// 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.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.CodeRefactorings;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Editing;
using Microsoft.CodeAnalysis.Shared.Extensions;

namespace Microsoft.CodeAnalysis.CSharp.ImplementInterface;

[ExportCodeRefactoringProvider(LanguageNames.CSharp, Name = PredefinedCodeRefactoringProviderNames.ImplementInterfaceImplicitly), Shared]
[method: ImportingConstructor]
[method: SuppressMessage("RoslynDiagnosticsReliability", "RS0033:Importing constructor should be [Obsolete]", Justification = "Used in test code: https://github.com/dotnet/roslyn/issues/42814")]
internal sealed class CSharpImplementImplicitlyCodeRefactoringProvider() :
    AbstractChangeImplementationCodeRefactoringProvider
{
    protected override string Implement_0 => FeaturesResources.Implement_0_implicitly;
    protected override string Implement_all_interfaces => FeaturesResources.Implement_all_interfaces_implicitly;
    protected override string Implement => FeaturesResources.Implement_implicitly;

    // We need to be an explicit impl in order to convert to implicit.
    protected override bool CheckExplicitNameAllowsConversion(ExplicitInterfaceSpecifierSyntax? explicitName)
        => explicitName != null;

    // If we don't implement any interface members explicitly we can't convert this to be
    // implicit.
    protected override bool CheckMemberCanBeConverted(ISymbol member)
    {
        var memberInterfaceImplementations = member.ExplicitInterfaceImplementations();
        if (memberInterfaceImplementations.Length == 0)
            return false;
        var containingTypeInterfaces = member.ContainingType.AllInterfaces;
        if (containingTypeInterfaces.Length == 0)
            return false;
        return memberInterfaceImplementations.Any(static (impl, containingTypeInterfaces) => containingTypeInterfaces.Contains(impl.ContainingType), containingTypeInterfaces);
    }

    // When converting to implicit, we don't need to update any references.
    protected override Task UpdateReferencesAsync(Project project, SolutionEditor solutionEditor, ISymbol implMember, INamedTypeSymbol containingType, CancellationToken cancellationToken)
        => Task.CompletedTask;

    protected override SyntaxNode ChangeImplementation(SyntaxGenerator generator, SyntaxNode decl, ISymbol _1, ISymbol _2)
        => generator.WithAccessibility(WithoutExplicitImpl(decl), Accessibility.Public);

    private static SyntaxNode WithoutExplicitImpl(SyntaxNode decl)
        => decl switch
        {
            MethodDeclarationSyntax member => member.WithExplicitInterfaceSpecifier(null),
            PropertyDeclarationSyntax member => member.WithExplicitInterfaceSpecifier(null),
            EventDeclarationSyntax member => member.WithExplicitInterfaceSpecifier(null),
            _ => throw ExceptionUtilities.UnexpectedValue(decl),
        };
}
