Initial commit: Aurora Moments self-hosted photo/video sharing platform

Django/DRF + PostgreSQL/Redis/Celery backend with accounts, library,
moments, and notifications apps; React/TypeScript/Vite frontend with
Instagram-style sidebar nav, feed, profiles, nested comment replies,
notifications, and photo/video upload with ffmpeg-generated posters.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

api/apps/moments/serializers.py

@@ -0,0 +1,103 @@
+from django.db import transaction
+from rest_framework import serializers
+
+from apps.accounts.serializers import UserSerializer
+from apps.library.models import LibraryItem
+from apps.library.serializers import LibraryItemSerializer
+
+from .models import Comment, Moment, MomentItem, Reaction
+
+
+class MomentItemSerializer(serializers.ModelSerializer):
+    library_item = LibraryItemSerializer(read_only=True)
+
+    class Meta:
+        model = MomentItem
+        fields = ["id", "library_item", "order"]
+
+
+class CommentSerializer(serializers.ModelSerializer):
+    author = UserSerializer(read_only=True)
+
+    class Meta:
+        model = Comment
+        fields = ["id", "moment", "author", "parent", "body", "created_at"]
+        read_only_fields = ["id", "moment", "author", "created_at"]
+
+    def validate_parent(self, value):
+        if value is None:
+            return value
+        if value.parent_id is not None:
+            raise serializers.ValidationError("Cannot reply to a reply; reply to the original comment instead.")
+        moment = self.context.get("moment")
+        if moment is not None and value.moment_id != moment.id:
+            raise serializers.ValidationError("Reply must target a comment on the same Moment.")
+        return value
+
+
+class ReactionSerializer(serializers.ModelSerializer):
+    user = UserSerializer(read_only=True)
+
+    class Meta:
+        model = Reaction
+        fields = ["id", "moment", "user", "reaction_type", "created_at"]
+        read_only_fields = ["id", "moment", "user", "created_at"]
+
+
+class MomentSerializer(serializers.ModelSerializer):
+    owner = UserSerializer(read_only=True)
+    items = MomentItemSerializer(many=True, read_only=True)
+    library_item_ids = serializers.PrimaryKeyRelatedField(
+        queryset=LibraryItem.objects.all(), many=True, write_only=True, source="library_items", required=False
+    )
+    comment_count = serializers.IntegerField(source="comments.count", read_only=True)
+    reaction_count = serializers.IntegerField(source="reactions.count", read_only=True)
+    viewer_reaction_id = serializers.SerializerMethodField()
+
+    class Meta:
+        model = Moment
+        fields = [
+            "id", "owner", "caption", "location", "audience", "items",
+            "library_item_ids", "comment_count", "reaction_count", "viewer_reaction_id",
+            "created_at", "updated_at",
+        ]
+        read_only_fields = [
+            "id", "owner", "items", "comment_count", "reaction_count", "viewer_reaction_id",
+            "created_at", "updated_at",
+        ]
+
+    def get_viewer_reaction_id(self, obj):
+        request = self.context.get("request")
+        if not request or not request.user.is_authenticated:
+            return None
+        # obj.reactions is prefetched by the view, so this doesn't re-query per moment.
+        reaction = next((r for r in obj.reactions.all() if r.user_id == request.user.id), None)
+        return reaction.id if reaction else None
+
+    def validate_library_item_ids(self, library_items):
+        request = self.context["request"]
+        seen_ids = set()
+        for item in library_items:
+            if item.owner_id != request.user.id:
+                raise serializers.ValidationError("Can only share items from your own library.")
+            if item.id in seen_ids:
+                raise serializers.ValidationError("The same photo was selected more than once.")
+            seen_ids.add(item.id)
+        return library_items
+
+    def validate(self, attrs):
+        library_items = attrs.get("library_items", [])
+        caption = attrs.get("caption", "")
+        if not library_items and not caption.strip():
+            raise serializers.ValidationError("A Moment needs a caption or at least one photo.")
+        return attrs
+
+    def create(self, validated_data):
+        library_items = validated_data.pop("library_items", [])
+        validated_data["owner"] = self.context["request"].user
+        with transaction.atomic():
+            moment = Moment.objects.create(**validated_data)
+            MomentItem.objects.bulk_create(
+                [MomentItem(moment=moment, library_item=item, order=i) for i, item in enumerate(library_items)]
+            )
+        return moment