aircox/forms/episode: limit available sounds

aircox/forms/episode.py

@@ -14,8 +14,18 @@ class EpisodeForm(ChildPageForm):
         fields = ChildPageForm.Meta.fields
 
 
+class EpisodeSoundForm(forms.ModelForm):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        if "instance" in kwargs:
+            """Limit available sounds."""
+            episode_sounds = kwargs["instance"].episode.episodesound_set.all()
+            self.fields["sound"].queryset = models.Sound.objects.filter(id__in=[x.sound.id for x in episode_sounds])
+
+
 EpisodeSoundFormSet = modelformset_factory(
     models.EpisodeSound,
+    form=EpisodeSoundForm,
     fields=(
         "position",
         "episode",