Endless Runner Game: Turn Corners

How do I add corners into my game? with using these scripts. I'm sorry if this is long but I'm new too Unity. I have a tile manager script(Underneath the character controller script), so the game can choose a random path for the player. I also have lane changes(Which you can see in the script), so when the player moves left. They, move to a certain spot, same thing if they went right. But, I don't want my player rotating right or left when the corner tile is not there. Also, once I have the corner tile, I need still need to make sure that the game is still creating a new path for that tile. Someone please help me.

public class PlayerController : MonoBehaviour {

 private CharacterController controller;
 private Vector3 direction;
 public float forwardSpeed;
 public float maxSpeed;

 private int desiredLane = 1; //0=left 1=middle 2=right
 public float laneDistance = 3; // the distance between two lanes
 public float jumpForce;
 public float Gravity = -20;
 public float AddForce;
 

 bool alive = true;

 


 // Start is called before the first frame update
 void Start()
 {
     controller = GetComponent<CharacterController>();
     
     
 }

 // Update is called once per frame
 void Update()
 {
     //Increase speed
     if(forwardSpeed < maxSpeed)
         forwardSpeed += 0.1f * Time.deltaTime;

     

     direction.z = forwardSpeed;
     

     if (controller.isGrounded)
     {
         direction.y = -1;
         if (SwipeManager.swipeUp) 
         {
             Jump();
         }
         if (Input.GetKeyDown(KeyCode.UpArrow))
         {
             Jump();
         }


     }
     else
     {
         direction.y += Gravity * Time.deltaTime;
     }
     //Gather the inputs on which lane we should be  on

     if (SwipeManager.swipeRight)
     {
         desiredLane++;
         if (desiredLane == 3)
             desiredLane = 2;       
     }

     if (Input.GetKeyDown(KeyCode.RightArrow))
     {
         desiredLane++;
         if (desiredLane == 3)
             desiredLane = 2;
     }
    
     if (Input.GetKeyDown(KeyCode.LeftArrow))
     {
         desiredLane--;
         if (desiredLane == -1)
             desiredLane = 0;
     }

     if (SwipeManager.swipeLeft)
     {
         desiredLane--;
         if (desiredLane == -1)
             desiredLane = 0;
     }

     //Calculate where we should be in the future

     Vector3 targetPosition = transform.position.z * transform.forward + transform.position.y * transform.up;

     if (desiredLane == 0)
     {
         targetPosition += Vector3.left * laneDistance;

     }
     
     else if (desiredLane == 2)
     {
         targetPosition += Vector3.right * laneDistance;
     }

     //transform.position = Vector3.Lerp(transform.position,targetPosition,80 * Time.deltaTime);
     if (transform.position == targetPosition)
         return;
     Vector3 diff = targetPosition - transform.position;
     Vector3 moveDir = diff.normalized * 25 * Time.deltaTime;
     if (moveDir.sqrMagnitude < diff.sqrMagnitude)
         controller.Move(moveDir);
     else
         controller.Move(diff);
 }


 private void FixedUpdate()
 {
     if (!PlayerManager.isGameStarted)
         return;
     controller.Move(direction * Time.fixedDeltaTime);
     
 }

 private void Jump()
 {
     direction.y = jumpForce;
 }
 public void Die ()
 {
     alive = false;
     // Restart the game
     Invoke("Restart", 2);
     if (!alive) return;

 }

 void Restart()
 {
      SceneManager.LoadScene(SceneManager.GetActiveScene().name);
     if (!alive) return;
 }

 private void OnControllerColliderHit(ControllerColliderHit hit)
 {
     if (hit.transform.tag == "Obstacle")
     {
         PlayerManager.gameOver = true;
         FindObjectOfType<AudioManager>().PlaySound("GameOver");
         FindObjectOfType<AudioManager>().StopSound("Main Theme");
     }
 }

 

}

public class TileManager : MonoBehaviour {

 public GameObject[] tilePrefabs;
 public float zSpawn = 0;
 public float tileLength = 50;
 public int numberOfTiles = 5;
 private List<GameObject> activeTiles = new List<GameObject>();
 public Transform playerTransform;

 // Start is called before the first frame update
 void Start()
 {
     for(int i= 0; i < numberOfTiles; i++)
     {
         if (i == 0)
             SpawnTile(0);
         else
             SpawnTile(Random.Range(0, tilePrefabs.Length)); 
     }
 }

 // Update is called once per frame
 void Update()
 {
     if (playerTransform.position.z -35 > zSpawn - (numberOfTiles * tileLength))
     {
         SpawnTile(Random.Range(0, tilePrefabs.Length));
         DeleteTile();
     }
 }
 public void SpawnTile(int tileIndex)
 {
     GameObject go =Instantiate(tilePrefabs[tileIndex], transform.forward * zSpawn, transform.rotation);
     activeTiles.Add(go);
     zSpawn += tileLength;
 }
 
 private void DeleteTile()
 {
     Destroy(activeTiles[0]);
     activeTiles.RemoveAt(0);
 }

}