using System;
using System.Collections.Generic;
using System.Text;
using System.Data.SqlClient;
using System.Threading;
using De.Lambertz.Essentials;
using System.Data;
using System.Windows.Forms;
using System.Management;
using Microsoft.Data.SqlClient;

namespace De.Lambertz.ODAL
{
    public class IDFactory : ISingelton
    {
        private static IDFactory me = null;
        public const String KEY_ANWENDER = "ANWENDER";
        public const String KEY_BEREICH = "BEREICH";
        public const String KEY_FACHBEREICH = "FBEREICH";
        public const String KEY_BESTELLGRUND = "BESTELLGRUND";
        public const String KEY_BESTELLUNG = "BESTELLUNG";
        public const String KEY_LIEFERADRESSE = "LIEFERADRESSE";
        public const String KEY_LIEFERART = "LIEFERART";
        public const String KEY_MENGENEINHEIT = "MENGENEINHEIT";
        public const String KEY_PARAMETER = "PARAMETER";
        public const String KEY_PREISLISTE = "PREISLISTE";
        public const String KEY_TEXTBAUSTEIN = "TEXTBAUSTEINE";
        public const String KEY_WAEM = "WAEM";
        public const String KEY_KONTO = "KONTO";
        public const String KEY_KORREKTUR_BUCHUNG = "KORBU";
        public const String KEY_ANSPRECHPARTNER = "ANSPRECHPARTNER";
        public const String KEY_TERMINSERIEN = "TERMINSERIEN";
        public const String KEY_LIEFERANTENZUORNDUNG = "LIEFERANTENZUORNDUNG";
        private string secureKeyPart = null;
        static readonly object padlock0 = new object(); //Threadsafe!!
        static readonly object padlock1 = new object(); //Threadsafe!!

        private IDFactory()
        {

        }

        public static IDFactory GetInstance()
        {
            lock (padlock0)
            {
                if (me == null)
                {
                    me = new IDFactory();
                    SingeltonManager.GetInstance().RegisterSingelton(me);
                }
                return me;
            }
        }

        private string getSecuryKeyPart()
        {
            if (secureKeyPart == null)
            {
                try
                {
                    ManagementClass oMClass = new ManagementClass("Win32_Processor");
                    ManagementObjectCollection colMObj = oMClass.GetInstances();
                    foreach (ManagementObject objMO in colMObj)
                    {
                        secureKeyPart = objMO.Properties["ProcessorId"].Value.ToString();
                    }
                }
                catch (Exception)
                {
                    secureKeyPart = DateTime.Now.Ticks.ToString();
                }
                if (secureKeyPart.Length > 40)
                {
                    secureKeyPart = secureKeyPart.Substring(0, 40);
                }
            }
            return secureKeyPart;
        }

        /// <summary>
        /// Holt die Verbindung zum MSSQL Server
        /// </summary>
        /// <returns></returns>
        private SqlConnection getConnection()
        {
            SqlConnection result = null;
            try
            {
                result = new SqlConnection();
                result.ConnectionString = DBTools.ConnectionStringODAL();
                result.Open();
            }
            catch (Exception)
            {
                result = null;
            }
            return result;
        }

        /// <summary>
        /// Schliesst die Verbindung zum MSSQL Server
        /// </summary>
        /// <returns></returns>
        private void returnConnection(SqlConnection con)
        {
            if (con != null && con.State == ConnectionState.Open)
            {
                con.Close();
            }
        }

        public int GetID(string key)
        {
            lock (padlock1)
            {
                int result = 0;
                string secureKey = key.Trim() + getSecuryKeyPart();

                SqlConnection con = getConnection();
                SqlCommand command;
                SqlDataReader reader;
                StringBuilder sql = new StringBuilder();

                bool ok = false;
                while (!ok)
                {
                    sql = new StringBuilder();
                    sql.Append("update ODAL.IDS set [KEY] = ");
                    sql.Append(DBTools.Txt(secureKey));
                    sql.Append(" where [KEY] = ");
                    sql.Append(DBTools.Txt(key));
                    command = new SqlCommand(sql.ToString(), con);
                    command.ExecuteNonQuery();

                    sql = new StringBuilder();
                    sql.Append("select ID ");
                    sql.Append("from ODAL.IDS ");
                    sql.Append("where [KEY] = ");
                    sql.Append(DBTools.Txt(secureKey));
                    command = new SqlCommand(sql.ToString(), con);
                    reader = command.ExecuteReader();
                    if (reader.Read())
                    {
                        ok = true;
                        result = DBTools.DBGetInt(reader, 0);
                    }
                    else
                    {
                        Thread.Sleep(50);
                    }
                    reader.Close();
                }
                result++;
                sql = new StringBuilder();
                sql.Append("update ODAL.IDS set [KEY] = ");
                sql.Append(DBTools.Txt(key));
                sql.Append(", ID = ");
                sql.Append(result.ToString());
                sql.Append(" where [KEY] = ");
                sql.Append(DBTools.Txt(secureKey));
                command = new SqlCommand(sql.ToString(), con);
                command.ExecuteNonQuery();

                returnConnection(con);
                return result;
            }
        }

        public void ManagedKill()
        {
            lock (padlock0)
            {
                me = null;
            }
        }

        public void ManagedReset(string userName)
        {
            lock (padlock0)
            {
                me = new IDFactory();
            }
        }
    }
}