source-weights fallback when the source is empty

feed

@@ -12,6 +12,7 @@ import os
 import posixpath
 import random
 import re
+import sys
 import urllib.request
 from argparse import ArgumentParser, ArgumentTypeError
 from bisect import bisect
@@ -24,6 +25,11 @@ from lxml import html
 from pytimeparse.timeparse import timeparse
 
 
+def debug(*args, **kwargs):
+    kwargs.setdefault("file", sys.stderr)
+    print(*args, **kwargs)
+
+
 def get_int(s):
     return int(re.findall(r"\d+", s)[0])
 
@@ -57,6 +63,10 @@ def weighted_choice(values, weights):
     Their meaning is "relative", that is [1,2,3] is the same as [2,4,6]
     """
     assert len(values) == len(weights)
+    if not values:
+        raise IndexError("Cannot do weighted choice from an empty sequence")
+    if sum(weights) == 0:
+        raise IndexError("Cannot do weighted choice where weight=0")
     total = 0
     cum_weights = []
     for w in weights:
@@ -488,17 +498,28 @@ def main():
     sources = args.urls
 
     if args.source_weights:
-        weights = tuple(map(int, args.source_weights.split(":")))
+        weights = list(map(int, args.source_weights.split(":")))
         if len(weights) != len(sources):
             parser.exit(
                 status=2, message="Weight must be in the" " same number as sources\n"
             )
-        sources = [weighted_choice(sources, weights)]
+    else:
+        weights = [1] * len(sources)
 
-    audios = []
-    for url in sources:
+    audio_by_source = OrderedDict()
+    for i, url in enumerate(sources):
         url_audios = retrieve(url, args)
-        audios += [au for au in url_audios if audio_passes_filters(au, args)]
+        url_audios = [au for au in url_audios if audio_passes_filters(au, args)]
+        audio_by_source[url] = url_audios
+        if not url_audios:
+            weights[i] = 0
+    if sum(weights) == 0:
+        return
+    sources = [weighted_choice(sources, weights)]
+
+    audios = []
+    for source_url in sources:
+        audios += audio_by_source[source_url]
 
     # sort
     if args.sort_by == "random":
@@ -548,16 +569,17 @@ def main():
         return
     for audio in audios[:-1]:
         if args.debug:
-            print(repr(audio))
+            debug(repr(audio))
         else:
             put(audio, args.copy)
         if args.slotsize is not None:
             duration = audio.duration
             if duration < args.slotsize:
+                # TODO: prendi musica da un'altra cartella
                 print("## musica per {} secondi".format(args.slotsize - duration))
     # finally, the last one
     if args.debug:
-        print(repr(audios[-1]))
+        debug(repr(audios[-1]))
     else:
         put(audios[-1], args.copy)