System clock (#677)

* Show toast when client clock is out of sync

* Fixed syntactical misarrangements

* Simplify getServerTime method

* Futher simplify getServerTime method

* Update js/modules/loki_app_dot_net_api.js

Co-Authored-By: Mikunj Varsani <Mikunj@users.noreply.github.com>

* Update js/modules/loki_app_dot_net_api.js

Co-Authored-By: Mikunj Varsani <Mikunj@users.noreply.github.com>

* Update loki_app_dot_net_api.js

Use cached timestamp value

* Update preload.js

Update some values to function scope

* Updated syntax

* Semifinal changes

* Improved efficiency and eliminated need for restart on clock update

* Remove await and immediately invoked function

_locales/en/messages.json

@@ -1429,6 +1429,12 @@
     "description":
       "Warning notification that this version of the app has expired"
   },
+  "clockOutOfSync": {
+    "message":
+      "Your clock is out of sync. Please update your clock and try again.",
+    "description":
+      "Notifcation that user's clock is out of sync with Loki's servers."
+  },
   "upgrade": {
     "message": "Upgrade",
     "description":

js/background.js

@@ -11,7 +11,7 @@
   libloki,
   libsignal,
   StringView,
-  BlockedNumberController
+  BlockedNumberController,
 */
 
 // eslint-disable-next-line func-names
@@ -125,6 +125,9 @@
     'loki/loki_icon_128.png',
   ]);
 
+  // Set server-client time difference
+  window.LokiPublicChatAPI.setClockParams();
+
   // We add this to window here because the default Node context is erased at the end
   //   of preload.js processing
   window.setImmediate = window.nodeSetImmediate;

js/modules/loki_app_dot_net_api.js

@@ -63,6 +63,42 @@ class LokiAppDotNetAPI extends EventEmitter {
     return thisServer;
   }
 
+  static async getServerTime() {
+    const url = `${window.getDefaultFileServer()}/loki/v1/time`;
+    let timestamp = NaN;
+
+    try {
+      const res = await nodeFetch(url);
+      if (res.ok) {
+        timestamp = await res.text();
+      }
+    } catch (e) {
+      return timestamp;
+    }
+
+    return Number(timestamp);
+  }
+
+  static async getTimeDifferential() {
+    // Get time differential between server and client in seconds
+    const serverTime = await this.getServerTime();
+    const clientTime = Math.ceil(Date.now() / 1000);
+
+    if (Number.isNaN(serverTime)) {
+      return 0;
+    }
+    return serverTime - clientTime;
+  }
+
+  static async setClockParams() {
+    // Set server-client time difference
+    const maxTimeDifferential = 30;
+    const timeDifferential = await this.getTimeDifferential();
+
+    window.clientClockSynced = Math.abs(timeDifferential) < maxTimeDifferential;
+    return window.clientClockSynced;
+  }
+
   // channel getter/factory
   async findOrCreateChannel(serverUrl, channelId, conversationId) {
     const server = await this.findOrCreateServer(serverUrl);

js/views/conversation_view.js

@@ -28,6 +28,11 @@
       return { toastMessage: i18n('expiredWarning') };
     },
   });
+  Whisper.ClockOutOfSyncToast = Whisper.ToastView.extend({
+    render_attributes() {
+      return { toastMessage: i18n('clockOutOfSync') };
+    },
+  });
   Whisper.BlockedToast = Whisper.ToastView.extend({
     render_attributes() {
       return { toastMessage: i18n('unblockToSend') };
@@ -1956,6 +1961,11 @@
       if (extension.expired()) {
         toast = new Whisper.ExpiredToast();
       }
+      if (!window.clientClockSynced) {
+        // Check to see if user has updated their clock to current time
+        const clockSynced = await window.LokiPublicChatAPI.setClockParams();
+        toast = clockSynced ? toast : new Whisper.ClockOutOfSyncToast();
+      }
       if (this.model.isPrivate() && storage.isBlocked(this.model.id)) {
         toast = new Whisper.BlockedToast();
       }