import type { S3Client } from "bun";

let client: S3Client | undefined;
let loading: Promise<S3Client> | undefined;

function required(name: string): string {
  const value = process.env[name];
  if (!value) throw new Error(`${name} is required for media storage.`);
  return value;
}

export async function getMediaStorage(): Promise<S3Client> {
  if (client) return client;
  if (!loading) {
    loading = import("bun").then(({ S3Client: BunS3Client }) => new BunS3Client({
      accessKeyId: required("S3_ACCESS_KEY_ID"),
      secretAccessKey: required("S3_SECRET_ACCESS_KEY"),
      bucket: required("S3_BUCKET"),
      endpoint: required("S3_ENDPOINT"),
      region: process.env.S3_REGION || "auto",
      virtualHostedStyle: process.env.S3_VIRTUAL_HOSTED_STYLE === "true",
    }));
  }
  client = await loading;
  return client;
}

export function publicMediaUrl(objectKey: string): string {
  const base = required("S3_PUBLIC_URL").replace(/\/+$/u, "");
  return `${base}/${objectKey.split("/").map(encodeURIComponent).join("/")}`;
}