#nullable enable

using System;
using NUnit.Framework;
using Unity.Burst;
using Unity.Collections;
using Unity.Jobs;

namespace ShrinkEventBus.Entities.Tests
{
    internal struct EcsPingEvent : IShrinkEvent
    {
        public int Value;
    }

    internal sealed class EcsPingSubscriber : IShrinkGeneratedSubscriber
    {
        public int Sum { get; private set; }

        public IDisposable AttachGenerated(IShrinkBusResolver resolver, ShrinkBusKey? defaultBus = null)
        {
            return ShrinkGeneratedBinding.Subscribe<EcsPingEvent>(resolver, defaultBus,
                string.Empty, this, OnPing, ShrinkEventPriority.Normal, 0, false);
        }

        private void OnPing(EcsPingEvent value) => Sum += value.Value;
    }

    [BurstCompile]
    internal struct PostPingJob : IJob
    {
        public ShrinkEcsEventWriter<EcsPingEvent> Writer;

        public void Execute()
        {
            Writer.Post(new EcsPingEvent { Value = 11 });
        }
    }

    public sealed class ShrinkEcsEventQueueTests
    {
        [Test]
        public void NativeWriterPlaybackUsesSameBusChannel()
        {
            using var host = new ShrinkEventBusHost();
            var bus = host.CreateBus(ShrinkBusKey.World("tests"), ShrinkBusOptions.Inline());
            var subscriber = new EcsPingSubscriber();
            using var binding = host.Attach(subscriber, ShrinkBusKey.World("tests"));
            using var queue = new ShrinkEcsEventQueue<EcsPingEvent>(Allocator.TempJob);

            queue.Writer.Post(new EcsPingEvent { Value = 2 });
            queue.Writer.Post(new EcsPingEvent { Value = 5 });
            var played = queue.Playback(bus);

            Assert.AreEqual(2, played);
            Assert.AreEqual(7, subscriber.Sum);
        }

        [Test]
        public void BurstJobWritesThenPlaybackUsesManagedBus()
        {
            using var host = new ShrinkEventBusHost();
            var bus = host.CreateBus(ShrinkBusKey.World("burst-tests"), ShrinkBusOptions.Inline());
            var subscriber = new EcsPingSubscriber();
            using var binding = host.Attach(subscriber, ShrinkBusKey.World("burst-tests"));
            using var queue = new ShrinkEcsEventQueue<EcsPingEvent>(Allocator.TempJob);
            var job = new PostPingJob { Writer = queue.Writer };

            job.Schedule().Complete();
            var played = queue.Playback(bus);

            Assert.AreEqual(1, played);
            Assert.AreEqual(11, subscriber.Sum);
        }
    }
}