4.5 — The Full State Machine: Patrol, Chase, Attack

Compare against your own file rather than copying it. This is the same machine arranged differently on purpose: the reference puts each state's code in its own method, so you can see that the arrangement was never the point — the state field, the selection that reads it, and the exits you wrote by hand are. Your names, your beat, your movement call and your damage flow are yours; the machine is what has to match.

// ------------------------------------------------------------------
//  REFERENCE FILE — Assets/Scripts/EnemyController.cs
//  Written to be read, not pasted. Build it with the walkthrough
//  above, one step at a time, then open this and compare.
//  If it is sitting in your project unchanged, that is the thing
//  to go and do now — the walkthrough is still above you.
// ------------------------------------------------------------------
using UnityEngine;

public class EnemyController : MonoBehaviour
{
    [SerializeField] private float moveSpeed = 2f;              // your number from 4.1
    [SerializeField] private float patrolDistance = 3f;         // the size of the beat (4.1)
    [SerializeField] private float aggroRadius = 5f;            // your number from 4.3
    [SerializeField] private int contactDamage = 1;             // your number from 4.4
    [SerializeField] private float damageCooldown = 0.75f;      // your number from 4.4

    private Vector3 spawnPoint;                 // 4.1 - the anchor, saved once in Start()
    private int direction = 1;                  // 4.1 - the sign that IS the beat
    private Transform playerTransform;          // 4.3 - however you acquired it
    private float lastDamageTime;               // 4.4 - the moment of the last hit

    // ---- all of today, in two lines: three names, and which one is live ----
    private enum EnemyState
    {
        Patrol,
        Chase,
        Attack
    }

    private EnemyState state = EnemyState.Patrol;   // frame one is a calm guard

    void Start()
    {
        spawnPoint = transform.position;
        playerTransform = GameObject.FindWithTag("Player").transform;   // or your wired reference
        lastDamageTime = -damageCooldown;           // "there has been no last hit"
    }

    private void Update()
    {
        // One measurement, and no early return: an enemy with no target is a
        // patrolling enemy, not an enemy that stops thinking.
        float distance = DistanceToPlayer();

        if (playerTransform == null)
        {
            state = EnemyState.Patrol;
        }

        switch (state)
        {
            case EnemyState.Patrol: PatrolTick(distance); break;
            case EnemyState.Chase:  ChaseTick(distance);  break;
            case EnemyState.Attack: AttackTick();         break;
        }
    }

    // Same machine, arranged differently: each state's code is its own method,
    // and the transition lives inside the method of the state it leaves.
    private float DistanceToPlayer()
    {
        if (playerTransform == null)
        {
            return float.MaxValue;                  // no player is never in range
        }
        return Vector3.Distance(transform.position, playerTransform.position);
    }

    private void PatrolTick(float distance)
    {
        if (distance <= aggroRadius)
        {
            state = EnemyState.Chase;
            return;
        }

        // ...your beat from 4.1, unchanged: the anchor check, the direction
        //    flip, the movement call and your SetInteger("Direction", ...)...
    }

    private void ChaseTick(float distance)
    {
        if (distance > aggroRadius)
        {
            state = EnemyState.Patrol;              // the exit nobody writes
            return;
        }

        // ...your pursuit from 4.3, unchanged: the normalized (player - me)
        //    vector, the movement call and your animator line...
    }

    private void AttackTick()
    {
        if (Time.time >= lastDamageTime + damageCooldown)
        {
            state = EnemyState.Chase;               // the swing is over
            return;
        }

        // Nothing here moves the enemy, so it stands still for the length of
        // its cooldown. If you would rather it kept coming, that is the one
        // line you move into this method - and it is a design decision.
    }

    private void OnCollisionStay2D(Collision2D collision)
    {
        if (!collision.gameObject.CompareTag("Player")) return;
        if (Time.time < lastDamageTime + damageCooldown) return;

        // ...the damage call you wrote in 4.4, unchanged...
        lastDamageTime = Time.time;

        state = EnemyState.Attack;      // physics is what enters ATTACK here
    }
}