/*!
 * This file is part of Share₂Fedi
 * https://github.com/kytta/share2fedi
 *
 * SPDX-FileCopyrightText: © 2023 Nikita Karamov <me@kytta.dev>
 * SPDX-License-Identifier: AGPL-3.0-only
 */

import { supportedProjects } from "$lib/project.ts";

interface Instance {
  domain: string;
  score: number;
  active_users_monthly: number;
  total_users: number;
}

const getInstancesForProject = async (
  project: keyof typeof supportedProjects,
): Promise<Instance[]> => {
  let instances: Instance[];
  try {
    const response = await fetch("https://api.fediverse.observer/", {
      headers: {
        Accept: "*/*",
        "Accept-Language": "en;q=1.0",
        "Content-Type": "application/json",
      },
      body: JSON.stringify({
        query:
          `{nodes(status:"UP",softwarename:"${project}"){domain score active_users_monthly total_users}}`,
      }),
      method: "POST",
    });
    const json = await response.json();
    instances = json.data.nodes;
  } catch (error) {
    console.error(`Could not fetch instances for "${project}"`, error);
    return [];
  }

  return instances.filter(
    (instance) =>
      instance.score > 90 &&
      // sanity check for some spammy-looking instances
      instance.total_users >= instance.active_users_monthly,
  );
};

export const getPopularInstanceDomains = async (): Promise<string[]> => {
  const instancesPerProject = await Promise.all(
    Object.keys(supportedProjects).map((project) =>
      getInstancesForProject(project)
    ),
  );
  const instances = instancesPerProject.flat();
  instances.sort((a, b) => b.active_users_monthly - a.active_users_monthly);

  return instances.slice(0, 200).map((instance) => instance.domain);
};