// 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.Diagnostics.CodeAnalysis;
using System.Linq;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.Shared.Extensions;
 
internal static class SyntaxNodeOrTokenExtensions
{
    public static bool AsNode(this SyntaxNodeOrToken nodeOrToken, [NotNullWhen(true)] out SyntaxNode? node)
    {
        if (nodeOrToken.IsNode)
        {
            node = nodeOrToken.AsNode();
            return node != null;
        }
 
        node = null;
        return false;
    }
 
    public static IEnumerable<SyntaxNodeOrToken> DepthFirstTraversal(this SyntaxNodeOrToken node)
    {
        using var pooledStack = SharedPools.Default<Stack<SyntaxNodeOrToken>>().GetPooledObject();
        var stack = pooledStack.Object;
        stack.Push(node);
 
        while (stack.TryPop(out var current))
        {
            yield return current;
 
            if (current.IsNode)
            {
                foreach (var child in current.ChildNodesAndTokens().Reverse())
                    stack.Push(child);
            }
        }
    }
 
    public static IEnumerable<SyntaxNode> DepthFirstTraversalNodes(this SyntaxNodeOrToken node)
    {
        foreach (var t in node.DepthFirstTraversal())
        {
            if (t.AsNode(out var childNode))
                yield return childNode;
        }
    }
 
    public static SyntaxTrivia[] GetTrivia(params SyntaxNodeOrToken[] nodesOrTokens)
        => nodesOrTokens.SelectMany(nodeOrToken => nodeOrToken.GetLeadingTrivia().Concat(nodeOrToken.GetTrailingTrivia())).ToArray();
 
    public static SyntaxNodeOrToken WithAppendedTrailingTrivia(this SyntaxNodeOrToken nodeOrToken, params SyntaxTrivia[] trivia)
        => WithAppendedTrailingTrivia(nodeOrToken, (IEnumerable<SyntaxTrivia>)trivia);
 
    public static SyntaxNodeOrToken WithAppendedTrailingTrivia(this SyntaxNodeOrToken nodeOrToken, IEnumerable<SyntaxTrivia> trivia)
        => nodeOrToken.AsNode(out var node) ? node.WithAppendedTrailingTrivia(trivia) : nodeOrToken.AsToken().WithAppendedTrailingTrivia(trivia);
}