using MoonTools.ECS;
using Nerfed.Runtime.Scheduling;

namespace Nerfed.Runtime.Systems.Synthetic;

public sealed class DummyLongJobConsumerSystem : MoonTools.ECS.System, IParallelSystemMetadata
{
    private readonly JobSystem jobs;
    private readonly DummyLongJobSharedState state;
    private readonly bool requireCompletion;

    public DummyLongJobConsumerSystem(
        World world,
        DummyLongJobSharedState state,
        JobSystem jobs,
        bool requireCompletion) : base(world)
    {
        this.state = state;
        this.jobs = jobs;
        this.requireCompletion = requireCompletion;
    }

    public string ScheduleName => nameof(DummyLongJobConsumerSystem);

    // Consumer/apply stage is where structural world work should happen in real systems.
    public SystemAccessDeclaration AccessDeclaration => SystemAccessDeclaration.Empty;

    public override void Update(TimeSpan delta)
    {
        JobHandle handle = state.InFlight;
        if (!handle.IsValid)
        {
            return;
        }

        if (!requireCompletion && !jobs.IsCompleted(handle))
        {
            return;
        }

        jobs.Wait(handle);
        jobs.TryForget(handle);

        state.InFlight = default;
        state.ConsumeCount++;
    }
}