BulletHell/Assets/BulletHellTemplate/Core/MonsterDamageEntity.cs

using UnityEngine;

namespace BulletHellTemplate
{
    /// <summary>
    /// Handles the damage entity that applies damage to the player upon collision.
    /// Ensures damage is applied only once per instance.
    /// </summary>
    [RequireComponent(typeof(Rigidbody), typeof(Collider))]
    public class MonsterDamageEntity : MonoBehaviour
    {
        private CharacterTypeData monsterDamageType;
        private float damageAmount;
        private Rigidbody rb;
        private float lifetime = 3f; // Duration before the damage entity is destroyed
        private float remainingLifetime;
        private bool isPaused = false;
        private Vector3 storedVelocity;
        private MonsterEntity monsterEntity;
        private bool damageApplied = false; // Tracks whether damage has already been applied

        private void Awake()
        {
            rb = GetComponent<Rigidbody>();
            GetComponent<Collider>().isTrigger = true;
            remainingLifetime = lifetime;
        }

        /// <summary>
        /// Sets the damage type and amount for this damage entity.
        /// </summary>
        /// <param name="damageType">The damage type associated with this entity.</param>
        /// <param name="damage">The amount of damage to apply upon collision.</param>
        /// <param name="velocity">The velocity with which the damage entity should move.</param>
        /// <param name="lifeTime">The lifetime of the damage entity before it is destroyed.</param>
        /// <param name="monster">The monster entity that owns this damage entity.</param>
        public void SetDamage(CharacterTypeData damageType, float damage, Vector3 velocity, float lifeTime, MonsterEntity monster)
        {
            monsterDamageType = damageType;
            damageAmount = damage;
            monsterEntity = monster;
            if (lifeTime > 0)
            {
                lifetime = lifeTime;
            }

            // Set velocity only if Rigidbody is not kinematic
            if (!rb.isKinematic)
            {
                rb.linearVelocity = velocity;
            }
        }

        private void Update()
        {
            // Handle pause state
            if (GameplayManager.Singleton.IsPaused())
            {
                if (!isPaused)
                {
                    isPaused = true;
                    storedVelocity = rb.linearVelocity;
                    rb.isKinematic = true; 
                }
            }
            else
            {
                if (isPaused)
                {
                    isPaused = false;
                    rb.isKinematic = false; // Restore non-kinematic state
                    rb.linearVelocity = storedVelocity; // Restore stored velocity
                }

                // Manage remaining lifetime
                remainingLifetime -= Time.deltaTime;
                if (remainingLifetime <= 0)
                {
                    Destroy(gameObject);
                }
            }
        }

        private void OnTriggerEnter(Collider other)
        {
            // Skip collision handling if paused or damage already applied
            if (GameplayManager.Singleton.IsPaused() || damageApplied || !other.CompareTag("Character"))
                return;

            CharacterEntity playerCharacter = other.GetComponent<CharacterEntity>();
            if (playerCharacter != null)
            {
                ApplyDamage(playerCharacter);
                damageApplied = true; // Ensure damage is applied only once
            }
        }

        /// <summary>
        /// Applies damage to the specified player character.
        /// </summary>
        /// <param name="target">The player character to apply damage to.</param>
        private void ApplyDamage(CharacterEntity target)
        {
            // Adjust damage based on the monster's damage type and the player's character type.
            float adjustedDamage = GameInstance.Singleton.TotalDamageWithElements(monsterDamageType, target.GetCharacterType(), damageAmount);
            target.ReceiveDamage(adjustedDamage);

            // Apply HP leech effect to the monster if applicable
            monsterEntity.ApplyHpLeech(adjustedDamage);
        }
    }
}