oz_poc/unity_project/Assets/BeatEmUp_GameTemplate3D/Scripts/UI/UIHUDHealthBar.cs

using UnityEngine;
using UnityEngine.UI;

[RequireComponent(typeof(Slider))]
public class UIHUDHealthBar : MonoBehaviour {

	public Text nameField;
	public Image playerPortrait;
	public Slider HpSlider;
	public bool isPlayer;
    public int playerNumber;

	void OnEnable() {
		HealthSystem.onHealthChange += UpdateHealth;
	}

	void OnDisable() {
		HealthSystem.onHealthChange -= UpdateHealth;
	}

	void Start(){
		if(!isPlayer) Invoke("HideOnDestroy", Time.deltaTime); //hide enemy healthbar at start
		if(isPlayer) SetPlayerPortraitAndName();
	}

	void UpdateHealth(float percentage, GameObject go){
		if(isPlayer && go.CompareTag("Player") && go.GetComponent<PlayerMovement>()?.playerNumber == playerNumber){
			HpSlider.value = percentage;
		} 	

		if(!isPlayer && go.CompareTag("Enemy")){
			HpSlider.gameObject.SetActive(true);
			HpSlider.value = percentage;
			nameField.text = go.GetComponent<EnemyActions>().enemyName;
			if(percentage == 0) Invoke("HideOnDestroy", 2);
		}
	}

	void HideOnDestroy(){
		HpSlider.gameObject.SetActive(false);
		nameField.text = "";
	}

	//loads the HUD icon of the player from the player prefab (Healthsystem)
	void SetPlayerPortraitAndName(){
		if(playerPortrait != null){
			GameObject[] players = GameObject.FindGameObjectsWithTag("Player");

            GameObject player = null;

            foreach (GameObject p in players)
            {
                if (p.GetComponent<PlayerMovement>()?.playerNumber == playerNumber)
                    player = p;
            }

			HealthSystem healthSystem = player?.GetComponent<HealthSystem>();

			if(player && healthSystem != null){

				//set portrait
				Sprite HUDPortrait = healthSystem.HUDPortrait;
				playerPortrait.overrideSprite = HUDPortrait;

				//set name
				nameField.text = healthSystem.PlayerName;
			}
            else
            {
                nameField.text = "PRESS START!";
                playerPortrait.enabled = false;
                HpSlider.gameObject.SetActive(false);
            }
		}
	}
}