refs.ts

import global from 'global';
import dedent from 'ts-dedent';
import {
  transformStoriesRawToStoriesHash,
  StoriesRaw,
  StoryInput,
  StoriesHash,
} from '../lib/stories';

import { ModuleFn } from '../index';

const { location, fetch } = global;

export interface SubState {
  refs: Refs;
}

type Versions = Record<string, string>;

export type SetRefData = Partial<
  Omit<ComposedRef, 'stories'> & {
    stories?: StoriesRaw;
  }
>;

export interface SubAPI {
  findRef: (source: string) => ComposedRef;
  setRef: (id: string, data: SetRefData, ready?: boolean) => void;
  updateRef: (id: string, ref: ComposedRefUpdate) => void;
  getRefs: () => Refs;
  checkRef: (ref: SetRefData) => Promise<void>;
  changeRefVersion: (id: string, url: string) => void;
  changeRefState: (id: string, ready: boolean) => void;
}

export type StoryMapper = (ref: ComposedRef, story: StoryInput) => StoryInput;
export interface ComposedRef {
  id: string;
  title?: string;
  url: string;
  type?: 'auto-inject' | 'unknown' | 'lazy' | 'server-checked';
  stories: StoriesHash;
  versions?: Versions;
  loginUrl?: string;
  version?: string;
  ready?: boolean;
  error?: any;
}

export type ComposedRefUpdate = Partial<
  Pick<
    ComposedRef,
    'title' | 'type' | 'stories' | 'versions' | 'loginUrl' | 'version' | 'ready' | 'error'
  >
>;

export type Refs = Record<string, ComposedRef>;
export type RefId = string;
export type RefUrl = string;

// eslint-disable-next-line no-useless-escape
const findFilename = /(\/((?:[^\/]+?)\.[^\/]+?)|\/)$/;

export const getSourceType = (source: string, refId: string) => {
  const { origin: localOrigin, pathname: localPathname } = location;
  const { origin: sourceOrigin, pathname: sourcePathname } = new URL(source);

  const localFull = `${localOrigin + localPathname}`.replace(findFilename, '');
  const sourceFull = `${sourceOrigin + sourcePathname}`.replace(findFilename, '');

  if (localFull === sourceFull) {
    return ['local', sourceFull];
  }
  if (refId || source) {
    return ['external', sourceFull];
  }
  return [null, null];
};

export const defaultStoryMapper: StoryMapper = (b, a) => {
  return { ...a, kind: a.kind.replace('|', '/') };
};

const addRefIds = (input: StoriesHash, ref: ComposedRef): StoriesHash => {
  return Object.entries(input).reduce((acc, [id, item]) => {
    return { ...acc, [id]: { ...item, refId: ref.id } };
  }, {} as StoriesHash);
};

const handle = async (request: Response | false): Promise<SetRefData> => {
  if (request) {
    return Promise.resolve(request)
      .then((response) => (response.ok ? response.json() : {}))
      .catch((error) => ({ error }));
  }
  return {};
};

const map = (
  input: StoriesRaw,
  ref: ComposedRef,
  options: { storyMapper?: StoryMapper }
): StoriesRaw => {
  const { storyMapper } = options;
  if (storyMapper) {
    return Object.entries(input).reduce((acc, [id, item]) => {
      return { ...acc, [id]: storyMapper(ref, item) };
    }, {} as StoriesRaw);
  }
  return input;
};

export const init: ModuleFn = ({ store, provider, singleStory }, { runCheck = true } = {}) => {
  const api: SubAPI = {
    findRef: (source) => {
      const refs = api.getRefs();

      return Object.values(refs).find(({ url }) => url.match(source));
    },
    changeRefVersion: (id, url) => {
      const { versions, title } = api.getRefs()[id];
      const ref = { id, url, versions, title, stories: {} } as SetRefData;

      api.checkRef(ref);
    },
    changeRefState: (id, ready) => {
      const { [id]: ref, ...updated } = api.getRefs();

      updated[id] = { ...ref, ready };

      store.setState({
        refs: updated,
      });
    },
    checkRef: async (ref) => {
      const { id, url, version, type } = ref;
      const isPublic = type === 'server-checked';

      // ref's type starts as either 'unknown' or 'server-checked'
      // "server-checked" happens when we were able to verify the storybook is accessible from node (without cookies)
      // "unknown" happens if the request was declined of failed (this can happen because the storybook doesn't exists or authentication is required)
      //
      // we then make a request for stories.json
      //
      // if this request fails when storybook is server-checked we mark the ref as "auto-inject", this is a fallback mechanism for local storybook, legacy storybooks, and storybooks that lack stories.json
      // if the request fails with type "unknown" we give up and show an error
      // if the request succeeds we set the ref to 'lazy' type, and show the stories in the sidebar without injecting the iframe first
      //
      // then we fetch metadata if the above fetch succeeded

      const loadedData: { error?: Error; stories?: StoriesRaw; loginUrl?: string } = {};
      const query = version ? `?version=${version}` : '';
      const credentials = isPublic ? 'omit' : 'include';

      // In theory the `/iframe.html` could be private and the `stories.json` could not exist, but in practice
      // the only private servers we know about (Chromatic) always include `stories.json`. So we can tell
      // if the ref actually exists by simply checking `stories.json` w/ credentials.

      const storiesFetch = await fetch(`${url}/stories.json${query}`, {
        headers: {
          Accept: 'application/json',
        },
        credentials,
      });

      if (!storiesFetch.ok && !isPublic) {
        loadedData.error = {
          message: dedent`
            Error: Loading of ref failed
              at fetch (lib/api/src/modules/refs.ts)

            URL: ${url}

            We weren't able to load the above URL,
            it's possible a CORS error happened.

            Please check your dev-tools network tab.
          `,
        } as Error;
      } else if (storiesFetch.ok) {
        const [stories, metadata] = await Promise.all([
          handle(storiesFetch),
          handle(
            fetch(`${url}/metadata.json${query}`, {
              headers: {
                Accept: 'application/json',
              },
              credentials,
              cache: 'no-cache',
            }).catch(() => false)
          ),
        ]);

        Object.assign(loadedData, { ...stories, ...metadata });
      }

      await api.setRef(id, {
        id,
        url,
        ...loadedData,
        error: loadedData.error,
        type: !loadedData.stories ? 'auto-inject' : 'lazy',
      });
    },

    getRefs: () => {
      const { refs = {} } = store.getState();

      return refs;
    },

    setRef: (id, { stories, ...rest }, ready = false) => {
      if (singleStory) return;
      const { storyMapper = defaultStoryMapper } = provider.getConfig();
      const ref = api.getRefs()[id];
      const after = stories
        ? addRefIds(
            transformStoriesRawToStoriesHash(map(stories, ref, { storyMapper }), { provider }),
            ref
          )
        : undefined;

      api.updateRef(id, { stories: after, ...rest, ready });
    },

    updateRef: (id, data) => {
      const { [id]: ref, ...updated } = api.getRefs();

      updated[id] = { ...ref, ...data };

      /* eslint-disable no-param-reassign */
      const ordered = Object.keys(initialState).reduce((obj: any, key) => {
        obj[key] = updated[key];
        return obj;
      }, {});
      /* eslint-enable no-param-reassign */

      store.setState({
        refs: ordered,
      });
    },
  };

  const refs = (!singleStory && provider.getConfig().refs) || {};

  const initialState: SubState['refs'] = refs;

  if (runCheck) {
    Object.entries(refs).forEach(([k, v]) => {
      api.checkRef(v as SetRefData);
    });
  }

  return {
    api,
    state: {
      refs: initialState,
    },
  };
};