6 files changed, 374 insertions, 0 deletions
diff --git a/src/AsyncEndpoint.cs b/src/AsyncEndpoint.cs
new file mode 100644
index 0000000..10998ab
--- /dev/null
+++ b/src/AsyncEndpoint.cs
@@ -0,0 +1,40 @@
+namespace I2R.Endpoints;
+
+public static partial class AsyncEndpoint<BaseEndpoint>
+{
+    public static class Req<TRequest>
+    {
+        public abstract class Res<TResponse>
+        {
+            public abstract Task<TResponse> HandleAsync(
+                TRequest request,
+                CancellationToken cancellationToken = default
+            );
+        }
+
+        public abstract class NoRes
+        {
+            public abstract Task HandleAsync(
+                TRequest request,
+                CancellationToken cancellationToken = default
+            );
+        }
+    }
+
+    public static class NoReq
+    {
+        public abstract class Res<TResponse>
+        {
+            public abstract Task<TResponse> HandleAsync(
+                CancellationToken cancellationToken = default
+            );
+        }
+
+        public abstract class NoRes
+        {
+            public abstract Task HandleAsync(
+                CancellationToken cancellationToken = default
+            );
+        }
+    }
+}
+\ No newline at end of file
diff --git a/src/EndpointFinder.cs b/src/EndpointFinder.cs
new file mode 100644
index 0000000..ce1b321
--- /dev/null
+++ b/src/EndpointFinder.cs
@@ -0,0 +1,19 @@
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+
+namespace I2R.Endpoints;
+
+public class EndpointFinder : ISyntaxReceiver
+{
+    public HashSet<ClassDeclarationSyntax> AsyncEndpoints { get; } = new();
+    public HashSet<ClassDeclarationSyntax> SyncEndpoints { get; } = new();
+
+    public void OnVisitSyntaxNode(SyntaxNode syntaxNode) {
+        if (syntaxNode is not ClassDeclarationSyntax endpoint) return;
+        if (endpoint.BaseList?.Types.Any(c => c.ToString().StartsWith("AsyncEndpoint")) ?? false) {
+            AsyncEndpoints.Add(endpoint);
+        } else if (endpoint.BaseList?.Types.Any(c => c.ToString().StartsWith("SyncEndpoint")) ?? false) {
+            SyncEndpoints.Add(endpoint);
+        }
+    }
+}
+\ No newline at end of file
diff --git a/src/EndpointGenerator.cs b/src/EndpointGenerator.cs
new file mode 100644
index 0000000..58dbff6
--- /dev/null
+++ b/src/EndpointGenerator.cs
@@ -0,0 +1,255 @@
+using System.Text;
+using System.Text.Json;
+using System.Text.RegularExpressions;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+
+namespace I2R.Endpoints;
+
+[Generator]
+public class EndpointGenerator : ISourceGenerator
+{
+    private const string SourceGenereatedComment = "// Generated, probably smart to leave it be";
+
+    public void Initialize(GeneratorInitializationContext context) {
+        context.RegisterForSyntaxNotifications(() => new EndpointFinder());
+    }
+
+    private Diagnostic CreateDebugDiagnostic(string message) {
+        var descriptor = new DiagnosticDescriptor("debug", "Debug", message, "debug", DiagnosticSeverity.Warning, true);
+        return Diagnostic.Create(descriptor, null, "");
+    }
+
+    public class NeededInfo
+    {
+        public string BaseEndpointClassName { get; set; }
+        public string BaseEnpointNamespaceName { get; set; }
+    }
+
+    private NeededInfo ExtractNeededInfo(ClassDeclarationSyntax classDeclarationSyntax) {
+        var baseType = classDeclarationSyntax.BaseList?.Types.FirstOrDefault();
+        if (baseType == default) {
+            return default;
+        }
+
+        var fullTypeName = baseType?.Type.ToString();
+        var typeNamespace = GetNamespace(baseType);
+        var className = Regex.Match(fullTypeName, "(!?<).+?(?=>)").Value.Replace("<", "");
+        return new NeededInfo() {
+            BaseEndpointClassName = className,
+            BaseEnpointNamespaceName = typeNamespace
+        };
+    }
+
+    public void Execute(GeneratorExecutionContext context) {
+        var asyncEndpoints = ((EndpointFinder) context.SyntaxReceiver)?.AsyncEndpoints;
+        var syncEndpoints = ((EndpointFinder) context.SyntaxReceiver)?.SyncEndpoints;
+        if (asyncEndpoints == null) {
