using SLSFramework.General;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.UI.Extensions;

namespace Continentis.MainGame.UI
{
    public class PointerArrow : MonoBehaviour
    {
        [Tooltip("箭头起点的Transform（例如：正在拖拽的卡牌）")]
        public RectTransform startPoint;

        [Tooltip("箭头线条")]
        public UILineRenderer arrowBody;
        
        [Tooltip("箭头头部的RectTransform")]
        public Image endPoint;

        [Header("曲线设置")]
        [Tooltip("曲线的弯曲程度，数值越大越弯曲")]
        public float curveOffset = 150f;

        [Tooltip("曲线的平滑度，点越多越平滑，性能开销也越大")]
        [Range(20, 100)]
        public int lineSegments = 50;

        public void SetArrow(Vector3 start, Vector3 end)
        {
            startPoint.position = start;

            Camera uiCamera = CombatUIManager.Instance.uiCamera;
            Camera worldCamera = CombatUIManager.Instance.combatCamera;
            RectTransform pageTransform = CombatUIManager.Instance.arrowsPage.rectTransform;
            
            Vector2 uiStart = SpaceConverter.WorldPointToUILocalPoint(pageTransform, start, uiCamera, worldCamera);
            Vector2 uiEnd = SpaceConverter.WorldPointToUILocalPoint(pageTransform, end, uiCamera, worldCamera);
            bool isEndOnLeftSide = uiEnd.x < uiStart.x;
            
            
            // 控制点在起点和终点的中点，并根据朝向进行偏移，使曲线更自然
            Vector2 midPoint = (uiStart + uiEnd) / 2f;
            Vector2 direction = (uiEnd - uiStart).normalized;
            Vector2 perpendicular = new Vector2(-direction.y, direction.x); // 计算垂直向量
            Vector2 controlPoint = midPoint + perpendicular * (isEndOnLeftSide ? -curveOffset : curveOffset);

            // 2. 计算贝塞尔曲线上所有的点
            Vector2[] points = new Vector2[lineSegments];
            for (int i = 0; i < lineSegments; i++)
            {
                float t = (float)i / (lineSegments - 1);
                // 二次贝塞尔曲线公式: B(t) = (1-t)² * P₀ + 2(1-t)t * P₁ + t² * P₂
                points[i] = Mathf.Pow(1 - t, 2) * uiStart +
                            2 * (1 - t) * t * controlPoint +
                            Mathf.Pow(t, 2) * uiEnd;
            }
            
            arrowBody.Points = points;
            arrowBody.SetAllDirty(); // 通知UI系统重绘
            
            
            endPoint.rectTransform.localPosition = uiEnd;
            Vector2 headDirection = (uiEnd - points[lineSegments - 2]).normalized;
            float angle = Vector2.SignedAngle(Vector2.up, headDirection);
            endPoint.rectTransform.localRotation = Quaternion.Euler(0, 0, angle);
        }

        public void SetColor(Color color)
        {
            endPoint.color = color;
            arrowBody.color = color;
        }
    }
}