// 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 System.Threading.Tasks;
using Microsoft.CodeAnalysis.Shared.Extensions;
using Microsoft.CodeAnalysis.Text;
using Microsoft.CodeAnalysis.ValueTracking;
 
namespace Microsoft.CodeAnalysis.Remote;
 
internal sealed class RemoteValueTrackingService : BrokeredServiceBase, IRemoteValueTrackingService
{
    internal sealed class Factory : FactoryBase<IRemoteValueTrackingService>
    {
        protected override IRemoteValueTrackingService CreateService(in ServiceConstructionArguments arguments)
            => new RemoteValueTrackingService(arguments);
    }
 
    public RemoteValueTrackingService(ServiceConstructionArguments arguments)
        : base(arguments)
    {
    }
 
    public ValueTask<ImmutableArray<SerializableValueTrackedItem>> TrackValueSourceAsync(Checksum solutionChecksum, TextSpan selection, DocumentId documentId, CancellationToken cancellationToken)
    {
        return RunServiceAsync(solutionChecksum, async solution =>
        {
            if (solution is null)
            {
                throw new InvalidOperationException();
            }
 
            var document = solution.GetRequiredDocument(documentId);
 
            var progress = new ValueTrackingProgressCollector();
            await ValueTracker.TrackValueSourceAsync(selection, document, progress, cancellationToken).ConfigureAwait(false);
 
            var items = progress.GetItems();
            return items.SelectAsArray(item => SerializableValueTrackedItem.Dehydrate(solution, item, cancellationToken));
        }, cancellationToken);
    }
 
    public ValueTask<ImmutableArray<SerializableValueTrackedItem>> TrackValueSourceAsync(Checksum solutionChecksum, SerializableValueTrackedItem previousTrackedItem, CancellationToken cancellationToken)
    {
        return RunServiceAsync(solutionChecksum, async solution =>
        {
            if (solution is null)
            {
                throw new InvalidOperationException();
            }
 
            var previousItem = await previousTrackedItem.RehydrateAsync(solution, cancellationToken).ConfigureAwait(false);
            if (previousItem is null)
            {
                return ImmutableArray<SerializableValueTrackedItem>.Empty;
            }
 
            var progress = new ValueTrackingProgressCollector();
            await ValueTracker.TrackValueSourceAsync(solution, previousItem, progress, cancellationToken).ConfigureAwait(false);
 
            var items = progress.GetItems();
            return items.SelectAsArray(item => SerializableValueTrackedItem.Dehydrate(solution, item, cancellationToken));
        }, cancellationToken);
    }
}