feat: add document preview overlay

app/utils/documentPreview.js

@@ -0,0 +1,25 @@
+import { getFileIcon } from './fileIcons'
+
+export const getPreviewType = (document) => {
+  if (!document) return null
+  const mime = (document.mimeType || '').toLowerCase()
+  const path = document.path || ''
+
+  const check = (prefix) => mime.startsWith(prefix) || path.startsWith(`data:${prefix}`)
+
+  if (check('image/')) return 'image'
+  if (mime === 'application/pdf' || path.startsWith('data:application/pdf')) return 'pdf'
+  if (check('audio/')) return 'audio'
+  if (check('video/')) return 'video'
+  if (check('text/') || mime.includes('json') || mime.includes('xml') || path.startsWith('data:application/json')) return 'text'
+  return null
+}
+
+export const canPreviewDocument = (document = {}) => !!getPreviewType(document)
+
+export const describeDocument = (document) => {
+  if (!document) return ''
+  const name = document.filename || document.name || ''
+  const icon = getFileIcon({ name, mime: document.mimeType })
+  return icon.label
+}