using UnityEngine;

namespace Ichni
{
    public static class SpaceConverter
    {
        /// <summary>
        /// 世界坐标转换为屏幕坐标
        /// </summary>
        /// <param name="worldPoint">屏幕坐标</param>
        /// <returns></returns>
        public static Vector2 WorldPointToScreenPoint(Vector3 worldPoint)
        {
            // Camera.main 世界摄像机
            Vector2 screenPoint = GameManager.instance.cameraManager.gameCamera.gameCamera.WorldToScreenPoint(worldPoint);
            return screenPoint;
        }

        /// <summary>
        /// 屏幕坐标转换为世界坐标
        /// </summary>
        /// <param name="screenPoint">屏幕坐标</param>
        /// <param name="planeZ">距离摄像机 Z 平面的距离</param>
        /// <returns></returns>
        public static Vector3 ScreenPointToWorldPoint(Vector2 screenPoint, float planeZ)
        {
            // Camera.main 世界摄像机
            Vector3 position = new Vector3(screenPoint.x, screenPoint.y, planeZ);
            Vector3 worldPoint = GameManager.instance.cameraManager.gameCamera.gameCamera.ScreenToWorldPoint(position);
            return worldPoint;
        }


        public static Vector2 WorldPointToUILocalPoint(RectTransform rt, Vector3 worldPosition)
        {
            // 将世界坐标转换为屏幕坐标
            var screenPosition = WorldPointToScreenPoint(worldPosition);
            // 将屏幕坐标转换为 UGUI 坐标
            Vector2 localPoint = ScreenPointToUILocalPoint(rt, screenPosition);

            return localPoint;
        }

        public static Vector3 WorldPointToUIPoint(RectTransform rt, Vector3 worldPosition)
        {
            // 将世界坐标转换为屏幕坐标
            var screenPosition = WorldPointToScreenPoint(worldPosition);
            // 将屏幕坐标转换为 UGUI 坐标
            Vector3 uiPoint = ScreenPointToUIPoint(rt, screenPosition);

            return uiPoint;
        }

        // RectTransformUtility.WorldToScreenPoint
        // RectTransformUtility.ScreenPointToWorldPointInRectangle
        // RectTransformUtility.ScreenPointToLocalPointInRectangle
        // 上面三个坐标转换的方法使用 Camera 的地方
        // 当 Canvas renderMode 为 RenderMode.ScreenSpaceCamera、RenderMode.WorldSpace 时 传递参数 canvas.worldCamera
        // 当 Canvas renderMode 为 RenderMode.ScreenSpaceOverlay 时 传递参数 null

        // UI 坐标转换为屏幕坐标
        public static Vector2 UIPointToScreenPoint(Vector3 worldPoint)
        {
            Vector2 screenPoint = RectTransformUtility.WorldToScreenPoint(GameManager.instance.cameraManager.uiCamera, worldPoint);
            return screenPoint;
        }

        // 屏幕坐标转换为 UGUI 坐标
        public static Vector3 ScreenPointToUIPoint(RectTransform rt, Vector2 screenPoint)
        {
            //UI屏幕坐标转换为世界坐标
            // 当 Canvas renderMode 为 RenderMode.ScreenSpaceCamera、RenderMode.WorldSpace 时 uiCamera 不能为空
            // 当 Canvas renderMode 为 RenderMode.ScreenSpaceOverlay 时 uiCamera 可以为空
            RectTransformUtility.ScreenPointToWorldPointInRectangle(rt, screenPoint, GameManager.instance.cameraManager.uiCamera, out Vector3 globalMousePos);
            // 转换后的 globalMousePos 使用下面方法赋值
            // target 为需要使用的 UI RectTransform
            // rt 可以是 target.GetComponent<RectTransform>(), 也可以是 target.parent.GetComponent<RectTransform>()
            // target.transform.position = globalMousePos;
            return globalMousePos;
        }

        // 屏幕坐标转换为 UGUI RectTransform 的 anchoredPosition
        public static Vector2 ScreenPointToUILocalPoint(RectTransform parentRT, Vector2 screenPoint)
        {
            RectTransformUtility.ScreenPointToLocalPointInRectangle(parentRT, screenPoint, GameManager.instance.cameraManager.uiCamera, out Vector2 localPos);
            // 转换后的 localPos 使用下面方法赋值
            // target 为需要使用的 UI RectTransform
            // parentRT 是 target.parent.GetComponent<RectTransform>()
            // 最后赋值 target.anchoredPosition = localPos;
            return localPos;
        }
        
        /// <summary>
        /// 获取目标 RectTransform 在目标空间 RectTransform 中的本地位置
        /// </summary>
        public static Vector2 GetLocalUIPosition(RectTransform targetRect, RectTransform targetSpace)
        {
            Vector2 screenPos = RectTransformUtility.WorldToScreenPoint(null, targetRect.position);
            RectTransformUtility.ScreenPointToLocalPointInRectangle(targetSpace, screenPos, null, out Vector2 localPos);
            return localPos;
        }
    }
}