// 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.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.CodeActions;
using Microsoft.CodeAnalysis.CSharp.CodeStyle;
using Microsoft.CodeAnalysis.CSharp.LanguageService;
using Microsoft.CodeAnalysis.CSharp.OrderModifiers;
using Microsoft.CodeAnalysis.Options;
using Microsoft.CodeAnalysis.OrderModifiers;
using Microsoft.CodeAnalysis.Shared.Extensions;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.CSharp.CodeFixes.HideBase;
 
using static CSharpSyntaxTokens;
 
internal sealed partial class HideBaseCodeFixProvider
{
    private sealed class AddNewKeywordAction(Document document, SyntaxNode node) : CodeAction
    {
        private readonly Document _document = document;
        private readonly SyntaxNode _node = node;
 
        public override string Title => CSharpCodeFixesResources.Hide_base_member;
 
        protected override async Task<Document> GetChangedDocumentAsync(CancellationToken cancellationToken)
        {
            var root = await _document.GetRequiredSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
            var configOptions = await _document.GetHostAnalyzerConfigOptionsAsync(cancellationToken).ConfigureAwait(false);
 
            var newNode = GetNewNode(_node, configOptions.GetOption(CSharpCodeStyleOptions.PreferredModifierOrder).Value);
            var newRoot = root.ReplaceNode(_node, newNode);
 
            return _document.WithSyntaxRoot(newRoot);
        }
 
        private static SyntaxNode GetNewNode(SyntaxNode node, string preferredModifierOrder)
        {
            var syntaxFacts = CSharpSyntaxFacts.Instance;
            var modifiers = syntaxFacts.GetModifiers(node);
            var newModifiers = modifiers.Add(NewKeyword);
 
            if (!CSharpOrderModifiersHelper.Instance.TryGetOrComputePreferredOrder(preferredModifierOrder, out var preferredOrder) ||
                !AbstractOrderModifiersHelpers.IsOrdered(preferredOrder, modifiers))
            {
                return syntaxFacts.WithModifiers(node, newModifiers);
            }
 
            var orderedModifiers = new SyntaxTokenList(
                newModifiers.OrderBy(CompareModifiers));
 
            return syntaxFacts.WithModifiers(node, orderedModifiers);
 
            int CompareModifiers(SyntaxToken left, SyntaxToken right)
                => GetOrder(left) - GetOrder(right);
 
            int GetOrder(SyntaxToken token)
                => preferredOrder.TryGetValue(token.RawKind, out var value) ? value : int.MaxValue;
        }
    }
}