added Protobuf definition

Directory.Packages.props

@@ -11,6 +11,7 @@
     <PackageVersion Include="Akka.Persistence.Sql.Hosting" Version="1.5.13" />
     <PackageVersion Include="Akka.Streams" Version="1.5.20" />
     <PackageVersion Include="Akka.Streams.TestKit" Version="1.5.20" />
+    <PackageVersion Include="Grpc.Tools" Version="2.63.0" />
     <PackageVersion Include="Microsoft.EntityFrameworkCore.SqlServer" Version="8.0.4" />
     <PackageVersion Include="MudBlazor" Version="6.19.1" />
   </ItemGroup>

src/DrawTogether.Actors/DrawTogether.Actors.csproj

@@ -9,6 +9,10 @@
     <ItemGroup>
       <PackageReference Include="Akka.Cluster.Hosting" />
       <PackageReference Include="Akka.Streams" />
+      <PackageReference Include="Grpc.Tools">
+        <PrivateAssets>all</PrivateAssets>
+        <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      </PackageReference>
     </ItemGroup>
 
     <ItemGroup>

src/DrawTogether.Actors/Serialization/Proto/DrawingProtocol.proto

@@ -0,0 +1,98 @@
+syntax = "proto3";
+
+package DrawTogether.Actors.Serialization.Proto;
+
+import "google/protobuf/timestamp.proto";
+
+/* Primitives */
+message UserId {
+    string id = 1;
+}
+
+message DrawingSessionId {
+    string id = 1;
+}
+
+message StrokeId {
+    int32 id = 1;
+}
+
+message Point {
+    double x = 1;
+    double y = 2;
+}
+
+message ConnectedStroke {
+    StrokeId id = 1;
+    repeated Point points = 2;
+    int32 strokeWidth = 3;
+    string strokeColor = 4;
+}
+
+/* Commands and events */
+message AddUser {
+    DrawingSessionId drawingSessionId = 1;
+    UserId userId = 2;
+}
+
+message RemoveUser {
+    DrawingSessionId drawingSessionId = 1;
+    UserId userId = 2;
+
+}
+
+message AddStroke {
+    DrawingSessionId drawingSessionId = 2;
+    ConnectedStroke connectedStroke = 3;
+}
+
+message RemoveStroke {
+    DrawingSessionId drawingSessionId = 1;
+    StrokeId strokeId = 2;
+}
+
+message ClearStrokes {
+    DrawingSessionId drawingSessionId = 1;
+}
+
+message SessionClosed {
+    DrawingSessionId drawingSessionId = 1;
+}
+
+/* State */
+
+message DrawingSessionState{
+    DrawingSessionId drawingSessionId = 1;
+    repeated ConnectedStroke connectedStrokes = 2;
+    repeated UserId connectedUsers = 3;
+    google.protobuf.Timestamp lastUpdated = 4;
+}
+
+/* Queries */
+
+message GetDrawingSessionState {
+    DrawingSessionId drawingSessionId = 1;
+}
+
+message SubscribeToDrawingSessionState {
+    DrawingSessionId drawingSessionId = 1;
+}
+
+message SubscribeAcknowledged {
+    DrawingSessionId drawingSessionId = 1;
+}
+
+message UnsuscribeFromDrawingSessionState {
+    DrawingSessionId drawingSessionId = 1;
+}
+
+message UnsuscribeAcknowledged {
+    DrawingSessionId drawingSessionId = 1;
+}
+
+message  DrawingActivityUpdated {
+    DrawingSessionId drawingSessionId = 1;
+    google.protobuf.Timestamp lastUpdated = 2;
+    int32 activeUsers = 3;
+    bool isRemoved = 4;
+}

src/DrawTogether.Entities/Drawings/Messages/DrawingSessionEvents.cs

@@ -6,8 +6,6 @@ public interface IDrawingSessionEvent : IWithDrawingSessionId { }
 
 public static class DrawingSessionEvents
 {
-    public sealed record DrawingSessionCreated(DrawingSessionId DrawingSessionId) : IDrawingSessionEvent;
-
     public sealed record StrokeAdded(DrawingSessionId DrawingSessionId, ConnectedStroke Stroke) : IDrawingSessionEvent;
 
     public sealed record StrokeRemoved(DrawingSessionId DrawingSessionId, StrokeId StrokeId) : IDrawingSessionEvent;

src/DrawTogether.Entities/Drawings/Messages/IWithDrawingSessionId.cs

@@ -1,6 +1,4 @@
-using DrawTogether.Entities.Users;
-
-namespace DrawTogether.Entities.Drawings.Messages;
+namespace DrawTogether.Entities.Drawings.Messages;
 
 /// <summary>
 /// Marker interface for messages that have a <see cref="DrawingSessionId"/>.