using System;
using System.Text;
using System.Security.Cryptography;

namespace WMS.Util
{
    /// <summary>
    /// MD5加密类
    /// </summary>
    public class SecurityUtil
    {
        #region MD5加密
        ///   <summary>
        ///   给一个字符串进行MD5加密
        ///   </summary>
        ///   <param   name="strText">待加密字符串</param>
        ///   <returns>加密后的字符串</returns>
        public static string MD5Encrypt(string strText)
        {
            MD5 md5 = new MD5CryptoServiceProvider();
            byte[] result = md5.ComputeHash(System.Text.Encoding.Default.GetBytes(strText));
            return System.Text.Encoding.Default.GetString(result);
        }

        /// <summary>
        /// MD5加密
        /// </summary>
        /// <param name="str">加密字符</param>
        /// <param name="code">加密位数16/32</param>
        /// <returns></returns>
        public static string MD5(string str, int code)
        {
            MD5CryptoServiceProvider crypto = new MD5CryptoServiceProvider();
            byte[] bytes = Encoding.UTF7.GetBytes(str);
            bytes = crypto.ComputeHash(bytes);
            StringBuilder sb = new StringBuilder();
            foreach (byte num in bytes)
            {
                sb.AppendFormat("{0:x2}", num);
            }
            if (code == 16)
            {
                return sb.ToString().Substring(8, 16);

            }
            else
            {
                return sb.ToString();
            }
        }
        #endregion

        #region  DES加密/解密

        /// <summary> 
        /// DES加密数据 
        /// </summary> 
        /// <param name="Text"></param> 
        /// <param name="sKey"></param> 
        /// <returns></returns> 
        public static string DesEncrypt(string Text, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray;
            inputByteArray = Encoding.Default.GetBytes(Text);
            des.Key = ASCIIEncoding.ASCII.GetBytes(MD5Encrypt(sKey).Substring(0, 8));
            des.IV = ASCIIEncoding.ASCII.GetBytes(MD5Encrypt(sKey).Substring(0, 8));
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            StringBuilder ret = new StringBuilder();
            foreach (byte b in ms.ToArray())
            {
                ret.AppendFormat("{0:X2}", b);
            }
            return ret.ToString();
        }

               /// <summary> 
        /// DES解密数据 
        /// </summary> 
        /// <param name="Text"></param> 
        /// <param name="sKey"></param> 
        /// <returns></returns> 
        public static string DesDecrypt(string Text, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            int len;
            len = Text.Length / 2;
            byte[] inputByteArray = new byte[len];
            int x, i;
            for (x = 0; x < len; x++)
            {
                i = Convert.ToInt32(Text.Substring(x * 2, 2), 16);
                inputByteArray[x] = (byte)i;
            }
            des.Key = ASCIIEncoding.ASCII.GetBytes(MD5Encrypt(sKey).Substring(0, 8));
            des.IV = ASCIIEncoding.ASCII.GetBytes(MD5Encrypt(sKey).Substring(0, 8));
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            return Encoding.Default.GetString(ms.ToArray());
        }

        #endregion

        #region Base64 编码
        /// <summary>
                /// Base64 编码
                /// </summary>
                /// <param name="encode">编码方式</param>
                /// <param name="source">要编码的字符串</param>
                /// <returns>返回编码后的字符串</returns>
        public static string EncodeBase64(Encoding encode, string source)
        {
            string result = "";
            byte[] bytes = encode.GetBytes(source);
            try
            {
                result = Convert.ToBase64String(bytes);
            }
            catch
            {
                result = source;
            }
            return result;
        }
        /// <summary>
        /// Base64 解码
        /// </summary>
        /// <param name="encode">解码方式</param>
        /// <param name="source">要解码的字符串</param>
        /// <returns>返回解码后的字符串</returns>
        public static string DecodeBase64(Encoding encode, string source)
        {
            string result = "";
            byte[] bytes = Convert.FromBase64String(source);
            try
            {
                result = encode.GetString(bytes);
            }
            catch
            {
                result = source;
            }
            return result;
        }
        #endregion

        #region  AES加密/解密 
        //AES加密
        public static string AesEncrypt(string value, string key, string iv = "")
        {
            if (string.IsNullOrEmpty(value)) return string.Empty;
            if (key == null) throw new Exception("未将对象引用设置到对象的实例。");
            if (key.Length < 16) throw new Exception("指定的密钥长度不能少于16位。");
            if (key.Length > 32) throw new Exception("指定的密钥长度不能多于32位。");
            if (key.Length != 16 && key.Length != 24 && key.Length != 32) throw new Exception("指定的密钥长度不明确。");
            if (!string.IsNullOrEmpty(iv))
            {
                if (iv.Length < 16) throw new Exception("指定的向量长度不能少于16位。");
            }

            var _keyByte = Encoding.UTF8.GetBytes(key);
            var _valueByte = Encoding.UTF8.GetBytes(value);
            using (var aes = new RijndaelManaged())
            {
                aes.IV = !string.IsNullOrEmpty(iv) ? Encoding.UTF8.GetBytes(iv) : Encoding.UTF8.GetBytes(key.Substring(0, 16));
                aes.Key = _keyByte;
                aes.Mode = CipherMode.CBC;
                aes.Padding = PaddingMode.PKCS7;
                var cryptoTransform = aes.CreateEncryptor();
                var resultArray = cryptoTransform.TransformFinalBlock(_valueByte, 0, _valueByte.Length);
                return Convert.ToBase64String(resultArray, 0, resultArray.Length);
            }
        }
        //AES解密
        public static string AesDecrypt(string value, string key, string iv = "")
        {
            if (string.IsNullOrEmpty(value)) return string.Empty;
            if (key == null) throw new Exception("未将对象引用设置到对象的实例。");
            if (key.Length < 16) throw new Exception("指定的密钥长度不能少于16位。");
            if (key.Length > 32) throw new Exception("指定的密钥长度不能多于32位。");
            if (key.Length != 16 && key.Length != 24 && key.Length != 32) throw new Exception("指定的密钥长度不明确。");
            if (!string.IsNullOrEmpty(iv))
            {
                if (iv.Length < 16) throw new Exception("指定的向量长度不能少于16位。");
            }

            var _keyByte = Encoding.UTF8.GetBytes(key);
            var _valueByte = Convert.FromBase64String(value);
            using (var aes = new RijndaelManaged())
            {
                aes.IV = !string.IsNullOrEmpty(iv) ? Encoding.UTF8.GetBytes(iv) : Encoding.UTF8.GetBytes(key.Substring(0, 16));
                aes.Key = _keyByte;
                aes.Mode = CipherMode.CBC;
                aes.Padding = PaddingMode.PKCS7;
                var cryptoTransform = aes.CreateDecryptor();
                var resultArray = cryptoTransform.TransformFinalBlock(_valueByte, 0, _valueByte.Length);
                return Encoding.UTF8.GetString(resultArray);
            }
        }
        #endregion
    }
}