feat: offer undo after changing tags in the tag sheet and the reader

src/lib/tag-undo-group.ts

@@ -0,0 +1,22 @@
+// One Undo for everything changed in a tag sheet. The sheet stays open so
+// several tags can be changed in a row (webmail setSelectionTagWithUndo), and
+// it covers the undo bar while it is up: the changes join one Undo, and the
+// bar shows for its full time once the sheet closes.
+
+import React from 'react';
+import { useEmailStore } from '../stores/email-store';
+
+let seq = 0;
+
+/** The undo group of a tag sheet while `open`; '' while it is closed. */
+export function useTagUndoGroup(open: boolean): string {
+  const group = React.useRef('');
+  if (open && !group.current) group.current = `tags:${++seq}`;
+  React.useEffect(() => {
+    if (open || !group.current) return;
+    const done = group.current;
+    group.current = '';
+    useEmailStore.getState().releaseUndoGroup(done);
+  }, [open]);
+  return open ? group.current : '';
+}

src/screens/EmailListScreen.tsx

@@ -22,6 +22,7 @@ import SenderAvatar from '../components/SenderAvatar';
 import { SwipeableRow } from '../components/SwipeableRow';
 import { MoveSheet } from '../components/MoveSheet';
 import { TagSheet } from '../components/TagSheet';
+import { useTagUndoGroup } from '../lib/tag-undo-group';
 import { OfflineBanner } from '../components/OfflineBanner';
 import { TrashRecoveryLink } from '../components/email/TrashRecoveryLink';
 import {
@@ -711,6 +712,8 @@ export default function EmailListScreen({
   // Batch (multi-select) sheets.
   const [batchMoveOpen, setBatchMoveOpen] = React.useState(false);
   const [tagSheetOpen, setTagSheetOpen] = React.useState(false);
+  // The sheet's changes share one Undo, shown once it closes.
+  const tagUndoGroup = useTagUndoGroup(tagSheetOpen);
 
   // Selection state
   const [selectedIds, setSelectedIds] = React.useState<Set<string>>(new Set());
@@ -1030,7 +1033,7 @@ export default function EmailListScreen({
   };
 
   const handleBatchTagToggle = (token: string, on: boolean) => {
-    setKeywordForEmails(selectedMessageIds, token, on).catch((err) =>
+    setKeywordForEmails(selectedMessageIds, token, on, undefined, { undoGroup: tagUndoGroup }).catch((err) =>
       reportKeywordFailure(t('notifications.tag_failed', 'Tagging failed'), err));
   };
 

src/screens/EmailThreadScreen.tsx

@@ -15,6 +15,7 @@ import {
 } from '../components/icons';
 import { pickEmailBody } from '../lib/email-body';
 import { confirmMailRemoval } from '../lib/mail-removal-confirm';
+import { useTagUndoGroup } from '../lib/tag-undo-group';
 import { NewTagRow } from '../components/NewTagRow';
 import { QuickRuleSheet } from '../components/filters/QuickRuleSheet';
 import { isSieveSupported } from '../api/sieve';
@@ -177,6 +178,8 @@ function EmailViewer({ route, navigation, embedded = false, onActiveChange }: Pr
   const [moreMenuOpen, setMoreMenuOpen] = React.useState(false);
   const [moveMenuOpen, setMoveMenuOpen] = React.useState(false);
   const [tagMenuOpen, setTagMenuOpen] = React.useState(false);
+  // Tag changes made in the sheet get one Undo, shown once it closes.
+  const tagUndoGroup = useTagUndoGroup(tagMenuOpen);
   const [rulesOpen, setRulesOpen] = React.useState(false);
   const [addressSheet, setAddressSheet] = React.useState<EmailAddress | null>(null);
   // Per-message override of the light/dark rendering (More sheet toggle).
@@ -378,8 +381,8 @@ function EmailViewer({ route, navigation, embedded = false, onActiveChange }: Pr
   // list row follows when the list holds that account (never a same-id row
   // of another one).
   const setKeyword = React.useCallback(
-    (target: Email, token: string, on: boolean) =>
-      setKeywordForEmails([target.id], token, on, { email: target, accountId: ownerAccountId }),
+    (target: Email, token: string, on: boolean, undoGroup?: string) =>
+      setKeywordForEmails([target.id], token, on, { email: target, accountId: ownerAccountId }, { undoGroup }),
     [setKeywordForEmails, ownerAccountId],
   );
 
