fix: allow pasted images in agent text box

Fixes #150

packages/browseros-agent/apps/agent/lib/attachments.test.ts

@@ -0,0 +1,96 @@
+import { describe, expect, it } from 'bun:test'
+import { stageAttachment } from './attachments'
+
+function restoreGlobal(name: string, value: unknown) {
+  if (value === undefined) {
+    Reflect.deleteProperty(globalThis, name)
+    return
+  }
+  Reflect.set(globalThis, name, value)
+}
+
+describe('stageAttachment', () => {
+  it('stages pasted clipboard images that do not have a filename', async () => {
+    const file = new File([new Uint8Array([1, 2, 3])], '', {
+      type: 'image/png',
+    })
+
+    const result = await stageAttachment(file)
+
+    expect(result.ok).toBe(true)
+    if (!result.ok) throw new Error(result.error.message)
+    expect(result.attachment.kind).toBe('image')
+    expect(result.attachment.name).toBe('image')
+    expect(result.attachment.mediaType).toBe('image/png')
+    expect(result.attachment.dataUrl).toStartWith('data:image/png;base64,')
+    expect(result.attachment.payload).toMatchObject({
+      kind: 'image',
+      mediaType: 'image/png',
+      dataUrl: result.attachment.dataUrl,
+    })
+  })
+
+  it('uses the recompressed blob media type for large pasted images', async () => {
+    const originalCreateImageBitmap = Reflect.get(
+      globalThis,
+      'createImageBitmap',
+    )
+    const originalOffscreenCanvas = Reflect.get(globalThis, 'OffscreenCanvas')
+    const originalHTMLCanvasElement = Reflect.get(
+      globalThis,
+      'HTMLCanvasElement',
+    )
+
+    class FakeOffscreenCanvas {
+      width: number
+      height: number
+
+      constructor(width: number, height: number) {
+        this.width = width
+        this.height = height
+      }
+
+      getContext() {
+        return {
+          drawImage() {},
+        }
+      }
+
+      async convertToBlob(options: { type?: string }) {
+        return new Blob([new Uint8Array([9, 8, 7])], {
+          type: options.type ?? 'image/jpeg',
+        })
+      }
+    }
+
+    try {
+      Reflect.set(globalThis, 'createImageBitmap', async () => ({
+        width: 4096,
+        height: 2048,
+        close() {},
+      }))
+      Reflect.set(globalThis, 'OffscreenCanvas', FakeOffscreenCanvas)
+      Reflect.set(globalThis, 'HTMLCanvasElement', class HTMLCanvasElement {})
+
+      const file = new File([new Uint8Array(2 * 1024 * 1024)], 'shot.png', {
+        type: 'image/png',
+      })
+
+      const result = await stageAttachment(file)
+
+      expect(result.ok).toBe(true)
+      if (!result.ok) throw new Error(result.error.message)
+      expect(result.attachment.mediaType).toBe('image/jpeg')
+      expect(result.attachment.dataUrl).toStartWith('data:image/jpeg;base64,')
+      expect(result.attachment.payload).toMatchObject({
+        kind: 'image',
+        mediaType: 'image/jpeg',
+        dataUrl: result.attachment.dataUrl,
+      })
+    } finally {
+      restoreGlobal('createImageBitmap', originalCreateImageBitmap)
+      restoreGlobal('OffscreenCanvas', originalOffscreenCanvas)
+      restoreGlobal('HTMLCanvasElement', originalHTMLCanvasElement)
+    }
+  })
+})

packages/browseros-agent/apps/agent/lib/attachments.ts

@@ -100,6 +100,7 @@ export async function stageAttachment(
     try {
       const compressed = await compressImageIfNeeded(file)
       const dataUrl = await readAsDataUrl(compressed)
+      const encodedMediaType = compressed.type || mediaType
       // Rough byte ceiling — `data:image/png;base64,...` doubles size with
       // base64. Reject early so we never POST something the route will 400.
       if (dataUrl.length > MAX_IMAGE_BYTES * 2) {
@@ -118,12 +119,12 @@ export async function stageAttachment(
         attachment: {
           id: makeId(),
           kind: 'image',
-          mediaType,
+          mediaType: encodedMediaType,
           name: file.name || 'image',
           dataUrl,
           payload: {
             kind: 'image',
-            mediaType,
+            mediaType: encodedMediaType,
             dataUrl,
             name: file.name || undefined,
           },