// 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.PooledObjects;
using Microsoft.CodeAnalysis.Structure;

namespace Microsoft.CodeAnalysis.CSharp.Structure;

internal sealed class SimpleLambdaExpressionStructureProvider : AbstractSyntaxNodeStructureProvider<SimpleLambdaExpressionSyntax>
{
    protected override void CollectBlockSpans(
        SyntaxToken previousToken,
        SimpleLambdaExpressionSyntax lambdaExpression,
        ArrayBuilder<BlockSpan> spans,
        BlockStructureOptions options,
        CancellationToken cancellationToken)
    {
        // fault tolerance
        if (lambdaExpression.Body.IsMissing)
        {
            return;
        }

        if (lambdaExpression.Body is not BlockSyntax lambdaBlock ||
            lambdaBlock.OpenBraceToken.IsMissing ||
            lambdaBlock.CloseBraceToken.IsMissing)
        {
            return;
        }

        var lastToken = CSharpStructureHelpers.GetLastInlineMethodBlockToken(lambdaExpression);
        if (lastToken.Kind() == SyntaxKind.None)
        {
            return;
        }

        spans.AddIfNotNull(CSharpStructureHelpers.CreateBlockSpan(
            lambdaExpression,
            lambdaExpression.ArrowToken,
            lastToken,
            compressEmptyLines: false,
            autoCollapse: false,
            type: BlockTypes.Expression,
            isCollapsible: true));
    }
}