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

namespace NXWMS.Client.Code.Security
{
    /// <summary>
    /// 加密算法类
    /// </summary>
    public static class SecurityCryptography
    {
        #region Base64加密解密
        /// <summary>
        /// Base64加密
        /// </summary>
        /// <param name="input">需要加密的字符串</param>
        /// <returns></returns>
        public static string Base64Encrypt(string input)
        {
            return Base64Encrypt(input, new UTF8Encoding());
        }

        /// <summary>
        /// Base64加密
        /// </summary>
        /// <param name="input">需要加密的字符串</param>
        /// <param name="encode">字符编码</param>
        /// <returns></returns>
        public static string Base64Encrypt(string input, Encoding encode)
        {
            return Convert.ToBase64String(encode.GetBytes(input));
        }

        /// <summary>
        /// Base64解密
        /// </summary>
        /// <param name="input">需要解密的字符串</param>
        /// <returns></returns>
        public static string Base64Decrypt(string input)
        {
            return Base64Decrypt(input, new UTF8Encoding());
        }

        /// <summary>
        /// Base64解密
        /// </summary>
        /// <param name="input">需要解密的字符串</param>
        /// <param name="encode">字符的编码</param>
        /// <returns></returns>
        public static string Base64Decrypt(string input, Encoding encode)
        {
            return encode.GetString(Convert.FromBase64String(input));
        }
        #endregion

        #region MD5 HASH算法
        /// <summary>
        /// MD5 HASH算法
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public static string GetMd5Hash(string input)
        {
            if (input == null)
            {
                return null;
            }

            MD5 md5Hash = MD5.Create();

            // 将输入字符串转换为字节数组并计算哈希数据 
            byte[] data = md5Hash.ComputeHash(Encoding.UTF8.GetBytes(input));

            // 创建一个 Stringbuilder 来收集字节并创建字符串 
            StringBuilder sBuilder = new StringBuilder();

            // 循环遍历哈希数据的每一个字节并格式化为十六进制字符串 
            for (int i = 0; i < data.Length; i++)
            {
                sBuilder.Append(data[i].ToString("x2"));
            }

            // 返回十六进制字符串 
            return sBuilder.ToString();
        }
        #endregion

        #region SHA1加密的字符串
        /// <summary>
        /// SHA1加密的字符串
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public static string GetSHA1(String input)
        {
            SHA1CryptoServiceProvider sha1 = new SHA1CryptoServiceProvider();
            byte[] str1 = Encoding.UTF8.GetBytes(input);
            byte[] str2 = sha1.ComputeHash(str1);
            sha1.Clear();
            (sha1 as IDisposable).Dispose();
            return Convert.ToBase64String(str2);
        }
        #endregion

        #region DES加密
        /// <summary>
        /// DES加密
        /// </summary>
        /// <param name="data">加密数据</param>
        /// <param name="key">8位字符的密钥字符串</param>
        /// <param name="iv">8位字符的初始化向量字符串</param>
        /// <returns></returns>
        public static string DESEncrypt(string data, string key = "thuman..", string iv = "thuman..")
        {
            byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(key);
            byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(iv);

            DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
            int i = cryptoProvider.KeySize;
            MemoryStream ms = new MemoryStream();
            CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateEncryptor(byKey, byIV), CryptoStreamMode.Write);

            StreamWriter sw = new StreamWriter(cst);
            sw.Write(data);
            sw.Flush();
            cst.FlushFinalBlock();
            sw.Flush();
            return Convert.ToBase64String(ms.GetBuffer(), 0, (int)ms.Length);
        }
        #endregion

        #region DES解密
        /// <summary>
        /// DES解密
        /// </summary>
        /// <param name="data">解密数据</param>
        /// <param name="key">8位字符的密钥字符串(需要和加密时相同)</param>
        /// <param name="iv">8位字符的初始化向量字符串(需要和加密时相同)</param>
        /// <returns></returns>
        public static string DESDecrypt(string data, string key = "thuman..", string iv = "thuman..")
        {
            byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(key);
            byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(iv);

            byte[] byEnc;
            try
            {
                byEnc = Convert.FromBase64String(data);
            }
            catch
            {
                return null;
            }

            DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
            MemoryStream ms = new MemoryStream(byEnc);
            CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateDecryptor(byKey, byIV), CryptoStreamMode.Read);
            StreamReader sr = new StreamReader(cst);
            return sr.ReadToEnd();
        }
        #endregion

    }
}