@@ -473,7 +476,7 @@ function EmailViewer({ route, navigation, embedded = false, onActiveChange }: Pr
     if (next[token]) delete next[token];
     else next[token] = true;
     updateLocalKeywords(email.id, next);
-    setKeyword(email, token, !!next[token]).catch((err) => {
+    setKeyword(email, token, !!next[token], tagUndoGroup || undefined).catch((err) => {
       updateLocalKeywords(email.id, email.keywords);
       toastFailure(t('notifications.tag_failed', 'Tagging failed'), err);
     });

src/stores/__tests__/email-store-keyword-undo.test.ts

@@ -1,4 +1,6 @@
 import { describe, it, expect, vi, beforeEach } from 'vitest';
+import fs from 'node:fs';
+import path from 'node:path';
 
 // Actions the viewer runs on the message it shows, which may live in another
 // account than the open folder (unified inbox, notification, deep link).
@@ -129,6 +131,63 @@ beforeEach(() => {
   useEmailStore.getState().reset();
 });
 
+describe('tag undo from a tag sheet', () => {
+  it('gathers the changes made in one sheet into one Undo that puts every tag back', async () => {
+    const tagged = { ...ROW, keywords: { $seen: true, '$label:blue': true } } as Email;
+    useEmailStore.setState({ mailboxes: MAILBOXES, currentMailboxId: 'a', emails: [tagged] });
+    const opts = { undoGroup: 'tags:1' };
+
+    await useEmailStore.getState().setKeywordForEmails(['e1'], '$label:orange', true, undefined, opts);
+    await useEmailStore.getState().setKeywordForEmails(['e1'], '$label:blue', false, undefined, opts);
+    // The bar sat under the sheet; closing it shows the bar from now.
+    useEmailStore.setState({ pendingUndo: { ...useEmailStore.getState().pendingUndo!, createdAt: 1 } });
+    useEmailStore.getState().releaseUndoGroup('tags:1');
+    const entry = useEmailStore.getState().pendingUndo!;
+    expect(entry.undoGroup).toBeUndefined();
+    expect(entry.createdAt).toBeGreaterThan(1);
+
+    await useEmailStore.getState().undoLast();
+    expect(mockPatchPerEmail).toHaveBeenCalledWith(
+      [{ id: 'e1', patch: { '$label:orange': null, '$label:blue': true } }],
+      undefined,
+    );
+    expect(useEmailStore.getState().emails[0].keywords).toEqual({ $seen: true, '$label:blue': true });
+  });
+
+  it('offers Undo for a tag set in the viewer\'s tag sheet, and none for its star', async () => {
+    useEmailStore.setState({ mailboxes: MAILBOXES, currentMailboxId: 'a', emails: [] });
+    const viewed = { email: ROW, accountId: undefined };
+
+    await useEmailStore.getState().setKeywordForEmails(['e1'], '$flagged', true, viewed);
+    expect(useEmailStore.getState().pendingUndo).toBeNull();
+
+    await useEmailStore.getState().setKeywordForEmails(['e1'], '$label:orange', true, viewed, { undoGroup: 'tags:2' });
+    expect(useEmailStore.getState().pendingUndo).toMatchObject({ kind: 'keywords', label: 'Email tagged' });
+
+    await useEmailStore.getState().undoLast();
+    expect(mockPatchPerEmail).toHaveBeenCalledWith([{ id: 'e1', patch: { '$label:orange': null } }], undefined);
+  });
+
+  it('starts a new Undo for the next sheet', async () => {
+    useEmailStore.setState({ mailboxes: MAILBOXES, currentMailboxId: 'a', emails: [ROW] });
+    await useEmailStore.getState().setKeywordForEmails(['e1'], '$label:orange', true, undefined, { undoGroup: 'tags:3' });
+    useEmailStore.getState().releaseUndoGroup('tags:3');
+    await useEmailStore.getState().setKeywordForEmails(['e1'], '$label:green', true, undefined, { undoGroup: 'tags:4' });
+
+    expect(useEmailStore.getState().pendingUndo?.keywordPatch).toEqual({ '$label:green': true });
+  });
+
+  it('wires both tag sheets to one Undo per sheet', () => {
+    const read = (rel: string) => fs.readFileSync(path.resolve(__dirname, '..', '..', rel), 'utf8');
+    const list = read('screens/EmailListScreen.tsx');
+    expect(list).toMatch(/const tagUndoGroup = useTagUndoGroup\(tagSheetOpen\);/);
+    expect(list).toMatch(/setKeywordForEmails\(selectedMessageIds, token, on, undefined, \{ undoGroup: tagUndoGroup \}\)/);
+    const viewer = read('screens/EmailThreadScreen.tsx');
+    expect(viewer).toMatch(/const tagUndoGroup = useTagUndoGroup\(tagMenuOpen\);/);
+    expect(viewer).toMatch(/setKeyword\(email, token, !!next\[token\], tagUndoGroup \|\| undefined\)/);
+  });
+});
+
 describe('keyword undo', () => {
   it('undoes a star made after a tag', async () => {
     useEmailStore.setState({ mailboxes: MAILBOXES, currentMailboxId: 'a', emails: [ROW] });

