// 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.Collections.Immutable;
using System.Composition;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.CodeActions;
using Microsoft.CodeAnalysis.CodeFixes;
using Microsoft.CodeAnalysis.CodeStyle;
using Microsoft.CodeAnalysis.CSharp.Formatting;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Diagnostics;
using Microsoft.CodeAnalysis.Editing;
using Microsoft.CodeAnalysis.Formatting;
using Microsoft.CodeAnalysis.Host.Mef;
using Microsoft.CodeAnalysis.Indentation;
using Microsoft.CodeAnalysis.Shared.Extensions;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.CSharp.ConvertNamespace
{
    using static ConvertNamespaceAnalysis;
    using static ConvertNamespaceTransform;
 
    [ExportCodeFixProvider(LanguageNames.CSharp, Name = PredefinedCodeFixProviderNames.ConvertNamespace), Shared]
    internal class ConvertNamespaceCodeFixProvider : SyntaxEditorBasedCodeFixProvider
    {
        [ImportingConstructor]
        [Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
        public ConvertNamespaceCodeFixProvider()
        {
        }
        public override ImmutableArray<string> FixableDiagnosticIds
            => ImmutableArray.Create(IDEDiagnosticIds.UseBlockScopedNamespaceDiagnosticId, IDEDiagnosticIds.UseFileScopedNamespaceDiagnosticId);
 
        public override Task RegisterCodeFixesAsync(CodeFixContext context)
        {
            var diagnostic = context.Diagnostics.First();
 
            var (title, equivalenceKey) = GetInfo(
                diagnostic.Id switch
                {
                    IDEDiagnosticIds.UseBlockScopedNamespaceDiagnosticId => NamespaceDeclarationPreference.BlockScoped,
                    IDEDiagnosticIds.UseFileScopedNamespaceDiagnosticId => NamespaceDeclarationPreference.FileScoped,
                    _ => throw ExceptionUtilities.UnexpectedValue(diagnostic.Id),
                });
 
            context.RegisterCodeFix(
                CodeAction.Create(title, GetDocumentUpdater(context), equivalenceKey),
                context.Diagnostics);
 
            return Task.CompletedTask;
        }
 
        protected override async Task FixAllAsync(
            Document document, ImmutableArray<Diagnostic> diagnostics,
            SyntaxEditor editor, CodeActionOptionsProvider fallbackOptions, CancellationToken cancellationToken)
        {
            var diagnostic = diagnostics.First();
 
            var namespaceDecl = (BaseNamespaceDeclarationSyntax)diagnostic.AdditionalLocations[0].FindNode(cancellationToken);
 
            var options = await document.GetCSharpCodeFixOptionsProviderAsync(fallbackOptions, cancellationToken).ConfigureAwait(false);
            var converted = await ConvertAsync(document, namespaceDecl, options.GetFormattingOptions(), cancellationToken).ConfigureAwait(false);
 
            editor.ReplaceNode(
                editor.OriginalRoot,
                await converted.GetRequiredSyntaxRootAsync(cancellationToken).ConfigureAwait(false));
        }
    }
}