AppleHillsProduction/Assets/Scripts/Pooling/BaseObjectPool.cs

using System.Collections.Generic;
using UnityEngine;

namespace Pooling
{
    /// <summary>
    /// Abstract base class for object pools.
    /// Provides common functionality for creating, retrieving, and returning pooled objects.
    /// </summary>
    /// <typeparam name="T">The type of component to pool</typeparam>
    public abstract class BaseObjectPool<T> : MonoBehaviour where T : Component
    {
        [Tooltip("Initial number of objects to pre-instantiate")]
        public int initialPoolSize = 10;
        
        [Tooltip("Maximum number of objects to keep in the pool")]
        public int maxPoolSize = 30;
        
        protected Stack<T> pooledObjects = new Stack<T>();
        protected T prefab;
        protected int totalCreated = 0;
        protected int totalReturned = 0;
        
        /// <summary>
        /// Initialize the pool with the specified prefab
        /// </summary>
        /// <param name="prefabToPool">The prefab to use for this pool</param>
        public virtual void Initialize(T prefabToPool)
        {
            prefab = prefabToPool;
            
            // Pre-instantiate objects
            for (int i = 0; i < initialPoolSize; i++)
            {
                CreateNew();
            }
            
            Debug.Log($"[{GetType().Name}] Initialized with {initialPoolSize} objects");
        }
        
        /// <summary>
        /// Creates a new instance and adds it to the pool
        /// </summary>
        protected virtual T CreateNew()
        {
            if (prefab == null)
            {
                Debug.LogError($"[{GetType().Name}] Prefab is null! Call Initialize first.");
                return null;
            }
            
            T obj = Instantiate(prefab, transform);
            obj.gameObject.SetActive(false);
            
            // Initialize IPoolable components if present
            IPoolable poolable = obj.GetComponent<IPoolable>();
            if (poolable != null)
            {
                poolable.OnDespawn();
            }
            
            pooledObjects.Push(obj);
            totalCreated++;
            return obj;
        }
        
        /// <summary>
        /// Gets an object from the pool, or creates a new one if the pool is empty
        /// </summary>
        /// <returns>An object ready to use</returns>
        public virtual T Get()
        {
            T obj;
            
            if (pooledObjects.Count > 0)
            {
                obj = pooledObjects.Pop();
            }
            else
            {
                obj = CreateNew();
                pooledObjects.Pop(); // Remove from pool since we're returning it
            }
            
            obj.gameObject.SetActive(true);
            
            // Call OnSpawn for IPoolable components
            IPoolable poolable = obj.GetComponent<IPoolable>();
            if (poolable != null)
            {
                poolable.OnSpawn();
            }
            
            return obj;
        }
        
        /// <summary>
        /// Returns an object to the pool
        /// </summary>
        /// <param name="obj">The object to return</param>
        public virtual void Return(T obj)
        {
            if (obj == null) return;
            
            // Call OnDespawn for IPoolable components
            IPoolable poolable = obj.GetComponent<IPoolable>();
            if (poolable != null)
            {
                poolable.OnDespawn();
            }
            
            // Only add to pool if we're under the maximum size
            if (pooledObjects.Count < maxPoolSize)
            {
                obj.gameObject.SetActive(false);
                obj.transform.SetParent(transform);
                pooledObjects.Push(obj);
                totalReturned++;
            }
            else
            {
                Destroy(obj.gameObject);
            }
        }
        
        /// <summary>
        /// Logs pool statistics
        /// </summary>
        public virtual void LogPoolStats()
        {
            Debug.Log($"[{GetType().Name}] Pooled objects: {pooledObjects.Count}/{maxPoolSize} (Created: {totalCreated}, Returned: {totalReturned})");
        }
        
#if UNITY_EDITOR
        private float _lastLogTime = 0f;
        
        protected virtual void Update()
        {
            // Log pool stats every 5 seconds if in the editor
            if (Time.time - _lastLogTime > 5f)
            {
                LogPoolStats();
                _lastLogTime = Time.time;
            }
        }
#endif
    }
}