1 files changed, 146 insertions, 0 deletions
diff --git a/code/source-generator/EndpointGenerator.cs b/code/source-generator/EndpointGenerator.cs
new file mode 100644
index 0000000..989a1c5
--- /dev/null
+++ b/code/source-generator/EndpointGenerator.cs
@@ -0,0 +1,146 @@
+using System.Text.RegularExpressions;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+
+namespace I2R.Endpoints.Generator;
+
+[Generator]
+public class EndpointGenerator : ISourceGenerator
+{
+    private const string SourceGenereatedComment = "// Generated by I2R.Endpoints, probably smart to leave it be";
+
+    public void Initialize(GeneratorInitializationContext context) {
+        context.RegisterForSyntaxNotifications(() => new EndpointFinder());
+    }
+
+    public void Execute(GeneratorExecutionContext context) {
+        var endpointClasses = ((EndpointFinder) context.SyntaxReceiver)?.Endpoints;
+        if (endpointClasses == null) {
+            context.ReportDiagnostic(CreateDebugDiagnostic("no endpoints were found"));
+            return;
+        }
+
+        foreach (var info in endpointClasses.Select(GetEndpointInfoFromClass)) {
+            context.AddSource(info.GeneratedFileName, info.IsSynchronous ? GetSyncSource(info) : GetAsyncSource(info));
+        }
+    }
+
+    private static Diagnostic CreateDebugDiagnostic(string message) {
+        var descriptor = new DiagnosticDescriptor("debug", "Debug", message, "debug", DiagnosticSeverity.Warning, true);
+        return Diagnostic.Create(descriptor, null, "");
+    }
+
+    private class EndpointInfo
+    {
+        public string BaseEndpointClassName { get; set; }
+        public bool IsSynchronous { get; set; }
+        public string GeneratedFileName { get; set; }
+    }
+
+    public static bool IsSyncEndpoint(string name) {
+        return name.StartsWith("SyncEndpoint");
+    }
+
+    public static bool IsAyncEndpoint(string name) {
+        return name.StartsWith("AsyncEndpoint");
+    }
+
+    private static EndpointInfo GetEndpointInfoFromClass(ClassDeclarationSyntax classDeclarationSyntax) {
+        var baseType = classDeclarationSyntax.BaseList?.Types.FirstOrDefault();
+        if (baseType == default) {
+            return default;
+        }
+
+        var fullTypeName = baseType.Type.ToString();
+        var className = Regex.Match(fullTypeName, "(!?<).+?(?=>)").Value.Replace("<", "");
+        return new EndpointInfo() {
+            BaseEndpointClassName = className,
+            IsSynchronous = IsSyncEndpoint(baseType.ToString()),
+            GeneratedFileName = className + ".endpoints.g.cs"
+        };
+    }
+
+    private static string GetSyncSource(EndpointInfo info) {
+        return $@"
+{SourceGenereatedComment}
+namespace {typeof(EndpointGenerator).Namespace};
+public static partial class SyncEndpoint<T{info.BaseEndpointClassName}>
+{{
+    public static class Req<TRequest>
+    {{
+        public abstract class Res<TResponse> : {info.BaseEndpointClassName}
+        {{
+            public abstract TResponse Handle(
+                TRequest request
+            );
+        }}
+
+        public abstract class NoRes : {info.BaseEndpointClassName}
+        {{
+            public abstract void Handle(
+                TRequest request
+            );
+        }}
+    }}
+
+    public static class NoReq
+    {{
+        public abstract class Res<TResponse> : {info.BaseEndpointClassName}
+        {{
+            public abstract TResponse Handle();
+        }}
+
+        public abstract class NoRes : {info.BaseEndpointClassName}
+        {{
+            public abstract void Handle();
+        }}
+    }}
+}}
+";
+    }
+
+    private static string GetAsyncSource(EndpointInfo info) {
+        return $@"
+{SourceGenereatedComment}
+namespace {typeof(EndpointGenerator).Namespace};
+public static partial class AsyncEndpoint<T>
+{{
+    public static class Req<TRequest>
+    {{
+        public abstract class Res<TResponse> : {info.BaseEndpointClassName}
+        {{
+            public abstract Task<TResponse> HandleAsync(
+                TRequest request,
+                CancellationToken cancellationToken = default
+            );
+        }}
+
+        public abstract class NoRes : {info.BaseEndpointClassName}
+        {{
+            public abstract Task HandleAsync(
+                TRequest request,
+                CancellationToken cancellationToken = default
+            );
+        }}
+    }}
+
+    public static class NoReq
+    {{
+        public abstract class Res<TResponse> : {info.BaseEndpointClassName}
+        {{
+            public abstract Task<TResponse> HandleAsync(
+                CancellationToken cancellationToken = default
+            );
+        }}
+
+        public abstract class NoRes : {info.BaseEndpointClassName}
+        {{
+            public abstract Task HandleAsync(
+                CancellationToken cancellationToken = default
+            );
+        }}
+    }}
+}}
+";
+    }
+}