// 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.Composition;
using System.Diagnostics.CodeAnalysis;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.CodeRefactorings;
using Microsoft.CodeAnalysis.Shared.Extensions;
 
namespace Microsoft.CodeAnalysis.GenerateDefaultConstructors;
 
/// <summary>
/// This <see cref="CodeRefactoringProvider"/> gives users a way to generate constructors for
/// a derived type that delegate to a base type.  For all accessible constructors in the base
/// type, the user will be offered to create a constructor in the derived type with the same
/// signature if they don't already have one.  This way, a user can override a type and easily
/// create all the forwarding constructors.
/// 
/// Importantly, this type is not responsible for generating constructors when the user types
/// something like "new MyType(x, y, z)", nor is it responsible for generating constructors
/// for a type based on the fields/properties of that type. Both of those are handled by other 
/// services.
/// </summary>
[ExportCodeRefactoringProvider(LanguageNames.CSharp, LanguageNames.VisualBasic,
    Name = PredefinedCodeRefactoringProviderNames.GenerateDefaultConstructors), Shared]
internal sealed class GenerateDefaultConstructorsCodeRefactoringProvider : CodeRefactoringProvider
{
    [ImportingConstructor]
    [SuppressMessage("RoslynDiagnosticsReliability", "RS0033:Importing constructor should be [Obsolete]", Justification = "Used in test code: https://github.com/dotnet/roslyn/issues/42814")]
    public GenerateDefaultConstructorsCodeRefactoringProvider()
    {
    }
 
    public override async Task ComputeRefactoringsAsync(CodeRefactoringContext context)
    {
        var (document, textSpan, cancellationToken) = context;
 
        // TODO: https://github.com/dotnet/roslyn/issues/5778
        // Not supported in REPL for now.
        if (document.Project.IsSubmission)
            return;
 
        if (document.Project.Solution.WorkspaceKind == WorkspaceKind.MiscellaneousFiles)
            return;
 
        var service = document.GetRequiredLanguageService<IGenerateDefaultConstructorsService>();
        var actions = await service.GenerateDefaultConstructorsAsync(
            document, textSpan, forRefactoring: true, cancellationToken).ConfigureAwait(false);
        context.RegisterRefactorings(actions);
    }
}