//
// ConvertIfStatementToSwitchStatementIssue.cs
//
// Author:
//       Mike Krüger <mkrueger@xamarin.com>
//
// Copyright (c) 2013 Xamarin Inc. (http://xamarin.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.Refactoring;
using System.Linq;

namespace ICSharpCode.NRefactory.CSharp.Refactoring
{
	[IssueDescription("'if' statement can be re-written as 'switch' statement",
	                  Description="Convert 'if' to 'switch'",
	                  Category = IssueCategories.Opportunities,
	                  IsEnabledByDefault = false,
	                  Severity = Severity.Hint)]
	public class ConvertIfStatementToSwitchStatementIssue : GatherVisitorCodeIssueProvider
	{
		protected override IGatherVisitor CreateVisitor(BaseRefactoringContext context)
		{
			return new GatherVisitor(context);
		}

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

			public override void VisitIfElseStatement(IfElseStatement ifElseStatement)
			{
				base.VisitIfElseStatement(ifElseStatement);

				if (ifElseStatement.Parent is IfElseStatement)
					return;

				var switchExpr = ConvertIfStatementToSwitchStatementAction.GetSwitchExpression (ctx, ifElseStatement.Condition);
				if (switchExpr == null)
					return;
				var switchSections = new List<SwitchSection> ();
				if (!ConvertIfStatementToSwitchStatementAction.CollectSwitchSections(switchSections, ctx, ifElseStatement, switchExpr))
					return;
				if (switchSections.Count(s => !s.CaseLabels.Any(l => l.Expression.IsNull)) <= 2)
					return;
				AddIssue(new CodeIssue(
					ifElseStatement.IfToken,
					ctx.TranslateString("Convert to 'switch' statement")) { IssueMarker = IssueMarker.DottedLine, ActionProvider = { typeof(ConvertIfStatementToSwitchStatementAction) } });

			}
		}
	}
}