using FirstVillain.Singleton;
using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using UnityEngine;
using UnityEngine.Pool;

namespace FirstVillain.ObjectPool
{
    //GameObject Pooling
    public class PoolManager : UnitySingleton<PoolManager>
    {
        [SerializeField] private int _capacity = 10;
        [SerializeField] private int _maxSize = 1000;
        [SerializeField] private bool _collectionCheck = true;

        //음... 클래스 타입별로 풀을 만드는건?
        private Dictionary<string, PoolItem> _poolDict = new();

        public GameObject Spawn(string path, Transform parent = null)
        {
            string name = Path.GetFileName(path);
            if(!_poolDict.ContainsKey(name))
            {
                CreatePoolItem(path);
            }

            var pooledObj = _poolDict[name].Pool.Get();

            if (parent != null)
            {
                pooledObj.transform.Reset(parent);
            }

            return pooledObj;
        }

        public T Spawn<T>(string path, Transform parent = null)
        {
            return Spawn(path, parent).GetComponent<T>();
        }

        public void ReleaseGameObject(GameObject obj)
        {
            if (_poolDict.ContainsKey(obj.name))
            {
                try
                {
                    obj.transform.Reset();
                    try
                    {
                        _poolDict[obj.name].Pool.Release(obj);
                    }
                    catch
                    {
                        obj.SetActive(false);
                    }
                }
                catch (Exception ex)
                {
                    Debug.LogError($"Exception has occured!!! Object : {obj.name} === {ex.Message}");
                }
            }
            else
            {
                Debug.LogWarning($"Object[{obj.name}] does not exist in pool dictionary. But it's been destroyed anyway :D");
                Destroy(obj);
            }
        }

        #region Create Pool
        //현재 Resources.Load 기반으로 구현...
        public void CreatePoolItem(string path)
        {
            string resourceName = Path.GetFileName(path);
            if(!_poolDict.ContainsKey(resourceName))
            {
                var resource = LoadAssetOnResources<GameObject>(path);
                var pool = new PoolItem(path, CreateNewObjectPool(resource, resourceName));
                _poolDict.Add(resourceName, pool);
            }
        }        

        private ObjectPool<GameObject> CreateNewObjectPool(GameObject prefab, string resourceName)
        {
            return new ObjectPool<GameObject>(
                        () =>
                        {
                            GameObject obj = Instantiate(prefab);
                            obj.name = resourceName;
                            return obj;
                        },
                        OnGetItem,
                        OnReleaseItem,
                        OnDestroyItem,
                        _collectionCheck /* Collection checks will throw errors if we try to release an item that is already in the pool.*/,
                        _capacity/*defalut capacity*/,
                        _maxSize
            );
        }

        private void OnGetItem(GameObject obj)
        {
            obj.SetActive(true);
        }

        private void OnReleaseItem(GameObject obj)
        {
            obj.SetActive(false);
        }

        private void OnDestroyItem(GameObject obj)
        {
            Destroy(obj);
        }

        #endregion Create Pool

        #region Resource Load

        //리소스 관리로 이전 예정
        public T LoadAssetOnResources<T>(string resourcePath) where T : UnityEngine.Object
        {
            var resourceObj = Resources.Load<T>(resourcePath);
            if (resourceObj == null)
            {
                throw new ResourceCriticalException($"Cannot Load Resources Object [{resourcePath}]");
            }

            return resourceObj;
        }
        #endregion Resource Load

        #region AssetBundle Refresh Shader
        private void RefreshShader<T>(UnityEngine.Object obj)
        {
            //AssetBundle은 custom shader를 포함하지 않으므로 불러올 시점에 shader를 재설정해준다.
            if (typeof(GameObject) == typeof(T))
            {
                GameObject go = obj as GameObject;
                if (go.GetComponents<Renderer>() != null)
                {
                    RefreshShader(go.GetComponents<Renderer>());
                }

                if (go.GetComponentsInChildren<Renderer>(true) != null)
                {
                    RefreshShader(go.GetComponentsInChildren<Renderer>(true));
                }

            }
            else if (typeof(Material) == typeof(T))
            {
                RefreshShader(obj as Material);
            }
        }

        private void RefreshShader(Material material)
        {
            Shader shader = Shader.Find(material.shader.name);
            if (shader != null)
            {
                material.shader = shader;
            }
            else
            {
                Debug.LogWarning(string.Format("unable to refresh shader: [{0}] in material [{1}]", material.shader.name, material.name));
            }
        }

        private void RefreshShader(Renderer[] renderers)
        {
            if (null == renderers)
            {
                return;
            }

            for (int i = 0; i < renderers.Length; i++)
            {
                Material[] materials = renderers[i].sharedMaterials;
                for (int j = 0; j < materials.Length; j++)
                {
                    if (materials[j] == null) { continue; }
                    RefreshShader(materials[j]);
                }
            }
        }
        #endregion AssetBundle Refresh Shader
    }
}