/*
 * Copyright 2020 Spotify AB
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import { EntityName } from '@backstage/catalog-model';
import type { Transformer } from './index';
import { TechDocsStorage } from '../../api';

type AddBaseUrlOptions = {
  techdocsStorageApi: TechDocsStorage;
  entityId: EntityName;
  path: string;
};

export const addBaseUrl = ({
  techdocsStorageApi,
  entityId,
  path,
}: AddBaseUrlOptions): Transformer => {
  return dom => {
    const updateDom = <T extends Element>(
      list: HTMLCollectionOf<T> | NodeListOf<T>,
      attributeName: string,
    ): void => {
      Array.from(list)
        .filter(elem => !!elem.getAttribute(attributeName))
        .forEach(async (elem: T) => {
          const elemAttribute = elem.getAttribute(attributeName);
          if (!elemAttribute) return;
          elem.setAttribute(
            attributeName,
            await techdocsStorageApi.getBaseUrl(elemAttribute, entityId, path),
          );
        });
    };

    updateDom<HTMLImageElement>(dom.querySelectorAll('img'), 'src');
    updateDom<HTMLScriptElement>(dom.querySelectorAll('script'), 'src');
    updateDom<HTMLLinkElement>(dom.querySelectorAll('link'), 'href');

    return dom;
  };
};
