BloodAndGore/Assets/Scripts/AI/Behaviours/Follow.cs

using UnityEngine;
using Saltosion.OneWeapon.Enemies;

namespace Saltosion.OneWeapon.AI.Behaviours {
    [RequireComponent(typeof(Enemy))]
    public class Follow : AIBehaviour {
        public Transform Target;
        public float CloseEnoughRadius;
        public float TargetPositionUpdateFrequency = 5f;

        private Enemy Enemy;
        private Vector2 TargetPosition;
        private float TargetPositionUpdateCooldown;

        private void Start() {
            Enemy = GetComponent<Enemy>();
        }

        private void Update() {
            if (Target != null && TargetPositionUpdateCooldown <= 0) {
                TargetPositionUpdateCooldown = 1.0f / TargetPositionUpdateFrequency;
                TargetPosition = Target.position;
            } else if (Target == null) {
                TargetPositionUpdateCooldown = 0.0f;
            } else {
                TargetPositionUpdateCooldown -= Time.deltaTime;
            }
        }

        public override bool CanBehave() {
            return Target != null;
        }

        public override void Execute() {
            if (Target != null) {
                Vector2 position = Enemy.transform.position;
                Vector2 delta = TargetPosition - position;
                if (delta.magnitude > CloseEnoughRadius) {
                    delta -= delta.normalized * CloseEnoughRadius;
                    Enemy.StartMovingTo(position + delta);
                    CurrentStatus = "Approach";
                } else {
                    Enemy.StopMoving();
                    CurrentStatus = "CloseEnough";
                }
            } else {
                Enemy.StopMoving();
                CurrentStatus = "NoTarget";
            }
        }
    }
}