using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Core
{
    /// <summary>
    /// Gestione licenze applicativi GLS (Legacy SteamWare)
    /// </summary>
    public class licenseManGLS
    {
        #region Public Methods

        /// <summary>
        /// restituisce data decodificata da authKey + applicazione + cliente...
        /// </summary>
        /// <param name="cliente">The cliente.</param>
        /// <param name="applicativo">The applicativo.</param>
        /// <param name="licenze">The licenze.</param>
        /// <param name="authKey">The authentication key.</param>
        /// <returns></returns>
        public static DateTime expiryDateByAuthKey(string cliente, string applicativo, int licenze, string authKey)
        {
            DateTime answ = DateTime.Today.AddYears(-10);

            string plainAuthKey = "";
            try
            {
                string passPhrase = string.Format("{0}|{1}", cliente.PadLeft(50, ':'), applicativo);
                plainAuthKey = SteamCrypto.DecryptString(authKey, passPhrase); // uso combinazione cliente+applicativo come passphrase!
                answ = Convert.ToDateTime(plainAuthKey.Replace(string.Format("{0}#{1}-", cliente, applicativo.PadLeft(20, '-')), "").Replace(string.Format("%{0}%", licenze), ""));
            }
            catch 
            { }
            return answ;
        }

        /// <summary>
        /// Fornisce chiave MD5 x un cliente/applicativo/expiryDate
        /// </summary>
        /// <param name="cliente"></param>
        /// <param name="applicativo"></param>
        /// <param name="licenze"></param>
        /// <param name="expiryDate"></param>
        /// <returns></returns>
        public static string getAuthKey(string cliente, string applicativo, int licenze, DateTime expiryDate)
        {
            string answ = "";
            // algoritmo MD5 formato cliente#applicativo#expDate, via SQLdiventa
            // SELECT CONVERT(VARCHAR(32), HashBytes('MD5', 'ETS#GPW#2013/12/31'), 2)
            string plainAuthKey = string.Format("{0}#{1}-{2}%{3}%", cliente, applicativo.PadLeft(20, '-'), expiryDate.ToString("yyyy/MM/dd"), licenze);
            string passPhrase = string.Format("{0}|{1}", cliente.PadLeft(50, ':'), applicativo);
            answ = SteamCrypto.EncryptString(plainAuthKey, passPhrase); // uso combinazione cliente+applicativo come passphrase!
            return answ;
        }

        /// <summary>
        /// Fornisce chiave MD5 x una chiave secondaria/di checksum data dai parametri in ingresso
        /// MasterKey/string[] chiavi singole child/expiryDate
        /// </summary>
        /// <param name="MasterKey">Chiave master da cui si parte</param>
        /// <param name="Payload">Payload che contiene le chiavi SUB (child) riferite alla master in formato JSon (compresso/no indent)</param>
        /// <returns></returns>
        public static string getChecksumKey(string MasterKey, string Payload)
        {
            string answ = "";
            answ = SteamCrypto.EncryptString(Payload, MasterKey);
            return answ;
        }

        /// <summary>
        /// numero di licenze attive per cliente/applicativo
        /// </summary>
        /// <param name="cliente"></param>
        /// <param name="applicativo"></param>
        /// <returns></returns>
        public static int getLicenseNum(string cliente, string applicativo)
        {
            // !!!FARE!!! chiamata a webservice 1/mese
            int answ = 1;
            // molto hard-coded e discutibile... licenze "perenni"
            switch (cliente)
            {
                default:
                    answ = 1;
                    break;
            }

            return answ;
        }

        #endregion Public Methods
    }
}