Handle file uploads the production way

import { S3Client, PutObjectCommand, GetObjectCommand, HeadObjectCommand, ListObjectsV2Command, DeleteObjectCommand } from '@aws-sdk/client-s3';
import { getSignedUrl } from '@aws-sdk/s3-request-presigner';
import { randomUUID } from 'crypto';

const BUCKET = process.env.S3_BUCKET ?? 'invoicedesk';

export const s3 = new S3Client({
  endpoint: process.env.S3_ENDPOINT,
  region: 'us-east-1',
  forcePathStyle: true,
  credentials: {
    accessKeyId: process.env.S3_ACCESS_KEY!,
    secretAccessKey: process.env.S3_SECRET_KEY!,
  },
});

const ALLOWED_TYPES = new Set(['image/png', 'image/jpeg', 'application/pdf']);

export function buildKey(orgId: string, filename: string) {
  const safeName = filename.replace(/[^a-zA-Z0-9._-]/g, '_').slice(-80);
  return `${orgId}/${randomUUID()}-${safeName}`;
}

export async function presignPut(key: string, contentType: string) {
  if (!ALLOWED_TYPES.has(contentType)) {
    throw new Error(`content type ${contentType} is not allowed`);
  }
  const command = new PutObjectCommand({ Bucket: BUCKET, Key: key, ContentType: contentType });
  return getSignedUrl(s3, command, { expiresIn: 60 });
}

export async function presignGet(key: string) {
  const command = new GetObjectCommand({ Bucket: BUCKET, Key: key });
  return getSignedUrl(s3, command, { expiresIn: 300 });
}

export async function headObject(key: string) {
  return s3.send(new HeadObjectCommand({ Bucket: BUCKET, Key: key }));
}

export async function listBucketKeys(prefix: string) {
  const out: string[] = [];
  let ContinuationToken: string | undefined;
  do {
    const res = await s3.send(new ListObjectsV2Command({ Bucket: BUCKET, Prefix: prefix, ContinuationToken }));
    (res.Contents ?? []).forEach((obj) => obj.Key && out.push(obj.Key));
    ContinuationToken = res.NextContinuationToken;
  } while (ContinuationToken);
  return out;
}

export async function listBucketObjects(prefix: string) {
  const out: { key: string; lastModified?: Date }[] = [];
  let ContinuationToken: string | undefined;
  do {
    const res = await s3.send(new ListObjectsV2Command({ Bucket: BUCKET, Prefix: prefix, ContinuationToken }));
    (res.Contents ?? []).forEach((obj) => obj.Key && out.push({ key: obj.Key, lastModified: obj.LastModified }));
    ContinuationToken = res.NextContinuationToken;
  } while (ContinuationToken);
  return out;
}

export async function deleteObject(key: string) {
  await s3.send(new DeleteObjectCommand({ Bucket: BUCKET, Key: key }));
}

export { BUCKET };