// 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 Microsoft.CodeAnalysis.CSharp.Extensions;
using Microsoft.CodeAnalysis.CSharp.Syntax;
 
namespace Microsoft.CodeAnalysis.CSharp.ConvertSwitchStatementToExpression
{
    internal static class ConvertSwitchStatementToExpressionHelpers
    {
        public static bool IsDefaultSwitchLabel(SwitchLabelSyntax node)
        {
            // default:
            if (node.IsKind(SyntaxKind.DefaultSwitchLabel))
            {
                return true;
            }
 
            if (node is CasePatternSwitchLabelSyntax @case)
            {
                // case _:
                if (@case.Pattern.IsKind(SyntaxKind.DiscardPattern))
                {
                    return @case.WhenClause == null;
                }
 
                // case var _:
                // case var x:
                if (@case.Pattern is VarPatternSyntax varPattern &&
                    varPattern.Designation.Kind() is SyntaxKind.DiscardDesignation or SyntaxKind.SingleVariableDesignation)
                {
                    return @case.WhenClause == null;
                }
            }
 
            return false;
        }
    }
}