From 6dd4fa72ec4ac94d33f64d7917ab99d198484309 Mon Sep 17 00:00:00 2001
From: Josh Washburne <recursive.green@gmail.com>
Date: Tue, 3 Apr 2018 16:24:54 -0400
Subject: [PATCH] Add/Remove artists for song objects in the API. Code cleanup.

---
 savepointradio/api/serializers/radio.py | 13 +++++++--
 savepointradio/api/views/radio.py       | 36 +++++++++++++++++++++++--
 2 files changed, 45 insertions(+), 4 deletions(-)

diff --git a/savepointradio/api/serializers/radio.py b/savepointradio/api/serializers/radio.py
index e2bd239..5fea26b 100644
--- a/savepointradio/api/serializers/radio.py
+++ b/savepointradio/api/serializers/radio.py
@@ -27,12 +27,15 @@ class GameSerializer(serializers.ModelSerializer):
         fields = ('id', 'title')
 
 
-class SongCreateSerializer(serializers.ModelSerializer):
+class SongSerializer(serializers.ModelSerializer):
     class Meta:
         model = Song
         fields = ('id', 'album', 'artists', 'published_date', 'game',
                   'num_played', 'last_played', 'length', 'song_type', 'title')
 
+
+class SongCreateSerializer(SongSerializer):
+
     def create(self, validated_data):
         artists_data = validated_data.pop('artists')
         song = Song.objects.create(**validated_data)
@@ -42,5 +45,11 @@ class SongCreateSerializer(serializers.ModelSerializer):
         return song
 
 
-class SongSerializer(SongCreateSerializer):
+class SongRetrieveSerializer(SongSerializer):
     artists = ArtistFullnameSerializer(many=True)
+
+
+class SongArtistsListSerializer(serializers.Serializer):
+    artists = serializers.ListField(child=serializers.IntegerField(),
+                                    min_length=1,
+                                    max_length=10)
diff --git a/savepointradio/api/views/radio.py b/savepointradio/api/views/radio.py
index e0140f1..3019eea 100644
--- a/savepointradio/api/views/radio.py
+++ b/savepointradio/api/views/radio.py
@@ -1,10 +1,14 @@
-from rest_framework import viewsets
+from rest_framework import status, viewsets
+from rest_framework.decorators import action
+from rest_framework.permissions import IsAdminUser
+from rest_framework.response import Response
 
 from radio.models import Album, Artist, Game, Song
 from ..permissions import IsAdminOrReadOnly
 from ..serializers.radio import (AlbumSerializer, ArtistSerializer,
                                  GameSerializer, SongSerializer,
-                                 SongCreateSerializer)
+                                 SongArtistsListSerializer,
+                                 SongCreateSerializer, SongRetrieveSerializer)
 
 
 class AlbumViewSet(viewsets.ModelViewSet):
@@ -38,4 +42,32 @@ class SongViewSet(viewsets.ModelViewSet):
         '''
         if self.action == 'create':
             return SongCreateSerializer
+        if self.action in ['list', 'retrieve']:
+            return SongRetrieveSerializer
         return SongSerializer
+
+    def _change_artists(self, request, remove=False):
+        song = self.get_object()
+        serializer = SongArtistsListSerializer(data=request.data)
+        if serializer.is_valid():
+            artists = Artist.objects.filter(pk__in=serializer.data['artists'])
+            for artist in artists:
+                if remove:
+                    song.artists.remove(artist)
+                else:
+                    song.artists.add(artist)
+            song.save()
+            message = 'Artists {} song.'.format(('added to',
+                                                 'removed from')[remove])
+            return Response({'detail': message})
+        else:
+            return Response(serializer.errors,
+                            status=status.HTTP_400_BAD_REQUEST)
+
+    @action(methods=['post'], detail=True, permission_classes=[IsAdminUser])
+    def add_artists(self, request, pk=None):
+        return self._change_artists(request)
+
+    @action(methods=['post'], detail=True, permission_classes=[IsAdminUser])
+    def remove_artists(self, request, pk=None):
+        return self._change_artists(request, remove=True)