using System;
using System.Collections.Generic;
using UnityEngine;

namespace Superlazy.UI
{
    public class SLUIRepeat : SLUIComponent
    {
        public string bindingValue;

        public SLValueComparison comparison;

        [NonSerialized]
        public GameObject prefab = null;

        private readonly Queue<GameObject> unused = new Queue<GameObject>();
        private readonly Queue<GameObject> bindObjects = new Queue<GameObject>();

        protected override void Validate()
        {
        }

        protected override void Init()
        {
            prefab = transform.GetChild(0).gameObject;
            prefab.SetActive(false);
        }

        protected override void Enable()
        {
            if (comparison.useCheckValue) comparison.OnEnable(bindParent.BindPath, OnChange);

            SLGame.AddNotify(bindParent.BindPath.CombinePath(bindingValue), OnChange);
        }

        protected override void Disable()
        {
            while (bindObjects.Count != 0)
            {
                DisableItem(bindObjects.Dequeue());
            }

            if (comparison.useCheckValue) comparison.OnDisable();
            SLGame.RemoveNotify(bindParent.BindPath.CombinePath(bindingValue), OnChange);

            if (unused.Count > 16) // 아이템이 너무 많으면 초기화를 한다
            {
                foreach (var unusedItem in unused)
                {
                    Destroy(unusedItem);
                }
                unused.Clear();
            }
        }

        private void DisableItem(GameObject obj)
        {
            obj.SetActive(false);
            unused.Enqueue(obj);
        }

        private void EnableItem(GameObject obj)
        {
            obj.SetActive(true);
            bindObjects.Enqueue(obj);
        }

        private void OnChange()
        {
            if (bindParent.Active == false) return;
            var sessionRoot = SLGame.SessionGet(bindParent.BindPath);
            if (sessionRoot == false) return; // TEMP: 세션루트가 삭제되었지만, 삭제되되기전 코루틴 처리가 있을 수 있음

            var session = SLGame.SessionGet(bindParent.BindPath).Get(bindingValue);
            if (comparison.useCheckValue && comparison.Result == false)
            {
                session = 0;
            }

            if (session < 0) session = 0;

            var current = bindObjects.Count;
            if (current > 32)
            {
                SLLog.Warn($"Too many repeat Count : {bindParent.BindPath}.{bindingValue} : {current}", this);
            }

            if (current > session)
            {
                while (current != session)
                {
                    DisableItem(bindObjects.Dequeue());
                    current--;
                }
            }
            else if (current < session)
            {
                while (current != session)
                {
                    if (unused.Count == 0)
                    {
                        var child = Instantiate(prefab, transform, false);
                        unused.Enqueue(child);
                    }
                    EnableItem(unused.Dequeue());
                    current++;
                }
            }
        }
    }
}