using System.Threading;
using AlicizaX.Resource.Runtime;
using Cysharp.Threading.Tasks;
using UnityEngine;

namespace AlicizaX
{
    public interface IResourceLoader
    {
        GameObject LoadPrefab(string location);
        UniTask<GameObject> LoadPrefabAsync(string location, CancellationToken cancellationToken = default);
        GameObject LoadGameObject(string location, Transform parent = null);
        UniTask<GameObject> LoadGameObjectAsync(string location, Transform parent = null, CancellationToken cancellationToken = default);
        void UnloadAsset(GameObject gameObject);
    }

    public class UnityResourcesLoader : IResourceLoader
    {
        public GameObject LoadPrefab(string location)
        {
            return Resources.Load<GameObject>(location);
        }

        public async UniTask<GameObject> LoadPrefabAsync(string location, CancellationToken cancellationToken = default)
        {
            return await Resources.LoadAsync<GameObject>(location).ToUniTask(cancellationToken: cancellationToken) as GameObject;
        }

        public GameObject LoadGameObject(string location, Transform parent = null)
        {
            var prefab = Resources.Load<GameObject>(location);
            if (prefab == null) return null;

            var instance = GameObject.Instantiate(prefab);
            if (instance != null && parent != null)
            {
                instance.transform.SetParent(parent);
            }

            return instance;
        }

        public async UniTask<GameObject> LoadGameObjectAsync(string location, Transform parent = null, CancellationToken cancellationToken = default)
        {
            var prefab = await Resources.LoadAsync<GameObject>(location).ToUniTask(cancellationToken: cancellationToken) as GameObject;
            if (prefab == null) return null;

            var instance = GameObject.Instantiate(prefab);
            if (instance != null && parent != null)
            {
                instance.transform.SetParent(parent);
            }

            return instance;
        }

        public void UnloadAsset(GameObject gameObject)
        {
            // Resources.UnloadAsset cannot unload GameObjects.
            // The prefab reference is nulled by the caller; Unity handles cleanup via UnloadUnusedAssets.
        }
    }

    public class AssetBundleResourceLoader : IResourceLoader
    {
        private IResourceModule _resourceModule;

        IResourceModule ResourceModule
        {
            get
            {
                if (_resourceModule == null)
                {
                    _resourceModule = ModuleSystem.GetModule<IResourceModule>();
                }

                return _resourceModule;
            }
        }


        public GameObject LoadPrefab(string location)
        {
            return ResourceModule.LoadAsset<GameObject>(location);
        }

        public async UniTask<GameObject> LoadPrefabAsync(string location, CancellationToken cancellationToken = default)
        {
            return await ResourceModule.LoadAssetAsync<GameObject>(location, cancellationToken);
        }

        public GameObject LoadGameObject(string location, Transform parent = null)
        {
            return ResourceModule.LoadGameObject(location, parent);
        }

        public async UniTask<GameObject> LoadGameObjectAsync(string location, Transform parent = null, CancellationToken cancellationToken = default)
        {
            return await ResourceModule.LoadGameObjectAsync(location, parent, cancellationToken);
        }

        public void UnloadAsset(GameObject gameObject)
        {
            ResourceModule.UnloadAsset(gameObject);
        }
    }
}