using Sandbox;
using System;
using System.Threading;

namespace VeloX;

public partial class VeloXCar
{
	public static float ExpDecay( float a, float b, float decay, float dt ) => b + (a - b) * MathF.Exp( -decay * dt );
	[Property, Feature( "Steer" )] public float SteerConeMaxSpeed { get; set; } = 1800;
	[Property, Feature( "Steer" )] public float SteerConeMaxAngle { get; set; } = 0.25f;
	[Property, Feature( "Steer" )] public float SteerConeChangeRate { get; set; } = 8;
	[Property, Feature( "Steer" )] public float CounterSteer { get; set; } = 0.1f;
	[Property, Feature( "Steer" )] public float MaxSteerAngle { get; set; } = 35f;

	[Sync] public float Steering { get; private set; }
	private float jTurnMultiplier;

	private float inputSteer;
	private void UpdateSteering( float dt )
	{
		var inputSteer = Input.AnalogMove.y;
		var absInputSteer = Math.Abs( inputSteer );

		var sideSlip = Math.Clamp( avgSideSlip, -1, 1 );

		var steerConeFactor = Math.Clamp( TotalSpeed / SteerConeMaxSpeed, 0, 1 );
		var steerCone = 1 - steerConeFactor * (1 - SteerConeMaxAngle);

		steerCone = Math.Clamp( steerCone, Math.Abs( sideSlip ), 1 );

		inputSteer = ExpDecay( this.inputSteer, inputSteer * steerCone, SteerConeChangeRate, dt );
		this.inputSteer = inputSteer;
		var counterSteer = sideSlip * steerConeFactor * (1 - absInputSteer);
		counterSteer = Math.Clamp( counterSteer, -1, 1 ) * CounterSteer;

		inputSteer = Math.Clamp( inputSteer + counterSteer, -1, 1 );
		Steering = inputSteer;
		SteerAngle = new( 0, -inputSteer * MaxSteerAngle, 0 );

		if ( ForwardSpeed < -100 )
			jTurnMultiplier = 0.5f;
		else
			jTurnMultiplier = ExpDecay( jTurnMultiplier, 1, 2, dt );
	}
}