using System.Collections.Generic;
using UnityEngine;

namespace XGame.Framework.UI
{
    public class UILayerBehaviour : MonoBehaviour
    {
        [SerializeField]
        private UILayer _layer;
        [SerializeField]
        private Canvas _uiCanvas;
        public Canvas UiCanvas => _uiCanvas;
        public Transform UIRoot => _uiCanvas.transform;

        private List<IUIPanel> _panels = new List<IUIPanel>();
        public UILayer Layer { 
            get => _layer; 
            set
            {
                _layer = value;
                _uiCanvas.sortingOrder = (byte)value * 100;
                gameObject.name = value.ToString();
            }
        }
        /// <summary>
        /// 加入子节点
        /// 将Transform移动到本地变换列表的末尾
        /// </summary>
        /// <param name="child"></param>
        public void AddPanel(IUIPanel panel)
        {
            var panelTr = (panel as UIPanel).transform;
            if (!_panels.Contains(panel))
            {
                panelTr.SetParent(UIRoot, false);
                panelTr.position = Vector3.zero;
                _panels.Add(panel);
                OnChildrenChanged();
            }
            //将Transform移动到本地变换列表的末尾
            panelTr.SetAsLastSibling();
        }
        /// <summary>
        /// 移除子节点
        /// </summary>
        /// <param name="child"></param>
        public void RemovePanel(IUIPanel panel)
        {
            if (!_panels.Contains(panel))
            {
                return;
            }
            _panels.Remove(panel);
            (panel as UIPanel).transform.SetParent(null, false);
            OnChildrenChanged();
        }

        private void OnChildrenChanged()
        {
            _uiCanvas.gameObject.SetActive(_uiCanvas.transform.childCount > 0);
        }
    }
}