Improved time upkeep for playing and pausing.

models/session.js

@@ -2,7 +2,8 @@ class Session {
   #id = null;
   #started = null;
   #current = null;
-  #lastScrobble = null;
+  lastScrobbleTimestamp = 0;
+  lastUpdateTimestamp = 0;
   pauseDuration = 0;
   playDuration = 0;
 
@@ -26,14 +27,6 @@ class Session {
   get started() {
     return this.#started;
   }
-
-  get lastScrobbleTimestamp() {
-    return this.#lastScrobble;
-  }
-
-  set lastScrobbleTimestamp(value) {
-    this.#lastScrobble = value;
-  }
 }
 
 module.exports = Session;

services/recorder.js

@@ -8,7 +8,6 @@ class Recorder {
   #scrobblers = [];
   #config = null;
   #logger = null;
-  #lastTick = null;
 
   constructor(sessions, trackers, scrobblers, config, logger) {
     this.#sessions = sessions;
@@ -17,12 +16,10 @@ class Recorder {
     this.#scrobblers = scrobblers;
     this.#config = config;
     this.#logger = logger;
-    this.#lastTick = Date.now();
   }
 
   async record() {
     const now = Date.now();
-    const timeDiff = now - this.#lastTick;
     const media = await this.#trackers.poll();
     const contexts = media.map(m => this.#fetchContext(m));
 
@@ -31,25 +28,30 @@ class Recorder {
     const stopped = sessionIds.filter(sessionId => !contexts.some(context => sessionId == context.session.id))
       .map(sessionId => this.#sessions.get(sessionId))
       .map(session => this.#fetchContext(session.playing));
-    const contextEnded = stopped.filter(context => this.#canScrobble(context.session, null, context.session.playing, now));
+    const contextEnded = stopped.filter(context => this.#canScrobble(context.session, null, context.session.playing));
 
     for (let context of contextEnded)
       context.session.playDuration = now - (context.session.lastScrobbleTimestamp || context.session.started) - context.session.pauseDuration;
 
     // Find ongoing sessions that have moved on to the next song.
-    const finishedPlaying = contexts.filter(context => this.#listen(context, now, timeDiff));
+    const finishedPlaying = contexts.filter(context => this.#listen(context, now));
 
     // Scrobble
     const scrobbling = finishedPlaying.concat(contextEnded);
-    for (let context of scrobbling)
+    for (let context of scrobbling) {
       await this.#scrobble(context);
 
+      if (context.session.playing == null)
+        continue;
+
+      context.session.playDuration = context.extraDuration;
+      context.session.pauseDuration = 0;
+    }
+
     // Remove dead sessions.
     for (let context of stopped) {
       this.#sessions.remove(context.session.id);
     }
-
-    this.#lastTick = now;
   }
 
   #fetchContext(media) {
@@ -60,39 +62,41 @@ class Recorder {
       this.#sessions.add(session);
     }
 
-    return { session, media, tracker }
+    return { session, media, tracker, extraDuration: 0 }
   }
 
-  #listen(context, timestamp, timeDiff) {
+  #listen(context, timestamp) {
     const session = context.session;
     const current = context.media;
     const previous = context.session.playing;
     session.playing = current;
-    session.playDuration = timestamp - (session.lastScrobbleTimestamp || session.started) - session.pauseDuration;
 
     if (!previous) {
       this.#logger.info(current, "A new session has started.");
+      session.lastUpdateTimestamp = timestamp;
       return false;
     }
 
-    if (session.playing.state == "paused" || previous.state == "paused")
-      session.pauseDuration += timeDiff - (session.playing.progress - previous.progress);
+    const updated = current.progress != previous.progress || current.id != previous.id || current.state != previous.state;
+    if (!updated)
+      return false;
 
-    if (this.#canScrobble(session, current, previous, timestamp)) {
-      session.pauseDuration = 0;
-      session.lastScrobbleTimestamp = timestamp - (timeDiff - (previous.duration - previous.progress));
-      return true;
-    } else if (current.progress < previous.progress && session.playing.id != previous.id) {
-      session.pauseDuration = 0;
-      if (current.progress < timeDiff)
-        session.lastScrobbleTimestamp = timestamp - session.playing.progress;
-      else
-        session.lastScrobbleTimestamp = timestamp;
+    const timeDiff = timestamp - session.lastUpdateTimestamp;
+    const progressDiff = Math.max(0, Math.min(current.progress - previous.progress, timeDiff));
+    session.playDuration += progressDiff;
+    session.pauseDuration += timeDiff - progressDiff;
+    
+    const canScrobble = this.#canScrobble(session, current, previous);
+    if (canScrobble || current.id != previous.id) {
+      context.extraDuration = Math.min(current.progress, timeDiff - (previous.duration - previous.progress));
+      session.lastScrobbleTimestamp = timestamp;
     }
-    return false;
+
+    session.lastUpdateTimestamp = timestamp;
+    return canScrobble;
   }
 
-  #canScrobble(session, current, previous, timestamp) {
+  #canScrobble(session, current, previous) {
     if (previous == null)
       return false;