src/stores/email-store.ts

@@ -55,6 +55,7 @@ import { useSettingsStore } from './settings-store';
 import { useOfflineCacheStore } from './offline-cache-store';
 import { useOutboxStore, applyOrQueue, applyOrQueueBatch, type OutboxOp } from './outbox-store';
 import { useTagCountsStore } from './tag-counts-store';
+import { patchDetail, peekDetail } from '../lib/email-detail-cache';
 
 // ── Refresh coalescing ─────────────────────────────────────────────────
 // Push events, mount effects and post-action follow-ups all call
@@ -358,6 +359,11 @@ export interface UndoEntry {
   label: string;
   /** Time the entry was created - the snackbar uses this to drive its timer. */
   createdAt: number;
+  /**
+   * The open tag sheet the changes came from: each further change made in it
+   * joins this entry, and closing it shows the bar afresh (releaseUndoGroup).
+   */
+  undoGroup?: string;
   /** JMAP account the messages live under; unset for the user's own mail. */
   accountId?: string;
   /**
@@ -380,9 +386,46 @@ export interface UndoEntry {
      * (a list that spans accounts); `accountId` above applies otherwise.
      */
     accountId?: string;
+    /** The viewer's message, not a row of the list: undo leaves the list alone. */
+    unlisted?: boolean;
   }>;
 }
 
+/** Options of setKeywordForEmails. */
+export interface KeywordChangeOptions {
+  /**
+   * The tag sheet the change is made in. Gives a viewer change an Undo too,
+   * and gathers every change made before the sheet closes into one Undo.
+   */
+  undoGroup?: string;
+}
+
+/**
+ * Adds a change made in the same tag sheet to its Undo: each message keeps
+ * the value a keyword had before the sheet first changed it.
+ */
+function joinKeywordUndo(
+  entry: UndoEntry,
+  items: UndoEntry['items'],
+  patch: KeywordPatch,
+): Pick<UndoEntry, 'keywordPatch' | 'items'> {
+  const before = entry.keywordPatch ?? {};
+  const itemKey = (it: UndoEntry['items'][number]) => `${it.accountId ?? ''}|${rowKeyOf(it.email)}`;
+  const earlier = new Map(entry.items.map((it) => [itemKey(it), it]));
+  const joined = items.map((it) => {
+    const prev = earlier.get(itemKey(it));
+    if (!prev) return it;
+    earlier.delete(itemKey(it));
+    const originalKeywords = { ...it.originalKeywords };
+    for (const keyword of Object.keys(before)) {
+      if (prev.originalKeywords?.[keyword]) originalKeywords[keyword] = true;
+      else delete originalKeywords[keyword];
+    }
+    return { ...it, originalKeywords };
+  });
+  return { keywordPatch: { ...before, ...patch }, items: [...earlier.values(), ...joined] };
+}
+
 // Cached emails for one mailbox (the base view: no search query, no filters).
 // `queryState` is the JMAP queryState for the matching Email/query, used to
 // drive Email/queryChanges on the next refresh.
@@ -502,7 +545,14 @@ export interface EmailState {
    * `Email/set`. With `viewed`, on the viewer's message in its own account;
    * the list row follows only when the list holds that account.
    */
-  setKeywordForEmails: (emailIds: string[], token: string, on: boolean, viewed?: ViewedEmail) => Promise<void>;
+  setKeywordForEmails: (
+    emailIds: string[], token: string, on: boolean, viewed?: ViewedEmail, options?: KeywordChangeOptions,
+  ) => Promise<void>;
+  /**
+   * A tag sheet closed: its changes' Undo shows for the bar's full time from
+   * now, as it sat under the sheet so far.
+   */
+  releaseUndoGroup: (undoGroup: string) => void;
   undoLast: () => Promise<void>;
   clearUndo: () => void;
   searchEmails: (query: string) => Promise<Email[]>;
@@ -2156,14 +2206,18 @@ export const useEmailStore = create<EmailState>()(
     if (refusal) throw refusal;
   },
 
