using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Runtime.Serialization.Json;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System.Web.Services.Protocols;
using System.Security.Cryptography;
using System.Text;
using System.Web.SessionState;
using System.Data;
using System.Drawing.Imaging;
using System.Drawing;
using System.IO;
using System.Data.SqlClient;
using System.Configuration;
using Org.BouncyCastle.Asn1.X509;

public static class globalClass
{
    public static string YearMonthDiff(DateTime self, DateTime target) {
        int years, months, days;
        // 因為只需取量，不決定誰大誰小，所以如果self < target時要交換將大的擺前面
        if (self < target)
        {
            DateTime tmp = target;
            target = self;
            self = tmp;
        }

        // 將年轉換成月份以便用來計算
        months = 12 * (self.Year - target.Year) + (self.Month - target.Month);

        // 如果天數要相減的量不夠時要向月份借天數補滿該月再來相減
        if (self.Day < target.Day)
        {
            months--;
            days = DateTime.DaysInMonth(target.Year, target.Month) - target.Day + self.Day;
        }
        else
        {
            days = self.Day - target.Day;
        }

        // 天數計算完成後將月份轉成年
        years = months / 12;
        months = months % 12;

        return years.ToString() + "歲" + months.ToString() + "月";
    }

    public static int MonthDiff(DateTime self, DateTime target)
    {
        int years, months, days;
        // 因為只需取量，不決定誰大誰小，所以如果self < target時要交換將大的擺前面
        if (self < target)
        {
            DateTime tmp = target;
            target = self;
            self = tmp;
        }

        // 將年轉換成月份以便用來計算
        months = 12 * (self.Year - target.Year) + (self.Month - target.Month);

        // 如果天數要相減的量不夠時要向月份借天數補滿該月再來相減
        if (self.Day < target.Day)
        {
            months--;
            days = DateTime.DaysInMonth(target.Year, target.Month) - target.Day + self.Day;
        }
        else
        {
            days = self.Day - target.Day;
        }

        return months;
    }

    public static string GetIPAddress()
    {
        System.Web.HttpContext context = System.Web.HttpContext.Current;
        string sIPAddress = context.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
        if (string.IsNullOrEmpty(sIPAddress))
        {
            return context.Request.ServerVariables["REMOTE_ADDR"];
        }
        else
        {
            string[] ipArray = sIPAddress.Split(new Char[] { ',' });
            return ipArray[0];
        }
    }
    public static string CreateRandomCode(int Number)
    {
        string allChar = "0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z";
        string[] allCharArray = allChar.Split(',');
        string randomCode = "";

        Random rand = new Random(Guid.NewGuid().GetHashCode());
        for (int i = 0; i <= Number - 1; i++)
        {
            int t = rand.Next(allCharArray.Length);
            randomCode += allCharArray[t];
        }
        return randomCode;
    }

    public static string appsettings(string key)
    {

        return ConfigurationManager.ConnectionStrings[key].ConnectionString;
    }

    public static string SHA256_Encode(string value)
    {
        byte[] bytValue = System.Text.Encoding.UTF8.GetBytes(value);
        try
        {
            SHA256 sha256 = new SHA256CryptoServiceProvider();
            byte[] retVal = sha256.ComputeHash(bytValue);
            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("GetSHA256HashFromString() fail,error:" + ex.Message);
        }

    }

}