feat: implement undo functionality for email actions with snackbar notification

src/api/email.ts

@@ -111,6 +111,27 @@ export async function moveEmail(
   ]);
 }
 
+// Restore each email's mailboxIds to the snapshot supplied. Used by undo to
+// reverse a move/archive/spam in one round-trip. JMAP "mailboxIds" replaces
+// the entire map, so we don't need to compute a diff against the current state.
+export async function restoreEmailMailboxes(
+  items: Array<{ id: string; mailboxIds: Record<string, boolean> }>,
+): Promise<void> {
+  if (items.length === 0) return;
+  const accountId = jmapClient.accountId;
+  const update: Record<string, { mailboxIds: Record<string, true> }> = {};
+  for (const item of items) {
+    const onlyTrue: Record<string, true> = {};
+    for (const [id, present] of Object.entries(item.mailboxIds)) {
+      if (present) onlyTrue[id] = true;
+    }
+    update[item.id] = { mailboxIds: onlyTrue };
+  }
+  await jmapClient.request([
+    ['Email/set', { accountId, update }, '0'],
+  ]);
+}
+
 // Archive one or more emails into the archive mailbox, optionally auto-sorting
 // into year or year/month subfolders. Mirrors the webmail implementation in
 // lib/jmap/client.ts so behavior stays in sync between platforms.

src/components/UndoSnackbar.tsx

@@ -0,0 +1,120 @@
+import React from 'react';
+import { View, Text, StyleSheet, Pressable, Animated, Easing } from 'react-native';
+import { useSafeAreaInsets } from 'react-native-safe-area-context';
+import { spacing, radius, typography, type ThemePalette } from '../theme/tokens';
+import { useColors } from '../theme/colors';
+import { useEmailStore } from '../stores/email-store';
+
+const VISIBLE_MS = 5000;
+
+export function UndoSnackbar() {
+  const c = useColors();
+  const styles = React.useMemo(() => makeStyles(c), [c]);
+  const insets = useSafeAreaInsets();
+  const entry = useEmailStore((s) => s.pendingUndo);
+  const undoLast = useEmailStore((s) => s.undoLast);
+  const clearUndo = useEmailStore((s) => s.clearUndo);
+  const slideY = React.useRef(new Animated.Value(120)).current;
+  const opacity = React.useRef(new Animated.Value(0)).current;
+  // Remember the last non-null entry so the bar's text/handlers stay valid
+  // while it animates out after pendingUndo flips to null.
+  const [shown, setShown] = React.useState(entry);
+
+  React.useEffect(() => {
+    if (entry) setShown(entry);
+  }, [entry]);
+
+  // Drive the auto-dismiss off the entry's createdAt so re-renders during
+  // animation don't reset the timer, and so consecutive actions reset it.
+  React.useEffect(() => {
+    if (!entry) {
+      Animated.parallel([
+        Animated.timing(slideY, { toValue: 120, duration: 180, easing: Easing.in(Easing.cubic), useNativeDriver: true }),
+        Animated.timing(opacity, { toValue: 0, duration: 180, useNativeDriver: true }),
+      ]).start(({ finished }) => {
+        if (finished) setShown(null);
+      });
+      return;
+    }
+
+    Animated.parallel([
+      Animated.timing(slideY, { toValue: 0, duration: 220, easing: Easing.out(Easing.cubic), useNativeDriver: true }),
+      Animated.timing(opacity, { toValue: 1, duration: 220, useNativeDriver: true }),
+    ]).start();
+
+    const elapsed = Date.now() - entry.createdAt;
+    const remaining = Math.max(0, VISIBLE_MS - elapsed);
+    const id = setTimeout(() => {
+      // Only clear if the entry is still the same one we scheduled for.
+      if (useEmailStore.getState().pendingUndo === entry) {
+        clearUndo();
+      }
+    }, remaining);
+    return () => clearTimeout(id);
+  }, [entry, slideY, opacity, clearUndo]);
+
+  if (!shown) return null;
+
+  return (
+    <Animated.View
+      pointerEvents="box-none"
+      style={[
+        styles.wrap,
+        { bottom: insets.bottom + spacing.md, opacity, transform: [{ translateY: slideY }] },
+      ]}
+    >
+      <View style={styles.bar}>
+        <Text style={styles.label} numberOfLines={1}>{shown.label}</Text>
+        <Pressable
+          onPress={() => { void undoLast(); }}
+          hitSlop={8}
+          style={({ pressed }) => [styles.undoBtn, pressed && styles.undoBtnPressed]}
+        >
+          <Text style={styles.undoText}>UNDO</Text>
+        </Pressable>
+      </View>
+    </Animated.View>
+  );
+}
+
+function makeStyles(c: ThemePalette) {
+  return StyleSheet.create({
+    wrap: {
+      position: 'absolute',
+      left: spacing.md,
+      right: spacing.md,
+    },
+    bar: {
+      flexDirection: 'row',
+      alignItems: 'center',
+      paddingVertical: spacing.sm + 2,
+      paddingLeft: spacing.lg,
+      paddingRight: spacing.sm,
+      borderRadius: radius.md,
+      backgroundColor: c.text,
+      shadowColor: '#000',
+      shadowOpacity: 0.3,
+      shadowRadius: 12,
+      shadowOffset: { width: 0, height: 6 },
+      elevation: 8,
+    },
+    label: {
+      ...typography.body,
+      color: c.background,
+      flex: 1,
+    },
+    undoBtn: {
+      paddingHorizontal: spacing.md,
+      paddingVertical: spacing.sm,
+      borderRadius: radius.sm,
+    },
+    undoBtnPressed: {
+      backgroundColor: 'rgba(255,255,255,0.1)',
+    },
+    undoText: {
+      ...typography.bodySemibold,
+      color: c.primary,
+      letterSpacing: 0.5,
+    },
+  });
+}

