From 252c741180a8fd06e2d216f6ade342dd11cdf816 Mon Sep 17 00:00:00 2001
From: David Lechner <david@pybricks.com>
Date: Thu, 28 Jan 2021 20:14:36 -0600
Subject: [PATCH] add app install button

---
 src/actions/app.ts                   | 51 ++++++++++++++++++++++++++
 src/components/SettingsDrawer.tsx    | 29 ++++++++++++++-
 src/components/settings-i18n.en.json |  3 ++
 src/components/settings-i18n.ts      |  1 +
 src/reducers/app.ts                  | 30 +++++++++++++++
 src/sagas/app.test.ts                | 55 ++++++++++++++++++++++++++--
 src/sagas/app.ts                     | 52 +++++++++++++++++++++++++-
 src/utils/dom.ts                     | 13 +++++++
 8 files changed, 228 insertions(+), 6 deletions(-)
 create mode 100644 src/utils/dom.ts

diff --git a/src/actions/app.ts b/src/actions/app.ts
index 34e92b2a..cd09b533 100644
--- a/src/actions/app.ts
+++ b/src/actions/app.ts
@@ -4,6 +4,7 @@
 // Actions for the app in general.
 
 import { Action } from 'redux';
+import { BeforeInstallPromptEvent } from '../utils/dom';
 
 /** App action types. */
 export enum AppActionType {
@@ -13,6 +14,14 @@ export enum AppActionType {
     CheckForUpdate = 'app.action.checkForUpdate',
     /** Indicates that checking for update finished. */
     DidCheckForUpdate = 'app.action.didCheckForUpdate',
+    /* Indicates the browser wants to prompt the use to install the app. */
+    DidBeforeInstallPrompt = 'app.action.didBeforeInstallPrompt',
+    /* Requests to prompt the user to install the app. */
+    InstallPrompt = 'app.action.installPrompt',
+    /* Indicates that the user responded to the install prompt. */
+    DidInstallPrompt = 'app.action.didInstallPrompt',
+    /* Indicates that the app was installed. */
+    DidInstall = 'app.action.didInstallPrompt',
     /** The app has just ben started. */
     DidStart = 'app.action.didStart',
     /** Open settings dialog. */
@@ -61,6 +70,44 @@ export function didCheckForUpdate(updateFound: boolean): AppDidCheckForUpdateAct
     return { type: AppActionType.DidCheckForUpdate, updateFound };
 }
 
+/* Action that indicates the browser wants to prompt the use to install the app. */
+export type AppDidBeforeInstallPromptAction = Action<AppActionType.DidBeforeInstallPrompt> & {
+    event: BeforeInstallPromptEvent;
+};
+
+/* Action that indicates the browser wants to prompt the use to install the app. */
+export function didBeforeInstallPrompt(
+    event: BeforeInstallPromptEvent,
+): AppDidBeforeInstallPromptAction {
+    return { type: AppActionType.DidBeforeInstallPrompt, event };
+}
+
+/* Action that requests to prompt the user to install the app. */
+export type AppInstallPromptAction = Action<AppActionType.InstallPrompt> & {
+    event: BeforeInstallPromptEvent;
+};
+
+/* Action that requests to prompt the user to install the app. */
+export function installPrompt(event: BeforeInstallPromptEvent): AppInstallPromptAction {
+    return { type: AppActionType.InstallPrompt, event };
+}
+
+/* Action that indicates that the user responded to the install prompt. */
+export type AppDidInstallPromptAction = Action<AppActionType.DidInstallPrompt>;
+
+/* Action that indicates that the user responded to the install prompt. */
+export function didInstallPrompt(): AppDidInstallPromptAction {
+    return { type: AppActionType.DidInstallPrompt };
+}
+
+/* Action that indicates app was installed. */
+export type AppDidInstallAction = Action<AppActionType.DidInstall>;
+
+/* Action that indicates app was installed. */
+export function didInstall(): AppDidInstallAction {
+    return { type: AppActionType.DidInstall };
+}
+
 /** Action that indicates the app has just started. */
 export type AppDidStartAction = Action<AppActionType.DidStart>;
 
