using System;

namespace Kreta.Framework.Logging
{
    /// <summary>
    /// Adatbázis naplóvezető osztály.
    /// </summary>
    public sealed class DatabaseLogWriter : LogWriterBase
    {
        private string m_ConnectionString;
        private string m_ServerName;

        private const string insertCommandText = @"
INSERT INTO T_LOG (C_TIMESTAMP, C_SERVER, C_EVENTTYPEID, C_LEVELID, C_SESSIONID, C_DETAILS, C_GENERATEDID, SERIAL) 
VALUES (GETDATE(), :pSERVER, :pEVENTTYPE, :pLEVEL, :pSESSIONID, :pDETAILS, :pGENERATEDID, 0)";

        private const string insertCommandTextWithIntezmeny = @"
INSERT INTO T_LOG (C_TIMESTAMP, C_SERVER, C_EVENTTYPEID, C_LEVELID, C_SESSIONID, C_DETAILS, C_GENERATEDID, C_INTEZMENYID, C_TANEVID, SERIAL) 
VALUES (GETDATE(), :pSERVER, :pEVENTTYPE, :pLEVEL, :pSESSIONID, :pDETAILS, :pGENERATEDID, :pINTEZMENYID, :pTANEVID, 0)";

        /// <summary>
        /// Az osztály konstruktora.
        /// </summary>
        /// <param name="connectionString">Az adatbázis kapcsolatot leíró karakterlánc</param>
        /// <param name="serverName">A naplózót használó kiszolgáló neve</param>
        public DatabaseLogWriter(string connectionString, string serverName)
        {
            if (string.IsNullOrWhiteSpace(connectionString))
            {
                throw new ArgumentNullException(nameof(connectionString));
            }

            if (string.IsNullOrWhiteSpace(serverName))
            {
                throw new ArgumentNullException(nameof(serverName));
            }

            m_ConnectionString = connectionString;
            m_ServerName = serverName;
        }

        private string ConnectionString
        {
            get
            {
                return m_ConnectionString;
            }
        }

        /// <summary>
        /// Naplóba vezeti az üzenetet.
        /// </summary>
        /// <param name="message">A naplóba vezetendő üzenet</param>
        protected override Guid? DoLog(ILogMessage message)
        {
            var logId = Guid.NewGuid();
            DbLog(message, logId);
            return logId;
        }

        protected override void DoLog(ILogMessage message, Guid logId)
        {
            DbLog(message, logId);
        }

        private bool ActivateContext()
        {
            if (UserContext.Instance == null || !UserContext.Instance.Activated)
            {
                SDAServer.Instance.SessionManager.ActivateSystemSession();
                return true;
            }
            return false;
        }

        private void DbLog(ILogMessage message, Guid logId)
        {
            if (message.Level < LogLevel.INFO)
            {
                // DEBUG-ot nem tolunk le adatbázisba!
                return;
            }

            var sessionActivated = ActivateContext();
            try
            {
                int? intezmenyId = null;
                int? tanevId = null;
                var commandText = insertCommandText;
                if (UserContext.Instance != null && UserContext.Instance.IntezmenyId > 0)
                {
                    commandText = insertCommandTextWithIntezmeny;
                    intezmenyId = UserContext.Instance.IntezmenyId;
                    if (UserContext.Instance.AktivTanevId > 0)
                    {
                        tanevId = UserContext.Instance.AktivTanevId;
                    }
                }

                using (SDA.DataProvider.SDAConnection connection = new SDA.DataProvider.SDAConnection(ConnectionString))
                {
                    using (SDA.DataProvider.SDACommand command = connection.CreateCommand())
                    {
                        command.CommandText = commandText;
                        if (intezmenyId.HasValue)
                        {
                            command.Parameters.Add("pINTEZMENYID", intezmenyId.Value);
                            if (tanevId.HasValue)
                            {
                                command.Parameters.Add("pTANEVID", tanevId.Value);
                            }
                            else
                            {
                                command.Parameters.Add("pTANEVID", DBNull.Value);
                            }
                        }

                        command.Parameters.Add("pSERVER", SDA.DataProvider.SDADBType.String, 36).Value = m_ServerName;
                        command.Parameters.Add("pEVENTTYPE", SDA.DataProvider.SDADBType.Int, 9).Value = message.EventType;
                        command.Parameters.Add("pLEVEL", SDA.DataProvider.SDADBType.Int, 9).Value = message.Level;
                        command.Parameters.Add("pGENERATEDID", logId);
                        command.Parameters.Add("pSESSIONID", SDA.DataProvider.SDADBType.String, 36).Value = message.SessionId == null ? DBNull.Value : (object)message.SessionId;

                        string details = LogUtil.FormatMessageDetails(message, "\r\n");
                        if (string.IsNullOrWhiteSpace(details))
                        {
                            command.Parameters.Add("pDETAILS", SDA.DataProvider.SDADBType.LongString).Value = DBNull.Value;
                        }
                        else
                        {
                            command.Parameters.Add("pDETAILS", SDA.DataProvider.SDADBType.LongString).Value = details;
                        }

                        connection.Open();
                        command.ExecuteNonQuery();
                    }
                }
            }
            catch (SDA.DataProvider.SDADataProviderException exception)
            {
                if (exception.Error == SDA.DataProvider.SDADataProviderError.CommunicationError)
                {
                    return;
                }

                if (exception.Error == SDA.DataProvider.SDADataProviderError.UniqueKeyViolation)
                {
                    // ezt a kivételt nyugodtan lenyelhetjük
                    return;
                }

                throw;
            }
            finally
            {
                if (sessionActivated)
                {
                    if (UserContext.Instance != null && UserContext.Instance.Activated)
                    {
                        SDAServer.Instance.SessionManager.DeactivateSystemSession();
                    }
                }
            }
        }
    }
}