// 
// RedundantFieldInitializerIssue.cs
// 
// Author:
//      Mansheng Yang <lightyang0@gmail.com>
// 
// Copyright (c) 2012 Mansheng Yang <lightyang0@gmail.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.Collections.Generic;
using ICSharpCode.NRefactory.TypeSystem;
using ICSharpCode.NRefactory.PatternMatching;

namespace ICSharpCode.NRefactory.CSharp.Refactoring
{
	[IssueDescription ("Initializing field with default value is redundant",
						Description = "Initializing field with default value is redundant.",
						Category = IssueCategories.Redundancies,
						Severity = Severity.Hint,
						IssueMarker = IssueMarker.GrayOut)]
	public class RedundantFieldInitializerIssue : ICodeIssueProvider
	{
		public IEnumerable<CodeIssue> GetIssues (BaseRefactoringContext context)
		{
			return new GatherVisitor (context).GetIssues ();
		}

		class GatherVisitor : GatherVisitorBase
		{
			public GatherVisitor(BaseRefactoringContext ctx)
				: base(ctx)
			{
			}

			public override void VisitFieldDeclaration (FieldDeclaration fieldDeclaration)
			{
				base.VisitFieldDeclaration (fieldDeclaration);

				var defaultValueExpr = ctx.GetDefaultValueExpression (fieldDeclaration.ReturnType);
				if (defaultValueExpr == null)
					return;

				foreach (var variable1 in fieldDeclaration.Variables) {
					var variable = variable1;
					if (!defaultValueExpr.Match (variable.Initializer).Success)
						continue;

					AddIssue (variable, ctx.TranslateString ("Remove redundant field initializer"),
						script => script.Replace (variable, new VariableInitializer (variable.Name)));
				}
			}

			
		}
	}
}