafieldFilterKeys[];

    if (filterKeys.length) {
      return appMetafields.filter((app) => {
        return filterKeys.every((key) => {
          if (key === 'id' || key === 'type') {
            return app.target[key] === filters[key];
          }

          return app.metafield[key] === filters[key];
        });
      });
    }

    return appMetafields;
  }, [filters, appMetafields]);
}