+            context.ReportDiagnostic(CreateDebugDiagnostic("no endpoints were found"));
+            return;
+        }
+
+        foreach (var endpoint in syncEndpoints) {
+            var info = ExtractNeededInfo(endpoint);
+            context.AddSource(info.BaseEndpointClassName + "s.g.cs", GetSyncSource(info.BaseEndpointClassName, info.BaseEnpointNamespaceName));
+        }
+
+        foreach (var endpoint in asyncEndpoints) {
+            var info = ExtractNeededInfo(endpoint);
+            context.AddSource(info.BaseEndpointClassName + "s.g.cs", GetAsyncSource(info.BaseEndpointClassName, info.BaseEnpointNamespaceName));
+        }
+    }
+
+    private string GetSyncSource(string className, string namespaceName) {
+        return $@"
+namespace {namespaceName};
+public static partial class SyncEndpoint<T{className}>
+{{
+    public static class Req<TRequest>
+    {{
+        public abstract class Res<TResponse> : {className}
+        {{
+            public abstract TResponse Handle(
+                TRequest request
+            );
+        }}
+
+        public abstract class NoRes : {className}
+        {{
+            public abstract void Handle(
+                TRequest request
+            );
+        }}
+    }}
+
+    public static class NoReq
+    {{
+        public abstract class Res<TResponse> : {className}
+        {{
+            public abstract TResponse Handle();
+        }}
+
+        public abstract class NoRes : {className}
+        {{
+            public abstract void Handle();
+        }}
+    }}
+}}
+";
+    }
+
+    private string GetAsyncSource(string className, string namespaceName) {
+        return $@"
+namespace {namespaceName};
+public static partial class AsyncEndpoint<T>
+{{
+    public static class Req<TRequest>
+    {{
+        public abstract class Res<TResponse> : {className}
+        {{
+            public abstract Task<TResponse> HandleAsync(
+                TRequest request,
+                CancellationToken cancellationToken = default
+            );
+        }}
+
+        public abstract class NoRes : {className}
+        {{
+            public abstract Task HandleAsync(
+                TRequest request,
+                CancellationToken cancellationToken = default
+            );
+        }}
+    }}
+
+    public static class NoReq
+    {{
+        public abstract class Res<TResponse> : {className}
+        {{
+            public abstract Task<TResponse> HandleAsync(
+                CancellationToken cancellationToken = default
+            );
+        }}
+
+        public abstract class NoRes : {className}
+        {{
+            public abstract Task HandleAsync(
+                CancellationToken cancellationToken = default
+            );
+        }}
+    }}
+}}
+";
+    }
+
+    // determine the namespace the class/enum/struct is declared in, if any
+    static string GetNamespace(BaseTypeSyntax syntax) {
+        // If we don't have a namespace at all we'll return an empty string
+        // This accounts for the "default namespace" case
+        string nameSpace = string.Empty;
+
+        // Get the containing syntax node for the type declaration
+        // (could be a nested type, for example)
+        SyntaxNode? potentialNamespaceParent = syntax.Parent;
+
+        // Keep moving "out" of nested classes etc until we get to a namespace
+        // or until we run out of parents
+        while (potentialNamespaceParent != null &&
+               potentialNamespaceParent is not NamespaceDeclarationSyntax
+               && potentialNamespaceParent is not FileScopedNamespaceDeclarationSyntax) {
+            potentialNamespaceParent = potentialNamespaceParent.Parent;
+        }
+
+        // Build up the final namespace by looping until we no longer have a namespace declaration
+        if (potentialNamespaceParent is BaseNamespaceDeclarationSyntax namespaceParent) {
+            // We have a namespace. Use that as the type
+            nameSpace = namespaceParent.Name.ToString();
+
+            // Keep moving "out" of the namespace declarations until we 
+            // run out of nested namespace declarations
+            while (true) {
+                if (namespaceParent.Parent is not NamespaceDeclarationSyntax parent) {
