How can I make WASD controls relative to camera Position?

So I have a camera that allows me to rotate around my player using my mouse. My character is controlled using WASD keys. This gets very confusing if lets say, I rotate my camera to the right side of my character, because then W visually makes my character move from left to right on the screen, rather than "forward". So how could I change this camera script in order to make WASD relative to its rotation?

Player script

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
     public class testscript : MonoBehaviour {
     
      public float speed = 6.0F;
      public float jumpSpeed = 8.0F;
      public float gravity = 20.0F;
      private Vector3 moveDirection = Vector3.zero;
     
      private CharacterController controller;
     
      private void Awake()
      {
          controller = GetComponent<CharacterController>();
      }
     
      void Update()
      {
          if (controller.isGrounded)
          {
              moveDirection = new Vector3(Input.GetAxis("Horizontal"), 0, Input.GetAxis("Vertical"));
     
              Quaternion rotation = Quaternion.LookRotation(moveDirection, Vector3.up);
              if (moveDirection != Vector3.zero)
                  transform.rotation = rotation;
     
              moveDirection *= speed;
              if (Input.GetButton("Jump"))
              {
                  moveDirection.y = jumpSpeed;
              }
     
              Debug.DrawLine(transform.position, moveDirection);
     
          }
          moveDirection.y -= gravity * Time.deltaTime;
          controller.Move(moveDirection * Time.deltaTime);
      }    
 }

Camera script

 using UnityEngine;
 using System.Collections;
 
 [AddComponentMenu("Camera-Control/Mouse Orbit with zoom")]
 public class MouseOrbitImproved : MonoBehaviour {
 
     public Transform target;
     public float distance = 5.0f;
     public float xSpeed = 120.0f;
     public float ySpeed = 120.0f;
 
     public float yMinLimit = -20f;
     public float yMaxLimit = 80f;
 
     public float distanceMin = .5f;
     public float distanceMax = 15f;
 
     private Rigidbody rigidbody;
 
     float x = 0.0f;
     float y = 0.0f;
 
     // Use this for initialization
     void Start () 
     {
         Vector3 angles = transform.eulerAngles;
         x = angles.y;
         y = angles.x;
 
         rigidbody = GetComponent<Rigidbody>();
 
         // Make the rigid body not change rotation
         if (rigidbody != null)
         {
             rigidbody.freezeRotation = true;
         }
     }
 
     void LateUpdate () 
     {
         if (target) 
         {
             x += Input.GetAxis("Mouse X") * xSpeed * distance * 0.02f;
             y -= Input.GetAxis("Mouse Y") * ySpeed * 0.02f;
 
             y = ClampAngle(y, yMinLimit, yMaxLimit);
 
             Quaternion rotation = Quaternion.Euler(y, x, 0);
 
             distance = Mathf.Clamp(distance - Input.GetAxis("Mouse ScrollWheel")*5, distanceMin, distanceMax);
 
             RaycastHit hit;
             if (Physics.Linecast (target.position, transform.position, out hit)) 
             {
                 distance -=  hit.distance;
             }
             Vector3 negDistance = new Vector3(0.0f, 0.0f, -distance);
             Vector3 position = rotation * negDistance + target.position;
 
             transform.rotation = rotation;
             transform.position = position;
         }
     }
 
     public static float ClampAngle(float angle, float min, float max)
     {
         if (angle < -360F)
             angle += 360F;
         if (angle > 360F)
             angle -= 360F;
         return Mathf.Clamp(angle, min, max);
     }
 }