using System.Collections.Generic;
using System.Linq;
using UnityEngine;
using UnityEngine.Pool;
using UnityEngine.UI;

namespace XericLibrary.Runtime.UIGraph
{
    /// <summary>
    /// 自定义渲染组件
    /// </summary>
    [RequireComponent(typeof(CanvasRenderer))]
    public class XericRendererComponent : MaskableGraphic
    {
        public virtual string ShaderName => "Hidden/Texture2D";
        
        #region 字段属性
        
        // 原始数据
        private readonly List<UIVertex> _vertexList = new List<UIVertex>();
        private readonly List<int> _indexList = new List<int>();
        // 阵列原点
        private List<Vector4> _arrayTransformList = new List<Vector4>();
        // 中间数据
        private List<UIVertex> _temp_vertexList = new List<UIVertex>();
        private List<int> _temp_indexList = new List<int>();

        private bool _dirty;
        
        #endregion

#if UNITY_EDITOR
        protected override void OnValidate()
        {
            base.OnValidate();
            
            if (m_Material == null)
                material = new Material(Shader.Find(ShaderName));
        }
#endif
        
        #region 绘制

        /// <summary>
        /// 刷新
        /// </summary>
        public virtual void Refresh()
        {
            SetVerticesDirty();
        }
        /// <summary>
        /// ui模型填充流程
        /// </summary>
        /// <param name="vh"></param>
        protected override void OnPopulateMesh(VertexHelper vh)
        {
            if (vh == null) return;
            vh.Clear();
            ClearCache();
            // 填充图元
            OnPopulatePrefabricateVertex(_vertexList, _indexList);
            // 阵列
            ArrayVertexList(_arrayTransformList);
            // 将顶点填充到mesh
            vh.AddUIVertexStream(_temp_vertexList, _temp_indexList);
        }

        /// <summary>
        /// 填充预制顶点
        /// </summary>
        /// <param name="vertexList">顶点列表</param>
        /// <param name="indexList">三角面索引</param>
        protected virtual void OnPopulatePrefabricateVertex(List<UIVertex> vertexList, List<int> indexList)
        {
        }


        /// <summary>
        /// 清除所有缓存
        /// </summary>
        protected void ClearCache()
        {
            _vertexList.Clear();
            _indexList.Clear();
        }
        
        /// <summary>
        /// 添加一个阵列节点
        /// </summary>
        /// <param name="offset">偏移</param>
        /// <param name="angle">角度</param>
        public int AddArrayModifier(Vector3 offset, float angle)
        {
            var index = _arrayTransformList.Count;
            _arrayTransformList.Add(new Vector4(offset.x, offset.y, offset.z, angle));
            Refresh();
            return index;
        }

        /// <summary>
        /// 清空阵列节点
        /// </summary>
        public void ClearArrayModifier()
        {
            _arrayTransformList.Clear();
            Refresh(); 
        }

        public bool ModifyArrayModifier(int index, Vector3 offset, float angle)
        {
            if (index < 0 || index >= _arrayTransformList.Count)
                return false;
            _arrayTransformList[index] = new Vector4(offset.x, offset.y, offset.z, angle);
            Refresh(); 
            return true;
        }
        
        #endregion

        #region 阵列

        /// <summary>
        /// 根据原点阵列
        /// </summary>
        /// <param name="vh"></param>
        /// <param name="trans"></param>
        protected void ArrayVertexList(List<Vector4> trans)
        {
            _temp_vertexList.Clear();
            _temp_indexList.Clear();
            
            if (trans == null || trans.Count == 0)
            {
                Copy();
                return;
            }

            for (int i = 0; i < trans.Count; i++)
                Copy2(i, trans[i]);

            void Copy()
            {
                _temp_vertexList.AddRange(_vertexList.GetRange(0, _vertexList.Count));
                _temp_indexList.AddRange(_indexList.GetRange(0, _indexList.Count));
            }
            void Copy2(int index, Vector4 transform)
            {
                _temp_vertexList.AddRange(_vertexList.Select(a =>
                {
                    var newPos = a.position;
                    if (transform.w != 0)
                    {
                        var rot = Quaternion.Euler(0, 0, transform.w);
                        newPos = rot * newPos;
                    }
                    newPos += (Vector3)transform;
                    return new UIVertex()
                    {
                        position = newPos,
                        normal = a.normal,
                        tangent = a.tangent,
                        color = a.color,
                        uv0 = a.uv0,
                        uv1 = a.uv1,
                        uv2 = a.uv2,
                        uv3 = a.uv3,
                    };
                }));
                _temp_indexList.AddRange(_indexList.Select(a => index * _vertexList.Count + a));
            }
        }

        #endregion
    }
}