-  setKeywordForEmails: async (emailIds, token, on, viewed) => {
+  setKeywordForEmails: async (emailIds, token, on, viewed, options) => {
     const state = get();
     const { targets, listed } = actionTargets(state, emailIds, viewed);
     if (targets.length === 0) return;
+    const undoGroup = options?.undoGroup;
+    // The list's changes get an Undo; the viewer's only from its tag sheet.
+    const offersUndo = (!viewed || !!undoGroup) && keywordUndoLabel(token, on, targets.length) !== null;
     // While this change is on its way the bar must not still offer the
     // previous one's Undo: tapping it right after a star undid the tag set
     // before, and the star stayed.
-    if (!viewed && keywordUndoLabel(token, on, targets.length) && get().pendingUndo) set({ pendingUndo: null });
+    const before = get().pendingUndo;
+    if (offersUndo && before && !(undoGroup && before.undoGroup === undoGroup)) set({ pendingUndo: null });
     // One Email/set per account the selection spans (#1082); the viewer's
     // message goes to the account it names.
     const groups = viewed ? [{ accountId: viewed.accountId, emails: targets }] : groupByAccount(state, targets);
@@ -2214,29 +2268,44 @@ export const useEmailStore = create<EmailState>()(
     for (const { accountId, emails } of written) {
       for (const e of emails) patchCache(e.id, { keywords: patch }, accountId);
     }
-    // Undo for a read, star or tag change from the list: each message gets
-    // back the keyword it had (the reader's own toggles get no bar).
+    // Undo for a read, star or tag change from the list, or a tag change in
+    // the viewer's tag sheet (webmail lib/email-action-toast.ts
+    // setSelectionTagWithUndo): each message gets back the keyword it had.
+    // The reader's own star and read toggles get no bar.
     const changed = written.flatMap(({ accountId, emails }) => emails.map((email) => ({ email, accountId })));
-    const label = !viewed && changed.length > 0 ? keywordUndoLabel(token, on, changed.length) : null;
+    const label = offersUndo && changed.length > 0 ? keywordUndoLabel(token, on, changed.length) : null;
     if (label) {
+      const items: UndoEntry['items'] = changed.map(({ email, accountId }) => ({
+        email,
+        originalMailboxIds: { ...email.mailboxIds },
+        originalKeywords: { ...email.keywords },
+        accountId,
+        ...(listed ? {} : { unlisted: true }),
+      }));
+      const current = get().pendingUndo;
+      const joined = undoGroup && current?.kind === 'keywords' && current.undoGroup === undoGroup
+        ? joinKeywordUndo(current, items, patch)
+        : { keywordPatch: patch, items };
       set({
         pendingUndo: {
           kind: 'keywords',
           label,
           createdAt: Date.now(),
-          keywordPatch: patch,
-          items: changed.map(({ email, accountId }) => ({
-            email,
-            originalMailboxIds: { ...email.mailboxIds },
-            originalKeywords: { ...email.keywords },
-            accountId,
-          })),
+          ...(undoGroup ? { undoGroup } : {}),
+          ...joined,
         },
       });
     }
     if (refusal) throw refusal;
   },
 
+  releaseUndoGroup: (undoGroup) => {
+    const entry = get().pendingUndo;
+    if (!entry || entry.undoGroup !== undoGroup) return;
+    const { undoGroup: _done, ...rest } = entry;
+    set({ pendingUndo: { ...rest, createdAt: Date.now() } });
+  },
+
   undoLast: async () => {
     const entry = get().pendingUndo;
     if (!entry) return;
@@ -2250,6 +2319,7 @@ export const useEmailStore = create<EmailState>()(
         id: it.email.id,
         key: rowKeyOf(it.email),
         accountId: it.accountId ?? entry.accountId,
+        listed: !it.unlisted,
         patch: revertKeywordPatch(keywordPatch, it.originalKeywords),
       }));
       const accounts = new Set(undo.map((u) => u.accountId ?? ''));
@@ -2269,14 +2339,19 @@ export const useEmailStore = create<EmailState>()(
         set({ error: err instanceof Error ? err.message : t('email_list.undo_failed', 'Undo failed') });
         return;
       }
-      const byKey = new Map(undo.map((u) => [u.key, u.patch]));
+      const byKey = new Map(undo.filter((u) => u.listed).map((u) => [u.key, u.patch]));
       set({
         emails: get().emails.map((e) => {
           const patch = byKey.get(rowKeyOf(e));
           return patch ? { ...e, keywords: applyKeywordPatch(e.keywords, patch) } : e;
         }),
       });
-      for (const u of undo) patchCache(u.id, { keywords: u.patch }, u.accountId);
+      for (const u of undo) {
+        patchCache(u.id, { keywords: u.patch }, u.accountId);
+        // The open viewer reads the message from the detail cache.
+        const held = peekDetail(u.id, u.accountId);
+        if (held) patchDetail(u.id, u.accountId, { keywords: applyKeywordPatch(held.keywords, u.patch) });
+      }
       return;
     }