Add an optional parameter to enable generation of internal interfaces

AutomaticInterface/AutomaticInterface/Builder.cs

@@ -52,11 +52,12 @@ is not ClassDeclarationSyntax classSyntax
         {
             return string.Empty;
         }
-        var namespaceName = GetNameSpace(typeSymbol);
-
+        var generationAttribute = GetGenerationAttribute(typeSymbol);
+        var namespaceName = GetNameSpace(typeSymbol, generationAttribute);
+        var asInternal = GetAsInternal(generationAttribute);
         var interfaceName = $"I{classSyntax.GetClassName()}";
 
-        var interfaceGenerator = new InterfaceBuilder(namespaceName, interfaceName);
+        var interfaceGenerator = new InterfaceBuilder(namespaceName, interfaceName, asInternal);
 
         interfaceGenerator.AddClassDocumentation(GetDocumentationForClass(classSyntax));
         interfaceGenerator.AddGeneric(GetGeneric(classSyntax, namedTypeSymbol));
@@ -77,15 +78,18 @@ is not ClassDeclarationSyntax classSyntax
         return generatedCode;
     }
 
-    private static string GetNameSpace(ISymbol typeSymbol)
-    {
-        var generationAttribute = typeSymbol
-            .GetAttributes()
-            .FirstOrDefault(x =>
-                x.AttributeClass != null
-                && x.AttributeClass.Name.Contains(AutomaticInterfaceGenerator.DefaultAttributeName)
-            );
+    private static AttributeData? GetGenerationAttribute(ISymbol typeSymbol)
+    {
+        return typeSymbol
+           .GetAttributes()
+           .FirstOrDefault(x =>
+               x.AttributeClass != null
+               && x.AttributeClass.Name.Contains(AutomaticInterfaceGenerator.DefaultAttributeName)
+           );
+    }
 
+    private static string GetNameSpace(ISymbol typeSymbol, AttributeData? generationAttribute)
+    {
         if (generationAttribute == null)
         {
             return typeSymbol.ContainingNamespace.ToDisplayString();
@@ -96,6 +100,18 @@ private static string GetNameSpace(ISymbol typeSymbol)
         return string.IsNullOrWhiteSpace(customNs)
             ? typeSymbol.ContainingNamespace.ToDisplayString()
             : customNs!;
+    }
+
+    private static bool GetAsInternal(AttributeData? generationAttribute)
+    {
+        if (generationAttribute == null)
+        {
+            return false;
+        }
+
+        var asInternal = (bool?)generationAttribute.ConstructorArguments.Skip(1).FirstOrDefault().Value;
+
+        return asInternal.GetValueOrDefault();
     }
 
     private static void AddMethodsToInterface(List<ISymbol> members, InterfaceBuilder codeGenerator)

AutomaticInterface/AutomaticInterface/InterfaceBuilder.cs

@@ -24,7 +24,7 @@ internal sealed record MethodInfo(
 
     public record EventInfo(string Name, string Type, string Documentation);
 
-    public class InterfaceBuilder(string nameSpaceName, string interfaceName)
+    public class InterfaceBuilder(string nameSpaceName, string interfaceName, bool asInternal)
     {
         private const string Autogenerated = """
             //--------------------------------------------------------------------------------------------------
@@ -104,7 +104,7 @@ public string Build()
             cb.AppendLine(
                 "[global::System.CodeDom.Compiler.GeneratedCode(\"AutomaticInterface\", \"\")]"
             );
-            cb.AppendLine($"public partial interface {interfaceName}{genericType}");
+            cb.AppendLine($"{(asInternal ? "internal" : "public")} partial interface {interfaceName}{genericType}");
             cb.AppendLine("{");
 
             cb.Indent();

AutomaticInterface/AutomaticInterface/RegisterAttributesExtensions.cs

@@ -27,7 +27,7 @@ namespace AutomaticInterface
                         [AttributeUsage(AttributeTargets.Class)]
                         internal sealed class {{{AutomaticInterfaceGenerator.DefaultAttributeName}}}Attribute : Attribute
                         {
-                            internal {{{AutomaticInterfaceGenerator.DefaultAttributeName}}}Attribute(string namespaceName = "") { }
+                            internal {{{AutomaticInterfaceGenerator.DefaultAttributeName}}}Attribute(string namespaceName = "", bool asInternal = false) { }
                         }
                     }
                     """,

