Add calculating waittimes for playing/requesting songs.

savepointradio/radio/utils.py

@@ -0,0 +1,45 @@
+from datetime import timedelta
+from decimal import *
+from random import randint
+
+from django.db import models
+from django.utils import timezone
+
+from core.utils import get_setting
+from .models import Song
+
+
+# Set decimal precision
+getcontext().prec = 16
+
+
+def get_playlist_length():
+    """
+    Total length of available songs in the playlist (in seconds).
+    """
+    songs = Song.music.available()
+    return songs.aggregate(models.Sum('length'))['length__sum']
+
+
+def get_waittime():
+    """
+    Default length in seconds before a song can be played again. This is based
+    on the replay ratio set in the application settings.
+    """
+    waittime = get_playlist_length() * Decimal(get_setting('replay_ratio'))
+    return waittime.quantize(Decimal('.01'), rounding=ROUND_UP)
+
+
+def get_next_allowed_play_time(song):
+    """
+    Length of time in seconds before a song can be played again.
+    """
+    if not song.last_played:
+        return Decimal('0.00')
+
+    waittime = get_waittime()
+    nextplay = song.last_played + timedelta(seconds=float(waittime))
+    current = (nextplay - timezone.now()).total_seconds()
+
+    return Decimal(current if current > 0 else 0).quantize(Decimal('.01'),
+                                                           rounding=ROUND_UP)