// 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.LanguageService;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.LanguageService;
using Microsoft.CodeAnalysis.PooledObjects;
using Microsoft.CodeAnalysis.Simplification;

namespace Microsoft.CodeAnalysis.CSharp.Simplification;

internal sealed partial class CSharpParenthesizedPatternReducer : AbstractCSharpReducer
{
    private static readonly ObjectPool<IReductionRewriter> s_pool = new(
        () => new Rewriter(s_pool));

    private static readonly Func<ParenthesizedPatternSyntax, SemanticModel, SimplifierOptions, CancellationToken, SyntaxNode> s_simplifyParentheses = SimplifyParentheses;

    public CSharpParenthesizedPatternReducer() : base(s_pool)
    {
    }

    protected override bool IsApplicable(CSharpSimplifierOptions options)
       => true;

    private static SyntaxNode SimplifyParentheses(
        ParenthesizedPatternSyntax node,
        SemanticModel semanticModel,
        SimplifierOptions options,
        CancellationToken cancellationToken)
    {
        if (node.CanRemoveParentheses())
        {
            var resultNode = CSharpSyntaxFacts.Instance.Unparenthesize(node);
            return SimplificationHelpers.CopyAnnotations(from: node, to: resultNode);
        }

        // We don't know how to simplify this.
        return node;
    }
}