// 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;
using System.Threading;
using Microsoft.CodeAnalysis.CSharp.Extensions;
using Microsoft.CodeAnalysis.CSharp.LanguageService;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.LanguageService;
using Microsoft.CodeAnalysis.PooledObjects;
using Microsoft.CodeAnalysis.Simplification;
 
namespace Microsoft.CodeAnalysis.CSharp.Simplification;
 
internal partial class CSharpParenthesizedExpressionReducer : AbstractCSharpReducer
{
    private static readonly ObjectPool<IReductionRewriter> s_pool = new(
        () => new Rewriter(s_pool));
 
    private static readonly Func<ParenthesizedExpressionSyntax, SemanticModel, SimplifierOptions, CancellationToken, SyntaxNode> s_simplifyParentheses = SimplifyParentheses;
 
    public CSharpParenthesizedExpressionReducer() : base(s_pool)
    {
    }
 
    protected override bool IsApplicable(CSharpSimplifierOptions options)
       => true;
 
    private static SyntaxNode SimplifyParentheses(
        ParenthesizedExpressionSyntax node,
        SemanticModel semanticModel,
        SimplifierOptions options,
        CancellationToken cancellationToken)
    {
        if (node.CanRemoveParentheses(semanticModel, cancellationToken))
        {
            // TODO(DustinCa): We should not be skipping elastic trivia below.
            // However, the formatter seems to mess up trailing trivia in some
            // cases if elastic trivia is there -- and it's not clear why.
            // Specifically remove the elastic trivia formatting rule doesn't
            // have any effect.
            var resultNode = CSharpSyntaxFacts.Instance.Unparenthesize(node);
            return SimplificationHelpers.CopyAnnotations(from: node, to: resultNode);
        }
 
        // We don't know how to simplify this.
        return node;
    }
}