godot 4, C#, state machine

IdleState.cs

using Godot;
using System;

public partial class IdleState : Node
{
    public override void _Ready()
    {
        base._Ready();
        
    }

    public override void _Notification(int what)
    {
        base._Notification(what);
        if (what == GameConstants.IDLE_STATE)
        {
            Player characterNode = GetOwner<Player>();
            characterNode.animationPlayerNode.Play(GameConstants.ANIM_IDLE);
        }
    }

}

MoveState.cs

using Godot;
using System;

public partial class MoveState : Node
{
    public override void _Ready()
    {
        base._Ready();
        Player characterNode = GetOwner<Player>();
        characterNode.animationPlayerNode.Play(GameConstants.ANIM_MOVE);
    }

    public override void _Notification(int what)
    {
        base._Notification(what);
        if(what == GameConstants.MOVE_STATE)
        {
            Player characterNode = GetOwner<Player>();
            characterNode.animationPlayerNode.Play(GameConstants.ANIM_MOVE);
        }
    }
}

StateMachine.cs

using Godot;
using System;

public partial class StateMachine : Node
{
    [Export] private Node currentState;
    [Export] private Node[] States;

    public override void _Ready()
    {
        currentState.Notification(GameConstants.IDLE_STATE);
    }
}