@@ -122,6 +169,10 @@ export type AppAction =
     | AppReloadAction
     | AppCheckForUpdatesAction
     | AppDidCheckForUpdateAction
+    | AppDidBeforeInstallPromptAction
+    | AppInstallPromptAction
+    | AppDidInstallPromptAction
+    | AppDidInstallAction
     | AppDidStartAction
     | AppOpenSettingsAction
     | AppCloseSettingsAction
diff --git a/src/components/SettingsDrawer.tsx b/src/components/SettingsDrawer.tsx
index 8020fdad..a9192332 100644
--- a/src/components/SettingsDrawer.tsx
+++ b/src/components/SettingsDrawer.tsx
@@ -19,7 +19,13 @@ import { WithI18nProps, withI18n } from '@shopify/react-i18n';
 import React from 'react';
 import { connect } from 'react-redux';
 import { Action, Dispatch } from '../actions';
-import { checkForUpdate, closeSettings, openAboutDialog, reload } from '../actions/app';
+import {
+    checkForUpdate,
+    closeSettings,
+    installPrompt,
+    openAboutDialog,
+    reload,
+} from '../actions/app';
 import { setBoolean, toggleBoolean } from '../actions/settings';
 import { RootState } from '../reducers';
 import { pseudolocalize } from '../settings/i18n';
@@ -31,6 +37,7 @@ import {
     tooltipDelay,
 } from '../settings/ui';
 import { SettingId } from '../settings/user';
+import { BeforeInstallPromptEvent } from '../utils/dom';
 import { isMacOS } from '../utils/os';
 import AboutDialog from './AboutDialog';
 import ExternalLinkIcon from './ExternalLinkIcon';
@@ -45,6 +52,8 @@ type StateProps = {
     serviceWorker: ServiceWorkerRegistration | null;
     checkingForUpdate: boolean;
     updateAvailable: boolean;
+    beforeInstallPrompt: BeforeInstallPromptEvent | null;
+    promptingInstall: boolean;
 };
 
 type DispatchProps = {
@@ -56,6 +65,7 @@ type DispatchProps = {
     onToggleDocs: () => void;
     onCheckForUpdate: (registration: ServiceWorkerRegistration) => void;
     onReload: (registration: ServiceWorkerRegistration) => void;
+    onInstallPrompt: (event: BeforeInstallPromptEvent) => void;
 };
 
 type SettingsProps = StateProps & DispatchProps & WithI18nProps;
@@ -71,6 +81,8 @@ class SettingsDrawer extends React.PureComponent<SettingsProps> {
             flashCurrentProgram,
             checkingForUpdate,
             updateAvailable,
+            beforeInstallPrompt,
+            promptingInstall,
             onClose,
             onShowDocsChanged,
             onDarkModeChanged,
@@ -78,6 +90,7 @@ class SettingsDrawer extends React.PureComponent<SettingsProps> {
             onAbout,
             onCheckForUpdate,
             onReload,
+            onInstallPrompt: onInstall,
             i18n,
         } = this.props;
         return (
@@ -219,6 +232,17 @@ class SettingsDrawer extends React.PureComponent<SettingsProps> {
                                 vertical={true}
                                 alignText="left"
                             >
+                                {beforeInstallPrompt && (
+                                    <Button
+                                        icon="add"
+                                        onClick={() => onInstall(beforeInstallPrompt)}
+                                        loading={promptingInstall}
+                                    >
+                                        {i18n.translate(
+                                            SettingsStringId.AppInstallLabel,
+                                        )}
+                                    </Button>
+                                )}
                                 {serviceWorker && !updateAvailable && (
                                     <Button
                                         icon="refresh"
@@ -293,6 +317,8 @@ const mapStateToProps = (state: RootState): StateProps => ({
     serviceWorker: state.app.serviceWorker,
     checkingForUpdate: state.app.checkingForUpdate,
     updateAvailable: state.app.updateAvailable,
+    beforeInstallPrompt: state.app.beforeInstallPrompt,
+    promptingInstall: state.app.promptingInstall,
 });
 
 const mapDispatchToProps = (dispatch: Dispatch): DispatchProps => ({
@@ -307,6 +333,7 @@ const mapDispatchToProps = (dispatch: Dispatch): DispatchProps => ({
     onToggleDocs: (): Action => dispatch(toggleBoolean(SettingId.ShowDocs)),
     onCheckForUpdate: (registration) => dispatch(checkForUpdate(registration)),
     onReload: (registration) => dispatch(reload(registration)),
+    onInstallPrompt: (event) => dispatch(installPrompt(event)),
 });
 
