Fill event gaps with noops, ensuring continuous flow

app/round/History.scala

@@ -7,9 +7,25 @@ import scalaz.effects._
 import chess.Color
 import memo.Builder
 
-case class VersionedEvent(js: JsObject, only: Option[Color], own: Boolean) {
+case class VersionedEvent(
+    version: Int,
+    typ: String,
+    data: JsValue,
+    only: Option[Color],
+    own: Boolean) {
 
-  def visible(m: Member): Boolean =
+  def jsFor(m: Member): JsObject = visibleBy(m).fold(
+    JsObject(Seq(
+      "v" -> JsNumber(version),
+      "t" -> JsString(typ),
+      "d" -> data
+    )),
+    JsObject(Seq(
+      "v" -> JsNumber(version)
+    ))
+  )
+
+  private def visibleBy(m: Member): Boolean =
     if (own && !m.owner) false else only.fold(_ == m.color, true)
 }
 
@@ -30,16 +46,14 @@ final class History(timeout: Int) {
   private def event(v: Int) = Option(events getIfPresent v)
 
   def +=(event: Event): VersionedEvent = {
-    privateVersion = privateVersion + 1
+    privateVersion = version + 1
     val vevent = VersionedEvent(
-      js = JsObject(Seq(
-        "v" -> JsNumber(privateVersion),
-        "t" -> JsString(event.typ),
-        "d" -> event.data
-      )),
+      version = version,
+      typ = event.typ,
+      data = event.data,
       only = event.only,
       own = event.owner)
-    events.put(privateVersion, vevent)
+    events.put(version, vevent)
     vevent
   }
 }

app/round/Hub.scala

@@ -90,11 +90,10 @@ final class Hub(
   }
 
   def batch(member: Member, vevents: List[VersionedEvent]) {
-    val filtered = vevents filter (_ visible member)
-    if (filtered.nonEmpty) {
+    if (vevents.nonEmpty) {
       member.channel push JsObject(Seq(
         "t" -> JsString("batch"),
-        "d" -> JsArray(filtered map (_.js))
+        "d" -> JsArray(vevents map (_ jsFor member))
       ))
     }
   }

public/javascripts/socket.js

@@ -107,12 +107,18 @@ $.websocket.prototype = {
         self.debug("already has event " + m.v);
         return;
       }
+      if (m.v > self.version + 1) {
+        self.debug("event gap detected from " + self.version + " to " + m.v);
+        return;
+      }
       self.version = m.v;
       self.debug("set version " + self.version);
     }
-    var h = self.settings.events[m.t];
-    if ($.isFunction(h)) h(m.d || null);
-    else self.debug(m.t + " not supported");
+    if (m.t) {
+      var h = self.settings.events[m.t];
+      if ($.isFunction(h)) h(m.d || null);
+      else self.debug(m.t + " not supported");
+    } 
   },
   debug: function(msg) { if (this.options.debug) console.debug("[" + this.options.name + "]", msg); },
   destroy: function() {