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

namespace GeneralTools
{
    /// <summary>
    /// 工程里 通用的方法写这里
    /// </summary>
    public class UtilityTool : MonoBehaviour
    {

        /// <summary>
        /// 删除transform下所有子物体
        /// </summary>
        /// <param name="tran"></param>
        public static void DeleteChild(Transform tran)
        {
            for (int i = tran.childCount - 1; i >= 0; i--)
            {
                DestroyImmediate(tran.GetChild(i).gameObject);
            }
        }
        /// <summary>
        /// 截取某摄像机画面
        /// </summary>
        /// <param name="camera"></param>
        /// <param name="rect"></param>
        /// <returns></returns>
        public static Texture2D GetScreenShot(Camera camera, Rect rect)
        {
            if (camera == null)
            {
                Debug.LogError("camera is null");
                return null;
            }
            // 创建一个RenderTexture对象  
            RenderTexture rt = new RenderTexture((int)rect.width, (int)rect.height, 0);
            // 临时设置相关相机的targetTexture为rt, 并手动渲染相关相机  
            camera.targetTexture = rt;
            camera.Render();
            //ps: --- 如果这样加上第二个相机，可以实现只截图某几个指定的相机一起看到的图像。  
            //ps: camera2.targetTexture = rt;  
            //ps: camera2.Render();  
            //ps: -------------------------------------------------------------------  

            // 激活这个rt, 并从中中读取像素。  
            RenderTexture.active = rt;
            Texture2D screenShot = new Texture2D((int)rect.width, (int)rect.height, TextureFormat.RGB24, false);
            screenShot.ReadPixels(rect, 0, 0);// 注：这个时候，它是从RenderTexture.active中读取像素  
            screenShot.Apply();

            // 重置相关参数，以使用camera继续在屏幕上显示  
            camera.targetTexture = null;
            //ps: camera2.targetTexture = null;  
            RenderTexture.active = null; // JC: added to avoid errors  
            Destroy(rt);
            return screenShot;
        }

        public enum TexStyle
        {
            JPG,
            PNG,
            EXR
        }
        /// <summary>
        /// Texture2D 转换为 byte[]
        /// </summary>
        /// <param name="tex"></param>
        /// <param name="style"></param>
        /// <returns></returns>
        public static byte[] TexConvertBytes(Texture2D tex, TexStyle style)
        {
            byte[] bytes = null; ;
            switch (style)
            {
                case TexStyle.JPG:
                    bytes = tex.EncodeToJPG();
                    break;
                case TexStyle.PNG:
                    bytes = tex.EncodeToPNG();
                    break;
                case TexStyle.EXR:
                    bytes = tex.EncodeToEXR();
                    break;
            }
            return bytes;
        }
        /// <summary>
        /// bytes数组 转 Texture2D
        /// </summary>
        /// <param name="bytes"></param>
        /// <param name="width"></param>
        /// <param name="height"></param>
        /// <returns></returns>
        public static Texture2D BytesConvertTex2D(byte[] bytes, int width, int height)
        {
            Texture2D tex = new Texture2D(width, height);
            try
            {
                tex.LoadImage(bytes);
            }
            catch (Exception)
            {
                Debug.LogError("bytes转图片失败");
                return null;
            }
            return tex;
        }
        //寻找子物体，用于初始化
        public static Transform FindChild(Transform trans, string childName)
        {
            Transform child = trans.Find(childName);
            if (child != null)
            {
                return child;
            }
            int count = trans.childCount;
            Transform go = null;
            for (int i = 0; i < count; ++i)
            {
                child = trans.GetChild(i);
                go = FindChild(child, childName);
                if (go != null)
                    return go;
            }
            return null;
        }

        public static T FindChild<T>(Transform trans, string childName) where T : Component
        {
            Transform go = FindChild(trans, childName);
            if (go == null)
                return null;
            return go.GetComponent<T>();
        }
        /// <summary>
        /// 返回trans下所有子物体的T集合
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="trans"></param>
        /// <returns></returns>
        public static List<T> CollectComponent<T>(Transform trans)
        {
            List<T> tempList = new List<T>();
            for (int i = 0; i < trans.childCount; i++)
            {
                T _t = trans.GetChild(i).GetComponent<T>();
                if (_t != null)
                {
                    tempList.Add(_t);
                }
                if (trans.GetChild(i).childCount > 0)
                {
                    tempList = tempList.Concat(CollectComponent<T>(trans.GetChild(i))).ToList();
                }
            }
            return tempList;
        }
        public static IEnumerator DelayToInvokeDo(Action action, float delaySeconds)
        {
            yield return new WaitForSeconds(delaySeconds);
            action();
        }
        public static IEnumerator DelayToInvokeDo(Action<object[]> action, float delaySeconds, params object[] objs)
        {
            yield return new WaitForSeconds(delaySeconds);
            action(objs);
        }
    }
}