// 
// InsertAnonymousMethodSignature.cs
//  
// Author:
//       Mike Krüger <mkrueger@novell.com>
// 
// Copyright (c) 2011 Mike Krüger <mkrueger@novell.com>
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
using System;
using ICSharpCode.NRefactory.TypeSystem;
using System.Linq;
using System.Text;
using System.Threading;
using System.Collections.Generic;

namespace ICSharpCode.NRefactory.CSharp.Refactoring
{
	[ContextAction("Insert anonymous method signature", Description = "Inserts a signature to parameterless anonymous methods.")]
	public class InsertAnonymousMethodSignatureAction : ICodeActionProvider
	{
		public IEnumerable<CodeAction> GetActions(RefactoringContext context)
		{
			IType type;
			var anonymousMethodExpression = GetAnonymousMethodExpression(context, out type);
			if (anonymousMethodExpression == null) {
				yield break;
			}
			yield return new CodeAction (context.TranslateString("Insert anonymous method signature"), script => {
				var delegateMethod = type.GetDelegateInvokeMethod();
				
				var sb = new StringBuilder ("(");
				for (int k = 0; k < delegateMethod.Parameters.Count; k++) {
					if (k > 0) {
						sb.Append(", ");
					}
					
					var paramType = delegateMethod.Parameters [k].Type;
					
					sb.Append(context.CreateShortType(paramType));
					sb.Append(" ");
					sb.Append(delegateMethod.Parameters [k].Name);
				}
				sb.Append(")");
				
				script.InsertText(context.GetOffset(anonymousMethodExpression.DelegateToken.EndLocation), sb.ToString());
			});
		}
		
		static AnonymousMethodExpression GetAnonymousMethodExpression (RefactoringContext context, out IType delegateType)
		{
			delegateType = null;
			
			var anonymousMethodExpression = context.GetNode<AnonymousMethodExpression> ();
			if (anonymousMethodExpression == null || !anonymousMethodExpression.DelegateToken.Contains (context.Location) || anonymousMethodExpression.HasParameterList)
				return null;
			
			IType resolvedType = null;
			var parent = anonymousMethodExpression.Parent;
			
			if (parent is AssignmentExpression) {
				resolvedType = context.Resolve (((AssignmentExpression)parent).Left).Type;
			} else if (parent is VariableInitializer) {
				resolvedType = context.Resolve (((VariableDeclarationStatement)parent.Parent).Type).Type;
			} else if (parent is InvocationExpression) {
				// TODO: handle invocations
			}
			if (resolvedType == null)
				return null;
			delegateType = resolvedType;
			if (delegateType.Kind != TypeKind.Delegate) 
				return null;
			
			return anonymousMethodExpression;
		}
	}
}