A* Pathfinding Enemy AI, How to search for something else when no path to player available

I've been following a tutorial on how to use A* path finding however, the game I'm making I require the enemy to search for the player, but since I will have objects to stop their path (barricades etc), I need them to first check that there is a path to the player and if not they search for a barricade to destroy and then search for the player again.

here is the current script:

 public class EnemyAlienAi : MonoBehaviour {

 public Transform target; //enemy target acquired

 public float updateRate = 4f; //how many times a second each second  we update our path

 private Seeker seeker;
 private Rigidbody2D rb;

 public Path path; //calculated path

 public float speed = 300f;
 public ForceMode2D fMode;

 [HideInInspector]
 public bool pathIsEnded = false;

 private bool searchingForPlayer = false;
 public float nextWayPointDistance = 2; //the max distance from the ai to a waypoint to continue to next waypoint
 private int currentWayPoint = 0; //waypoint currently moving towards

 void Start () {
 
     seeker = GetComponent<Seeker> ();
     rb = GetComponent<Rigidbody2D> ();

     transform.position = new Vector3 (transform.position.x, transform.position.y, 0f);

     if (target == null) {
         //Debug.Log ("No target");
         if (!searchingForPlayer) {
             searchingForPlayer = true;
             StartCoroutine (SearchForPlayer ());
         }
         return;
         //insert a search for target
     }

     seeker.StartPath (transform.position, target.position, OnPathComplete);

     StartCoroutine ("UpdatePath");

 }

 void Update(){

     var dir = target.position - transform.position;
     var angle = Mathf.Atan2(dir.y, dir.x) * Mathf.Rad2Deg;
     transform.rotation = Quaternion.AngleAxis(angle + 90, Vector3.forward);
 }

 IEnumerator SearchForPlayer(){
     GameObject searchResult = GameObject.FindGameObjectWithTag ("Player");
     if (searchResult == null) {
         yield return new WaitForSeconds (0.5f);
         StartCoroutine (SearchForPlayer ());
     } else {
         target = searchResult.transform;
         searchingForPlayer = false;
         StartCoroutine (UpdatePath ());
         return false;
     }
 }

 IEnumerator UpdatePath(){
     if (target == null) {
         //Debug.Log ("No target");
         if (!searchingForPlayer) {
             searchingForPlayer = true;
             StartCoroutine (SearchForPlayer ());
         }
         return false;
         //insert a search for target
     }

     seeker.StartPath (transform.position, target.position, OnPathComplete);

     yield return new WaitForSeconds (1f / updateRate);
     StartCoroutine (UpdatePath());
 }

 public void OnPathComplete(Path p){
     Debug.Log ("We have a path, did it have an error? " + p.error);
     if (!p.error) {
         path = p;
         currentWayPoint = 0;
     }
 }

 void FixedUpdate(){

     if (target == null) {
         //Debug.Log ("No target");
         if (!searchingForPlayer) {
             searchingForPlayer = true;
             StartCoroutine (SearchForPlayer ());
         }
         return;
         //insert a search for target
     }

     //TODO: always look at player?

     if (path == null) {
         return;
     }
     if (currentWayPoint >= path.vectorPath.Count) {
         if (pathIsEnded == true) {
             return;
         }
         Debug.Log ("Path reached.");
         pathIsEnded = true;
     }

     pathIsEnded = false;

     Vector3 dir = (path.vectorPath[currentWayPoint] - transform.position).normalized; // direction to next waypoint
     dir *= speed * Time.fixedDeltaTime;

     rb.AddForce (dir, fMode);//move the ai
     float dist = Vector3.Distance(transform.position, path.vectorPath[currentWayPoint]);
     if (dist < nextWayPointDistance){
         currentWayPoint++;
         return;
     }
 }

`}