// 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.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
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;
 
namespace Microsoft.CodeAnalysis.CSharp.CodeFixes.HideBase;
 
using static CSharpSyntaxTokens;
 
internal sealed partial class HideBaseCodeFixProvider
{
    private static async Task<Document> GetChangedDocumentAsync(
        Document document, SyntaxNode node, CancellationToken cancellationToken)
    {
        var root = await document.GetRequiredSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
        var modifierOrder = await GetModifierOrderAsync(document, cancellationToken).ConfigureAwait(false);
 
        return document.WithSyntaxRoot(root.ReplaceNode(node, GetNewNode(node, modifierOrder)));
    }
 
    private static SyntaxNode GetNewNode(SyntaxNode node, Dictionary<int, int>? preferredOrder)
    {
        var syntaxFacts = CSharpSyntaxFacts.Instance;
        var modifiers = syntaxFacts.GetModifiers(node);
        var newModifiers = modifiers.Add(NewKeyword);
 
        if (preferredOrder is null ||
            !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;
    }
}