Introduce wrapper base for IRefactoringPreviewProviders

Author: MDoerner

Rubberduck.Refactorings/Abstract/RefactoringPreviewProviderWrapperBase.cs

@@ -0,0 +1,41 @@
+using Rubberduck.Parsing.Rewriter;
+using Rubberduck.Parsing.VBA.Parsing;
+using Rubberduck.VBEditor;
+
+namespace Rubberduck.Refactorings
+{
+    public abstract class RefactoringPreviewProviderWrapperBase<TModel> : IRefactoringPreviewProvider<TModel>
+        where TModel : class, IRefactoringModel
+    {
+        private readonly IRewritingManager _rewritingManager;
+        private readonly ICodeOnlyRefactoringAction<TModel> _refactoringAction;
+
+        protected RefactoringPreviewProviderWrapperBase(
+            ICodeOnlyRefactoringAction<TModel> refactoringAction,
+            IRewritingManager rewritingManager)
+        {
+            _refactoringAction = refactoringAction;
+            _rewritingManager = rewritingManager;
+        }
+
+        protected abstract QualifiedModuleName ComponentToShow(TModel model);
+
+        public string Preview(TModel model)
+        {
+            var rewriteSession = RewriteSession(RewriteSessionCodeKind);
+            _refactoringAction.Refactor(model, rewriteSession);
+            var componentToShow = ComponentToShow(model);
+            var rewriter = rewriteSession.CheckOutModuleRewriter(componentToShow);
+            return rewriter.GetText();
+        }
+
+        private IExecutableRewriteSession RewriteSession(CodeKind codeKind)
+        {
+            return codeKind == CodeKind.AttributesCode
+                ? _rewritingManager.CheckOutAttributesSession()
+                : _rewritingManager.CheckOutCodePaneSession();
+        }
+
+        protected virtual CodeKind RewriteSessionCodeKind => CodeKind.CodePaneCode;
+    }
+}