AutomaticInterface/AutomaticInterfaceExample/DemoClassWithAsInternal.cs

@@ -0,0 +1,22 @@
+using System;
+using AutomaticInterface;
+
+namespace AutomaticInterfaceExample
+{
+    /// <summary>
+    /// Class Documentation will be copied
+    /// </summary>
+    [GenerateAutomaticInterface(asInternal: true)]
+    [System.Diagnostics.CodeAnalysis.SuppressMessage(
+        "Major Code Smell",
+        "S1144:Unused private types or members should be removed",
+        Justification = "Demo class"
+    )]
+    public class DemoClass3 : IDemoClass3
+    {
+        /// <summary>
+        /// This is a test method
+        /// </summary>
+        public void Test() { }
+    }
+}

AutomaticInterface/Tests/Misc/Misc.AsInternal.verified.txt

@@ -0,0 +1,20 @@
+//--------------------------------------------------------------------------------------------------
+// <auto-generated>
+//     This code was generated by a tool.
+//
+//     Changes to this file may cause incorrect behavior and will be lost if the code is regenerated.
+// </auto-generated>
+//--------------------------------------------------------------------------------------------------
+
+#nullable enable
+namespace AutomaticInterfaceExample
+{
+    [global::System.CodeDom.Compiler.GeneratedCode("AutomaticInterface", "")]
+    internal partial interface IDemoClass
+    {
+        /// <inheritdoc cref="AutomaticInterfaceExample.DemoClass.AMethod(AutomaticInterfaceExample.DemoClass?, string)" />
+        string AMethod(global::AutomaticInterfaceExample.DemoClass? x, string y);
+
+    }
+}
+#nullable restore

AutomaticInterface/Tests/Misc/Misc.AsInternalExplicitFalse.verified.txt

@@ -0,0 +1,20 @@
+//--------------------------------------------------------------------------------------------------
+// <auto-generated>
+//     This code was generated by a tool.
+//
+//     Changes to this file may cause incorrect behavior and will be lost if the code is regenerated.
+// </auto-generated>
+//--------------------------------------------------------------------------------------------------
+
+#nullable enable
+namespace AutomaticInterfaceExample
+{
+    [global::System.CodeDom.Compiler.GeneratedCode("AutomaticInterface", "")]
+    public partial interface IDemoClass
+    {
+        /// <inheritdoc cref="AutomaticInterfaceExample.DemoClass.AMethod(AutomaticInterfaceExample.DemoClass?, string)" />
+        string AMethod(global::AutomaticInterfaceExample.DemoClass? x, string y);
+
+    }
+}
+#nullable restore

AutomaticInterface/Tests/Misc/Misc.cs

@@ -292,4 +292,44 @@ class DemoClass
 
         await Verify(Infrastructure.GenerateCode(code));
     }
+
+    [Fact]
+    public async Task AsInternal()
+    {
+        const string code = """
+
+            using AutomaticInterface;
+            namespace AutomaticInterfaceExample;
+            [GenerateAutomaticInterface(asInternal: true)]
+            public class DemoClass
+            {
+                public string AMethod(DemoClass? x, string y)
+                {
+                    return "Ok";
+                }
+            }
+
+            """;
+        await Verify(Infrastructure.GenerateCode(code));
+    }
+
+    [Fact]
+    public async Task AsInternalExplicitFalse()
+    {
+        const string code = """
+
+            using AutomaticInterface;
+            namespace AutomaticInterfaceExample;
+            [GenerateAutomaticInterface(asInternal: false)]
+            public class DemoClass
+            {
+                public string AMethod(DemoClass? x, string y)
+                {
+                    return "Ok";
+                }
+            }
+
+            """;
+        await Verify(Infrastructure.GenerateCode(code));
+    }
 }