 export default connect(
diff --git a/src/components/settings-i18n.en.json b/src/components/settings-i18n.en.json
index 6d5488cb..fc418949 100644
--- a/src/components/settings-i18n.en.json
+++ b/src/components/settings-i18n.en.json
@@ -39,6 +39,9 @@
         },
         "app": {
             "title": "App",
+            "install": {
+                "label": "Install as App"
+            },
             "checkForUpdate": {
                 "label": "Check for Update"
             },
diff --git a/src/components/settings-i18n.ts b/src/components/settings-i18n.ts
index 9f49fbb6..9c89b66e 100644
--- a/src/components/settings-i18n.ts
+++ b/src/components/settings-i18n.ts
@@ -20,6 +20,7 @@ export enum SettingsStringId {
     HelpChatLabel = 'settings.help.chat.label',
     HelpBugsLabel = 'settings.help.bugs.label',
     AppTitle = 'settings.app.title',
+    AppInstallLabel = 'settings.app.install.label',
     AppCheckForUpdateLabel = 'settings.app.checkForUpdate.label',
     AppRestartLabel = 'settings.app.restart.label',
     AppAboutLabel = 'settings.app.about.label',
diff --git a/src/reducers/app.ts b/src/reducers/app.ts
index 44436048..1ff47bd7 100644
--- a/src/reducers/app.ts
+++ b/src/reducers/app.ts
@@ -7,6 +7,7 @@ import { Reducer, combineReducers } from 'redux';
 import { Action } from '../actions';
 import { AppActionType } from '../actions/app';
 import { ServiceWorkerActionType } from '../actions/service-worker';
+import { BeforeInstallPromptEvent } from '../utils/dom';
 
 export interface AppState {
     readonly showSettings: boolean;
@@ -15,6 +16,8 @@ export interface AppState {
     readonly serviceWorker: ServiceWorkerRegistration | null;
     readonly checkingForUpdate: boolean;
     readonly updateAvailable: boolean;
+    readonly beforeInstallPrompt: BeforeInstallPromptEvent;
+    readonly promptingInstall: boolean;
 }
 
 const showSettings: Reducer<boolean, Action> = (state = false, action) => {
@@ -88,6 +91,31 @@ const updateAvailable: Reducer<boolean, Action> = (state = false, action) => {
     }
 };
 
+const beforeInstallPrompt: Reducer<BeforeInstallPromptEvent | null, Action> = (
+    state = null,
+    action,
+) => {
+    switch (action.type) {
+        case AppActionType.DidBeforeInstallPrompt:
+            return action.event;
+        case AppActionType.DidInstall:
+            return null;
+        default:
+            return state;
+    }
+};
+
+const promptingInstall: Reducer<boolean, Action> = (state = false, action) => {
+    switch (action.type) {
+        case AppActionType.InstallPrompt:
+            return true;
+        case AppActionType.DidInstallPrompt:
+            return false;
+        default:
+            return state;
+    }
+};
+
 export default combineReducers({
     showSettings,
     showAboutDialog,
@@ -95,4 +123,6 @@ export default combineReducers({
     serviceWorker,
     checkingForUpdate,
     updateAvailable,
+    beforeInstallPrompt,
+    promptingInstall,
 });
diff --git a/src/sagas/app.test.ts b/src/sagas/app.test.ts
index 86a50431..0bcfd496 100644
--- a/src/sagas/app.test.ts
+++ b/src/sagas/app.test.ts
@@ -2,9 +2,40 @@
 // Copyright (c) 2021 The Pybricks Authors
 
 import { AsyncSaga, delay } from '../../test';
-import { checkForUpdate, didCheckForUpdate, reload } from '../actions/app';
+import {
+    checkForUpdate,
+    didBeforeInstallPrompt,
+    didCheckForUpdate,
+    didInstallPrompt,
+    installPrompt,
+    reload,
+} from '../actions/app';
+import { BeforeInstallPromptEvent } from '../utils/dom';
 import app from './app';
 
+test('monitorAppInstalled', async () => {
+    const saga = new AsyncSaga(app);
+
+    window.dispatchEvent(new Event('appinstalled'));
+
+    const action = await saga.take();
+    expect(action).toStrictEqual(didInstallPrompt());
+
+    await saga.end();
+});
+
+test('monitorBeforeInstallPrompt', async () => {
+    const saga = new AsyncSaga(app);
+
+    const event = new Event('beforeinstallprompt') as BeforeInstallPromptEvent;
+    window.dispatchEvent(event);
+
+    const action = await saga.take();
+    expect(action).toStrictEqual(didBeforeInstallPrompt(event));
+
+    await saga.end();
+});
+
 test('reload', async () => {
     const saga = new AsyncSaga(app);
 
@@ -22,9 +53,6 @@ test('reload', async () => {
 
     saga.put(reload(registration as ServiceWorkerRegistration));
 
