using System.Collections.Concurrent;
using System.Threading.Channels;
using StellaOps.TimelineIndexer.Core.Abstractions;
using StellaOps.TimelineIndexer.Core.Models;

namespace StellaOps.TimelineIndexer.Tests;

public sealed class InMemoryTimelineEventSubscriber : ITimelineEventSubscriber
{
    private readonly Channel<TimelineEventEnvelope> _channel;

    public InMemoryTimelineEventSubscriber(IEnumerable<TimelineEventEnvelope>? seed = null)
    {
        _channel = Channel.CreateUnbounded<TimelineEventEnvelope>(new UnboundedChannelOptions
        {
            SingleReader = false,
            SingleWriter = false
        });

        if (seed is not null)
        {
            foreach (var envelope in seed)
            {
                _channel.Writer.TryWrite(envelope);
            }
            _channel.Writer.TryComplete();
        }
    }

    public void Enqueue(TimelineEventEnvelope envelope)
    {
        _channel.Writer.TryWrite(envelope);
    }

    public void Complete() => _channel.Writer.TryComplete();

    public IAsyncEnumerable<TimelineEventEnvelope> SubscribeAsync(CancellationToken cancellationToken = default)
    {
        return _channel.Reader.ReadAllAsync(cancellationToken);
    }
}