Handle infinite-spinner errors and properly inform the user

www/common/common-realtime.js

@@ -9,23 +9,33 @@ define([
         AppConfig.badStateTimeout: 30000;
 
     var connected = false;
+    var intr;
+    var infiniteSpinnerHandlers = [];
 
     /*
         TODO make this not blow up when disconnected or lagging...
     */
     common.whenRealtimeSyncs = function (Cryptpad, realtime, cb) {
-        realtime.sync();
-
         window.setTimeout(function () {
             if (realtime.getAuthDoc() === realtime.getUserDoc()) {
                 return void cb();
+            } else {
+                realtime.onSettle(cb);
             }
 
-            var to = setTimeout(function () {
-                if (!connected) { return; }
+            if (intr) { return; }
+            intr = window.setInterval(function () {
+                var l;
+                try {
+                    l = realtime.getLag();
+                } catch (e) {
+                    throw new Error("ChainPad.getLag() does not exist, please `bower update`");
+                }
+                if (l.lag < BAD_STATE_TIMEOUT || !connected) { return; }
                 realtime.abort();
                 // don't launch more than one popup
                 if (common.infiniteSpinnerDetected) { return; }
+                infiniteSpinnerHandlers.forEach(function (ish) { ish(); });
 
                 // inform the user their session is in a bad state
                 Cryptpad.confirm(Messages.realtime_unrecoverableError, function (yes) {
@@ -33,14 +43,12 @@ define([
                     window.location.reload();
                 });
                 common.infiniteSpinnerDetected = true;
-            }, BAD_STATE_TIMEOUT);
-            realtime.onSettle(function () {
-                clearTimeout(to);
-                cb();
-            });
+            }, 2000);
         }, 0);
     };
 
+    common.onInfiniteSpinner = function (f) { infiniteSpinnerHandlers.push(f); };
+
     common.setConnectionState = function (bool) {
         if (typeof(bool) !== 'boolean') { return; }
         connected = bool;