PlayerCharacterController

using UnityEngine;

[RequireComponent(typeof(CharacterController), typeof(EffectorHandlerComponent))]
public class PlayerCharacterController : MonoBehaviour
{
    [SerializeField] float moveSpeed = 8;
    [SerializeField] float gravity = 9.81f;

    CharacterController characterController;
    EffectorHandlerComponent effectorHandlerComponent;

    private void Awake()
    {
        characterController = GetComponent<CharacterController>();
        effectorHandlerComponent = GetComponent<EffectorHandlerComponent>();
    }

    public void Update()
    {
        //Input direction is 0 if we do nothing
        Vector3 moveDirection = Vector3.zero;

        //Get inputs for left and right
        if (Input.GetKey(KeyCode.D))
        {
            moveDirection = Vector3.right;
        }
        else if (Input.GetKey(KeyCode.A))
        {
            moveDirection = Vector3.left;
        }

        //Multiply moveDirection by moveSpeed and add gravity
        Vector3 moveVector = (moveDirection * moveSpeed) + Vector3.down * gravity;

        //Ask the effector handler for displacement vectors caused by any Effectors
        //If none displacement vector will be Vector3.zero and will change nothing
        //There are better ways than to call GetEffectorDisplacement every frame but for now this will do,
        //The cost is trivial either way
        Vector3 displacementVector = effectorHandlerComponent.GetEffectorDisplacements();

        //Call move every frame, not just when input so we can apply gravity and displacement
        characterController.Move((moveVector + displacementVector) * Time.deltaTime);
    }
}