Add a defaults button to the folder mapping dialog

Mapping the Exchange/Kerio special folders onto mailcow's by hand is
repetitive work that scales with the number of accounts. "By default"
maps Deleted Items to Trash, Junk E-mail to Junk, Sent Items to Sent and
unchecks Public Folders, which mailcow has no counterpart for.

The destination select only offered the source folder as a name to
create, so a target missing on the destination could not be selected at
all. It now also offers the current selection, and marks any name absent
from the destination as "(create)".

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

web/src/app.css

@@ -488,11 +488,23 @@
   cursor: pointer;
 }
 
+.map-toolbar {
+  display: flex;
+  align-items: center;
+  gap: 14px;
+  margin-bottom: 12px;
+  flex-wrap: wrap;
+}
+
+.map-toolbar .btn {
+  padding: 6px 12px;
+  font-size: 11px;
+}
+
 .map-all {
   display: flex;
   align-items: center;
   gap: 8px;
-  margin-bottom: 12px;
   font-size: 11px;
   text-transform: uppercase;
   letter-spacing: 0.08em;

web/src/components/FolderMappingModal.tsx

@@ -20,6 +20,21 @@ function defaultDst(src: string, dstFolders: string[], initial: Record<string, s
   return src
 }
 
+// Exchange/Kerio special folders and their mailcow counterparts. Keyed by the
+// lowercased source name so casing differences between servers don't matter.
+const DEFAULT_TARGETS: Record<string, string> = {
+  'deleted items': 'Trash',
+  'deleted messages': 'Trash',
+  'junk e-mail': 'Junk',
+  'junk email': 'Junk',
+  spam: 'Junk',
+  'sent items': 'Sent',
+  'sent messages': 'Sent',
+}
+
+// Source folders with no counterpart on mailcow — unchecked by the defaults.
+const DEFAULT_EXCLUDED = new Set(['public folders'])
+
 export function FolderMappingModal({
   open, srcFolders, dstFolders, initialMapping, initialExcluded, accountLabel, onConfirm, onCancel,
 }: Props) {
@@ -31,16 +46,40 @@ export function FolderMappingModal({
 
   // Options per select: all destination folders, plus the source name itself
   // (marked "create") when it does not already exist on the destination.
+  const valueFor = (src: string) => choice[src] ?? defaultDst(src, dstFolders, initialMapping)
+
+  // Options per select: all destination folders, plus any name not present there
+  // — the source folder itself and the current selection — marked "create".
   const options = useMemo(() => {
     const set = new Set(dstFolders)
-    return (src: string) => {
+    return (src: string, current: string) => {
       const opts = [...dstFolders]
-      if (!set.has(src)) opts.unshift(src)
+      if (!set.has(current)) opts.unshift(current)
+      if (!set.has(src) && src !== current) opts.unshift(src)
       return opts
     }
   }, [dstFolders])
 
-  const valueFor = (src: string) => choice[src] ?? defaultDst(src, dstFolders, initialMapping)
+  // Collapse the Exchange/Kerio folder layout onto mailcow's in one click: the
+  // per-account mapping is otherwise repetitive work when importing many users.
+  function applyDefaults() {
+    const nextChoice = { ...choice }
+    const nextSynced = { ...synced }
+    for (const src of srcFolders) {
+      const key = src.trim().toLowerCase()
+      if (DEFAULT_EXCLUDED.has(key)) {
+        nextSynced[src] = false
+        continue
+      }
+      const target = DEFAULT_TARGETS[key]
+      if (target) {
+        nextChoice[src] = target
+        nextSynced[src] = true
+      }
+    }
+    setChoice(nextChoice)
+    setSynced(nextSynced)
+  }
 
   function confirm() {
     const mapping: Record<string, string> = {}
@@ -70,6 +109,15 @@ export function FolderMappingModal({
           Route each source folder to an existing destination folder. Leaving a folder mapped to its own name
           creates it on the destination if missing (e.g. map <code>Спам</code> → <code>Spam</code> to avoid duplicates).
         </p>
+        <div className="map-toolbar">
+          <button
+            type="button"
+            className="btn btn-ghost"
+            onClick={applyDefaults}
+            title="Map Deleted Items → Trash, Junk E-mail → Junk, Sent Items → Sent and skip Public Folders"
+          >
+            By default
+          </button>
           <label className="map-all">
             <input
               type="checkbox"
@@ -81,6 +129,7 @@ export function FolderMappingModal({
             />
             sync all folders
           </label>
+        </div>
         <div className="map-grid">
           {srcFolders.map((src) => {
             const on = synced[src] !== false
@@ -107,10 +156,10 @@ export function FolderMappingModal({
                   disabled={!on}
                   onChange={(e) => setChoice((c) => ({ ...c, [src]: e.target.value }))}
                 >
-                  {options(src).map((f) => (
+                  {options(src, val).map((f) => (
                     <option key={f} value={f}>
                       {f}
-                      {f === src && !dstFolders.includes(src) ? ' (create)' : ''}
+                      {dstFolders.includes(f) ? '' : ' (create)'}
                     </option>
                   ))}
                 </select>