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

namespace LineUI
{
    [RequireComponent(typeof(CanvasRenderer))]
    [RequireComponent(typeof(RectTransform))]
    public class Line : Graphic
    {
        [SerializeField] private bool loop = false;
        [SerializeField] private float thickness = 1f;
        [SerializeField] private int roundCount = 0;
        [SerializeField] private Vector2 quadrilateralSize = new Vector2(100, 100);
        [SerializeField] private Color quadColor = Color.red;
        [SerializeField] private List<Vector2> screenPositions = new List<Vector2>();

        [SerializeField] private Color maskColor = Color.red;
        //是否绘制内四边形
        [SerializeField] bool bDrawQuad = true;
        //是否绘制外围蒙板
        [SerializeField] bool bDrawMask = false;
        //[SerializeField] private Color quadTextColor = Color.black;
        //[SerializeField] private int quadFontSize = 14;

        //private List<Vector2> quadsToDraw = new List<Vector2>();
        //private List<string> quadTextToDraw = new List<string>();
        //private List<GameObject> quadObjects = new List<GameObject>();
        //private Stack<GameObject> objectPool = new Stack<GameObject>();


        private const int ObjectPoolLimit = 4;

        public RectTransform RectTr => rectTransform;

        public float MyThickness
        {
            get => thickness;
            set
            {
                if (value >= 10)
                {
                    thickness = value;
                }
            }
        }

        public void SetLine(List<Vector2> screenPositions)
        {
            this.screenPositions = screenPositions;
            SetVerticesDirty();
        }

        public void SetDrawQuad(bool value) {
            bDrawQuad = value;
        }
        public void SetDrawMask(bool value)
        {
            bDrawMask = value;
        }
        protected override void OnPopulateMesh(VertexHelper vh)
        {
            vh.Clear();
            //quadsToDraw.Clear();
            //quadTextToDraw.Clear();

            if (screenPositions.Count < 2)
                return;


            SetLineVertices(vh);
            SetLineTriangles(vh);

            if(bDrawQuad) SetQuadrilateralVertices(vh);

            if(bDrawMask) DrawMask(vh); // 绘制蒙版
        }

        private void SetLineVertices(VertexHelper vh)
        {
            UIVertex vert = UIVertex.simpleVert;
            vert.color = color;

            List<Vector2> _screenPositions = new List<Vector2>(screenPositions);
            if (loop)
            {
                _screenPositions.Add(screenPositions[0]);
                _screenPositions.Add(screenPositions[1]);
            }

            float lastAngle = 0;
            for (int i = 1; i < _screenPositions.Count; i++)
            {
                Vector2 previousPos = _screenPositions[i - 1];
                Vector2 currentPos = _screenPositions[i];
                Vector2 dif = currentPos - previousPos;
                float angle = Vector2.SignedAngle(Vector2.right, dif);

                Vector2 offset = Quaternion.Euler(0, 0, angle) * Vector3.up * thickness;

                if (i > 1)
                {
                    float anglePerRound = (angle - lastAngle) / roundCount;
                    for (int j = 0; j <= roundCount; j++)
                    {
                        float ang = lastAngle + anglePerRound * j;
                        Vector2 roundOffset = Quaternion.Euler(0, 0, ang) * Vector2.up * thickness;
                        vert.position = previousPos - roundOffset;
                        vh.AddVert(vert);
                        vert.position = previousPos + roundOffset;
                        vh.AddVert(vert);
                    }
                }
                lastAngle = angle;

                vert.position = previousPos - offset;
                vh.AddVert(vert);

                vert.position = previousPos + offset;
                vh.AddVert(vert);

                vert.position = currentPos - offset;
                vh.AddVert(vert);

                vert.position = currentPos + offset;
                vh.AddVert(vert);
            }
        }

        private void SetQuadrilateralVertices(VertexHelper vh)
        {
            UIVertex vert = UIVertex.simpleVert;
            vert.color = quadColor;

            List<Vector2> _screenPositions = new List<Vector2>(screenPositions);
            if (loop)
            {
                _screenPositions.Add(screenPositions[0]);
                _screenPositions.Add(screenPositions[1]);
            }

            for (int i = 1; i < _screenPositions.Count; i++)
            {
                Vector2 previousPos = _screenPositions[i - 1];
                Vector2 currentPos = _screenPositions[i];
                if (i > 1)
                {
                    Vector2 prevDir = (_screenPositions[i - 1] - _screenPositions[i - 2]).normalized;
                    Vector2 currentDir = (currentPos - previousPos).normalized;
                    int index = i == 4 ? 4 : i % 4;
                    if (index == 4 || index == 2)
                    {

                        DrawSquareAtCorner(vh, previousPos, prevDir, currentDir, quadrilateralSize.x, quadrilateralSize.y, index);
                    }
                    else {

                        DrawSquareAtCorner(vh, previousPos, prevDir, currentDir, quadrilateralSize.y, quadrilateralSize.x, index);
                    }
                }
            }
        }

        private void DrawSquareAtCorner(VertexHelper vh, Vector2 corner, Vector2 prevDir, Vector2 currentDir, float width, float height, int index)
        {
            UIVertex vert = UIVertex.simpleVert;
            vert.color = quadColor;

            Vector2[] corners = new Vector2[4];
            corners[0] = corner;
            corners[1] = corner + prevDir * -width;
            corners[2] = corner + prevDir * -width + currentDir * height;
            corners[3] = corner + currentDir * height;

            foreach (Vector2 pos in corners)
            {
                vert.position = pos;
                vh.AddVert(vert);
            }

            int startIndex = vh.currentVertCount - 4;
            vh.AddTriangle(startIndex, startIndex + 1, startIndex + 2);
            vh.AddTriangle(startIndex + 2, startIndex + 3, startIndex);

