using System;
using System.Globalization;
using System.IO;
using System.Security.Cryptography;
using System.Text;

namespace Pub.Class
{
    public static class EncryptExtensions
    {
        private static readonly byte[] AESKeys = {0x41, 0x72, 0x65, 0x79, 0x6F, 0x75, 0x6D, 0x79, 0x53, 0x6E, 0x6F, 0x77, 0x6D, 0x61, 0x6E, 0x3F};
        private static readonly byte[] DESKeys = {0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF};

        public static string AESEncode(this string encryptString, string encryptKey)
        {
            encryptKey = encryptKey.SubString(32, "");
            encryptKey = encryptKey.PadRight(32, ' ');

            var rijndaelProvider = new RijndaelManaged();
            rijndaelProvider.Key = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 32));
            rijndaelProvider.IV = AESKeys;
            ICryptoTransform rijndaelEncrypt = rijndaelProvider.CreateEncryptor();

            byte[] inputData = Encoding.UTF8.GetBytes(encryptString);
            byte[] encryptedData = rijndaelEncrypt.TransformFinalBlock(inputData, 0, inputData.Length);

            return Convert.ToBase64String(encryptedData);
        }

        public static string AESDecode(this string decryptString, string decryptKey)
        {
            try
            {
                decryptKey = decryptKey.SubString(32, "");
                decryptKey = decryptKey.PadRight(32, ' ');

                var rijndaelProvider = new RijndaelManaged();
                rijndaelProvider.Key = Encoding.UTF8.GetBytes(decryptKey);
                rijndaelProvider.IV = AESKeys;
                ICryptoTransform rijndaelDecrypt = rijndaelProvider.CreateDecryptor();

                byte[] inputData = Convert.FromBase64String(decryptString);
                byte[] decryptedData = rijndaelDecrypt.TransformFinalBlock(inputData, 0, inputData.Length);

                return Encoding.UTF8.GetString(decryptedData);
            }
            catch
            {
                return string.Empty;
            }
        }

        public static string DESEncode(this string encryptString, string encryptKey)
        {
            encryptKey = encryptKey.SubString(8, "");
            encryptKey = encryptKey.PadRight(8, ' ');
            byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));
            byte[] rgbIV = DESKeys;
            byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
            var dCSP = new DESCryptoServiceProvider();
            var mStream = new MemoryStream();
            var cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
            cStream.Write(inputByteArray, 0, inputByteArray.Length);
            cStream.FlushFinalBlock();
            return Convert.ToBase64String(mStream.ToArray());
        }

        public static string DESDecode(this string decryptString, string decryptKey)
        {
            try
            {
                decryptKey = decryptKey.SubString(8, "");
                decryptKey = decryptKey.PadRight(8, ' ');
                byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);
                byte[] rgbIV = DESKeys;
                byte[] inputByteArray = Convert.FromBase64String(decryptString);
                var DCSP = new DESCryptoServiceProvider();

                var mStream = new MemoryStream();
                var cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                return Encoding.UTF8.GetString(mStream.ToArray());
            }
            catch
            {
                return string.Empty;
            }
        }

        public static string Base64Encode(this string encryptString)
        {
            byte[] encbuff = Encoding.UTF8.GetBytes(encryptString);
            return Convert.ToBase64String(encbuff);
        }

        public static string Base64Decode(this string decryptString)
        {
            byte[] decbuff = Convert.FromBase64String(decryptString);
            return Encoding.UTF8.GetString(decbuff);
        }

        public static string RSADecrypt(this string s, string key)
        {
            string result = null;

            if (string.IsNullOrEmpty(s)) throw new ArgumentException("An empty string value cannot be encrypted.");

            if (string.IsNullOrEmpty(key)) throw new ArgumentException("Cannot decrypt using an empty key. Please supply a decryption key.");

            var cspp = new CspParameters();
            cspp.KeyContainerName = key;

            var rsa = new RSACryptoServiceProvider(cspp);
            rsa.PersistKeyInCsp = true;

            string[] decryptArray = s.Split(new[] {"-"}, StringSplitOptions.None);
            byte[] decryptByteArray = Array.ConvertAll(decryptArray, (a => Convert.ToByte(byte.Parse(a, NumberStyles.HexNumber))));

            byte[] bytes = rsa.Decrypt(decryptByteArray, true);

            result = Encoding.UTF8.GetString(bytes);

            return result;
        }

        public static string RSAEncrypt(this string s, string key)
        {
            if (string.IsNullOrEmpty(s)) throw new ArgumentException("An empty string value cannot be encrypted.");

            if (string.IsNullOrEmpty(key)) throw new ArgumentException("Cannot encrypt using an empty key. Please supply an encryption key.");

            var cspp = new CspParameters();
            cspp.KeyContainerName = key;

            var rsa = new RSACryptoServiceProvider(cspp);
            rsa.PersistKeyInCsp = true;

            byte[] bytes = rsa.Encrypt(Encoding.UTF8.GetBytes(s), true);

            return BitConverter.ToString(bytes);
        }

        public static string MD5(this string str)
        {
            string cl1 = str;
            string pwd = "";
            MD5 md5 = System.Security.Cryptography.MD5.Create(); // 加密后是一个字节类型的数组 
            byte[] s = md5.ComputeHash(Encoding.Unicode.GetBytes(cl1));
            for (int i = 0; i < s.Length; i++)
            {
// 通过使用循环，将字节类型的数组转换为字符串，此字符串是常规字符格式化所得 
                pwd = pwd + s[i].ToString("x"); // 将得到的字符串使用十六进制类型格式。格式后的字符是小写的字母，如果使用大写（X）则格式后的字符是大写字符 
            }
            return pwd;
        }

        public static string MD5CSP(this string encypStr)
        {
            string retStr;
            var m5 = new MD5CryptoServiceProvider();

            //创建md5对象
            byte[] inputBye;
            byte[] outputBye;

            //使用GB2312编码方式把字符串转化为字节数组．
            inputBye = Encoding.GetEncoding("GB2312").GetBytes(encypStr);

            outputBye = m5.ComputeHash(inputBye);

            retStr = BitConverter.ToString(outputBye);
            retStr = retStr.Replace("-", "").ToLower();
            return retStr;
        }

        public static string SHA256(this string str)
        {
            byte[] SHA256Data = Encoding.UTF8.GetBytes(str);
            var Sha256 = new SHA256Managed();
            byte[] Result = Sha256.ComputeHash(SHA256Data);
            return Convert.ToBase64String(Result); //返回长度为44字节的字符串
        }
    }
}