Add optional mobile guide toast

This adds an optional toast which Element deployments can enable to nudge users
towards the mobile apps once they are inside the app.

Part of https://github.com/vector-im/element-web/issues/16283

src/components/structures/MatrixChat.tsx

@@ -81,6 +81,7 @@ import ThreepidInviteStore, { IThreepidInvite, IThreepidInviteWireFormat } from
 import {UIFeature} from "../../settings/UIFeature";
 import { CommunityPrototypeStore } from "../../stores/CommunityPrototypeStore";
 import DialPadModal from "../views/voip/DialPadModal";
+import { showToast as showMobileGuideToast } from '../../toasts/MobileGuideToast';
 
 /** constants for MatrixChat.state.view */
 export enum Views {
@@ -1186,6 +1187,11 @@ export default class MatrixChat extends React.PureComponent<IProps, IState> {
         ) {
             showAnalyticsToast(this.props.config.piwik?.policyUrl);
         }
+        if (SdkConfig.get().mobileGuideToast) {
+            // The toast contains further logic to detect mobile platforms,
+            // check if it has been dismissed before, etc.
+            showMobileGuideToast();
+        }
     }
 
     private showScreenAfterLogin() {

src/i18n/strings/en_EN.json

@@ -726,6 +726,9 @@
     "Notifications": "Notifications",
     "Enable desktop notifications": "Enable desktop notifications",
     "Enable": "Enable",
+    "Mobile experience": "Mobile experience",
+    "Element Web is currently experimental on mobile. The native apps are recommended for most people.": "Element Web is currently experimental on mobile. The native apps are recommended for most people.",
+    "Learn more": "Learn more",
     "Your homeserver has exceeded its user limit.": "Your homeserver has exceeded its user limit.",
     "Your homeserver has exceeded one of its resource limits.": "Your homeserver has exceeded one of its resource limits.",
     "Contact your <a>server admin</a>.": "Contact your <a>server admin</a>.",
@@ -2190,7 +2193,6 @@
     "We call the places where you can host your account ‘homeservers’.": "We call the places where you can host your account ‘homeservers’.",
     "Other homeserver": "Other homeserver",
     "Use your preferred Matrix homeserver if you have one, or host your own.": "Use your preferred Matrix homeserver if you have one, or host your own.",
-    "Learn more": "Learn more",
     "About homeservers": "About homeservers",
     "Sign out and remove encryption keys?": "Sign out and remove encryption keys?",
     "Clear Storage and Sign Out": "Clear Storage and Sign Out",

src/toasts/MobileGuideToast.ts

@@ -0,0 +1,61 @@
+/*
+Copyright 2021 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { _t } from "../languageHandler";
+import GenericToast from "../components/views/toasts/GenericToast";
+import ToastStore from "../stores/ToastStore";
+
+const onAccept = () => {
+    window.location.href = "mobile_guide/";
+};
+
+const onReject = () => {
+    document.cookie = "element_mobile_redirect_to_guide=false;path=/;max-age=14400";
+    hideToast();
+};
+
+const TOAST_KEY = "mobileguide";
+
+export const showToast = () => {
+    const isIos = /iPad|iPhone|iPod/.test(navigator.userAgent) && !window.MSStream;
+    const isAndroid = /Android/.test(navigator.userAgent);
+    if (!isIos && !isAndroid) {
+        return;
+    }
+    if (document.cookie.includes("element_mobile_redirect_to_guide=false")) {
+        return;
+    }
+    ToastStore.sharedInstance().addOrReplaceToast({
+        key: TOAST_KEY,
+        title: _t("Mobile experience"),
+        props: {
+            description: _t(
+                "Element Web is currently experimental on mobile. " +
+                "The native apps are recommended for most people.",
+            ),
+            acceptLabel: _t("Learn more"),
+            onAccept,
+            rejectLabel: _t("Dismiss"),
+            onReject,
+        },
+        component: GenericToast,
+        priority: 99,
+    });
+};
+
+export const hideToast = () => {
+    ToastStore.sharedInstance().dismissToast(TOAST_KEY);
+};