using System;
using System.Collections;
using AibisDream.Kit;
using UnityEngine.AddressableAssets;
using UnityEngine.ResourceManagement.AsyncOperations;
using UnityEngine.SceneManagement;

namespace AibisDream
{
    public class SceneLoader : Singleton<SceneLoader>
    {
        #region 场景转换参数

        private string currentScene;
        private AsyncOperationHandle _loadHandle;
        private string sceneToLoad;
        private bool isLoading;

        #endregion

        #region 场景切换事件

        public event Action LoadSceneEvent;
        public event Action UnloadSceneEvent;

        #endregion

        /// <summary>
        /// 同步场景转换
        /// </summary>
        /// <param name="targetScene">目标场景</param>
        public void LoadScene(string targetScene)
        {
            StartCoroutine(LoadSceneAsync(targetScene));
        }

        /// <summary>
        /// 异步场景转换
        /// </summary>
        /// <param name="targetScene">目标场景</param>
        /// <returns></returns>
        public IEnumerator LoadSceneAsync(string targetScene)
        {
            if (isLoading)
            {
                yield return null;
            }
            else
            {
                // 场景转换参数
                isLoading = true;
                sceneToLoad = targetScene;
                if (currentScene != null)
                {
                    UnloadSceneEvent?.Invoke();
                    yield return Addressables.UnloadSceneAsync(_loadHandle);
                }

                
                _loadHandle = Addressables.LoadSceneAsync(sceneToLoad, LoadSceneMode.Additive);
                yield return _loadHandle;

                LoadSceneEvent?.Invoke();
                
                currentScene = sceneToLoad;
                isLoading = false;
            }
        }

        public IEnumerator UnloadSceneAsync(string sceneToUnload)
        {
            if (isLoading)
            {
                yield return null;
            }
            else
            {
                isLoading = true;

                if (currentScene == sceneToUnload)
                {
                    UnloadSceneEvent?.Invoke();
                    yield return Addressables.UnloadSceneAsync(_loadHandle, true);
                    currentScene = null;
                }

                isLoading = false;
            }
        }
    }
}