implement mix tracklist balancing

app/crons/__init__.py

@@ -7,6 +7,9 @@ from app.utils.threading import background
 
 @background
 def start_cron_jobs():
+    """
+    This is the function that triggers the cron jobs.
+    """
     Mixes().run()
     
     # schedule.run_pending()

app/crons/mixes.py

@@ -4,10 +4,16 @@ from app.store.homepage import HomepageStore
 
 
 class Mixes(CronJob):
+    """
+    This cron job creates mixes displayed on the homepage.
+    """
     def __init__(self):
         super().__init__("mixes", 5)
 
     def run(self):
+        """
+        Creates the artist mixes
+        """
         print("⭐⭐⭐⭐ Mixes cron job running")
         mixes = MixesPlugin()
         artist_mixes = mixes.get_artists()

app/plugins/mixes.py

@@ -3,6 +3,7 @@ import string
 import requests
 from urllib.parse import quote
 
+from app.db.userdata import SimilarArtistTable
 from app.models.artist import Artist
 from app.models.mix import Mix
 from app.models.track import Track
@@ -10,6 +11,7 @@ from app.plugins import Plugin, plugin_method
 from app.store.artists import ArtistStore
 from app.store.tracks import TrackStore
 from app.utils.dates import get_date_range
+from app.utils.mixes import balance_mix
 from app.utils.remove_duplicates import remove_duplicates
 from app.utils.stats import get_artists_in_period
 
@@ -62,6 +64,7 @@ class MixesPlugin(Plugin):
 
         # sort by trackhash order
         trackmatches = sorted(trackmatches, key=lambda x: trackhashes.index(x.weakhash))
+        trackmatches = balance_mix(trackmatches)
         return trackmatches
 
     @plugin_method
@@ -123,6 +126,7 @@ class MixesPlugin(Plugin):
                     indexed.add(artist["artisthash"])
                     period["created"] += 1
 
+        print(f"⭐⭐⭐⭐ Created {len(mixes)} mixes")
         return mixes
 
     def get_mix_description(self, tracks: list[Track], artishash: str):
@@ -162,3 +166,38 @@ class MixesPlugin(Plugin):
                 "artisthash": artist["artisthash"],
             },
         )
+
+
+    def fallback_create_artist_mix(self, artist: dict[str, str], similar_artists: list[str], trackhashes: set[str], limit: int):
+        """
+        Creates an artist mix by selecting random tracks from similar artists.
+
+        This is used when:
+        - The Swing Music recommendation server is down.
+        - The artist has less than self.MIN_TRACK_MIX_LENGTH tracks from the cloud mix.
+        - When we need to dilute the mix to balance the artist distribution.
+
+        :param artist: The artist to create a mix for.
+        :param similar_artists: A list of similar artists to select tracks from. If not provided, we try reading from the local database. When we exhaust the passed list, we also try reading from the local database.
+        :param trackhashes: A set of trackhashes to omit from the new tracklist.
+        :param limit: The maximum number of tracks to select.
+        """
+        artists = similar_artists
+
+        if len(similar_artists) == 0:
+            local_similar_artists = SimilarArtistTable.get_by_hash(artist["artisthash"])
+
+            if local_similar_artists:
+                artists = [a.artisthash for a in local_similar_artists.similar_artists]
+
+        if len(artists) == 0:
+            return []
+
+        # CHECKPOINT: I'M TIRED AF AND I NEED TO SLEEP
+        # The plan:
+        # Figure out which artists we should skip for the new tracklist
+        # these would be artists with a large number of tracks in the mix already
+
+        # Since the artisthashes are ordered by similarity score, we iterate from the start
+        # and go forward collecting tracks that aren't in the mix yet.
+        # 

