// 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.
 
#nullable disable
 
using System.Collections.Immutable;
using System.Diagnostics;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.CSharp.Extensions;
using Microsoft.CodeAnalysis.CSharp.LanguageService;
using Microsoft.CodeAnalysis.Formatting;
using Microsoft.CodeAnalysis.LanguageService;
using Microsoft.CodeAnalysis.Text;
 
namespace Microsoft.CodeAnalysis.CSharp;
 
using static CSharpSyntaxTokens;
 
internal sealed partial class CSharpSyntaxFactsServiceFactory
{
    private sealed class CSharpSyntaxFactsService : CSharpSyntaxFacts, ISyntaxFactsService
    {
        internal static new readonly CSharpSyntaxFactsService Instance = new();
 
        public bool IsInNonUserCode(SyntaxTree syntaxTree, int position, CancellationToken cancellationToken)
        {
            if (syntaxTree == null)
            {
                return false;
            }
 
            return syntaxTree.IsInNonUserCode(position, cancellationToken);
        }
 
        private static readonly SyntaxAnnotation s_annotation = new();
 
        public void AddFirstMissingCloseBrace<TContextNode>(
            SyntaxNode root, TContextNode contextNode,
            out SyntaxNode newRoot, out TContextNode newContextNode) where TContextNode : SyntaxNode
        {
            newRoot = new AddFirstMissingCloseBraceRewriter(contextNode).Visit(root);
            newContextNode = (TContextNode)newRoot.GetAnnotatedNodes(s_annotation).Single();
        }
 
        private class AddFirstMissingCloseBraceRewriter : CSharpSyntaxRewriter
        {
            private readonly SyntaxNode _contextNode;
            private bool _seenContextNode = false;
            private bool _addedFirstCloseCurly = false;
 
            public AddFirstMissingCloseBraceRewriter(SyntaxNode contextNode)
                => _contextNode = contextNode;
 
            public override SyntaxNode Visit(SyntaxNode node)
            {
                if (node == _contextNode)
                {
                    _seenContextNode = true;
 
                    // Annotate the context node so we can find it again in the new tree
                    // after we've added the close curly.
                    return node.WithAdditionalAnnotations(s_annotation);
                }
 
                // rewrite this node normally.
                var rewritten = base.Visit(node);
                if (rewritten == node)
                {
                    return rewritten;
                }
 
                // This node changed.  That means that something underneath us got
                // rewritten.  (i.e. we added the annotation to the context node).
                Debug.Assert(_seenContextNode);
 
                // Ok, we're past the context node now.  See if this is a node with 
                // curlies.  If so, if it has a missing close curly then add in the 
                // missing curly.  Also, even if it doesn't have missing curlies, 
                // then still ask to format its close curly to make sure all the 
                // curlies up the stack are properly formatted.
                var braces = rewritten.GetBraces();
                if (braces.openBrace.Kind() == SyntaxKind.None &&
                    braces.closeBrace.Kind() == SyntaxKind.None)
                {
                    // Not an item with braces.  Just pass it up.
                    return rewritten;
                }
 
                // See if the close brace is missing.  If it's the first missing one 
                // we're seeing then definitely add it.
                if (braces.closeBrace.IsMissing)
                {
                    if (!_addedFirstCloseCurly)
                    {
                        var closeBrace = CloseBraceToken
                            .WithAdditionalAnnotations(Formatter.Annotation);
                        rewritten = rewritten.ReplaceToken(braces.closeBrace, closeBrace);
                        _addedFirstCloseCurly = true;
                    }
                }
                else
                {
                    // Ask for the close brace to be formatted so that all the braces
                    // up the spine are in the right location.
                    rewritten = rewritten.ReplaceToken(braces.closeBrace,
                        braces.closeBrace.WithAdditionalAnnotations(Formatter.Annotation));
                }
 
                return rewritten;
            }
        }
 
        public Task<ImmutableArray<SyntaxNode>> GetSelectedFieldsAndPropertiesAsync(SyntaxTree tree, TextSpan textSpan, bool allowPartialSelection, CancellationToken cancellationToken)
            => CSharpSelectedMembers.Instance.GetSelectedFieldsAndPropertiesAsync(tree, textSpan, allowPartialSelection, cancellationToken);
    }
}