fe-middleware/src/services/ImageService.ts

import GelbooruServiceResponse from "src/types/GelbooruServiceResponse";
import Image from "src/types/Image";
import BotApiService from "src/services/BotApiService";
import GelbooruApiService from "src/services/GelbooruApiService";
import logger from "src/logger";

class ImageService {
  postsQueue: Image[] = [];

  async get(): Promise<Image> {
    while (this.postsQueue.length === 0) {
      const validPosts = await this.getNewValidImages();
      this.postsQueue = validPosts;
      logger.info(`Got ${validPosts.length} images from remote`);
    }
    return this.postsQueue.pop() as Image;
  }

  private async getNewValidImages(): Promise<Image[]> {
    const gelbooruResponse: GelbooruServiceResponse =
      await GelbooruApiService.get();
    const posts = gelbooruResponse.posts;

    const botResponse = await BotApiService.getAll();
    const imagesUrls = botResponse.images.map((image) => image.url);

    const validPosts = Promise.all(
      posts
        .filter((post) => !imagesUrls.some((url) => url === post.url))
        .map((post): Image => {
          return { url: post.url, tags: post.tags };
        })
    );

    return validPosts;
  }
}

export default new ImageService();