// 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.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.CodeActions;
using Microsoft.CodeAnalysis.CodeFixes;
using Microsoft.CodeAnalysis.CSharp.Formatting;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Diagnostics;
using Microsoft.CodeAnalysis.Editing;
using Microsoft.CodeAnalysis.Host.Mef;
using Microsoft.CodeAnalysis.Shared.Extensions;

namespace Microsoft.CodeAnalysis.CSharp.ConvertProgram;

using static ConvertProgramTransform;

[ExportCodeFixProvider(LanguageNames.CSharp, Name = PredefinedCodeFixProviderNames.ConvertToTopLevelStatements), Shared]
[method: ImportingConstructor]
[method: Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
internal sealed class ConvertToTopLevelStatementsCodeFixProvider() : SyntaxEditorBasedCodeFixProvider
{
    public override ImmutableArray<string> FixableDiagnosticIds
        => [IDEDiagnosticIds.UseTopLevelStatementsId];

    public override async Task RegisterCodeFixesAsync(CodeFixContext context)
    {
        var document = context.Document;
        var cancellationToken = context.CancellationToken;

        var options = await document.GetCSharpSyntaxFormattingOptionsAsync(cancellationToken).ConfigureAwait(false);
        var priority = options.PreferTopLevelStatements.Notification.Severity == ReportDiagnostic.Hidden
            ? CodeActionPriority.Low
            : CodeActionPriority.Default;

        RegisterCodeFix(context, CSharpAnalyzersResources.Convert_to_top_level_statements, nameof(ConvertToTopLevelStatementsCodeFixProvider), priority);
    }

    protected override async Task FixAllAsync(
        Document document, ImmutableArray<Diagnostic> diagnostics, SyntaxEditor editor, CancellationToken cancellationToken)
    {
        var methodDeclaration = (MethodDeclarationSyntax)diagnostics[0].AdditionalLocations[0].FindNode(cancellationToken);

        var newDocument = await ConvertToTopLevelStatementsAsync(document, methodDeclaration, cancellationToken).ConfigureAwait(false);
        var newRoot = await newDocument.GetRequiredSyntaxRootAsync(cancellationToken).ConfigureAwait(false);

        editor.ReplaceNode(editor.OriginalRoot, newRoot);
    }
}