Add interface generation

src/Pure.DI/InterfaceGeneration/GeneratedInterfaceDetails.cs

@@ -0,0 +1,47 @@
+namespace Pure.DI;
+
+using System.Linq;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+
+internal sealed class GeneratedInterfaceDetails(
+    AttributeData? generationAttribute,
+    ITypeSymbol typeSymbol,
+    ClassDeclarationSyntax classSyntax)
+{
+    public string NamespaceName { get; } = PrepareNamespaceValue(generationAttribute, typeSymbol.ContainingNamespace.ToDisplayString());
+
+    public string InterfaceName { get; } = PrepareValue(
+        generationAttribute,
+        InterfaceGenerator.InterfaceParameterName,
+        $"I{classSyntax.Identifier.Text}");
+
+    public string AccessLevel { get; } = PrepareValue(
+        generationAttribute,
+        InterfaceGenerator.AsInternalParameterName,
+        false)
+        ? "internal"
+        : "public";
+
+    private static string PrepareNamespaceValue(AttributeData? generationAttribute, string defaultValue)
+    {
+        var value = PrepareValue(generationAttribute, InterfaceGenerator.NamespaceParameterName, defaultValue);
+        return value ?? defaultValue;
+    }
+
+    private static T PrepareValue<T>(AttributeData? generationAttribute, string key, T defaultValue)
+    {
+        var parameterSymbol = generationAttribute?.AttributeConstructor?.Parameters.SingleOrDefault(x => x.Name == key);
+        if (parameterSymbol != null)
+        {
+            var index = generationAttribute!.AttributeConstructor!.Parameters.IndexOf(parameterSymbol);
+            var result = generationAttribute.ConstructorArguments[index].Value;
+            if (result != null)
+            {
+                return (T)result;
+            }
+        }
+
+        return defaultValue;
+    }
+}