// 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.CodeActions;
using Microsoft.CodeAnalysis.CodeRefactorings;
using Microsoft.CodeAnalysis.CSharp.Extensions;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Shared.Extensions;

namespace Microsoft.CodeAnalysis.CSharp.MakeLocalFunctionStatic;

[ExportCodeRefactoringProvider(LanguageNames.CSharp, Name = PredefinedCodeRefactoringProviderNames.MakeLocalFunctionStatic), Shared]
internal sealed class MakeLocalFunctionStaticCodeRefactoringProvider : CodeRefactoringProvider
{
    [ImportingConstructor]
    [SuppressMessage("RoslynDiagnosticsReliability", "RS0033:Importing constructor should be [Obsolete]", Justification = "Used in test code: https://github.com/dotnet/roslyn/issues/42814")]
    public MakeLocalFunctionStaticCodeRefactoringProvider()
    {
    }

    public override async Task ComputeRefactoringsAsync(CodeRefactoringContext context)
    {
        var (document, textSpan, cancellationToken) = context;

        var syntaxTree = (await document.GetSyntaxTreeAsync(cancellationToken).ConfigureAwait(false))!;
        if (!MakeLocalFunctionStaticHelper.IsStaticLocalFunctionSupported(syntaxTree.Options.LanguageVersion()))
            return;

        var localFunction = await context.TryGetRelevantNodeAsync<LocalFunctionStatementSyntax>().ConfigureAwait(false);
        if (localFunction == null)
            return;

        if (localFunction.Modifiers.Any(SyntaxKind.StaticKeyword))
            return;

        var semanticModel = await document.GetRequiredSemanticModelAsync(cancellationToken).ConfigureAwait(false);

        if (MakeLocalFunctionStaticHelper.CanMakeLocalFunctionStaticByRefactoringCaptures(localFunction, semanticModel, out var captures))
        {
            context.RegisterRefactoring(CodeAction.Create(
                CSharpAnalyzersResources.Make_local_function_static,
                cancellationToken => MakeLocalFunctionStaticCodeFixHelper.MakeLocalFunctionStaticAsync(document, localFunction, captures, cancellationToken),
                nameof(CSharpAnalyzersResources.Make_local_function_static)));
        }
    }
}