using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using UnityEngine;

namespace Wing.Utils
{
    public class UtilsHelper
    {
        public static string GetDataPath()
        {
            string path = "";
            if (Application.platform == RuntimePlatform.Android || Application.platform == RuntimePlatform.IPhonePlayer)
            {
                path = Application.persistentDataPath + "/";
            }
            else if (Application.platform == RuntimePlatform.WindowsPlayer)
            {
                path = Application.dataPath + "/";
            }
            else if (Application.platform == RuntimePlatform.WindowsEditor)
            {
                path = Application.dataPath + "/../";
            }
            else
            {
                path = Application.persistentDataPath + "/";
            }

            return path;
        }

        public static string GetResourcePath()
        {
            return GetDataPath() + "ResData";
        }

        public static IEnumerator LoadTexture(string url, Action<Texture2D> cb)
        {
            //这里的url可以是web路径也可以是本地路径file://  
            WWW www = new WWW(url);
            //挂起程序段，等资源下载完成后，继续执行下去  
            yield return www;

            //判断是否有错误产生  
            if (string.IsNullOrEmpty(www.error))
            {
                //把下载好的图片回调给调用者  
                cb.Invoke(www.texture);
                //释放资源  
                www.Dispose();
            }
        }

        public static IEnumerator Load(string url, Action<WWW> cb)
        {
            //这里的url可以是web路径也可以是本地路径file://  
            WWW www = new WWW(url);
            //挂起程序段，等资源下载完成后，继续执行下去  
            yield return www;

            //判断是否有错误产生  
            if (string.IsNullOrEmpty(www.error))
            {
                //把下载好的图片回调给调用者  
                cb.Invoke(www);
                //释放资源  
                www.Dispose();
            }
        }

        public static IEnumerator Load(string url, Action<WWW,object> cb, object data)
        {
            //这里的url可以是web路径也可以是本地路径file://  
            WWW www = new WWW(url);
            //挂起程序段，等资源下载完成后，继续执行下去  
            yield return www;

            //判断是否有错误产生  
            if (string.IsNullOrEmpty(www.error))
            {
                //把下载好的图片回调给调用者  
                cb.Invoke(www, data);
                //释放资源  
                www.Dispose();
            }
        }

        public static IEnumerator LoadAssetBundle(string url, Action<AssetBundle> ab)
        {
            WWW www = new WWW(url);
            yield return www;

            if (string.IsNullOrEmpty(www.error))
            {
                ab.Invoke(www.assetBundle);
                www.Dispose();
            }
        }

        public static string StringMD5(string data)
        {
            byte[] result = Encoding.Default.GetBytes(data.Trim());
            MD5 md5 = new MD5CryptoServiceProvider();
            byte[] output = md5.ComputeHash(result);
            return BitConverter.ToString(output).Replace("-", "");
        }

        public static void SaveTextureFile(Texture2D incomingTexture, string filename)
        {
            byte[] bytes = incomingTexture.EncodeToPNG();
            string dir = Path.GetDirectoryName(filename);
            if (!Directory.Exists(dir))
            {
                Directory.CreateDirectory(dir);
            }
            File.WriteAllBytes(filename, bytes);
        }

        public static bool SaveRenderTextureToPNG(Texture inputTex, Material mat, string filename)
        {
            RenderTexture temp = RenderTexture.GetTemporary(inputTex.width, inputTex.height, 0, RenderTextureFormat.ARGB32);
            Graphics.Blit(inputTex, temp, mat);
            bool ret = SaveRenderTextureToPNG(temp, filename);
            RenderTexture.ReleaseTemporary(temp);
            return ret;
        }
        
        public static bool SaveRenderTextureToPNG(RenderTexture rt, string filename)
        {
            Texture2D png = CreateTexture2DFromRT(rt);

            SaveTextureFile(png, filename);

            Texture2D.DestroyImmediate(png);
            png = null;
            return true;
        }

        public static Texture2D CreateTexture2DFromRT(RenderTexture rt, Rect? rect = null)
        {
            RenderTexture prev = RenderTexture.active;
            RenderTexture.active = rt;
            if(rect == null)
            {
                rect = new Rect(0, 0, rt.width, rt.height);
            }
            else
            {
                float width = rect.Value.width;
                if(rect.Value.width + rect.Value.x > rt.width)
                {
                    width = rt.width - rect.Value.x;
                }
                float height = rect.Value.height;
                if(rect.Value.height + rect.Value.y > rt.height)
                {
                    height = rt.height - rect.Value.y;
                }
                rect = new Rect(rect.Value.x, rect.Value.y, width, height);
            }
            Texture2D texture = new Texture2D((int)rect.Value.width, (int)rect.Value.height, TextureFormat.ARGB32, false);
            texture.ReadPixels(rect.Value, 0 , 0);
            texture.Apply();

            RenderTexture.active = prev;
            return texture;

        }
    }
}