GameDev.CoreSystems/Scripts/Damageable.cs

using UnityEngine;
using UnityEngine.Events;

namespace GameDev.CoreSystems
{
    public class Damageable : MonoBehaviour, IDamageable
    {
        [Header("RuntimeSet")]
        [SerializeField] private SoDamageableRuntimeSet _activeDamageableRuntimeSet;

        [field: Header("Health")]
        [field: SerializeField] public int CurrentHealth { get; private set; }
        [field: SerializeField] public int MaxHealth { get; private set; }

        [field: Header("Modifiers")]
        [field: SerializeField] public bool IsInvulnerable { get; private set; }

        public UnityEvent DeathEvent;

        /// <summary>
        /// Used to ensure only one damage dealer gets the kill score  
        /// </summary>
        private bool _isAlreadyDead;

        private void OnEnable()
        {
            _activeDamageableRuntimeSet.Add(this);
        }

        private void OnDisable()
        {
            _activeDamageableRuntimeSet.Remove(this);
        }

        #region Methods

        public void ModifyHealth(int healthChange, GameObject source)
        {
            var receivingDamage = healthChange < 0;
            var receivingHealing = healthChange > 0;

            if (IsInvulnerable && receivingDamage) return;

            CurrentHealth += healthChange;

            source.TryGetComponent(out Weapon weapon);

            if (weapon != null && !_isAlreadyDead)
            {
                weapon.IncrementDamageDealt(-healthChange);
            }

            if (CurrentHealth > 0 || _isAlreadyDead) return;

            _isAlreadyDead = true;

            if (weapon != null)
            {
                weapon.IncrementKillCount();
            }

            print($"{transform.parent.parent.name} died");
            DeathEvent.Invoke();
        }

        #endregion

        #region Setters

        public void SetCurrentHealth(int newHealth) => CurrentHealth = newHealth;

        public void SetMaxHealth(int newHealth) => MaxHealth = newHealth;

        public void SetInvulnerable(bool newState) => IsInvulnerable = newState;

        #endregion

        #region Getters

        public int GetCurrentHealth() => CurrentHealth;

        public int GetMaxHealth() => MaxHealth;

        public float GetHealthFactor() => (float)CurrentHealth / (float)MaxHealth;

        #endregion
    }
}