using System.Collections.Generic;
using System.Threading;
using Cysharp.Threading.Tasks;
using RebootKit.Engine.Foundation;
using UnityEngine;
using UnityEngine.AddressableAssets;
using UnityEngine.ResourceManagement.AsyncOperations;
using UnityEngine.ResourceManagement.ResourceProviders;
using UnityEngine.SceneManagement;

namespace RebootKit.Engine.Services.Simulation {
    public class WorldService : IService {
        readonly List<Actor> m_Actors = new();
        WorldConfig m_Config;

        public void Dispose() {
            KillAllActors();
        }

        public async UniTask Load(WorldConfig worldConfig) {
            m_Config = worldConfig;

            AsyncOperationHandle<SceneInstance> handle = worldConfig.mainScene.LoadSceneAsync(LoadSceneMode.Additive, false);
            await handle.ToUniTask();
            
            await handle.Result.ActivateAsync();
            SceneManager.SetActiveScene(handle.Result.Scene);

            foreach (GameObject root in handle.Result.Scene.GetRootGameObjects()) {
                foreach (Actor actor in root.GetComponentsInChildren<Actor>()) {
                    RegisterActor(actor);
                }
            }
        }

        public async UniTask<TActor> SpawnActor<TActor>(AssetReferenceT<GameObject> asset, CancellationToken cancellationToken) where TActor : Actor {
            GameObject gameObject = await Addressables.InstantiateAsync(asset);
            if (cancellationToken.IsCancellationRequested) {
                asset.ReleaseInstance(gameObject);
                return null;
            }

            if (gameObject.TryGetComponent(out TActor actor)) {
                return actor;
            }

            asset.ReleaseInstance(gameObject);
            return null;
        }

        public void RegisterActor(Actor actor) {
            m_Actors.Add(actor);
        }

        public void KillActor(Actor actor) {
            Addressables.ReleaseInstance(actor.gameObject);
        }

        public void KillAllActors() {
            foreach (Actor actor in m_Actors) {
                Addressables.ReleaseInstance(actor.gameObject);
            }

            m_Actors.Clear();
        }
    }
}