feat: tell plugins when the selection or the open folder changes

stores/__tests__/email-store-plugin-selection-hooks.test.ts

@@ -0,0 +1,70 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { useEmailStore } from '../email-store';
+import { clearAllHooks, emailHooks } from '@/lib/plugin-hooks';
+import type { Email, Mailbox } from '@/lib/jmap/types';
+
+// onEmailSelectionChange and onMailboxChange follow the store state, so every
+// path that changes the selection or the open folder fires them once.
+
+function makeEmail(id: string, overrides: Partial<Email> = {}): Email {
+  return { id, threadId: `t-${id}`, keywords: {}, mailboxIds: { inbox: true }, ...overrides } as Email;
+}
+
+const mailboxes = [
+  { id: 'inbox', name: 'Inbox', role: 'inbox' },
+  { id: 'projects', name: 'Projects' },
+] as Mailbox[];
+
+beforeEach(() => {
+  clearAllHooks();
+  useEmailStore.setState({
+    mailboxes,
+    accountMailboxes: {},
+    viewingAccountId: null,
+    selectedMailbox: 'inbox',
+    emails: [makeEmail('a'), makeEmail('b'), makeEmail('c', { sourceClientAccountId: 'x', sourceAccountId: 'y' })],
+    selectedEmailKeys: new Set(),
+    lastSelectedEmailKey: null,
+    listRows: null,
+  });
+});
+
+afterEach(() => clearAllHooks());
+
+describe('onEmailSelectionChange', () => {
+  it('reports the selected ids each time the selection changes', () => {
+    const changed = vi.fn();
+    emailHooks.onEmailSelectionChange.register('t', changed);
+    const store = useEmailStore.getState();
+
+    store.toggleEmailSelection(makeEmail('a'));
+    store.selectRangeEmails(makeEmail('b'));
+    store.selectAllEmails();
+    store.clearSelection();
+    // Clearing an empty selection is no change.
+    store.clearSelection();
+
+    expect(changed.mock.calls).toEqual([
+      [{ emailIds: ['a'] }],
+      [{ emailIds: ['a', 'b'] }],
+      [{ emailIds: ['a', 'b', 'c'] }],
+      [{ emailIds: [] }],
+    ]);
+  });
+});
+
+describe('onMailboxChange', () => {
+  it('reports the folder opened, its role and the one left', () => {
+    const changed = vi.fn();
+    emailHooks.onMailboxChange.register('t', changed);
+
+    useEmailStore.getState().selectMailbox('projects');
+    useEmailStore.getState().selectMailbox('projects');
+    useEmailStore.getState().selectMailbox('inbox');
+
+    expect(changed.mock.calls).toEqual([
+      [{ mailboxId: 'projects', role: null, previousMailboxId: 'inbox' }],
+      [{ mailboxId: 'inbox', role: 'inbox', previousMailboxId: 'projects' }],
+    ]);
+  });
+});

stores/email-store.ts

@@ -7,7 +7,7 @@ import { useCalendarStore } from "@/stores/calendar-store";
 import { orderKeywords, placeHeldRows, type HeldKeywords, type SortLevel } from "@/lib/message-list-order";
 import { SearchFilters, DEFAULT_SEARCH_FILTERS, buildJMAPFilter, isFilterEmpty } from "@/lib/jmap/search-utils";
 import { emailHooks } from "@/lib/plugin-hooks";
-import { allowEmailMove, emitEmailMove, keywordChangeLists, mailboxToView, quotaToView } from "@/lib/plugin-mail-hooks";
+import { allowEmailMove, emitEmailMove, idsFromSelectionKeys, keywordChangeLists, mailboxToView, quotaToView } from "@/lib/plugin-mail-hooks";
 import { emailSummary } from "@/lib/plugin-projection";
 import { resolveThreadRoute } from "@/lib/thread-routing";
 import { emailKeyFor, threadKeyFor, threadIdFromKey, KEYWORD_PREFIX, KEYWORD_PREFIX_LEGACY } from "@/lib/thread-utils";
@@ -6385,6 +6385,19 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
 // every path that changes it (clicks, keyboard, a batch action clearing the
 // selection, an account switch) fires them once.
 useEmailStore.subscribe((state, prev) => {
+  if (state.selectedEmailKeys !== prev.selectedEmailKeys && emailHooks.onEmailSelectionChange.size > 0) {
+    const changed = state.selectedEmailKeys.size !== prev.selectedEmailKeys.size
+      || [...state.selectedEmailKeys].some(key => !prev.selectedEmailKeys.has(key));
+    if (changed) void emailHooks.onEmailSelectionChange.emit({ emailIds: idsFromSelectionKeys(state.selectedEmailKeys) });
+  }
+  if (state.selectedMailbox !== prev.selectedMailbox && state.selectedMailbox && emailHooks.onMailboxChange.size > 0) {
+    const mailbox = mailboxesInView(state).find(mb => mb.id === state.selectedMailbox);
+    void emailHooks.onMailboxChange.emit({
+      mailboxId: state.selectedMailbox,
+      role: mailbox?.role ?? (state.isUnifiedView ? state.unifiedRole : null) ?? null,
+      previousMailboxId: prev.selectedMailbox || null,
+    });
+  }
   if (state.quota && state.quota !== prev.quota
     && (state.quota.used !== prev.quota?.used || state.quota.total !== prev.quota?.total)) {
     void emailHooks.onQuotaChange.emit(quotaToView(state.quota));