platform/src/servers/api/upload/upload.ts

import { createRouter } from '../../create-router';
import { mkdir } from 'node:fs/promises';
import { join } from 'node:path';
import { getTmpAttachmentsDir, getAttachmentsDir } from '@@/data-path';

const MAX_FILE_SIZE = 5 * 1024 * 1024; // 5 MB

export const uploadRouter = createRouter();

uploadRouter.post('/', async (ctx) => {
  const user = ctx.get('user');
  const body = ctx.get('body') as Record<string, unknown>;

  const file = body.file as File | null;
  const sessionId = (body.sessionId as string) || null;

  if (!file || !(file instanceof File)) {
    return ctx.json({ error: 'file is required' }, 400);
  }

  if (!file.type.startsWith('image/')) {
    return ctx.json({ error: 'Only image files are allowed' }, 400);
  }

  if (file.size > MAX_FILE_SIZE) {
    return ctx.json({ error: 'File exceeds 5 MB limit' }, 400);
  }

  try {
    const buffer = Buffer.from(await file.arrayBuffer());
    const ext = file.name.split('.').pop() || 'png';
    const filename = `${crypto.randomUUID()}.${ext}`;

    let saveDir: string;
    if (sessionId) {
      saveDir = getAttachmentsDir(user.email, sessionId);
    } else {
      saveDir = getTmpAttachmentsDir(user.email);
    }

    await mkdir(saveDir, { recursive: true });
    await Bun.write(join(saveDir, filename), buffer);

    const base64 = buffer.toString('base64');
    const dataUrl = `data:${file.type};base64,${base64}`;

    return ctx.json({ filename: file.name, dataUrl, attachmentId: filename });
  } catch (err) {
    const message = err instanceof Error ? err.message : 'Upload failed';
    return ctx.json({ error: message }, 500);
  }
});