# Setting up Variables first

// Variables
 /////////////
 private bool walkPointSet;
 private bool alreadyAttacked;
 private bool playerInSightRange;
 private bool playerInAttackRange;

 private Transform player;
 private Vector3 walkPoint;
 private NavMeshAgent agent;

 [Header("Values")]
 [SerializeField] private float fireRate;
 [SerializeField] private float sightRange;
 [SerializeField] private float attackRange;
 [SerializeField] private float walkPointRange;

 [Header("Components")]
 [SerializeField] private LayerMask groundLayer;
 [SerializeField] private LayerMask playerLayer;

## Getting Components

// References
 //////////////
 private void Start()
 {
     agent = GetComponent<NavMeshAgent>(); // Getting navmesh agent
     player = GameObject.FindGameObjectWithTag("Player").transform; // Getting player body
 }

## Doing checks for player state like patroling, chase player & attack player

private void FixedUpdate()
 {
     playerInSightRange = Physics.CheckSphere(transform.position, sightRange, playerLayer); // Checking if player is in sight range
     playerInAttackRange = Physics.CheckSphere(transform.position, attackRange, playerLayer); // Checking if player is in attack range

     if (!playerInSightRange && !playerInAttackRange) Patroling(); // Start petroling
     if (playerInSightRange && !playerInAttackRange) ChasePlayer(); // Chasing player
     if (playerInSightRange && playerInAttackRange) AttackPlayer(); // Attacking player
 }

## Code for Patroling

private void Patroling()
 {
     if (!walkPointSet) SearchWalkPoint(); // If no walkpoint is set
     else if (walkPointSet)
         agent.SetDestination(walkPoint);

     // Serching walk poing
     void SearchWalkPoint()
     {
         float randomZ = Random.Range(-walkPointRange, walkPointRange); // Random z range
         float randomX = Random.Range(-walkPointRange, walkPointRange); // Random x range

         walkPoint = new Vector3(transform.position.x + randomX, transform.position.y, transform.position.z + randomZ); // Getting random location

         // Setting walkpoint to true
         if (Physics.Raycast(walkPoint, -transform.up, Mathf.Infinity, groundLayer))
             walkPointSet = true;
     }

     // Getting distence left to walk
     Vector3 distanceToWalkPoint = transform.position - walkPoint;
     if (distanceToWalkPoint.magnitude < 1)
         walkPointSet = false; // Setting walkpoint to false
 }

## Code for chasing player

private void ChasePlayer() { agent.SetDestination(player.position); } // Chasing player

## Code for Attacking player

private void AttackPlayer()
 {
     // Stopping enemy from moving
     agent.SetDestination(transform.position);
     transform.LookAt(player); // Looking at player

     // If not attacked then attack
     if (!alreadyAttacked)
     {
         ////////////////////////
         /// Attack Code here ///
         ////////////////////////

         alreadyAttacked = true; // If attacked
         // Setting fireRate
         Invoke(nameof(ResetAttack), fireRate);
     }
 }

 // Resetting attack
 private void ResetAttack() { alreadyAttacked = false; }

# All Code at once

// Variables
 /////////////
 private bool walkPointSet;
 private bool alreadyAttacked;
 private bool playerInSightRange;
 private bool playerInAttackRange;

 private Transform player;
 private Vector3 walkPoint;
 private NavMeshAgent agent;

 [Header("Values")]
 [SerializeField] private float fireRate;
 [SerializeField] private float sightRange;
 [SerializeField] private float attackRange;
 [SerializeField] private float walkPointRange;

 [Header("Components")]
 [SerializeField] private LayerMask groundLayer;
 [SerializeField] private LayerMask playerLayer;

 // References
 //////////////
 private void Start()
 {
     agent = GetComponent<NavMeshAgent>(); // Getting navmesh agent
     player = GameObject.FindGameObjectWithTag("Player").transform; // Getting player body
 }

 private void FixedUpdate()
 {
     playerInSightRange = Physics.CheckSphere(transform.position, sightRange, playerLayer); // Checking if player is in sight range
     playerInAttackRange = Physics.CheckSphere(transform.position, attackRange, playerLayer); // Checking if player is in attack range

     if (!playerInSightRange && !playerInAttackRange) Patroling(); // Start petroling
     if (playerInSightRange && !playerInAttackRange) ChasePlayer(); // Chasing player
     if (playerInSightRange && playerInAttackRange) AttackPlayer(); // Attacking player
 }

 private void Patroling()
 {
     if (!walkPointSet) SearchWalkPoint(); // If no walkpoint is set
     else if (walkPointSet)
         agent.SetDestination(walkPoint);

     // Serching walk poing
     void SearchWalkPoint()
     {
         float randomZ = Random.Range(-walkPointRange, walkPointRange); // Random z range
         float randomX = Random.Range(-walkPointRange, walkPointRange); // Random x range

         walkPoint = new Vector3(transform.position.x + randomX, transform.position.y, transform.position.z + randomZ); // Getting random location

         // Setting walkpoint to true
         if (Physics.Raycast(walkPoint, -transform.up, Mathf.Infinity, groundLayer))
             walkPointSet = true;
     }

     // Getting distence left to walk
     Vector3 distanceToWalkPoint = transform.position - walkPoint;
     if (distanceToWalkPoint.magnitude < 1)
         walkPointSet = false; // Setting walkpoint to false
 }

 private void ChasePlayer() { agent.SetDestination(player.position); } // Chasing player

 private void AttackPlayer()
 {
     // Stopping enemy from moving
     agent.SetDestination(transform.position);
     transform.LookAt(player); // Looking at player

     // If not attacked then attack
     if (!alreadyAttacked)
     {
         ////////////////////////
         /// Attack Code here ///
         ////////////////////////

         alreadyAttacked = true; // If attacked
         // Setting fireRate
         Invoke(nameof(ResetAttack), fireRate);
     }
 }

 // Resetting attack
 private void ResetAttack() { alreadyAttacked = false; }