added Akka.NET messages

Directory.Packages.props

@@ -5,6 +5,7 @@
   <!-- Akka.NET Package Versions -->
   <ItemGroup>
     <PackageVersion Include="Akka" Version="1.5.20" />
+    <PackageVersion Include="Akka.Cluster.Hosting" Version="1.5.20" />
     <PackageVersion Include="Akka.Hosting" Version="1.5.20" />
     <PackageVersion Include="Akka.Hosting.TestKit" Version="1.5.20" />
     <PackageVersion Include="Akka.Streams" Version="1.5.20" />

DrawTogether.sln

@@ -25,6 +25,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "infrastructure", "infrastru
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "DrawTogether.Entities", "src\DrawTogether.Entities\DrawTogether.Entities.csproj", "{7F01390E-AF15-442C-831C-C574D6AAFC1F}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "DrawTogether.Actors", "src\DrawTogether.Actors\DrawTogether.Actors.csproj", "{5863DD74-00DE-4DE9-9F0A-FCBC32195E78}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -95,6 +97,18 @@ Global
 		{7F01390E-AF15-442C-831C-C574D6AAFC1F}.Release|x64.Build.0 = Release|Any CPU
 		{7F01390E-AF15-442C-831C-C574D6AAFC1F}.Release|x86.ActiveCfg = Release|Any CPU
 		{7F01390E-AF15-442C-831C-C574D6AAFC1F}.Release|x86.Build.0 = Release|Any CPU
+		{5863DD74-00DE-4DE9-9F0A-FCBC32195E78}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{5863DD74-00DE-4DE9-9F0A-FCBC32195E78}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{5863DD74-00DE-4DE9-9F0A-FCBC32195E78}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{5863DD74-00DE-4DE9-9F0A-FCBC32195E78}.Debug|x64.Build.0 = Debug|Any CPU
+		{5863DD74-00DE-4DE9-9F0A-FCBC32195E78}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{5863DD74-00DE-4DE9-9F0A-FCBC32195E78}.Debug|x86.Build.0 = Debug|Any CPU
+		{5863DD74-00DE-4DE9-9F0A-FCBC32195E78}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{5863DD74-00DE-4DE9-9F0A-FCBC32195E78}.Release|Any CPU.Build.0 = Release|Any CPU
+		{5863DD74-00DE-4DE9-9F0A-FCBC32195E78}.Release|x64.ActiveCfg = Release|Any CPU
+		{5863DD74-00DE-4DE9-9F0A-FCBC32195E78}.Release|x64.Build.0 = Release|Any CPU
+		{5863DD74-00DE-4DE9-9F0A-FCBC32195E78}.Release|x86.ActiveCfg = Release|Any CPU
+		{5863DD74-00DE-4DE9-9F0A-FCBC32195E78}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

src/DrawTogether.Actors/Class1.cs

@@ -0,0 +1,43 @@
+using Akka.Actor;
+using Akka.Cluster.Sharding;
+
+namespace DrawTogether.Actors;
+
+/// <summary>
+/// A generic "child per entity" parent actor.
+/// </summary>
+/// <remarks>
+/// Intended for simplifying unit tests where we don't want to use Akka.Cluster.Sharding.
+/// </remarks>
+public sealed class GenericChildPerEntityParent : UntypedActor
+{
+    public static Props Props(IMessageExtractor extractor, Func<string, Props> propsFactory)
+    {
+        return Akka.Actor.Props.Create(() => new GenericChildPerEntityParent(extractor, propsFactory));
+    }
+
+    /*
+     * Re-use Akka.Cluster.Sharding's infrastructure here to keep things simple.
+     */
+    private readonly IMessageExtractor _extractor;
+    private readonly Func<string, Props> _propsFactory;
+
+    public GenericChildPerEntityParent(IMessageExtractor extractor, Func<string, Props> propsFactory)
+    {
+        _extractor = extractor;
+        _propsFactory = propsFactory;
+    }
+
+    protected override void OnReceive(object message)
+    {
+        var result = _extractor.EntityId(message);
+        if (result is null)
+        {
+            Unhandled(message);
+            return;
+        }
+
+        Context.Child(result).GetOrElse(() => Context.ActorOf(_propsFactory(result), result))
+            .Forward(_extractor.EntityMessage(message));
+    }
+}

src/DrawTogether.Actors/DrawTogether.Actors.csproj

@@ -0,0 +1,17 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net8.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+    </PropertyGroup>
+
+    <ItemGroup>
+      <PackageReference Include="Akka.Cluster.Hosting" />
+    </ItemGroup>
+
+    <ItemGroup>
+      <Folder Include="Drawings\" />
+    </ItemGroup>
+
+</Project>