src/screens/EmailListScreen.tsx

@@ -12,6 +12,7 @@ import SidebarDrawer from '../components/SidebarDrawer';
 import SenderAvatar from '../components/SenderAvatar';
 import { SwipeableRow } from '../components/SwipeableRow';
 import { MoveSheet } from '../components/MoveSheet';
+import { UndoSnackbar } from '../components/UndoSnackbar';
 import { OfflineBanner } from '../components/OfflineBanner';
 import { useNetworkStore } from '../stores/network-store';
 import { useEmailStore, type EmailFilters } from '../stores/email-store';
@@ -840,6 +841,8 @@ export default function EmailListScreen({ onEmailPress, onComposePress }: EmailL
           }
         }}
       />
+
+      <UndoSnackbar />
     </SafeAreaView>
   );
 }

src/stores/email-store.ts

@@ -11,6 +11,7 @@ import {
   moveEmail,
   archiveEmails as apiArchiveEmails,
   deleteEmail as apiDeleteEmail,
+  restoreEmailMailboxes,
   searchEmails as apiSearchEmails,
 } from '../api/email';
 import { toWildcardQuery } from '../lib/search-utils';
@@ -27,6 +28,19 @@ export interface EmailFilters {
   isUnread?: boolean;
 }
 
+// Snapshot of an action that can still be reversed via the undo snackbar.
+// We store the full email object so undo can re-insert it into the visible list
+// optimistically without waiting for a refetch.
+export interface UndoEntry {
+  kind: 'archive' | 'delete' | 'move' | 'spam';
+  /** Human-readable label shown in the snackbar (e.g. "Email archived"). */
+  label: string;
+  /** Time the entry was created - the snackbar uses this to drive its timer. */
+  createdAt: number;
+  /** Each item is one email's pre-action mailboxIds, used to restore it. */
+  items: Array<{ email: Email; originalMailboxIds: Record<string, boolean> }>;
+}
+
 export interface EmailState {
   mailboxes: Mailbox[];
   currentMailboxId: string | null;
@@ -36,6 +50,7 @@ export interface EmailState {
   error: string | null;
   searchQuery: string;
   filters: EmailFilters;
+  pendingUndo: UndoEntry | null;
 
   fetchMailboxes: () => Promise<void>;
   selectMailbox: (mailboxId: string) => Promise<void>;
@@ -49,6 +64,8 @@ export interface EmailState {
   moveToMailbox: (emailId: string, fromMailboxId: string, toMailboxId: string) => Promise<void>;
   archiveEmail: (emailId: string) => Promise<void>;
   deleteEmail: (emailId: string, trashMailboxId: string, currentMailboxId: string) => Promise<void>;
+  undoLast: () => Promise<void>;
+  clearUndo: () => void;
   searchEmails: (query: string) => Promise<Email[]>;
   setSearchQuery: (query: string) => void;
   setFilters: (filters: EmailFilters) => void;
@@ -106,6 +123,7 @@ export const useEmailStore = create<EmailState>()(
   error: null,
   searchQuery: '',
   filters: {},
+  pendingUndo: null,
 
   fetchMailboxes: async () => {
     try {
@@ -119,6 +137,8 @@ export const useEmailStore = create<EmailState>()(
 
