Reintroduce NotificationController for in-app notifications

src/notification/NotificationController.test.ts

@@ -0,0 +1,113 @@
+import { ControllerMessenger } from '../ControllerMessenger';
+import {
+  ControllerActions,
+  NotificationController,
+  NotificationControllerStateChange,
+} from './NotificationController';
+
+const name = 'NotificationController';
+
+/**
+ * Constructs a unrestricted controller messenger.
+ *
+ * @returns A unrestricted controller messenger.
+ */
+function getUnrestrictedMessenger() {
+  return new ControllerMessenger<
+    ControllerActions,
+    NotificationControllerStateChange
+  >();
+}
+
+/**
+ * Constructs a restricted controller messenger.
+ *
+ * @param controllerMessenger - An optional unrestricted messenger
+ * @returns A restricted controller messenger.
+ */
+function getRestrictedMessenger(
+  controllerMessenger = getUnrestrictedMessenger(),
+) {
+  return controllerMessenger.getRestricted<typeof name, never, never>({
+    name,
+  });
+}
+
+const origin = 'snap_test';
+const message = 'foo';
+
+describe('NotificationController', () => {
+  it('action: NotificationController:show', async () => {
+    const unrestricted = getUnrestrictedMessenger();
+    const messenger = getRestrictedMessenger(unrestricted);
+
+    const controller = new NotificationController({
+      messenger,
+    });
+
+    expect(
+      await unrestricted.call('NotificationController:show', origin, message),
+    ).toBeUndefined();
+    const notifications = Object.values(controller.state.notifications);
+    expect(notifications).toHaveLength(1);
+    expect(notifications).toContainEqual({
+      createdDate: expect.any(Number),
+      id: expect.any(String),
+      message,
+      origin,
+      readDate: null,
+    });
+  });
+
+  it('action: NotificationController:markViewed', async () => {
+    const unrestricted = getUnrestrictedMessenger();
+    const messenger = getRestrictedMessenger(unrestricted);
+
+    const controller = new NotificationController({
+      messenger,
+    });
+
+    expect(
+      await unrestricted.call('NotificationController:show', origin, message),
+    ).toBeUndefined();
+    const notifications = Object.values(controller.state.notifications);
+    expect(notifications).toHaveLength(1);
+    expect(
+      await unrestricted.call('NotificationController:markRead', [
+        notifications[0].id,
+        'foo',
+      ]),
+    ).toBeUndefined();
+
+    const newNotifications = Object.values(controller.state.notifications);
+    expect(newNotifications).toContainEqual({
+      ...notifications[0],
+      readDate: expect.any(Number),
+    });
+
+    expect(newNotifications).toHaveLength(1);
+  });
+
+  it('action: NotificationController:dismiss', async () => {
+    const unrestricted = getUnrestrictedMessenger();
+    const messenger = getRestrictedMessenger(unrestricted);
+
+    const controller = new NotificationController({
+      messenger,
+    });
+
+    expect(
+      await unrestricted.call('NotificationController:show', origin, message),
+    ).toBeUndefined();
+    const notifications = Object.values(controller.state.notifications);
+    expect(notifications).toHaveLength(1);
+    expect(
+      await unrestricted.call('NotificationController:dismiss', [
+        notifications[0].id,
+        'foo',
+      ]),
+    ).toBeUndefined();
+
+    expect(Object.values(controller.state.notifications)).toHaveLength(0);
+  });
+});

