// 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.Syntax;
using Microsoft.CodeAnalysis.Shared.Collections;
using Microsoft.CodeAnalysis.Structure;
 
namespace Microsoft.CodeAnalysis.CSharp.Structure
{
    internal class AnonymousMethodExpressionStructureProvider : AbstractSyntaxNodeStructureProvider<AnonymousMethodExpressionSyntax>
    {
        protected override void CollectBlockSpans(
            SyntaxToken previousToken,
            AnonymousMethodExpressionSyntax anonymousMethod,
            ref TemporaryArray<BlockSpan> spans,
            BlockStructureOptions options,
            CancellationToken cancellationToken)
        {
            // fault tolerance
            if (anonymousMethod.Block.IsMissing ||
                anonymousMethod.Block.OpenBraceToken.IsMissing ||
                anonymousMethod.Block.CloseBraceToken.IsMissing)
            {
                return;
            }
 
            var lastToken = CSharpStructureHelpers.GetLastInlineMethodBlockToken(anonymousMethod);
            if (lastToken.Kind() == SyntaxKind.None)
            {
                return;
            }
 
            var startToken = anonymousMethod.ParameterList != null
                ? anonymousMethod.ParameterList.GetLastToken(includeZeroWidth: true)
                : anonymousMethod.DelegateKeyword;
 
            spans.AddIfNotNull(CSharpStructureHelpers.CreateBlockSpan(
                anonymousMethod,
                startToken,
                lastToken,
                compressEmptyLines: false,
                autoCollapse: false,
                type: BlockTypes.Expression,
                isCollapsible: true));
        }
    }
}