AI passes through walls and flies

I've made an AI that follows the player when within range, attacks when very close, and goes idle when out of range. The AI flies around to get to the player and can pass through the walls of my building (imported from maya with "generate colliders" on).

I've tried adding a rigid body, but the AI falls through the building.

I'm trying to make the AI follow the building mesh as my player would, and would attack upon reaching the player but would not allow the AI to attack continuously as the player can only take 2 hits.

If someone can help me out, I'd greatly appreciate it :D I'm new to coding in c# and unity

here's my code: using UnityEngine; using System.Collections;

 public class EnemyAI : MonoBehaviour {
     
     public float Speed = 0.5f;
     public GameObject ghost;
     
     private float XMove;
     private float YMove;
     private RaycastHit rCast;
     private Transform player;
     private float distanceFromPlayer;
     
     public static EnemyAI Instance;
     private int hp = 100;
     private int attack = 0;
     
     void Awake(){
         Instance = this;    
         Audio.Instance.audio.enabled = false;
     }
     
     void Start(){
         player = GameObject.FindGameObjectWithTag("Player").transform;    
     }
     
     void Update(){
         distanceFromPlayer = Vector3.Distance(transform.position, player.position);
 
         if(distanceFromPlayer <= 0.5f){
             if(attack == 0){
                 attack = 1;
                     ghost.animation.CrossFade("G_Attack");
                 Audio.Instance.audio.enabled = false;
                 //yield WaitForSeconds = 2;
                 //while(ghost.animation.isPlaying){
                     if(Physics.Raycast(transform.position, transform.forward, out rCast)){
                         Debug.Log("Damage Taken");
                         hp = hp - 50;
                         Debug.Log("Player Health = " + hp);
                         
                         if(hp <= 0){
                             Debug.Log("Player DEAD");
                             EnemyAI.Instance.enabled = false;
                         }
                     }
             }
             else{
                 
             }
             //}
             
         }
         else if(distanceFromPlayer < 5){
             //Debug.Log("Chase!");
             transform.rotation = Quaternion.Slerp(transform.rotation, 
                 Quaternion.LookRotation(player.position - transform.position), Time.deltaTime * 4);
             transform.Translate(0,0,.05f);
             ghost.animation.CrossFade("G_Walk");
             Audio.Instance.audio.enabled = false;
             attack = 0;
         }
         else{
             //Debug.Log("Out of Range");    
             ghost.animation.CrossFade("G_Idle");
             ghost.animation["G_Idle"].speed = .5f;
             Audio.Instance.audio.enabled = true;
             attack = 0;
         }
             
             
     
     }