// 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.Collections.Immutable;
using System.Composition;
using System.Diagnostics.CodeAnalysis;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.CodeActions;
using Microsoft.CodeAnalysis.CodeFixes;
using Microsoft.CodeAnalysis.CSharp.CodeFixes.UseExpressionBodyForLambda;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Diagnostics;
using Microsoft.CodeAnalysis.Editing;
using Microsoft.CodeAnalysis.Shared.Extensions;
 
namespace Microsoft.CodeAnalysis.CSharp.UseExpressionBodyForLambda;
 
[ExportCodeFixProvider(LanguageNames.CSharp, Name = PredefinedCodeFixProviderNames.UseExpressionBodyForLambda), 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 UseExpressionBodyForLambdaCodeFixProvider() : SyntaxEditorBasedCodeFixProvider
{
    public override ImmutableArray<string> FixableDiagnosticIds { get; } = [IDEDiagnosticIds.UseExpressionBodyForLambdaExpressionsDiagnosticId];
 
    public override Task RegisterCodeFixesAsync(CodeFixContext context)
    {
        var document = context.Document;
        var diagnostic = context.Diagnostics[0];
 
        var title = diagnostic.GetMessage();
        var codeAction = CodeAction.Create(
            title,
            c => FixWithSyntaxEditorAsync(document, diagnostic, c),
            title);
 
        context.RegisterCodeFix(codeAction, context.Diagnostics);
        return Task.CompletedTask;
    }
 
    protected override Task FixAllAsync(Document document, ImmutableArray<Diagnostic> diagnostics, SyntaxEditor editor, CancellationToken cancellationToken)
        => FixAllImplAsync(document, diagnostics, editor, cancellationToken);
 
    private static async Task FixAllImplAsync(Document document, ImmutableArray<Diagnostic> diagnostics, SyntaxEditor editor, CancellationToken cancellationToken)
    {
        var semanticModel = await document.GetRequiredSemanticModelAsync(cancellationToken).ConfigureAwait(false);
        foreach (var diagnostic in diagnostics)
        {
            cancellationToken.ThrowIfCancellationRequested();
            AddEdits(editor, semanticModel, diagnostic, cancellationToken);
        }
    }
 
    private static Task<Document> FixWithSyntaxEditorAsync(Document document, Diagnostic diagnostic, CancellationToken cancellationToken)
        => FixAllWithEditorAsync(
            document, editor => FixAllImplAsync(document, [diagnostic], editor, cancellationToken), cancellationToken);
 
    private static void AddEdits(
        SyntaxEditor editor, SemanticModel semanticModel,
        Diagnostic diagnostic, CancellationToken cancellationToken)
    {
        var declarationLocation = diagnostic.AdditionalLocations[0];
        var originalDeclaration = (LambdaExpressionSyntax)declarationLocation.FindNode(getInnermostNodeForTie: true, cancellationToken);
 
        editor.ReplaceNode(
            originalDeclaration,
            (current, _) => UseExpressionBodyForLambdaCodeActionHelpers.Update(semanticModel, originalDeclaration, (LambdaExpressionSyntax)current, cancellationToken));
    }
}