using System;
using System.Text;
using System.Security.Cryptography;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Xml;

public partial class Balance : System.Web.UI.Page
{
    public Random rnd = new Random();
    public string MD5(string instr)
    {
        string strHash = string.Empty;

        foreach (byte b in new MD5CryptoServiceProvider().ComputeHash(Encoding.Default.GetBytes(instr)))
        {
            strHash += b.ToString("X2").ToLower();
        }
        return strHash;
    }
    public string XmlGet(string link, string name)
    {
        XmlTextReader reader = new XmlTextReader(link);
        while (reader.Read())
        {
            if (reader.NodeType == XmlNodeType.Element && name.Equals(reader.LocalName))
            {
                return ((UInt16)reader.ReadElementContentAsInt()).ToString();
            }
        }
        return string.Empty;
    }
    public int UnixTime()
    {
        TimeSpan ts;
        ts = (DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0));
        return (int)ts.TotalSeconds;
    }
    protected void Page_Load(object sender, EventArgs e)
    {
        string apiid = Request.QueryString["api_id"];
        if (apiid == "652647")
        {
            string userid = Request.QueryString["user_id"];
            string viewerid = Request.QueryString["viewer_id"];
            string authkey = Request.QueryString["auth_key"];
            string paykey = "123456";
            string version = "2.0";
            string test = MD5(apiid + "_" + viewerid + "_" + paykey);
            if (test == authkey)
            {
                int time = UnixTime();
                int unique = rnd.Next(50000);
                string sig = MD5("api_id=" + apiid + "method=secure.getBalancerandom=" + unique + "timestamp=" + time + "uid=" + viewerid + "v=" + version + paykey);
                string xml = @"http://api.vkontakte.ru/api.php?api_id=" + apiid + "&method=secure.getBalance&random=" + unique + "&sig=" + sig + "&timestamp=" + time + "&uid=" + viewerid + "&v=" + version;

                    Response.Write("<?xml version='1.0' encoding='utf-8'?><root><balance>" + XmlGet(xml, "balance") + "</balance></root>");
            }
            else
            {
                Response.Write("<?xml version='1.0' encoding='utf-8'?><root><balance>0</balance></root>");
            }
        }
        else
        {
            Response.Write(@"<font color=""red"">Ошибка доступа</font>");
        }
    }
}