            // Store the quad's center position and text for later use
            //Vector2 quadCenter = corner + (prevDir * -width + currentDir * height) / 2;
            //quadsToDraw.Add(quadCenter);
            //quadTextToDraw.Add(index.ToString());
        }

        private void SetLineTriangles(VertexHelper vh)
        {
            for (int i = 0; i < vh.currentVertCount - 2; i += 2)
            {
                int index = i;
                vh.AddTriangle(index, index + 1, index + 3);
                vh.AddTriangle(index + 3, index + 2, index);
            }
        }

        private void DrawMask(VertexHelper vh)
        {
            UIVertex vert = UIVertex.simpleVert;
            vert.color = maskColor;

            //// 屏幕四个角的坐标
            //Vector2[] screenCorners = new Vector2[]
            //{
            //    new Vector2(-Screen.width / 2, -Screen.height / 2), // 左下角
            //    new Vector2(Screen.width / 2, -Screen.height / 2),  // 右下角
            //    new Vector2(Screen.width / 2, Screen.height / 2),   // 右上角
            //    new Vector2(-Screen.width / 2, Screen.height / 2),  // 左上角
            //};

            // 获取 RectTransform 的实际四个角坐标
            Rect rect = rectTransform.rect;

            Vector2[] screenCorners = new Vector2[]
            {
                new Vector2(rect.xMin, rect.yMin), // 左下角
                new Vector2(rect.xMax, rect.yMin), // 右下角
                new Vector2(rect.xMax, rect.yMax), // 右上角
                new Vector2(rect.xMin, rect.yMax), // 左上角
            };

            // 添加四个点作为内框（中间区域的四个顶点）
            Vector2[] innerCorners = screenPositions.ToArray();

            // 分别绘制四个蒙版区域

            // 1. 左上区域：围绕左上角和内框左上、右上
            AddQuad(vh, screenCorners[3], innerCorners[3], innerCorners[2], screenCorners[2]);

            // 2. 右上区域：围绕右上角和内框右上、右下
            AddQuad(vh, innerCorners[2], screenCorners[2], screenCorners[1], innerCorners[1]);

            // 3. 右下区域：围绕右下角和内框右下、左下
            AddQuad(vh, innerCorners[0], innerCorners[1], screenCorners[1], screenCorners[0]);

            // 4. 左下区域：围绕左下角和内框左下、左上
            AddQuad(vh, screenCorners[3], screenCorners[0], innerCorners[0], innerCorners[3]);

        }

        private void AddQuad(VertexHelper vh, Vector2 corner1, Vector2 corner2, Vector2 corner3, Vector2 corner4)
        {
            UIVertex vert = UIVertex.simpleVert;
            vert.color = maskColor;

            vert.position = corner1;
            vh.AddVert(vert);
            vert.position = corner2;
            vh.AddVert(vert);
            vert.position = corner3;
            vh.AddVert(vert);
            vert.position = corner4;
            vh.AddVert(vert);

            Debug.Log("vh.currentVertCount:"+ vh.currentVertCount);
            int startIndex = vh.currentVertCount - 4;
            vh.AddTriangle(startIndex, startIndex + 1, startIndex + 2);
            vh.AddTriangle(startIndex + 2, startIndex + 3, startIndex);
        }






        //private void LateUpdate()
        //{
        //    foreach (var quadObj in quadObjects)
        //    {
        //        if (quadObj != null)
        //        {
        //            objectPool.Push(quadObj);
        //        }
        //    }
        //    quadObjects.Clear();

        //    for (int i = 0; i < quadsToDraw.Count; i++)
        //    {
        //        GameObject quadGO = GetQuadObject();
        //        if (quadGO != null)
        //        {
        //            quadGO.SetActive(true);
        //            quadGO.GetComponent<RectTransform>().anchoredPosition = quadsToDraw[i];

        //            Text quadTextComponent = quadGO.GetComponent<Text>();
        //            quadTextComponent.text = quadTextToDraw[i];
        //            quadTextComponent.fontSize = quadFontSize;
        //            quadTextComponent.color = quadTextColor;

        //            quadTextComponent.alignment = TextAnchor.MiddleCenter;
        //        }
        //    }
        //    quadsToDraw.Clear();
        //    quadTextToDraw.Clear();
        //}

        //private GameObject GetQuadObject()
        //{
        //    if (objectPool.Count > 0)
        //    {
        //        GameObject quadGO = objectPool.Pop();
        //        if (quadGO != null)
        //        {
        //            quadObjects.Add(quadGO);
        //            return quadGO;
        //        }
        //    }

        //    if (quadObjects.Count < ObjectPoolLimit)
        //    {
        //        GameObject newQuadGO = new GameObject("QuadText", typeof(RectTransform), typeof(Text));
        //        newQuadGO.transform.SetParent(this.transform);
        //        Text quadTextComponent = newQuadGO.GetComponent<Text>();
        //        quadTextComponent.alignment = TextAnchor.MiddleCenter;
        //        quadTextComponent.rectTransform.sizeDelta = new Vector2(quadrilateralSize.x, quadrilateralSize.y);

        //        quadObjects.Add(newQuadGO);
        //        return newQuadGO;
        //    }

        //    return null;
        //}
    }
}