From 47e1eec122eec8c3cdba484ba098f3327e9551fe Mon Sep 17 00:00:00 2001
From: Tom Hacohen <tom@stosb.com>
Date: Wed, 20 May 2020 15:15:24 +0300
Subject: [PATCH] Incoming invitations: implement incoming invitations and
 accepting them

---
 django_etesync/models.py      |  5 +++++
 django_etesync/serializers.py | 38 +++++++++++++++++++++++++++++------
 django_etesync/views.py       | 26 ++++++++++++++++++++++++
 3 files changed, 63 insertions(+), 6 deletions(-)

diff --git a/django_etesync/models.py b/django_etesync/models.py
index e0a79f6..cbfa269 100644
--- a/django_etesync/models.py
+++ b/django_etesync/models.py
@@ -150,6 +150,7 @@ class CollectionInvitation(models.Model):
     version = models.PositiveSmallIntegerField(default=1)
     fromMember = models.ForeignKey(CollectionMember, on_delete=models.CASCADE)
     # FIXME: make sure to delete all invitations for the same collection once one is accepted
+    # Make sure to not allow invitations if already a member
 
     user = models.ForeignKey(settings.AUTH_USER_MODEL, related_name='incoming_invitations', on_delete=models.CASCADE)
     signedEncryptionKey = models.BinaryField(editable=False, blank=False, null=False)
@@ -165,6 +166,10 @@ class CollectionInvitation(models.Model):
     def __str__(self):
         return '{} {}'.format(self.fromMember.collection.uid, self.user)
 
+    @cached_property
+    def collection(self):
+        return self.fromMember.collection
+
 
 class UserInfo(models.Model):
     owner = models.OneToOneField(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, primary_key=True)
diff --git a/django_etesync/serializers.py b/django_etesync/serializers.py
index 54b8d9c..185eb6e 100644
--- a/django_etesync/serializers.py
+++ b/django_etesync/serializers.py
@@ -268,18 +268,20 @@ class CollectionInvitationSerializer(serializers.ModelSerializer):
         slug_field=User.USERNAME_FIELD,
         queryset=User.objects
     )
-    collection = serializers.SlugRelatedField(
-        source='fromMember__collection',
-        slug_field='uid',
-        read_only=True,
-    )
-    fromPubkey = BinaryBase64Field(source='fromMember__user__userinfo__pubkey', read_only=True)
+    collection = serializers.SerializerMethodField('get_collection')
+    fromPubkey = serializers.SerializerMethodField('get_from_pubkey')
     signedEncryptionKey = BinaryBase64Field()
 
     class Meta:
         model = models.CollectionInvitation
         fields = ('username', 'uid', 'collection', 'signedEncryptionKey', 'accessLevel', 'fromPubkey', 'version')
 
+    def get_collection(self, obj):
+        return obj.collection.uid
+
+    def get_from_pubkey(self, obj):
+        return b64encode(obj.fromMember.user.userinfo.pubkey)
+
     def create(self, validated_data):
         collection = self.context['collection']
         request = self.context['request']
@@ -301,6 +303,30 @@ class CollectionInvitationSerializer(serializers.ModelSerializer):
         return instance
 
 
+class InvitationAcceptSerializer(serializers.Serializer):
+    encryptionKey = BinaryBase64Field()
+
+    def create(self, validated_data):
+
+        with transaction.atomic():
+            invitation = self.context['invitation']
+            encryption_key = validated_data.get('encryptionKey')
+
+            member = models.CollectionMember.objects.create(
+                    collection=invitation.collection,
+                    user=invitation.user,
+                    accessLevel=invitation.accessLevel,
+                    encryptionKey=encryption_key,
+                    )
+
+            invitation.delete()
+
+            return member
+
+    def update(self, instance, validated_data):
+        raise NotImplementedError()
+
+
 class UserSerializer(serializers.ModelSerializer):
     class Meta:
         model = User
diff --git a/django_etesync/views.py b/django_etesync/views.py
index ffb9503..a1d6d09 100644
--- a/django_etesync/views.py
+++ b/django_etesync/views.py
@@ -49,6 +49,7 @@ from .serializers import (
         CollectionItemChunkSerializer,
         CollectionMemberSerializer,
         CollectionInvitationSerializer,
+        InvitationAcceptSerializer,
         UserSerializer,
     )
 
@@ -456,6 +457,31 @@ class CollectionInvitationViewSet(BaseViewSet):
         return queryset.filter(fromMember__collection=collection)
 
 
+class InvitationIncomingViewSet(BaseViewSet):
+    allowed_methods = ['GET', 'DELETE']
+    queryset = CollectionInvitation.objects.all()
+    serializer_class = CollectionInvitationSerializer
+    lookup_field = 'uid'
+    lookup_url_kwarg = 'invitation_uid'
+
+    def get_queryset(self, queryset=None):
+        if queryset is None:
+            queryset = type(self).queryset
+
+        return queryset.filter(user=self.request.user)
+
+    @action_decorator(detail=True, allowed_methods=['POST'], methods=['POST'])
+    def accept(self, request, invitation_uid=None):
+        invitation = get_object_or_404(self.get_queryset(), uid=invitation_uid)
+        context = self.get_serializer_context()
+        context.update({'invitation': invitation})
+
+        serializer = InvitationAcceptSerializer(data=request.data, context=context)
+        serializer.is_valid(raise_exception=True)
+        serializer.save()
+        return Response(status=status.HTTP_201_CREATED)
+
+
 class AuthenticationViewSet(viewsets.ViewSet):
     allowed_methods = ['POST']