// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System.Threading;
using Microsoft.CodeAnalysis.CSharp.Extensions.ContextQuery;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Shared.Extensions;

namespace Microsoft.CodeAnalysis.CSharp.Completion.KeywordRecommenders;

internal sealed class CaseKeywordRecommender() : AbstractSyntacticSingleKeywordRecommender(SyntaxKind.CaseKeyword)
{
    protected override bool IsValidContext(int position, CSharpSyntaxContext context, CancellationToken cancellationToken)
    {
        return
            context.TargetToken.IsSwitchLabelContext() ||
            IsAfterGotoInSwitchContext(context);
    }

    internal static bool IsAfterGotoInSwitchContext(CSharpSyntaxContext context)
    {
        var token = context.TargetToken;

        if (token.Kind() == SyntaxKind.GotoKeyword &&
            token.GetAncestor<SwitchStatementSyntax>() != null)
        {
            // todo: what if we're in a lambda... or a try/finally or 
            // something?  Might want to filter this out.
            return true;
        }

        return false;
    }
}