using System.Collections;
using System.IO;
using ET;
using UnityEngine;
using UnityEngine.Networking;

namespace VEngine
{

    public class EncryptHelper
    {
        public static string resKey;

        private static char[] _resKeyChars;
        public static char[] resKeyChars
        {
            get
            {
                if(_resKeyChars == null && !string.IsNullOrEmpty(resKey))
                {
                    _resKeyChars = resKey.ToCharArray();
                }
                return _resKeyChars;
            }
        }
        /// <summary>
        /// 创建加密过的数据
        /// </summary>
        public static byte[] CreateEncryptData(string filePath, string secretKey)
        {
            byte[] encryptData;
            char[] key = secretKey.ToCharArray();
            using (FileStream fs = new FileStream(filePath, FileMode.Open))
            {
                encryptData = new byte[fs.Length];
                fs.Read(encryptData, 0, encryptData.Length);
                for (int i = 0; i < key.Length; i++)
                {
                    encryptData[i] = (byte)(encryptData[i] ^ key[i % key.Length]);
                }
            }
            return encryptData;
        }

        /// <summary>
        /// 获取解密的数据(无密钥的情况下直接获取数据)
        /// </summary>
        internal static byte[] GetDecryptData(string filePath, char[] secretKey = null)
        {
            byte[] encryptData;
            using (UnityWebRequest webRequest = UnityWebRequest.Get(filePath))
            {
                webRequest.SendWebRequest();
                while (!webRequest.isDone) { }
#if UNITY_2020_1_OR_NEWER
                if (webRequest.result == UnityWebRequest.Result.Success)
#else
                if (string.IsNullOrEmpty(webRequest.error))
#endif
                {
                    encryptData = webRequest.downloadHandler.data;
                    if (secretKey != null)
                    {
                        for (int i = 0; i < secretKey.Length; i++)
                        {
                            encryptData[i] = (byte)(encryptData[i] ^ secretKey[i % secretKey.Length]);
                        }
                    }
                }
                else
                {
                    encryptData = null;
                }
            }
            return encryptData;
        }
    }
    
}