EnemyController

using System;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.AI;

[RequireComponent(typeof(NavMeshAgent))]
public class EnemyController : MonoBehaviour {

    enum EnemyState {
        Idle, // просто стоїть
        Pursuit, // переслідує ціль
        Battle // атакує
    }

    public Transform aimPoint;
    public Inventory inventory;

    public float aggroDistance;
    public float alertDistance;

    private NavMeshAgent agent;

    private EnemyState state;
    private Vector3 lastPlayerSeenLocation;

    private readonly RaycastHit[] _hits = new RaycastHit[10];

    private void Awake() {
        agent = GetComponent<NavMeshAgent>();
        lastPlayerSeenLocation = transform.position;
    }

    private void Update() {
        var playerLocation = PlayerController.Me.transform.position;

        bool playerSeenAtThisUpdate = false;

        state = EnemyState.Idle;
        // Якщо гравець в зоні бачення ворогу
        if (Vector3.Distance(aimPoint.position, PlayerController.Me.aimPoint.position) <= aggroDistance) {
            Vector3 direction = (PlayerController.Me.aimPoint.position - aimPoint.position).normalized;
            Ray ray = new Ray(aimPoint.position, direction);
            int hits = Physics.RaycastNonAlloc(ray, _hits, aggroDistance);
            Array.Sort(_hits, 0, hits, new RaycastHitComparer(ray.origin));

            // Якщо між ворогом і гравцем нема перешкод
            if (_hits[0].transform != null && CompareLayer(_hits[0].transform.gameObject, PlayerController.Me.playerLayer)) {
                playerSeenAtThisUpdate = true;

                // Ворог дивиться на гравця
                Vector3 lookPos = new Vector3(PlayerController.Me.aimPoint.position.x, transform.position.y, PlayerController.Me.aimPoint.position.z);
                transform.LookAt(lookPos);
                lastPlayerSeenLocation = playerLocation;

                state = EnemyState.Battle;
            } else
                state = EnemyState.Pursuit;

        } else if (Vector3.Distance(transform.position, lastPlayerSeenLocation) > 1f) {
            state = EnemyState.Pursuit;
        }

        if (state == EnemyState.Idle) {
            lastPlayerSeenLocation = transform.position; // загубив гравця
            agent.SetDestination(transform.position); // бот зупиняється
            if (inventory != null) // бот не атакує
                inventory.SetFiring(false);

        } else if (state == EnemyState.Pursuit) {
            agent.SetDestination(lastPlayerSeenLocation); // ворог йде туди, де він бачив гравця
            if (inventory != null) // бот не атакує
                inventory.SetFiring(false);
            if (playerSeenAtThisUpdate)
                NotifyOthers(playerLocation);

        } else { // battle
            agent.SetDestination(transform.position); // бот зупиняється
            if (inventory != null) // бот атакує
                inventory.SetFiring(true);
            if (playerSeenAtThisUpdate)
                NotifyOthers(playerLocation);
        }
    }

    private void NotifyOthers(Vector3 lastPlayerSeenLocation) {
        EnemyController[] allBots = FindObjectsOfType<EnemyController>();
        for (int i = 0; i < allBots.Length; i++) {
            if (allBots[i] != this && Vector3.Distance(transform.position, allBots[i].transform.position) <= alertDistance) {
                allBots[i].SayThatPlayerHasBeenInPosition(lastPlayerSeenLocation);
            }
        }
    }

    public void SayThatPlayerHasBeenInPosition(Vector3 lastPlayerSeenLocation) {
        this.lastPlayerSeenLocation = lastPlayerSeenLocation;
    }

    private void OnDrawGizmosSelected() {
        if (aimPoint != null) {
            Gizmos.color = new Color(0f, 1f, 1f, 0.2f);
            Gizmos.DrawSphere(aimPoint.position, aggroDistance);
        }

        var player = FindObjectOfType<PlayerController>();
        if (Physics.Linecast(aimPoint.position, player.aimPoint.position, out RaycastHit hit)) {
            Gizmos.color = Color.blue;
            Gizmos.DrawLine(aimPoint.position, player.aimPoint.position);
        }
    }

    private static bool CompareLayer(GameObject target, LayerMask layers) {
        return ((1 << target.layer) & layers) != 0;
    }
}

public class RaycastHitComparer : IComparer<RaycastHit> {
    private Vector3 origin;

    public RaycastHitComparer(Vector3 origin) {
        this.origin = origin;
    }

    public int Compare(RaycastHit x, RaycastHit y) {
        bool xIsValid = x.collider != null;
        bool yIsValid = y.collider != null;

        if (!xIsValid && !yIsValid)
            return 0;

        if (!xIsValid)
            return 1;

        if (!yIsValid)
            return -1;

        float distanceX = Vector3.Distance(origin, x.point);
        float distanceY = Vector3.Distance(origin, y.point);

        return distanceX.CompareTo(distanceY);
    }
}