import type { FastifyInstance } from "fastify";
import { readFileSync } from "fs";
import { join } from "path";

interface PackageJson {
  version: string;
}

let cachedVersion: string | null = null;

function getVersion(): string {
  if (cachedVersion) {
    return cachedVersion;
  }

  try {
    const packageJsonPath = join(process.cwd(), "package.json");
    const packageJson = JSON.parse(readFileSync(packageJsonPath, "utf-8")) as PackageJson;
    cachedVersion = packageJson.version;
    return cachedVersion;
  } catch {
    return "unknown";
  }
}

export default async function (app: FastifyInstance): Promise<void> {
  app.get("/", async (_request, reply) => {
    reply.send({ version: getVersion() });
  });
}