// 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.Immutable;
using System.Threading;
using Microsoft.CodeAnalysis.Host;
using Microsoft.CodeAnalysis.PooledObjects;
using Microsoft.CodeAnalysis.Shared.Extensions;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.FindSymbols
{
    internal sealed partial class TopLevelSyntaxTreeIndex
    {
        private static TopLevelSyntaxTreeIndex CreateIndex(
            Document document, SyntaxNode root, Checksum checksum, CancellationToken cancellationToken)
        {
            var infoFactory = document.GetRequiredLanguageService<IDeclaredSymbolInfoFactoryService>();
 
            using var _1 = ArrayBuilder<DeclaredSymbolInfo>.GetInstance(out var declaredSymbolInfos);
            using var _2 = PooledDictionary<string, ArrayBuilder<int>>.GetInstance(out var extensionMethodInfo);
            try
            {
                infoFactory.AddDeclaredSymbolInfos(
                    document, root, declaredSymbolInfos, extensionMethodInfo, cancellationToken);
 
                return new TopLevelSyntaxTreeIndex(
                    checksum,
                    new DeclarationInfo(declaredSymbolInfos.ToImmutable()),
                    new ExtensionMethodInfo(
                        extensionMethodInfo.ToImmutableDictionary(
                            static kvp => kvp.Key,
                            static kvp => kvp.Value.ToImmutable())));
            }
            finally
            {
                foreach (var (_, builder) in extensionMethodInfo)
                    builder.Free();
            }
        }
    }
}