RenaiApp/src/main/modules/nhentai/nhentai-app-window.ts

import type { WebContents } from 'electron';
import os from 'os';
import path from 'path';
import { Readable } from 'stream';
import { URL } from 'url';
import { createReadStream, remove } from 'fs-extra';
import { injectable } from 'inversify';
import { inject } from '../../core/inject';
import { SiteAppWindow } from '../app-window/site-app-window';
import { WindowClosedError } from '../app-window/window-closed-error';
import type { SessionHelperInterface } from '../session/session-helper-interface';
import type { NhentaiAppWindowInterface } from './nhentai-app-window-interface';
import {
  url as nhentaiUrl,
  hostname as nhentaiHostname,
  paths as nhentaiPaths,
  getFavoritePageUrl,
  nextFavoritePageSelector,
  coverLinkSelector,
  downloadLinkId,
  getGalleryId,
} from './nhentai-util';

const waitInterval = 2000;

@injectable()
export class NhentaiAppWindow extends SiteAppWindow implements NhentaiAppWindowInterface {
  public constructor(@inject('session-helper') sessionHelper: SessionHelperInterface) {
    super(sessionHelper, nhentaiUrl);
  }

  public async getFavorites(): Promise<NodeJS.ReadableStream> {
    const release = await this.acquireLock();
    try {
      if (this.isClosed()) {
        await this.open();
      }

      if (!(await this.isLoggedIn())) {
        await this.login();
      }

      this._window?.setProgressBar(0, { mode: 'indeterminate' });
      const bookUrls: string[] = [];
      for await (const wc of this.getFavoritePageWebContentsGenerator()) {
        bookUrls.push(
          ...((await wc.executeJavaScript(
            `Array.from(document.querySelectorAll('${coverLinkSelector}')).map((el) => el.href)`
          )) as string[])
        );
      }

      const readable = Readable.from(
        (async function* (thisArg): AsyncGenerator<Nhentai.Favorite, undefined> {
          for (let i = 0; i < bookUrls.length; i++) {
            const bookUrl = bookUrls[i];
            yield await thisArg.getBookTorrent(bookUrl);
            thisArg._window?.setProgressBar(i / bookUrls.length);
          }
          return;
        })(this),
        {
          objectMode: true,
        }
      );
      readable.once('end', () => {
        this.close();
        release();
      });

      return readable;
    } catch (e) {
      release();
      throw e;
    }
  }

  protected getCsp(): Session.ContentSecurityPolicy {
    return {
      'default-src': ['nhentai.net'],
      'script-src': ['nhentai.net', "'unsafe-eval'"],
      'script-src-elem': ['*.nhentai.net', "'unsafe-inline'", '*.google.com', '*.gstatic.com'],
      'style-src': [
        '*.nhentai.net',
        "'unsafe-inline'",
        'fonts.googleapis.com',
        'cdnjs.cloudflare.com',
        'maxcdn.bootstrapcdn.com',
        '*.gstatic.com',
      ],
      'img-src': ['*.nhentai.net', 'data:', '*.gstatic.com', '*.google.com'],
      'font-src': ['fonts.gstatic.com', 'cdnjs.cloudflare.com', 'maxcdn.bootstrapcdn.com'],
      'frame-src': ['*.google.com'],
      'connect-src': ['nhentai.net', '*.google.com'],
      'worker-src': ['*.google.com'],
    };
  }

  protected onWillNavigate(event: Electron.Event, navigationUrl: string): void {
    const url = new URL(navigationUrl);

    if (url.hostname !== nhentaiHostname) {
      event.preventDefault();
    }
  }

  private async isLoggedIn(): Promise<boolean> {
    if (!this._window) {
      throw new WindowClosedError();
    }
    return this._window.webContents
      .executeJavaScript(
        `fetch('${
          nhentaiUrl + nhentaiPaths.favorites
        }', {credentials: 'include', redirect: 'manual'}).then((res) => res.status)`
      )
      .then((status: number) => status === HttpCode.OK);
  }

  /**
   * @throws WindowClosedError when this._window is null
   */
  private async login(): Promise<void> {
    if (!this._window) {
      throw new WindowClosedError();
    }
    await this.loadUrlSafe(nhentaiUrl + nhentaiPaths.login);

    return new Promise((resolve, reject) => {
      const timeout = setInterval(() => {
        this.isLoggedIn()
          .then((loggedIn) => {
            if (loggedIn) {
              clearTimeout(timeout);
              resolve();
            }
          })
          .catch((reason) => reject(reason));
      }, waitInterval);
    });
  }

  private async *getFavoritePageWebContentsGenerator(): AsyncGenerator<WebContents, undefined> {
    if (!this._window) {
      throw new WindowClosedError();
    }
    await this.loadUrlSafe(getFavoritePageUrl());
    while (true) {
      yield this._window.webContents;
      const hasNextPage = (await this._window.webContents.executeJavaScript(
        `!!document.querySelector('${nextFavoritePageSelector}')`
      )) as boolean;
      if (hasNextPage) {
        const nextPageHref = (await this._window.webContents.executeJavaScript(
          `document.querySelector('${nextFavoritePageSelector}').href`
        )) as string;
        await this.loadUrlSafe(nextPageHref);
      } else {
        break;
      }
    }
    return;
  }

  private async getBookTorrent(bookUrl: string): Promise<Nhentai.Favorite> {
    if (!this._window) {
      throw new WindowClosedError();
    }
    const galleryId = getGalleryId(bookUrl);
    const fileName = `${galleryId}.torrent`;
    const filePath = path.resolve(os.tmpdir(), fileName);
    await this.loadUrlSafe(bookUrl);
    const downloadLink: string = (await this._window.webContents.executeJavaScript(
      `document.getElementById('${downloadLinkId}').href`
    )) as string;
    await this.downloadUrlSafe(downloadLink, filePath);

    const readable = createReadStream(filePath, { emitClose: true });

    readable.once('close', () => {
      void remove(filePath);
    });

    return {
      name: fileName,
      torrentFile: readable,
    };
  }
}