Smarter ZIP download naming.

frontend/src/utils/fileutil.ts

@@ -6,3 +6,44 @@ export const exists = (path: string[]) => {
   const p = path.join('/')
   return store.document.some(doc => (doc.loc ? `${doc.loc}/${doc.name}` : doc.name) === p)
 }
+
+/** Strip file extension intelligently (handles .tar.gz, name.with.dots.pdf, etc.) */
+export const stripExt = (name: string): string => {
+  // Common compound extensions
+  const compoundExts = ['.tar.gz', '.tar.bz2', '.tar.xz', '.tar.zst']
+  const lower = name.toLowerCase()
+  for (const ext of compoundExts) {
+    if (lower.endsWith(ext)) return name.slice(0, -ext.length)
+  }
+  // Regular extension: only strip if the extension looks like one (2-5 chars, alphanumeric)
+  const lastDot = name.lastIndexOf('.')
+  if (lastDot > 0) {
+    const ext = name.slice(lastDot + 1)
+    if (ext.length >= 2 && ext.length <= 5 && /^[a-zA-Z0-9]+$/.test(ext)) {
+      return name.slice(0, lastDot)
+    }
+  }
+  return name
+}
+
+/** Generate a sensible zip filename for a selection of items */
+export const zipName = (items: { name: string; loc: string }[]): string => {
+  const names = items.map(d => d.name)
+  if (names.length === 1) {
+    // Single item - use its name
+    return stripExt(names[0]!)
+  }
+  // Check if all items share the same direct parent folder
+  const locs = items.map(d => d.loc)
+  const sameLoc = locs.every(loc => loc === locs[0])
+  if (sameLoc && locs[0]) {
+    // All items in same folder - use folder name
+    return locs[0].split('/').pop()!
+  }
+  if (names.length <= 3) {
+    // Few items from different folders - join basenames with dot
+    return names.map(stripExt).join('.')
+  }
+  // Many items from different folders - first basename + indicator
+  return `${stripExt(names[0]!)}.etc`
+}