using Sandbox;
using Sandbox.Audio;
using System.Threading;
using System.Threading.Tasks;

namespace Sandbox;

public sealed class DSPReverb : Component, Component.ITriggerListener
{
	[Property] public MixerHandle TargetMixer { get; set; }
	[Property] public DspPresetHandle Preset { get; set; }
	[Property] [Range( 0f, 10f, 0.1f )] public float FadeDuration { get; set; } = 1f;
	[Property] public BBox Bounds { get; set; } = new BBox( Vector3.One * -100f, Vector3.One * 100f );

	private DspProcessor _processor;
	private BoxCollider _triggerCollider;

	private CancellationTokenSource _cts;

	protected override void OnAwake()
	{
		base.OnAwake();

		_triggerCollider = Components.Create<BoxCollider>();
		_triggerCollider.IsTrigger = true;
		_triggerCollider.Static = true;
		_triggerCollider.Scale = Bounds.Size;
		_triggerCollider.Center = Bounds.Center;
	}

	public void OnTriggerEnter( Collider other )
	{
		if ( other.Components.TryGet<Dedugan>( out Dedugan dedugan ) )
		{
			if ( dedugan.Connection == Dedugan.Local.Connection )
			{
				_cts?.Cancel();
				_cts = new CancellationTokenSource();

				if ( _processor != null ) { TargetMixer.Get().RemoveProcessor( _processor ); }

				_processor = new DspProcessor( Preset.Name );
				_processor.Mix = 0f;
				TargetMixer.Get().AddProcessor( _processor );

				_processor.Mix = 1f;
				// _ = UpdateMixAsync(1f);
			}
		}
	}

	private async Task UpdateMixAsync( float targetMix )
	{
		float startMix = _processor.Mix;
		float elapsed = FadeDuration *
		                ((targetMix == 0f || startMix == 0f) ? 0f : Math.Min( startMix / targetMix, 1f ));
		float lastTime = Time.Now;

		while ( elapsed < FadeDuration && !_cts.IsCancellationRequested )
		{
			await Task.FixedUpdate();

			float delta = Time.Now - lastTime;
			elapsed += delta;

			float t = Math.Clamp( elapsed / FadeDuration, 0f, 1f );
			_processor.Mix = Math.Clamp( startMix + (targetMix - startMix) * t, 0f, 1f );

			lastTime = Time.Now;
		}

		if ( !_cts.IsCancellationRequested )
		{
			_processor.Mix = targetMix;
		}
	}

	public void OnTriggerExit( Collider other )
	{
		if ( other.Components.TryGet<Dedugan>( out Dedugan dedugan ) )
		{
			if ( dedugan.Connection == Dedugan.Local.Connection )
			{
				_cts?.Cancel();
				_cts = new CancellationTokenSource();

				_processor.Mix = 0f;
			}
		}

		// _ = UpdateMixAsync(0f).ContinueWith( (_) =>
		// {
		// 	if (_processor == null) return;
		// 	
		// 	TargetMixer.Get().RemoveProcessor(_processor);
		// 	_processor = null;
		// } );
	}

	protected override void DrawGizmos()
	{
		base.DrawGizmos();
		Gizmo.Draw.Color = Color.Green;
		Gizmo.Draw.LineBBox( Bounds );
	}
}