   selectMailbox: async (mailboxId) => {
     // Reset search/filters when switching mailbox - matches webmail behavior.
+    // Switching mailboxes invalidates any pending undo: the snackbar would be
+    // stale and the restored email would re-appear in a different view.
     set({
       currentMailboxId: mailboxId,
       loading: true,
@@ -127,6 +147,7 @@ export const useEmailStore = create<EmailState>()(
       totalEmails: 0,
       searchQuery: '',
       filters: {},
+      pendingUndo: null,
     });
     try {
       const filter = buildJmapFilter(mailboxId, '', {});
@@ -254,8 +275,23 @@ export const useEmailStore = create<EmailState>()(
   },
 
   moveToMailbox: async (emailId, fromMailboxId, toMailboxId) => {
+    const email = get().emails.find((e) => e.id === emailId);
+    const original = email ? { ...email.mailboxIds } : null;
+
     await moveEmail(emailId, fromMailboxId, toMailboxId);
     set({ emails: get().emails.filter((e) => e.id !== emailId) });
+
+    if (email && original) {
+      const targetName = get().mailboxes.find((m) => m.id === toMailboxId)?.name;
+      set({
+        pendingUndo: {
+          kind: 'move',
+          label: targetName ? `Email moved to ${targetName}` : 'Email moved',
+          createdAt: Date.now(),
+          items: [{ email, originalMailboxIds: original }],
+        },
+      });
+    }
   },
 
   archiveEmail: async (emailId) => {
@@ -270,6 +306,7 @@ export const useEmailStore = create<EmailState>()(
     if (email.mailboxIds?.[archiveMailbox.id]) return;
 
     const mode = useSettingsStore.getState().archiveMode;
+    const original = { ...email.mailboxIds };
 
     await apiArchiveEmails(
       [{ id: email.id, receivedAt: email.receivedAt }],
@@ -278,7 +315,15 @@ export const useEmailStore = create<EmailState>()(
       mailboxes,
     );
 
-    set({ emails: get().emails.filter((e) => e.id !== emailId) });
+    set({
+      emails: get().emails.filter((e) => e.id !== emailId),
+      pendingUndo: {
+        kind: 'archive',
+        label: 'Email archived',
+        createdAt: Date.now(),
+        items: [{ email, originalMailboxIds: original }],
+      },
+    });
 
     // Auto-sort modes may have created new year/month folders - refresh the
     // mailbox list so the sidebar picks them up on the next render.
@@ -288,10 +333,60 @@ export const useEmailStore = create<EmailState>()(
   },
 
   deleteEmail: async (emailId, trashMailboxId, currentMailboxId) => {
+    const email = get().emails.find((e) => e.id === emailId);
+    const original = email ? { ...email.mailboxIds } : null;
+    const isPermanent = currentMailboxId === trashMailboxId;
+
     await apiDeleteEmail(emailId, trashMailboxId, currentMailboxId);
     set({ emails: get().emails.filter((e) => e.id !== emailId) });
+
+    // Permanent destroy can't be undone - skip the snackbar so we don't
+    // promise an undo we can't deliver.
+    if (email && original && !isPermanent) {
+      set({
+        pendingUndo: {
+          kind: 'delete',
+          label: 'Email moved to Trash',
+          createdAt: Date.now(),
+          items: [{ email, originalMailboxIds: original }],
+        },
+      });
+    }
   },
 
+  undoLast: async () => {
+    const entry = get().pendingUndo;
+    if (!entry) return;
+    set({ pendingUndo: null });
+
+    try {
+      await restoreEmailMailboxes(
+        entry.items.map((it) => ({ id: it.email.id, mailboxIds: it.originalMailboxIds })),
+      );
+    } catch (err) {
+      set({ error: err instanceof Error ? err.message : 'Undo failed' });
+      return;
+    }
+
+    // Re-insert each restored email into the visible list if its original
+    // mailboxIds include the current view. Server is the source of truth for
+    // ordering, but local re-insertion gives the user instant feedback.
+    const { currentMailboxId, emails } = get();
+    if (currentMailboxId) {
+      const restored = entry.items
+        .filter((it) => it.originalMailboxIds[currentMailboxId])
+        .map((it) => ({ ...it.email, mailboxIds: it.originalMailboxIds }));
+      if (restored.length > 0) {
+        const merged = [...restored, ...emails].sort(
+          (a, b) => new Date(b.receivedAt).getTime() - new Date(a.receivedAt).getTime(),
+        );
+        set({ emails: merged });
+      }
+    }
+  },
+
+  clearUndo: () => set({ pendingUndo: null }),
+
   searchEmails: async (query) => {
     const ids = await apiSearchEmails(query);
     if (ids.length === 0) return [];