// 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 TypeOfKeywordRecommender() : AbstractSyntacticSingleKeywordRecommender(SyntaxKind.TypeOfKeyword)
{
    protected override bool IsValidContext(int position, CSharpSyntaxContext context, CancellationToken cancellationToken)
    {
        return
            (context.IsAnyExpressionContext && !context.IsConstantExpressionContext) ||
            context.IsStatementContext ||
            context.IsGlobalStatementContext ||
            IsAttributeArgumentContext(context);
    }

    private static bool IsAttributeArgumentContext(CSharpSyntaxContext context)
    {
        return
            context.IsAnyExpressionContext &&
            context.LeftToken.GetAncestor<AttributeSyntax>() != null;
    }
}