[longplay] Fix how we store long plays

vrobbler/apps/scrobbles/mixins.py

@@ -165,23 +165,18 @@ class LongPlayScrobblableMixin(ScrobblableMixin):
         return reverse("scrobbles:longplay-finish", kwargs={"uuid": self.uuid})
 
     def first_long_play_scrobble_for_user(self, user) -> Optional["Scrobble"]:
-        return (
-            get_scrobbles_for_media(self, user)
-            .filter(
-                log__long_play_complete=False,
-                log__serial_scrobble_id__isnull=True,
-            )
-            .order_by("timestamp")
-            .first()
-        )
+        last = self.last_long_play_scrobble_for_user(user)
+        if not last:
+            return None
+        current = last
+        while current.long_play_last_scrobble and not current.long_play_last_scrobble.long_play_complete:
+            current = current.long_play_last_scrobble
+        return current
 
     def last_long_play_scrobble_for_user(self, user) -> Optional["Scrobble"]:
         return (
             get_scrobbles_for_media(self, user)
-            .filter(
-                log__long_play_complete=False,
-                log__serial_scrobble_id__isnull=False,
-            )
-            .order_by("timestamp")
-            .last()
+            .filter(long_play_complete=False)
+            .order_by("-timestamp")
+            .first()
         )