FIX video.js event firing issues fore RecsysPlugin

- The `rateChange` event now logs the updated speed,
   not just the    time at which it occurred.
- The `scrub` now (more) accurately logs the position
   it came from before the destination.
- The recsys events get consolidated for logical consistency.

ui/component/viewers/videoViewer/internal/plugins/videojs-recsys/plugin.js

@@ -98,6 +98,7 @@ class RecsysPlugin extends Component {
     this.lastTimeUpdate = null;
     this.currentTimeUpdate = null;
     this.loadedAt = Date.now();
+    this.playInitiated = false;
 
     // Plugin event listeners
     player.on('playing', (event) => this.onPlay(event));
@@ -112,11 +113,83 @@ class RecsysPlugin extends Component {
   }
 
   addRecsysEvent(recsysEvent) {
+    if (!this.playInitiated) {
+      switch (recsysEvent.event) {
+        case RecsysData.event.start:
+          this.playInitiated = true;
+          break;
+        case RecsysData.event.scrub:
+          // If playback hasn't started, swallow scrub events. They offer some
+          // information, but if there isn't a subsequent play event, it's
+          // mostly nonsensical.
+          return undefined;
+        case RecsysData.event.stop:
+          // If playback hasn't started, swallow stop events. This means
+          // you're going to start from an offset but the start event
+          // captures that information. (With the ambiguity that you can't
+          // tell if they scrubbed, landed at the offset, or restarted. But
+          // I don't think that matters much.)
+          return undefined;
+        case RecsysData.event.speed:
+          if (this.recsysEvents.length > 0 && this.recsysEvents[0].event === RecsysData.event.speed) {
+            // video.js will sometimes fire the default play speed followed by the
+            // user preference. This is not useful information so we can keep the latter.
+            this.recsysEvents.pop();
+          }
+      }
+    } else {
+      const lastEvent = this.recsysEvents[this.recsysEvents.length - 1];
+
+      switch (recsysEvent.event) {
+        case RecsysData.event.scrub:
+          if (lastEvent.event === RecsysData.event.stop) {
+            // Video.js fires a stop before the seek. This extra information isn't
+            // useful to log though, so this code prunes the stop event if it was
+            // within 0.25 seconds.
+            if (Math.abs(lastEvent.offset - recsysEvent.offset) < 0.25) {
+              this.recsysEvents.pop();
+              recsysEvent.offset = lastEvent.arg;
+            }
+          } else if (lastEvent.event === RecsysData.event.start) {
+            // If the last event was a play and this event is a scrub close to
+            // that play position, I think it's just a weird emit order for
+            // video.js and we don't need to log the scrub.
+            if (Math.abs(lastEvent.offset - recsysEvent.arg) < 0.25) {
+              return undefined;
+            }
+          }
+          break;
+        case RecsysData.event.start:
+          if (lastEvent.event === RecsysData.event.scrub) {
+            // If the last event was a seek and this is a play,
+            // it's reasonable to just implicitly assume the play occurred,
+            // no need to create the play event.
+            return undefined;
+          } else if (lastEvent.event === RecsysData.event.start) {
+            // A start followed by a start is a buffering event.
+            // It may make sense to keep these. A user may abandon
+            // a page *not because it's bad content but because
+            // there are network troubles right now*.
+          }
+          break;
+      }
+    }
+
     this.recsysEvents.push(recsysEvent);
   }
 
   getRecsysEvents() {
-    return this.recsysEvents;
+    return this.recsysEvents.map((event) => {
+      if (event !== RecsysData.event.stop) {
+        return event;
+      }
+
+      // I used the arg in stop events to smuggle the seek time into
+      // the scrub events. But the backend doesn't expect it.
+      const dup = { ...event };
+      delete dup.arg;
+      return dup;
+    });
   }
 
   sendRecsysEvents() {
@@ -137,7 +210,11 @@ class RecsysPlugin extends Component {
   }
 
   onPause(event) {
-    const recsysEvent = newRecsysEvent(RecsysData.event.stop, this.player.currentTime());
+    // The API doesn't want an `arg` for `STOP` events. However, video.js
+    // emits these before the seek events, and that seems to be the easiest
+    // way to lift time you are seeking from into the scrub record (via lastTimeUpdate).
+    // Hacky, but works.
+    const recsysEvent = newRecsysEvent(RecsysData.event.stop, this.player.currentTime(), this.lastTimeUpdate);
     this.log('onPause', recsysEvent);
     this.addRecsysEvent(recsysEvent);
   }
@@ -149,7 +226,9 @@ class RecsysPlugin extends Component {
   }
 
   onRateChange(event) {
-    const recsysEvent = newRecsysEvent(RecsysData.event.speed, this.player.currentTime());
+    // This is actually a bug. The offset should be the offset. The change speed should be change speed.
+    // Otherise, you don't know where it changed and the time calc is wrong.
+    const recsysEvent = newRecsysEvent(RecsysData.event.speed, this.player.currentTime(), this.player.playbackRate());
     this.log('onRateChange', recsysEvent);
     this.addRecsysEvent(recsysEvent);
   }
@@ -160,6 +239,10 @@ class RecsysPlugin extends Component {
   }
 
   onSeeked(event) {
+    // The problem? `lastTimeUpdate` is wrong.
+    // So every seeks l
+
+    // If the immediately prior event is a pause?
     const recsysEvent = newRecsysEvent(RecsysData.event.scrub, this.lastTimeUpdate, this.player.currentTime());
     this.log('onSeeked', recsysEvent);
     this.addRecsysEvent(recsysEvent);