// 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 enable

using System;
using System.ComponentModel;
using System.Globalization;

namespace WinformsControlsTest
{
    public partial class Dialogs
    {
        /// <summary>
        /// Provides a predefined set of GUIDs to chose from in order to configure <see cref="ExposedClientGuidMetadata.ClientGuid"/>.
        /// </summary>
        private sealed class ClientGuidConverter : GuidConverter
        {
            private StandardValuesCollection? _values;

            public override bool GetStandardValuesSupported(ITypeDescriptorContext context) => true;
            public override bool GetStandardValuesExclusive(ITypeDescriptorContext context) => true;

            public override object? ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
            {
                // base class is for plain Guid, but ClientGuid is nullable Guid, which we need to implement separately
                if ((value is null) || (value is string str && str.Length == 0))
                    return null;

                return base.ConvertFrom(context, culture, value);
            }

            public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context)
            {
                if (_values is null)
                {
                    // chose from two GUIDs we pregenerated for testing
                    _values = new StandardValuesCollection(new Guid?[]
                    {
                        null,
                        new Guid("38EA9AE9-13BE-4992-9482-DAD370894BBD"),
                        new Guid("46DFEE70-A89E-4D9A-8842-6D46DBC1F195"),
                    });
                }

                return _values;
            }
        }
    }
}
