Starting on source generator

src/Shiny.Mediator.SourceGenerators/MediatorSourceGenerator.cs

@@ -1,27 +1,52 @@
-using Microsoft.CodeAnalysis;
+using System.Text;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Text;
+using SourceGeneratorsKit;
 
 namespace Shiny.Mediator.SourceGenerators;
 
 
 [Generator]
 public class MediatorSourceGenerator : ISourceGenerator
 {
+    readonly SyntaxReceiver syntaxReceiver = new RegisterHandlerAttributeSyntaxReceiver();
     // SyntaxReceiver syntaxReceiver = new ClassesWithInterfacesReceiver("IEnumerable");
+
     public void Initialize(GeneratorInitializationContext context)
     {
-        // context.RegisterForSyntaxNotifications(() => syntaxReceiver);
+        context.RegisterForPostInitialization(x => x.AddSource("RegisterHandlerAttribute.g.cs", SourceText.From(
+            """
+            namespace Shiny.Mediator;
+
+            [System.AttributeUsage(AttributeTargets.Class, Inherited = true, AllowMultiple = false)]
+            public class RegisterHandlerAttribute : System.Attribute {}
+            """
+        )));
+       context.RegisterForSyntaxNotifications(() => syntaxReceiver);
     }
 
 
     public void Execute(GeneratorExecutionContext context)
     {
-        // if (!(context.SyntaxContextReceiver is SyntaxReceiver receiver))
-        // {
-        //     return;
-        // }
-        // foreach (INamedTypeSymbol classSymbol in this.syntaxReceiver.Classes)
-        // {
-        //     // process your class here.
-        // }
+        if (!(context.SyntaxContextReceiver is SyntaxReceiver receiver))
+            return;
+
+        var sb = new StringBuilder();
+        sb
+            .AppendLine("namespace Shiny.Mediator;")
+            .AppendLine()
+            .AppendLine("public static class __ShinyMediatorSourceGenExtensions {")
+            .AppendLine(
+                "\tpublic static global::Microsoft.Extensions.DependencyInjection.IServiceCollection AddDiscoveredMediatorHandlers(this global::Microsoft.Extensions.DependencyInjection.IServiceCollection services) {");
+
+        foreach (var classSymbol in this.syntaxReceiver.Classes)
+            sb.AppendLine($"\t\tservices.AddSingletonAsImplementedInterfaces<{classSymbol.ToDisplayString()}>();");
+
+        sb
+            .AppendLine("\treturn services;")
+            .AppendLine("\t}")
+            .AppendLine("}");
+
+        context.AddSource("__MediatorHandlersRegistration.g.cs", SourceText.From(sb.ToString()));
     }
 }

src/Shiny.Mediator.SourceGenerators/RegisterHandlerAttributeSyntaxReceiver.cs

@@ -0,0 +1,25 @@
+using Microsoft.CodeAnalysis;
+using SourceGeneratorsKit;
+
+namespace Shiny.Mediator.SourceGenerators;
+
+
+public class RegisterHandlerAttributeSyntaxReceiver : SyntaxReceiver
+{
+    public override bool CollectClassSymbol => true;
+
+    protected override bool ShouldCollectClassSymbol(INamedTypeSymbol classSymbol)
+    {
+        var hasAttribute = classSymbol.HasAttribute("RegisterHandlerAttribute");
+        if (!hasAttribute)
+            return false;
+
+        if (classSymbol.IsImplements("Shiny.Mediator.IEventHandler`1"))
+            return false;
+
+        if (classSymbol.IsImplements("Shiny.Mediator.IRequestHandler`1"))
+            return false;
+
+        return false;
+    }
+}