// 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.
 
#nullable disable
 
using System.Collections.Generic;
using System.Linq;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Shared.Extensions;
 
namespace Microsoft.CodeAnalysis.CSharp.Extensions
{
    internal static class MemberAccessExpressionSyntaxExtensions
    {
        public static SimpleNameSyntax GetNameWithTriviaMoved(this MemberAccessExpressionSyntax memberAccess)
            => memberAccess.Name
                .WithLeadingTrivia(GetLeadingTriviaForSimplifiedMemberAccess(memberAccess))
                .WithTrailingTrivia(memberAccess.GetTrailingTrivia());
 
        private static SyntaxTriviaList GetLeadingTriviaForSimplifiedMemberAccess(MemberAccessExpressionSyntax memberAccess)
        {
            // We want to include any user-typed trivia that may be present between the 'Expression', 'OperatorToken' and 'Identifier' of the MemberAccessExpression.
            // However, we don't want to include any elastic trivia that may have been introduced by the expander in these locations. This is to avoid triggering
            // aggressive formatting. Otherwise, formatter will see this elastic trivia added by the expander and use that as a cue to introduce unnecessary blank lines
            // etc. around the user's original code.
            return SyntaxFactory.TriviaList(WithoutElasticTrivia(
                memberAccess.GetLeadingTrivia()
                    .AddRange(memberAccess.Expression.GetTrailingTrivia())
                    .AddRange(memberAccess.OperatorToken.LeadingTrivia)
                    .AddRange(memberAccess.OperatorToken.TrailingTrivia)
                    .AddRange(memberAccess.Name.GetLeadingTrivia())));
        }
 
        private static IEnumerable<SyntaxTrivia> WithoutElasticTrivia(IEnumerable<SyntaxTrivia> list)
            => list.Where(t => !t.IsElastic());
    }
}