src/notification/NotificationController.ts

@@ -0,0 +1,176 @@
+import type { Patch } from 'immer';
+import { nanoid } from 'nanoid';
+
+import { hasProperty } from '../util';
+import { BaseController } from '../BaseControllerV2';
+
+import type { RestrictedControllerMessenger } from '../ControllerMessenger';
+
+/**
+ * @typedef NotificationControllerState
+ * @property notifications - Stores existing notifications to be shown in the UI
+ */
+export type NotificationControllerState = {
+  notifications: Record<string, Notification>;
+};
+
+/**
+ * @typedef Notification - Stores information about in-app notifications, to be shown in the UI
+ * @property id - A UUID that identifies the notification
+ * @property origin - The origin that requested the notification
+ * @property createdDate - The notification creation date in milliseconds elapsed since the UNIX epoch
+ * @property readDate - The notification read date in milliseconds elapsed since the UNIX epoch or null if unread
+ * @property message - The notification message
+ */
+export type Notification = {
+  id: string;
+  origin: string;
+  createdDate: number;
+  readDate: number | null;
+  message: string;
+};
+
+const name = 'NotificationController';
+
+export type NotificationControllerStateChange = {
+  type: `${typeof name}:stateChange`;
+  payload: [NotificationControllerState, Patch[]];
+};
+
+export type GetNotificationControllerState = {
+  type: `${typeof name}:getState`;
+  handler: () => NotificationControllerState;
+};
+
+export type ShowNotification = {
+  type: `${typeof name}:show`;
+  handler: NotificationController['show'];
+};
+
+export type DismissNotification = {
+  type: `${typeof name}:dismiss`;
+  handler: NotificationController['dismiss'];
+};
+
+export type MarkNotificationRead = {
+  type: `${typeof name}:markRead`;
+  handler: NotificationController['markRead'];
+};
+
+export type ControllerActions =
+  | GetNotificationControllerState
+  | ShowNotification
+  | DismissNotification
+  | MarkNotificationRead;
+
+export type NotificationControllerMessenger = RestrictedControllerMessenger<
+  typeof name,
+  ControllerActions,
+  NotificationControllerStateChange,
+  never,
+  never
+>;
+
+const metadata = {
+  notifications: { persist: true, anonymous: false },
+};
+
+const defaultState = {
+  notifications: {},
+};
+
+/**
+ * Controller that handles storing notifications and showing them to the user
+ */
+export class NotificationController extends BaseController<
+  typeof name,
+  NotificationControllerState,
+  NotificationControllerMessenger
+> {
+  /**
+   * Creates a NotificationController instance.
+   *
+   * @param options - Constructor options.
+   * @param options.messenger - A reference to the messaging system.
+   * @param options.state - Initial state to set on this controller.
+   */
+  constructor({
+    messenger,
+    state,
+  }: {
+    messenger: NotificationControllerMessenger;
+    state?: Partial<NotificationControllerState>;
+  }) {
+    super({
+      name,
+      metadata,
+      messenger,
+      state: { ...defaultState, ...state },
+    });
+
+    this.messagingSystem.registerActionHandler(
+      `${name}:show` as const,
+      (origin: string, message: string) => this.show(origin, message),
+    );
+
+    this.messagingSystem.registerActionHandler(
+      `${name}:dismiss` as const,
+      (ids: string[]) => this.dismiss(ids),
+    );
+
+    this.messagingSystem.registerActionHandler(
+      `${name}:markRead` as const,
+      (ids: string[]) => this.markRead(ids),
+    );
+  }
+
+  /**
+   * Shows a notification.
+   *
+   * @param origin - The origin trying to send a notification
+   * @param message - A message to show on the notification
+   */
+  show(origin: string, message: string) {
+    const id = nanoid();
+    const notification = {
+      id,
+      origin,
+      createdDate: Date.now(),
+      readDate: null,
+      message,
+    };
+    this.update((state) => {
+      state.notifications[id] = notification;
+    });
+  }
+
+  /**
+   * Dimisses a list of notifications.
+   *
+   * @param ids - A list of notification IDs
+   */
+  dismiss(ids: string[]) {
+    this.update((state) => {
+      for (const id of ids) {
+        if (hasProperty(state.notifications, id)) {
+          delete state.notifications[id];
+        }
+      }
+    });
+  }
+
+  /**
+   * Marks a list of notifications as read.
+   *
+   * @param ids - A list of notification IDs
+   */
+  markRead(ids: string[]) {
+    this.update((state) => {
+      for (const id of ids) {
+        if (hasProperty(state.notifications, id)) {
+          state.notifications[id].readDate = Date.now();
+        }
+      }
+    });
+  }
+}