Enemy zombie AI

I need help with the following script:

-the zombies find random object with tag "Barricade" and lurk around it.
-the go through any rigidbody and box collider with the tag "Barricade" that it s in their way. They simply ignore the colliders.
-they don't always perform the attack function when they get in melee.

I need help with:
I want the zombies to find the objects with the tag "barricade" and attack them randomly when they get in melee range. Also i want them to record collisions.




using UnityEngine;
using System.Collections;

public class AiFindTag : MonoBehaviour
{

public Transform target;
public string enemyTag = "Barricade";
float f_RotSpeed = 3.0f;
float f_MoveSpeed = 3.0f;
public float attackDist=2f;
public float attackTimer =3f;
public float cooldown;
public int health = 150;
public GameObject theCrate;

void Start()
{
InvokeRepeating("UpdateTarget", 0f, 0.5f);
cooldown = 2.0f;
}

public void takeDamage(int amount) {
health -= amount;
if (health <= 0)
{
Die();
}
}

void Die() {
Destroy(gameObject);
if (Random.value > 0.9)
{
GameObject crateSpawn = (GameObject)Instantiate(theCrate, transform.position, transform.rotation);
}
}


void UpdateTarget()
{
GameObject[] enemies = GameObject.FindGameObjectsWithTag(enemyTag);
float shortestDistance = Mathf.Infinity;
GameObject nearestEnemy = null;






foreach (GameObject enemy in enemies)
{
float distanceToEnemy = Vector3.Distance(transform.position, enemy.transform.position);
if (distanceToEnemy < shortestDistance)
{
shortestDistance = distanceToEnemy;
nearestEnemy = enemy;
}
}

if (nearestEnemy != null)
{
// target = nearestEnemy.transform;
target = enemies[Random.Range(0, enemies.Length)].transform;
}
else
{
// target = null;
}


}

void Update()
{


if (target == null)
return;

transform.rotation = Quaternion.Slerp(transform.rotation, Quaternion.LookRotation(target.position - transform.position), f_RotSpeed * Time.deltaTime); ;
//move to player


transform.position += transform.forward * f_MoveSpeed * Time.deltaTime;

if (attackTimer > 0)
attackTimer -= Time.deltaTime;

if (attackTimer < 0)
attackTimer = 0;

if (attackTimer == 0)
{

Attack();
attackTimer = cooldown;
}

}


private void Attack()
{
float distance = Vector3.Distance(target.transform.position, transform.position);


Vector3 dir = (target.transform.position - transform.position).normalized;
float direction = Vector3.Dot(dir, transform.forward);


if (distance < attackDist)
{
if (direction > 0)
{

Debug.Log("Atacked");
}
}
}

}

 

Step one: format the code so people can read it?
Step two: probably more likely to get help in the https://forum.unity3d.com/forums/editor-general-support.10/ forum?