// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

#nullable disable

using System;
using System.Collections.Generic;
using Microsoft.Extensions.Internal;

namespace Microsoft.AspNetCore.Razor.Language;

internal class DirectiveTokenDescriptorComparer : IEqualityComparer<DirectiveTokenDescriptor>
{
    public static readonly DirectiveTokenDescriptorComparer Default = new DirectiveTokenDescriptorComparer();

    protected DirectiveTokenDescriptorComparer()
    {
    }

    public bool Equals(DirectiveTokenDescriptor descriptorX, DirectiveTokenDescriptor descriptorY)
    {
        if (descriptorX == descriptorY)
        {
            return true;
        }

        return descriptorX != null &&
            descriptorX.Kind == descriptorY.Kind &&
            descriptorX.Optional == descriptorY.Optional;
    }

    public int GetHashCode(DirectiveTokenDescriptor descriptor)
    {
        if (descriptor == null)
        {
            throw new ArgumentNullException(nameof(descriptor));
        }

        var hashCodeCombiner = HashCodeCombiner.Start();
        hashCodeCombiner.Add(descriptor.Kind);
        hashCodeCombiner.Add(descriptor.Optional ? 1 : 0);

        return hashCodeCombiner.CombinedHash;
    }
}