﻿// 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.Generic;
using System.Collections.Immutable;
using System.Linq;
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.LanguageService;
using Microsoft.CodeAnalysis.Shared.Extensions;
using Roslyn.Utilities;

namespace Microsoft.CodeAnalysis.SimplifyThisOrMe
{
    internal abstract partial class AbstractSimplifyThisOrMeCodeFixProvider<TMemberAccessExpressionSyntax>
        : SyntaxEditorBasedCodeFixProvider
        where TMemberAccessExpressionSyntax : SyntaxNode
    {
        protected abstract string GetTitle();
        protected abstract SyntaxNode Rewrite(SyntaxNode root, ISet<TMemberAccessExpressionSyntax> memberAccessNodes);

        public sealed override ImmutableArray<string> FixableDiagnosticIds { get; } =
            ImmutableArray.Create(IDEDiagnosticIds.RemoveThisOrMeQualificationDiagnosticId);

        public sealed override Task RegisterCodeFixesAsync(CodeFixContext context)
        {
            context.RegisterCodeFix(
                CodeAction.Create(
                    GetTitle(),
                    GetDocumentUpdater(context),
                    IDEDiagnosticIds.RemoveThisOrMeQualificationDiagnosticId),
                context.Diagnostics);

            return Task.CompletedTask;
        }

        protected sealed override async Task FixAllAsync(
            Document document, ImmutableArray<Diagnostic> diagnostics,
            SyntaxEditor editor, CodeActionOptionsProvider fallbackOptions, CancellationToken cancellationToken)
        {
            var root = await document.GetRequiredSyntaxRootAsync(cancellationToken).ConfigureAwait(false);

            var syntaxFacts = document.GetLanguageService<ISyntaxFactsService>();
            var memberAccessNodes = diagnostics.Select(
                d => (TMemberAccessExpressionSyntax)d.AdditionalLocations[0].FindNode(getInnermostNodeForTie: true, cancellationToken)).ToSet();

            var newRoot = Rewrite(root, memberAccessNodes);
            editor.ReplaceNode(root, newRoot);
        }
    }
}
