using log4net;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace DSWeb.Common.Helper
{
    public static class MD5Helper
    {
        static ILog log = LogManager.GetLogger(typeof(MD5Helper));
        public static string GetMD5HashFromBytes(byte[] arr)
        {
            try
            {
                MD5 md5 = new MD5CryptoServiceProvider();
                byte[] retVal = md5.ComputeHash(arr);
                StringBuilder sb = new StringBuilder();
                for (int i = 0; i < retVal.Length; i++)
                {
                    sb.Append(retVal[i].ToString("x2"));
                }
                return sb.ToString();
            }
            catch (Exception ex)
            {
                log.Error("计算文件MD5错误");
                log.Error(ex.Message);
                log.Error(ex.StackTrace);
                throw new Exception("GetMD5HashFromFile() fail,error:" + ex.Message);
            }
        }

        public static string GetMD5HashFromFile(string fileName)
        {
            try
            {
                FileStream file = new FileStream(fileName, System.IO.FileMode.Open);
                MD5 md5 = new MD5CryptoServiceProvider();
                byte[] retVal = md5.ComputeHash(file);
                file.Close();
                StringBuilder sb = new StringBuilder();
                for (int i = 0; i < retVal.Length; i++)
                {
                    sb.Append(retVal[i].ToString("x2"));
                }
                return sb.ToString();
            }
            catch (Exception ex)
            {
                throw new Exception("GetMD5HashFromFile() fail,error:" + ex.Message);
            }
        }
    }
}