type Tag = {
  name: string;
  digest: string;
};

class DockerHub {
  getLatestVersions = async (imageName: string): Promise<string[]> => {
    const imagePath = imageName.includes("/")
      ? imageName
      : `library/${imageName}`;

    const tagsResponse = await this.fetch(
      `/${imagePath}/tags?page_size=10&ordering=last_updated`
    ).then((res) => res.json());

    const tags: Tag[] = tagsResponse.results;
    if (tags.length === 0) {
      throw new Error(`No tags found for ${imageName}`);
    }

    const latestTag = tags.find((tag) => tag.name === "latest");
    if (!latestTag) {
      return [];
    }

    const latestTags = tags
      .filter((tag) => tag.digest === latestTag.digest)
      .map((tag) => tag.name);

    // Example: "1.0.0-alpine" is a variant of "1.0.0"
    const isVariant = (tag: Tag) => {
      return latestTags.some((latestTag) => tag.name.includes(latestTag + "-"));
    };
    return latestTags
      .concat(tags.filter(isVariant).map((tag) => tag.name))
      .map((tag) => `${imageName}:${tag}`)
      .sort();
  };

  private fetch = async (url: string): Promise<Response> => {
    const fullUrl = `https://hub.docker.com/v2/repositories${url}`;
    console.debug("-> Docker: Fetching", fullUrl);
    return fetch(fullUrl);
  };
}

export default DockerHub;