character-system/Runtime/UI/HealthBarController.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using Sirenix.OdinInspector;

namespace KairoEngine.CharacterSystem
{
    public class HealthBarController : MonoBehaviour
    {
        public GameObject healthBarUiPrefab;
        public Transform canvasParent;

        private Dictionary<DamageController, HealthBarUi> healthBars;

        private List<HealthBarUi> unusedHealthBars;

        void OnEnable()
        {
            DamageEvents.OnDamage += OnDamage;
            DamageEvents.OnHeal += OnHeal;
        }

        void OnDisable()
        {
            DamageEvents.OnDamage -= OnDamage;
            DamageEvents.OnHeal -= OnHeal;
        }

        void Start()
        {
            healthBars = new Dictionary<DamageController, HealthBarUi>();
            unusedHealthBars = new List<HealthBarUi>();
            unusedHealthBars.Add(CreateHealthBar());
        }

        void Update()
        {
            RemoveUnused();
        }

        private void OnDamage(DamageData damageData)
        {
            //Debug.Log("Showing Health Bar for " + damageController.character.unique_name);
            HealthBarUi healthBar = GetHealthBarFor(damageData.damageController);
            healthBar.Setup(damageData.damageController);
            healthBar.gameObject.SetActive(true);
        }

        private void OnHeal(DamageController damageController, int damage)
        {
            //Debug.Log("Showing Health Bar for " + damageController.character.unique_name);
            HealthBarUi healthBar = GetHealthBarFor(damageController);
            healthBar.Setup(damageController);
            healthBar.gameObject.SetActive(true);
        }

        private HealthBarUi CreateHealthBar()
        {
            GameObject obj = Instantiate(healthBarUiPrefab, canvasParent);
            obj.SetActive(false);
            return obj.GetComponent<HealthBarUi>();
        }

        private HealthBarUi GetHealthBarFor(DamageController damageController)
        {
            // Find Health Bar in use
            HealthBarUi healthBar;
            if(healthBars.TryGetValue(damageController, out healthBar))
            {
                 if(healthBar != null) return healthBar;
            }
            // Look for Health Bar in unused
            if(unusedHealthBars.Count > 0)
            {
                healthBar = unusedHealthBars[unusedHealthBars.Count - 1];
                unusedHealthBars.RemoveAt(unusedHealthBars.Count - 1);
            } 
            else
            {
                // Create new Health Bar
                healthBar = CreateHealthBar();
            }
            healthBars.Add(damageController, healthBar);
            return healthBar;
        }

        private void RemoveUnused()
        {
            List<DamageController> removeList = new List<DamageController>();
            List<HealthBarUi> moveList = new List<HealthBarUi>();
            foreach(KeyValuePair<DamageController, HealthBarUi> healthBar in healthBars)
            {
                if(healthBar.Value.gameObject.activeSelf == false)
                {
                    removeList.Add(healthBar.Key);
                    moveList.Add(healthBar.Value);
                }
            }
            for (int i = 0; i < removeList.Count; i++)
            {
                healthBars.Remove(removeList[i]);
                unusedHealthBars.Add(moveList[i]);
            }
        }
    }
}