Enemy rotates when hits wall

hi so i have a 2d game where an enemy goes right>left and left>right but i want the enemy to rotate towards the direction he is moving so move right > left >wall> rotate 180 > right >left here is the code. thank you

public float walkSpeed = 2.0f;

 public float wallLeft = 0.0f;
 
 public float wallRight = 5.0f;

 float walkingDirection = 1.0f;
 Vector2 walkAmount;

 // Update is called once per frame
 void Update () {

     walkAmount.x = walkingDirection * walkSpeed * Time.deltaTime;

     if (walkingDirection > 0.0f && transform.position.x >= wallRight)
         walkingDirection = -1.0f;
     else if (walkingDirection < 0.0f && transform.position.x <= wallLeft)
         walkingDirection = 1.0f;

     transform.Translate(walkAmount);
 }

}