diff --git a/recommendation_engine.py b/recommendation_engine.py
index 03c6919..ab0f3cc 100644
--- a/recommendation_engine.py
+++ b/recommendation_engine.py
@@ -96,21 +96,21 @@ class Engine:
         # Make sure sanity check exists in front-end (error if it does not add up to 16).
         video_num = nc + np + ns 
 
-        for event in user.get('events', []):
-            if event.get('event') == "grid" and event.get('data').get('index') not in grid_events:
-                grid_events[event.get('data').get('index')] = event.get('data')
-            if len(grid_events) == video_num:
-                break
-
-        # # The version where the loop also extract play_index (requires "index" in play event data):
-        # play_index = None
         # for event in user.get('events', []):
         #     if event.get('event') == "grid" and event.get('data').get('index') not in grid_events:
         #         grid_events[event.get('data').get('index')] = event.get('data')
-        #     if event.get('event') == "play" and not play_index:
-        #         play_index = event.get('data').get('index') 
-        #     if len(grid_events) == video_num and play_index:
-        #         break 
+        #     if len(grid_events) == video_num:
+        #         break
+
+        # # The version where the loop also extract play_index (requires "index" in play event data):
+        play_index = None
+        for event in user.get('events', []):
+            if event.get('event') == "grid" and event.get('data').get('index') not in grid_events:
+                grid_events[event.get('data').get('index')] = event.get('data')
+            if event.get('event') == "play" and not play_index:
+                play_index = event.get('data').get('index') 
+            if len(grid_events) == video_num and play_index:
+                break 
 
         prev_grid_list = sorted([v for v in grid_events.values()], key=lambda k:k['index'])
 
@@ -119,50 +119,45 @@ class Engine:
             return self.get_recommendations(user)
 
         else:
-            # Once the "index" is added to play event data, played index will be excluded from the random shuffle 
-            # and deterministically added to staySame pool.
-
-            # video_indx = [*range(playIndex)]+[*range(playIndex+1,video_num)]
-            video_indx = list(range(video_num))
+            # played index is excluded from the random shuffle and deterministically added to staySame pool.
+            video_indx = [*range(play_index)]+[*range(play_index+1,video_num)]
+            # video_indx = list(range(video_num))
             random.shuffle(video_indx)
+            video_indx.append(play_index)
+            next_clip_index = video_indx[:nc]
+            next_playlist_index = video_indx[nc:nc+np]
+            stay_same_index = video_indx[nc+np:]
+
             rec_list = []
-            # For now, randomly choose a clip in the same playlist instead of switching to the next clip. 
-            # This will be changed once the clip position is tracked in the user data as "playlistPostion"
-            for i in video_indx[:nc]:
-                if prev_grid_list[i].get('playlist') is None:
-                # add this to deal with the absence of "playlist" data in a grid event temporarily.
-                # If there's no playlist data recorded, add the nextClip pool to nextPlaylist pool for now.
-                    np += nc
-                    nc = 0
-                    break
-                else:
-                # if "playlist" and "playlistPostion" data exists in grid event (it should be in the future)
-                    for playlist in playlists:    
-                        if playlist.get('name')== prev_grid_list[i].get('playlist'):
-                            # Discuss how this behavour should be: should it switch to a new playlist if it is the end of the playlist clip sequence already?
-                            # if prev_grid_list[i].get('index') == len(playlist['clips']):
-                            #     playlist_pos = 0
-                            # else:
-                            #     playlist_pos = prev_grid_list[i].get('index') + 1
-                            
-                            rec_list.append((i, {
-                                'clips': playlist['clips'],
-                                'position': random.randrange(len(playlist['clips'])),
-                                # 'position': playlist_pos,
-                                'name': playlist['name'],
-                                'tags': playlist['tags'],
-                            }))
+            # select next clip for nextClip pool except when the playlist has only one clip. 
+            for i in next_clip_index:
+                for playlist in self.playlists:
+                    if playlist.get('name')== prev_grid_list[i].get('playlist'):
+                        if len(playlist["clips"]) == 1:
+                            next_playlist_index.append(i)
+                            break
+                        # Discuss how this behavour should be: should it switch to a new playlist if it is the end of the playlist clip sequence already?
+                        elif prev_grid_list[i].get('playlistPosition') + 1 == len(playlist['clips']):
+                            playlist_pos = 0
+                        else:
+                            playlist_pos = prev_grid_list[i].get('playlistPosition') + 1
+                        
+                        rec_list.append((i, {
+                            'clips': playlist['clips'],
+                            # 'position': random.randrange(len(playlist['clips'])),
+                            'position': playlist_pos,
+                            'name': playlist['name'],
+                            'tags': playlist['tags'],
+                        }))
 
             # randomly select playlists (excluding the playlists from the current grid once "playlist" is recorded for grid events)
             # for nextPlaylist pool.
-            vids_exclude = []
-            # vids_exclude = [e.get("playlist") for e in prev_grid_list]
+            vids_exclude = [e.get("playlist") for e in prev_grid_list]
             video = self.get_recommendations(user, vids_exclude)
-            rec_list += [(i, video[i]) for i in video_indx[nc:nc+np]]
+            rec_list += [(i, video[i]) for i in next_playlist_index]
 
             #staySame pool
-            # video_indx.append(playIndex)
-            rec_list += [(i,{}) for i in video_indx[nc+np:]]
+            rec_list += [(i,{}) for i in stay_same_index]
 
             rec_list = sorted(rec_list, key=lambda k:k[0])
             return [e[1] for e in rec_list]