import type { FastifyReply, FastifyRequest, RouteOptions } from "fastify";
import { IsNull } from "typeorm";

import log from "~/log.js";
import MercuryDataSource from "~/db/index.js";
import { Blog } from "~entities/blog.js";
import { BASE_URL } from "~/config.js";

const route: RouteOptions = {
  method: "GET",
  url: "/.well-known/webfinger",
  handler: async (req, res) => {
    // TypeScript complains if we just use plain `req.query` :(
    const encodedResource = (req.query as { resource: string }).resource;

    if (!encodedResource || typeof encodedResource !== "string") {
      res.status(400).send({
        error: "resource query parameter is missing or invalid",
      });
      return;
    }
    const resource = decodeURIComponent(encodedResource);

    log.debug("Handling WebFinger request for %s", resource);

    if (resource.startsWith("acct:")) {
      await handleAcctWebfinger(req, res, resource);
      return;
    }

    res.status(500).send({ error: "Unhandled WebFinger resource type" });
  },
};

export default route;

async function handleAcctWebfinger(
  req: FastifyRequest,
  res: FastifyReply,
  resource: string
): Promise<void> {
  const [username, domain] = resource.slice("acct:".length).split("@");
  if (domain !== process.env.DOMAIN) {
    res.status(404).send({
      error: "Account not found",
    });
    return;
  }

  const blog = await MercuryDataSource.getRepository(Blog).findOneBy({
    username: username,
    host: IsNull(),
  });
  if (!blog) {
    res.status(404).send({
      error: "Account not found",
    });
    return;
  }

  res.send({
    subject: resource,
    aliases: [
      `${BASE_URL}/@${blog.username}`,
      `${BASE_URL}/blogs/${blog.username}`,
    ],
    links: [
      {
        rel: "http://webfinger.net/rel/profile-page",
        type: "text/html",
        href: `${BASE_URL}/@${blog.username}`,
      },
      {
        rel: "self",
        type: "application/activity+json",
        href: `${BASE_URL}/blogs/${blog.username}`,
      },
    ],
  });
}