#nullable enable
using System;
using Godot;
using ShrinkEventBus;

public partial class WorldDemoWorld : Node
{
    private IDisposable? _binding;
    private bool _restoring = true;
    private readonly DemoWorldSubscriber _subscriber = new();
    public ShrinkBusKey Key { get; } = ShrinkBusKey.World(Guid.NewGuid().ToString("N"));
    public IShrinkEventBus Bus { get; private set; } = null!;
    public int ReadyCount => _subscriber.ReadyCount;
    public int EffectCount => _subscriber.EffectCount;

    public override void _EnterTree()
    {
        Bus = EventBus.CreateBus(Key, new ShrinkBusOptions
        {
            Scheduler = ShrinkBusSchedulerKind.MainThread,
            DispatchMode = ShrinkDispatchMode.Ordered,
            QueueCapacity = 32
        });
        _binding = EventBus.Attach(_subscriber, Key);
    }

    public void Restore(bool fail)
    {
        Post(new DemoEffect());
        if (fail) throw new InvalidOperationException("Candidate restore failed.");
    }

    public void Commit()
    {
        _restoring = false;
        Post(new DemoWorldReady());
    }

    private void Post<T>(T value) where T : IShrinkEvent
    {
        if (!_restoring) Bus.Post(value);
    }

    public override void _ExitTree()
    {
        _binding?.Dispose();
        _binding = null;
        EventBus.RemoveBus(Key);
    }
}

public readonly struct DemoWorldReady : IShrinkEvent { }
public readonly struct DemoEffect : IShrinkEvent { }

[ShrinkEventSubscriber]
public sealed class DemoWorldSubscriber
{
    public int ReadyCount { get; private set; }
    public int EffectCount { get; private set; }
    [ShrinkSubscribe] private void OnReady(DemoWorldReady value) => ReadyCount++;
    [ShrinkSubscribe] private void OnEffect(DemoEffect value) => EffectCount++;
}