// 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.Diagnostics;
using Microsoft.CodeAnalysis.Editing;
using Microsoft.CodeAnalysis.Host.Mef;

namespace Microsoft.CodeAnalysis.RemoveUnnecessarySuppressions
{
    [ExportCodeFixProvider(LanguageNames.CSharp, LanguageNames.VisualBasic, Name = PredefinedCodeFixProviderNames.RemoveUnnecessarySuppressions), Shared]
    internal sealed class RemoveUnnecessarySuppressionsCodeFixProvider : SyntaxEditorBasedCodeFixProvider
    {
        [ImportingConstructor]
        [Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
        public RemoveUnnecessarySuppressionsCodeFixProvider()
        {
        }

        public override ImmutableArray<string> FixableDiagnosticIds
            => ImmutableArray.Create(IDEDiagnosticIds.InvalidSuppressMessageAttributeDiagnosticId);

        internal override CodeFixCategory CodeFixCategory
            => CodeFixCategory.CodeQuality;

        public override Task RegisterCodeFixesAsync(CodeFixContext context)
        {
            foreach (var diagnostic in context.Diagnostics)
            {
                context.RegisterCodeFix(
                    new MyCodeAction(c => FixAsync(context.Document, diagnostic, c)),
                    diagnostic);
            }

            return Task.CompletedTask;
        }

        protected override Task FixAllAsync(Document document, ImmutableArray<Diagnostic> diagnostics, SyntaxEditor editor, CancellationToken cancellationToken)
        {
            foreach (var diagnostic in diagnostics)
            {
                var node = editor.OriginalRoot.FindNode(diagnostic.Location.SourceSpan);
                if (node != null)
                {
                    editor.RemoveNode(node);
                }
            }

            return Task.CompletedTask;
        }

        private class MyCodeAction : CustomCodeActions.DocumentChangeAction
        {
            public MyCodeAction(Func<CancellationToken, Task<Document>> createChangedDocument)
                : base(CodeFixesResources.Remove_redundant_suppression, createChangedDocument, nameof(RemoveUnnecessarySuppressionsCodeFixProvider))
            {
            }
        }
    }
}