// 
// UseExplicitType.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 System.Linq;
using ICSharpCode.NRefactory.PatternMatching;
using ICSharpCode.NRefactory.TypeSystem;
using System.Threading;
using System.Collections.Generic;

namespace ICSharpCode.NRefactory.CSharp.Refactoring
{
	[ContextAction("Use explicit type", Description = "Converts local variable declaration to be explicit typed.")]
	public class UseExplicitTypeAction: ICodeActionProvider
	{
		public IEnumerable<CodeAction> GetActions(RefactoringContext context)
		{
			var varDecl = GetVariableDeclarationStatement(context);
			AstNode node;
			IType type;
			if (varDecl != null) {
				type = context.Resolve(varDecl.Variables.First().Initializer).Type;
				node = varDecl;
			} else {
				var foreachStatement = GetForeachStatement(context);
				if (foreachStatement == null) {
					yield break;
				}
				type = context.Resolve(foreachStatement.VariableType).Type;
				node = foreachStatement;
			}

			if (!(!type.Equals(SpecialType.NullType) && !type.Equals(SpecialType.UnknownType) && !ContainsAnonymousType(type))) {
				yield break;
			}
			yield return new CodeAction (context.TranslateString("Use explicit type"), script => {
				if (varDecl != null) {
					script.Replace (varDecl.Type, context.CreateShortType (type));
				} else {
					var foreachStatement = GetForeachStatement (context);
					script.Replace (foreachStatement.VariableType, context.CreateShortType (type));
				}
			}, node);
		}

		static bool ContainsAnonymousType (IType type)
		{
			if (type.Kind == TypeKind.Anonymous)
				return true;

			var arrayType = type as ArrayType;
			return arrayType != null && ContainsAnonymousType (arrayType.ElementType);
		}

		static VariableDeclarationStatement GetVariableDeclarationStatement (RefactoringContext context)
		{
			var result = context.GetNode<VariableDeclarationStatement> ();
			if (result != null && result.Variables.Count == 1 && !result.Variables.First ().Initializer.IsNull && result.Type.Contains (context.Location.Line, context.Location.Column) && result.Type.IsVar ()) {
				if (context.Resolve (result.Variables.First ().Initializer) == null)
					return null;
				return result;
			}
			return null;
		}
		
		static ForeachStatement GetForeachStatement (RefactoringContext context)
		{
			var result = context.GetNode<ForeachStatement> ();
			if (result != null && result.VariableType.Contains (context.Location) && result.VariableType.IsVar ())
				return result;
			return null;
		}
	}
}