+                    break;
+                }
+
+                // Add the outer namespace as a prefix to the final namespace
+                nameSpace = $"{namespaceParent.Name}.{nameSpace}";
+                namespaceParent = parent;
+            }
+        }
+
+        // return the final namespace
+        return nameSpace;
+    }
+}
+
+
+/*
+    public static class Req<TRequest> : BaseEndpoint
+    {
+        public abstract class Res<TResponse> : BaseEndpoint
+        {
+            public abstract Task<TResponse> HandleAsync(
+                TRequest request,
+                CancellationToken cancellationToken = default
+            );
+        }
+
+        public abstract class NoRes
+        {
+            public abstract Task HandleAsync(
+                TRequest request,
+                CancellationToken cancellationToken = default
+            );
+        }
+    }
+
+    public static class NoReq
+    {
+        public abstract class Res<TResponse>
+        {
+            public abstract Task<TResponse> HandleAsync(
+                CancellationToken cancellationToken = default
+            );
+        }
+
+        public abstract class NoRes
+        {
+            public abstract Task HandleAsync(
+                CancellationToken cancellationToken = default
+            );
+        }
+    }
+ */
+
+/*
+    public static class Req<TRequest>
+    {
+        public abstract class Res<TResponse>
+        {
+            public abstract TResponse Handle(
+                TRequest request
+            );
+        }
+
+        public abstract class NoRes
+        {
+            public abstract void Handle(
+                TRequest request
+            );
+        }
+    }
+
+    public static class NoReq
+    {
+        public abstract class Res<TResponse>
+        {
+            public abstract TResponse Handle();
+        }
+
+        public abstract class NoRes
+        {
+            public abstract void Handle();
+        }
+    }
+ */
+\ No newline at end of file
diff --git a/src/Helpers.cs b/src/Helpers.cs
new file mode 100644
index 0000000..0159ae8
--- /dev/null
+++ b/src/Helpers.cs
@@ -0,0 +1,11 @@
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+
+namespace I2R.Endpoints;
+
+public static class Helpers
+{
+    public static bool Inherits(this ClassDeclarationSyntax source, string name) {
+        return source.BaseList?.Types.Select(baseType => baseType)
+            .Any(baseType => baseType.ToString() == name) ?? false;
+    }
+}
+\ No newline at end of file
diff --git a/src/I2R.Endpoints.csproj b/src/I2R.Endpoints.csproj
new file mode 100644
index 0000000..c4d4c67
--- /dev/null
+++ b/src/I2R.Endpoints.csproj
@@ -0,0 +1,15 @@
+<Project Sdk="Microsoft.NET.Sdk">
+    <PropertyGroup>
+        <TargetFramework>net7.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        
+    </PropertyGroup>
+    <ItemGroup>
+        <FrameworkReference Include="Microsoft.AspNetCore.App" />
+        <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.3">
+            <PrivateAssets>all</PrivateAssets>
+            <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+        </PackageReference>
+        <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.4.0" />
+    </ItemGroup>
+</Project>
diff --git a/src/SyncEndpoint.cs b/src/SyncEndpoint.cs
new file mode 100644
index 0000000..fc82288
--- /dev/null
+++ b/src/SyncEndpoint.cs
@@ -0,0 +1,34 @@
+namespace I2R.Endpoints;
+
+public static partial class SyncEndpoint<BaseEndpoint>
+{
+    public static class Req<TRequest>
+    {
+        public abstract class Res<TResponse>
+        {
+            public abstract TResponse Handle(
+                TRequest request
+            );
+        }
+
+        public abstract class NoRes
+        {
+            public abstract void Handle(
+                TRequest request
+            );
+        }
+    }
+
+    public static class NoReq
+    {
+        public abstract class Res<TResponse>
+        {
+            public abstract TResponse Handle();
+        }
+
+        public abstract class NoRes
+        {
+            public abstract void Handle();
+        }
+    }
+}
+\ No newline at end of file