using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using Gs2.Core.Exception;
using Gs2.Core.Model;
#if GS2_ENABLE_UNITASK
using Cysharp.Threading.Tasks;
#endif
using Gs2.Unity.Core;
using Gs2.Unity.Core.Exception;
using Gs2.Unity.Core.ScriptableObject;
using Gs2.Unity.Gs2Version.Model;
using Gs2.Unity.Util;
using Gs2.Util.LitJson;
using UnityEngine;
using UnityEngine.Events;

namespace Gs2.Unity.Util
{
    [AddComponentMenu("GS2/Core/Gs2ClientHolder")]
    public class Gs2ClientHolder : MonoBehaviour
    {
        public Gs2Domain Gs2 { get; private set; }
        public bool Initialized => Gs2 != null;
        
        public string activeEnvironmentName;
        public List<Gs2Environment> environments;
        public Gs2.Unity.Gs2Distributor.ScriptableObject.Namespace distributorNamespace;

        [Serializable]
        private class InitializedEvent : UnityEvent
        {
            
        }
        
        [SerializeField]
        private InitializedEvent onInitialized = new InitializedEvent();
        
        public event UnityAction OnInitialized
        {
            add => this.onInitialized.AddListener(value);
            remove => this.onInitialized.RemoveListener(value);
        }
        
        [SerializeField]
        internal ErrorEvent onError = new ErrorEvent();
        
        public event UnityAction<Gs2Exception, Func<IEnumerator>> OnError
        {
            add => this.onError.AddListener(value);
            remove => this.onError.RemoveListener(value);
        }

        protected internal static Gs2ClientHolder _instance;
        
        public static Gs2ClientHolder Instance
        {
            get
            {
                if (_instance == null)
                {
                    var clientHolders = GameObject.FindObjectsOfType<Gs2ClientHolder>();
                    if (clientHolders.Length > 0)
                    {
                        return clientHolders[0];
                    }

                    _instance = new GameObject("Gs2ClientHolder").AddComponent<Gs2ClientHolder>();
                }
                return _instance;
            }
        }

        public void Awake()
        {
            var items = FindObjectsOfType<Gs2ClientHolder>();
            foreach (var item in items)
            {
                if (item != this)
                {
                    DestroyImmediate(this.gameObject);
                }
            }
        }

        public IEnumerator Start() {
            var environment = environments.FirstOrDefault(
                v => v.name == this.activeEnvironmentName
            );
            if (environment == null) {
                this.onError.Invoke(new UnknownException(new [] {
                        new RequestError(
                            "environment",
                            "prefab.GS2ClientHolder.activeEnvironmentName.error.notFound"
                        )
                    }
                ), null);
                yield break;
            }
            var future = Gs2Client.CreateFuture(
                new BasicGs2Credential(
                    environment.clientId,
                    environment.clientSecret
                ),
                environment.region,
                this.distributorNamespace == null ? "default" : this.distributorNamespace.NamespaceName
            );
            yield return future;
            if (future.Error != null)
            {
                onError.Invoke(future.Error, null);
                yield break;
            }
            
            Gs2 = future.Result;

            this.onInitialized.Invoke();
        }
        
        public void DebugErrorHandler(Gs2Exception e, Func<IEnumerator> retry) {
            if (e is CanIgnoreException) {
                return;
            }
            Debug.LogError($"{e.GetType()} {string.Join(",", e.Errors.Select(v => v.Message))} : Retryable={retry != null}");
        }
    }
}