public partial class MovementController : Node
{
	[ExportGroup("Movement")]
	[Export] public float Acceleration  { get; set; } =  4.0f;
	[Export] public float MaxSpeed      { get; set; } =  2.1f;
	[Export] public float FrictionFloor { get; set; } = 12.0f;
	[Export] public float FrictionAir   { get; set; } =  2.0f;
	public float Gravity { get; } = (float)ProjectSettings.GetSetting("physics/3d/default_gravity");

	[ExportGroup("Jumping")]
	[Export] public float JumpVelocity { get; set; } = 4.0f;
	/// <summary> Time (in seconds) after pressing the jump button a jump may occur late. </summary>
	[Export] public float JumpEarlyTime { get; set; } = 0.0f;
	/// <summary> Time (in seconds) after leaving a jumpable surface when a jump may still occur. </summary>
	[Export] public float JumpCoyoteTime { get; set; } = 0.0f;

	public bool IsSprinting { get; private set; }
	/// <summary> The raw input movement vector with a maximum length of 1. </summary>
	[Export] public Vector2 InputVector { get; private set; }

	public bool IsMoving => LocalMoveVector.Length() > 0.01f;
	/// <summary> The actual amount the player is moving, relative to the world. Y is always 0. </summary>
	public Vector3 GlobalMoveVector { get; private set; }
	/// <summary> The actual amount the player is moving, relative to the player's viewpoint. Y is always 0. </summary>
	public Vector3 LocalMoveVector { get; private set; }
	/// <summary>  </summary>
	public float LocalMoveAngle { get; private set; }

	public float TimeSinceJumpPressed { get; private set; } = float.PositiveInfinity;
	public float TimeSinceOnFloor     { get; private set; } = float.PositiveInfinity;

	Player _player;
	public override void _Ready()
		=> _player = GetParent<Player>();

	public override void _UnhandledInput(InputEvent @event)
	{
		if (!_player.IsLocal) return;

		// TODO: Sprinting.

		if (@event.IsActionPressed("move_jump")) {
			TimeSinceJumpPressed = 0.0f;
			GetViewport().SetInputAsHandled();
		}
	}

	public override void _PhysicsProcess(double delta)
	{
		var velocity = _player.Velocity;
		velocity.Y -= Gravity * (float)delta;

		// Get the (normalized) movement vector from the current input.
		InputVector = _player.IsLocal
			? Input.GetVector("move_strafe_left", "move_strafe_right", "move_forward", "move_back")
			: Vector2.Zero;

		var horVelocity = velocity with { Y = 0 };
		var basis  = _player.Basis.Rotated(Vector3.Up, _player.Camera.CurrentYaw);
		var target = basis * new Vector3(InputVector.X, 0, InputVector.Y) * MaxSpeed;
		var isMoving = target.Dot(horVelocity) > 0.0f;

		var isOnFloor = _player.IsOnFloor();
		var accel = isMoving  ? Acceleration
		          : isOnFloor ? FrictionFloor
		                      : FrictionAir;

		if (IsSprinting) {
			target *= 5;
			accel  *= 5;
		}

		horVelocity = horVelocity.Lerp(target, accel * (float)delta);
		velocity.X = horVelocity.X;
		velocity.Z = horVelocity.Z;

		if (isOnFloor) TimeSinceOnFloor = 0.0f;
		else           TimeSinceOnFloor += (float)delta;

		if ((TimeSinceJumpPressed <= JumpEarlyTime) && (TimeSinceOnFloor <= JumpCoyoteTime)) {
			TimeSinceJumpPressed = TimeSinceOnFloor = float.PositiveInfinity;
			velocity.Y = JumpVelocity;
		} else
			TimeSinceJumpPressed += (float)delta;

		_player.Velocity = velocity;
		_player.MoveAndSlide();

		// TODO: Very simplified, but works for now.
		GlobalMoveVector = _player.Velocity with { Y = 0 };
		LocalMoveVector  = _player.Basis.Inverse() * GlobalMoveVector;
		LocalMoveAngle   = Vector3.Forward.SignedAngleTo(LocalMoveVector, Vector3.Up);
	}
}