// 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;
using System.Threading;
using Microsoft.CodeAnalysis.CSharp.Extensions;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.PooledObjects;

namespace Microsoft.CodeAnalysis.CSharp.Simplification;

internal sealed partial class CSharpDefaultExpressionReducer
{
    private sealed class Rewriter : AbstractReductionRewriter
    {
        public Rewriter(ObjectPool<IReductionRewriter> pool)
            : base(pool)
        {
            _simplifyDefaultExpression = SimplifyDefaultExpression;
        }

        private readonly Func<DefaultExpressionSyntax, SemanticModel, CSharpSimplifierOptions, CancellationToken, SyntaxNode> _simplifyDefaultExpression;

        private SyntaxNode SimplifyDefaultExpression(
            DefaultExpressionSyntax node,
            SemanticModel semanticModel,
            CSharpSimplifierOptions options,
            CancellationToken cancellationToken)
        {
            var preferSimpleDefaultExpression = options.PreferSimpleDefaultExpression.Value;

            if (node.CanReplaceWithDefaultLiteral(ParseOptions, preferSimpleDefaultExpression, semanticModel, cancellationToken))
            {
                return SyntaxFactory.LiteralExpression(SyntaxKind.DefaultLiteralExpression)
                                    .WithTriviaFrom(node);
            }

            return node;
        }

        public override SyntaxNode VisitDefaultExpression(DefaultExpressionSyntax node)
            => SimplifyNode(
                node,
                newNode: base.VisitDefaultExpression(node),
                simplifier: _simplifyDefaultExpression);
    }
}