app/utils/mixes.py

@@ -0,0 +1,95 @@
+from app.models.track import Track
+from typing import List, Dict, Tuple
+from collections import Counter
+
+
+def violates_gap_rule(balanced_mix: Dict[int, Track], position: int, track: Track, gap: int = 3) -> bool:
+    """
+    Check if placing the track at the given position violates the gap rule.
+    """
+    track_artists = set(artist['artisthash'] for artist in track.artists)
+    
+    for i in range(max(0, position - gap), position):
+        if i in balanced_mix:
+            existing_artists = set(artist['artisthash'] for artist in balanced_mix[i].artists)
+            if track_artists.intersection(existing_artists):
+                return True
+    return False
+
+def find_next_position(balanced_mix: Dict[int, Track], start: int, track: Track, total_tracks: int) -> int:
+    """
+    Find the next available position for the track, starting from 'start' and wrapping around.
+    """
+    for i in range(start, total_tracks):
+        if i not in balanced_mix and not violates_gap_rule(balanced_mix, i, track):
+            return i
+    for i in range(start):
+        if i not in balanced_mix and not violates_gap_rule(balanced_mix, i, track):
+            return i
+    return start  # If no better position is found, return the original position
+
+def is_tracklist_balanced(tracks: List[Track], gap: int = 3) -> Tuple[bool, bool]:
+    """
+    Checks if a tracklist is balanced or can be balanced.
+    
+    Args:
+    - tracks: List of Track objects
+    - gap: Minimum number of tracks between songs by the same artist (default 3)
+    
+    Returns:
+    - A tuple (can_be_balanced, is_currently_balanced)
+    """
+    total_tracks = len(tracks)
+    
+    # Count tracks per artist (considering only the first artist)
+    artist_counts = Counter(track.artists[0]['artisthash'] for track in tracks)
+    
+    # Calculate the maximum number of tracks an artist can have in a balanced list
+    max_tracks_per_artist = (total_tracks + gap) // (gap + 1)
+    
+    # Check if it's mathematically possible to balance the tracklist
+    can_be_balanced = all(count <= max_tracks_per_artist for count in artist_counts.values())
+
+    if not can_be_balanced:
+        return False, False
+    
+    # Check if the current arrangement is balanced
+    is_currently_balanced = True
+    artist_last_positions = {}
+    
+    for i, track in enumerate(tracks):
+        artist = track.artists[0]['artisthash']
+        if artist in artist_last_positions:
+            if i - artist_last_positions[artist] <= gap:
+                is_currently_balanced = False
+                break
+        artist_last_positions[artist] = i
+    
+    return can_be_balanced, is_currently_balanced
+
+def balance_mix(tracks: List[Track]) -> List[Track]:
+    """
+    Balances the mix by ensuring that the tracks in a mix are distributed evenly.
+    Preserves the overall rating order of tracks while minimizing disruption.
+    """
+    can_be_balanced, is_balanced = is_tracklist_balanced(tracks)
+    
+    if not can_be_balanced:
+        print("Warning: This tracklist cannot be perfectly balanced.")
+        # Proceed with best-effort balancing
+    
+    if is_balanced:
+        return tracks  # Already balanced, no need to modify
+    
+    balanced_mix: Dict[int, Track] = {}
+    total_tracks = len(tracks)
+
+    for i, track in enumerate(tracks):
+        if i in balanced_mix or not violates_gap_rule(balanced_mix, i, track):
+            balanced_mix[i] = track
+        else:
+            new_position = find_next_position(balanced_mix, i, track, total_tracks)
+            balanced_mix[new_position] = track
+
+    # Convert the dictionary back to a list, preserving the new order
+    return [balanced_mix[i] for i in sorted(balanced_mix.keys())]

manage.py

@@ -60,7 +60,7 @@ mimetypes.add_type("application/manifest+json", ".webmanifest")
 
 
 # Background tasks
-@background
+# @background
 def bg_run_setup():
     IndexEverything()
 
@@ -73,21 +73,19 @@ def bg_run_setup():
 @background
 def run_swingmusic():
     log_startup_info()
-    bg_run_setup()
     register_plugins()
-    start_cron_jobs()
 
     # start_watchdog()
 
     setproctitle.setproctitle(f"swingmusic ::{FLASKVARS.get_flask_port()}")
+    # bg_run_setup()
+    start_cron_jobs()
 
 
 # Setup function calls
 Info.load()
 ProcessArgs()
 run_setup()
-load_into_mem()
-run_swingmusic()
 
 
 # Create the Flask app
@@ -226,6 +224,10 @@ def print_memory_usage(response: Response):
 
 
 if __name__ == "__main__":
+
+    load_into_mem()
+    run_swingmusic()
+    
     host = FLASKVARS.get_flask_host()
     port = FLASKVARS.get_flask_port()