// 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 OperatorDeclarationStructureProvider : AbstractSyntaxNodeStructureProvider<OperatorDeclarationSyntax>
    {
        protected override void CollectBlockSpans(
            SyntaxToken previousToken,
            OperatorDeclarationSyntax operatorDeclaration,
            ref TemporaryArray<BlockSpan> spans,
            BlockStructureOptions options,
            CancellationToken cancellationToken)
        {
            CSharpStructureHelpers.CollectCommentBlockSpans(operatorDeclaration, ref spans, options);
 
            // fault tolerance
            if (operatorDeclaration.Body == null ||
                operatorDeclaration.Body.OpenBraceToken.IsMissing ||
                operatorDeclaration.Body.CloseBraceToken.IsMissing)
            {
                return;
            }
 
            SyntaxNodeOrToken current = operatorDeclaration;
            var nextSibling = current.GetNextSibling();
 
            // Check IsNode to compress blank lines after this node if it is the last child of the parent.
            //
            // Whitespace between operators is collapsed in Metadata as Source.
            var compressEmptyLines = options.IsMetadataAsSource
                && (!nextSibling.IsNode || nextSibling.IsKind(SyntaxKind.OperatorDeclaration));
 
            spans.AddIfNotNull(CSharpStructureHelpers.CreateBlockSpan(
                operatorDeclaration,
                operatorDeclaration.ParameterList.GetLastToken(includeZeroWidth: true),
                compressEmptyLines: compressEmptyLines,
                autoCollapse: true,
                type: BlockTypes.Member,
                isCollapsible: true));
        }
    }
}