// 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.Diagnostics;
using Roslyn.Utilities;

#if CODE_STYLE
using WorkspacesResources = Microsoft.CodeAnalysis.CodeStyleResources;
#endif

namespace Microsoft.CodeAnalysis.Options
{
    [NonDefaultable]
    internal readonly partial record struct OptionKey2
    {
        public IOption2 Option { get; }
        public string? Language { get; }

        public OptionKey2(IOption2 option, string? language)
        {
            Debug.Assert(option.IsPerLanguage == language is not null);

            Option = option;
            Language = language;
        }

        public OptionKey2(IPerLanguageValuedOption option, string language)
        {
            Debug.Assert(option.IsPerLanguage);
            if (language == null)
            {
                throw new ArgumentNullException(WorkspacesResources.A_language_name_must_be_specified_for_this_option);
            }

            this.Option = option ?? throw new ArgumentNullException(nameof(option));
            this.Language = language;
        }

        public OptionKey2(ISingleValuedOption option)
        {
            Debug.Assert(!option.IsPerLanguage);
            this.Option = option ?? throw new ArgumentNullException(nameof(option));
            this.Language = null;
        }

        public override string ToString()
        {
            if (Option is null)
            {
                return "";
            }

            var languageDisplay = Option.IsPerLanguage
                ? $"({Language}) "
                : string.Empty;

            return languageDisplay + Option.ToString();
        }
    }
}