-    // yield to allow generators to complete
-    await delay(0);
-
     expect(registration.unregister).toHaveBeenCalled();
     expect(location.reload).toHaveBeenCalled();
 
@@ -52,3 +80,22 @@ test('checkForUpdates', async () => {
 
     await saga.end();
 });
+
+test('installPrompt', async () => {
+    const saga = new AsyncSaga(app);
+
+    // mock registration as if service worker was register on app startup
+    const event: Partial<BeforeInstallPromptEvent> = {
+        prompt: jest.fn(),
+        userChoice: Promise.resolve({ outcome: 'accepted', platform: 'web' }),
+    };
+
+    saga.put(installPrompt(event as BeforeInstallPromptEvent));
+
+    expect(event.prompt).toHaveBeenCalled();
+
+    const action = await saga.take();
+    expect(action).toStrictEqual(didInstallPrompt());
+
+    await saga.end();
+});
diff --git a/src/sagas/app.ts b/src/sagas/app.ts
index 1f069fb7..85eac92d 100644
--- a/src/sagas/app.ts
+++ b/src/sagas/app.ts
@@ -1,13 +1,54 @@
 // SPDX-License-Identifier: MIT
 // Copyright (c) 2021 The Pybricks Authors
 
-import { call, put, takeEvery } from 'typed-redux-saga/macro';
+import { eventChannel } from 'redux-saga';
+import { call, fork, put, take, takeEvery } from 'typed-redux-saga/macro';
 import {
     AppActionType,
     AppCheckForUpdatesAction,
+    AppInstallPromptAction,
     AppReloadAction,
+    didBeforeInstallPrompt,
     didCheckForUpdate,
+    didInstall,
+    didInstallPrompt,
 } from '../actions/app';
+import { BeforeInstallPromptEvent } from '../utils/dom';
+
+function* monitorAppInstalled(): Generator {
+    const chan = eventChannel<Event>((emit) => {
+        const listener = (e: Event) => {
+            emit(e);
+        };
+        // chromium-only event
+        window.addEventListener('appinstalled', listener);
+        // istanbul ignore next: currently we don't ever stop monitoring
+        return () => window.removeEventListener('appinstalled', listener);
+    });
+
+    while (true) {
+        yield* take(chan);
+        yield* put(didInstall());
+    }
+}
+
+function* monitorBeforeInstallPrompt(): Generator {
+    const chan = eventChannel<BeforeInstallPromptEvent>((emit) => {
+        const listener = (e: BeforeInstallPromptEvent) => {
+            emit(e);
+        };
+        // @ts-expect-error: chromium-only event
+        window.addEventListener('beforeinstallprompt', listener);
+        // istanbul ignore next: currently we don't ever stop monitoring
+        // @ts-expect-error: chromium-only event
+        return () => window.removeEventListener('beforeinstallprompt', listener);
+    });
+
+    while (true) {
+        const event = yield* take(chan);
+        yield* put(didBeforeInstallPrompt(event));
+    }
+}
 
 function* reload(action: AppReloadAction): Generator {
     yield* call(() => action.registration.unregister());
@@ -20,7 +61,16 @@ function* checkForUpdate(action: AppCheckForUpdatesAction): Generator {
     yield* put(didCheckForUpdate(updateFound));
 }
 
+function* installPrompt(action: AppInstallPromptAction): Generator {
+    yield* call(() => action.event.prompt());
+    yield* call(() => action.event.userChoice);
+    yield* put(didInstallPrompt());
+}
+
 export default function* app(): Generator {
+    yield* fork(monitorAppInstalled);
+    yield* fork(monitorBeforeInstallPrompt);
     yield* takeEvery(AppActionType.Reload, reload);
     yield* takeEvery(AppActionType.CheckForUpdate, checkForUpdate);
+    yield* takeEvery(AppActionType.InstallPrompt, installPrompt);
 }
diff --git a/src/utils/dom.ts b/src/utils/dom.ts
new file mode 100644
index 00000000..de9082d0
--- /dev/null
+++ b/src/utils/dom.ts
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2021 The Pybricks Authors
+
+// Chromium-only API
+// https://developer.mozilla.org/en-US/docs/Web/API/BeforeInstallPromptEvent
+export interface BeforeInstallPromptEvent extends Event {
+    readonly platforms: string[];
+    readonly userChoice: Promise<{
+        outcome: 'accepted' | 'dismissed';
+        platform: string;
+    }>;
+    prompt(): Promise<void>;
+}