src/DrawTogether.Entities/CommandResult.cs

@@ -0,0 +1,21 @@
+namespace DrawTogether.Entities;
+
+public enum ResultCode
+{
+    Ok,
+    NoOp,
+    BadRequest,
+    Unauthorized,
+    TimeOut
+}
+
+public sealed record CommandResult
+{
+    public ResultCode Code { get; init; }
+
+    public string? Message { get; init; }
+
+    public static CommandResult Ok() => new() { Code = ResultCode.Ok };
+
+    public bool IsError => Code != ResultCode.Ok && Code != ResultCode.NoOp;
+}

src/DrawTogether.Entities/DrawTogether.Entities.csproj

@@ -6,8 +6,4 @@
         <Nullable>enable</Nullable>
     </PropertyGroup>
 
-    <ItemGroup>
-      <Folder Include="Users\" />
-    </ItemGroup>
-
 </Project>

src/DrawTogether.Entities/Drawings/DrawingSessionId.cs

@@ -0,0 +1,3 @@
+namespace DrawTogether.Entities.Drawings;
+
+public sealed class DrawingSessionId(string SessionId);

src/DrawTogether.Entities/Drawings/DrawingSessionState.cs

@@ -0,0 +1,12 @@
+using System.Collections.Immutable;
+using DrawTogether.Entities.Drawings.Messages;
+using DrawTogether.Entities.Users;
+
+namespace DrawTogether.Entities.Drawings;
+
+public sealed record DrawingSessionState(DrawingSessionId DrawingSessionId) : IWithDrawingSessionId
+{
+    public ImmutableDictionary<StrokeId, ConnectedStroke> Strokes { get; init; } = ImmutableDictionary<StrokeId, ConnectedStroke>.Empty;
+
+    public ImmutableHashSet<UserId> ConnectedUsers { get; init; } = ImmutableHashSet<UserId>.Empty;
+}

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

@@ -0,0 +1,18 @@
+using DrawTogether.Entities.Users;
+
+namespace DrawTogether.Entities.Drawings.Messages;
+
+public interface IDrawingSessionCommand : IWithDrawingSessionId{ }
+
+public static class DrawingSessionCommands
+{
+    public sealed record AddStroke(DrawingSessionId DrawingSessionId, ConnectedStroke Stroke) : IDrawingSessionCommand;
+
+    public sealed record RemoveStroke(DrawingSessionId DrawingSessionId, StrokeId StrokeId) : IDrawingSessionCommand;
+
+    public sealed record ClearStrokes(DrawingSessionId DrawingSessionId) : IDrawingSessionCommand;
+
+    public sealed record AddUser(DrawingSessionId DrawingSessionId, UserId UserId) : IDrawingSessionCommand;
+
+    public sealed record RemoveUser(DrawingSessionId DrawingSessionId, UserId UserId) : IDrawingSessionCommand;
+}

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

@@ -0,0 +1,25 @@
+using DrawTogether.Entities.Users;
+
+namespace DrawTogether.Entities.Drawings.Messages;
+
+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;
+
+    public sealed record StrokesCleared(DrawingSessionId DrawingSessionId) : IDrawingSessionEvent;
+
+    public sealed record UserAdded(DrawingSessionId DrawingSessionId, UserId UserId) : IDrawingSessionEvent;
+
+    public sealed record UserRemoved(DrawingSessionId DrawingSessionId, UserId UserId) : IDrawingSessionEvent;
+
+    /// <summary>
+    /// Occurs when the last user leaves the session.
+    /// </summary>
+    public sealed record DrawingSessionClosed(DrawingSessionId DrawingSessionId) : IDrawingSessionEvent;
+}

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

@@ -0,0 +1,14 @@
+namespace DrawTogether.Entities.Drawings.Messages;
+
+public interface IDrawingSessionQuery : IWithDrawingSessionId { }
+
+public static class DrawingSessionQueries
+{
+    public sealed record GetDrawingSessionState(DrawingSessionId DrawingSessionId) : IDrawingSessionQuery;
+
+    public sealed record GetDrawingSessionUsers(DrawingSessionId DrawingSessionId) : IDrawingSessionQuery;
+
+    public sealed record SubscribeToDrawingSession(DrawingSessionId DrawingSessionId) : IDrawingSessionQuery;
+
+    public sealed record UnsubscribeFromDrawingSession(DrawingSessionId DrawingSessionId) : IDrawingSessionQuery;
+}

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

@@ -0,0 +1,11 @@
+using DrawTogether.Entities.Users;
+
+namespace DrawTogether.Entities.Drawings.Messages;
+
+/// <summary>
+/// Marker interface for messages that have a <see cref="DrawingSessionId"/>.
+/// </summary>
+public interface IWithDrawingSessionId
+{
+    DrawingSessionId DrawingSessionId { get; }
+}

src/DrawTogether.Entities/Users/UserId.cs

@@ -0,0 +1,3 @@
+namespace DrawTogether.Entities.Users;
+
+public sealed class UserId(string IdentityName);