// Copyright (c) 2009 Sun Microsystems, Inc.
//
// MySQL Connector/NET is licensed under the terms of the GPLv2
// <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most 
// MySQL Connectors. There are special exceptions to the terms and 
// conditions of the GPLv2 as it is applied to this software, see the 
// FLOSS License Exception
// <http://www.mysql.com/about/legal/licensing/foss-exception.html>.
//
// This program is free software; you can redistribute it and/or modify 
// it under the terms of the GNU General Public License as published 
// by the Free Software Foundation; version 2 of the License.
//
// This program is distributed in the hope that it will be useful, but 
// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 
// for more details.
//
// You should have received a copy of the GNU General Public License along 
// with this program; if not, write to the Free Software Foundation, Inc., 
// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA

using System;
using System.Text;
using MySql.Data.Types;
using System.Diagnostics;
using System.Collections.Generic;
using MySql.Data.MySqlClient.Properties;
using System.Threading;
using MySql.Data.Common;

namespace MySql.Data.MySqlClient
{
    internal class TracingDriver : Driver
    {
        private static long driverCounter;
        private long driverId;
        private ResultSet activeResult;
        private int rowSizeInBytes;

        public TracingDriver(MySqlConnectionStringBuilder settings)
            : base(settings)
        {
            driverId = Interlocked.Increment(ref driverCounter);
        }

        public override void Open()
        {
            base.Open();
            MySqlTrace.TraceEvent(TraceEventType.Information, MySqlTraceEventType.ConnectionOpened, 
                Resources.TraceOpenConnection, driverId, Settings.ConnectionString, ThreadID);
        }

        public override void Close()
        {
            base.Close();
            MySqlTrace.TraceEvent(TraceEventType.Information, MySqlTraceEventType.ConnectionClosed, 
                Resources.TraceCloseConnection, driverId);
        }

        public override void SendQuery(MySqlPacket p)
        {
            rowSizeInBytes = 0;
            string cmdText = Encoding.GetString(p.Buffer, 5, p.Length - 5);
            string normalized_query = null;

            if (cmdText.Length > 300)
            {
                QueryNormalizer normalizer = new QueryNormalizer();
                normalized_query = normalizer.Normalize(cmdText);
                cmdText = cmdText.Substring(0, 300);
            }

            base.SendQuery(p);

            MySqlTrace.TraceEvent(TraceEventType.Information, MySqlTraceEventType.QueryOpened, 
                Resources.TraceQueryOpened, driverId, ThreadID, cmdText);
            if (normalized_query != null)
                MySqlTrace.TraceEvent(TraceEventType.Information, MySqlTraceEventType.QueryNormalized,
                    Resources.TraceQueryNormalized, driverId, ThreadID, normalized_query);
        }

        protected override int GetResult(int statementId, ref int affectedRows, ref int insertedId)
        {
            try
            {
                int fieldCount = base.GetResult(statementId, ref affectedRows, ref insertedId);
                MySqlTrace.TraceEvent(TraceEventType.Information, MySqlTraceEventType.ResultOpened, 
                    Resources.TraceResult, driverId, fieldCount, affectedRows, insertedId);

                return fieldCount;
            }
            catch (MySqlException ex)
            {
                // we got an error so we report it
                MySqlTrace.TraceEvent(TraceEventType.Information, MySqlTraceEventType.Error, 
                    Resources.TraceOpenResultError, driverId, ex.Number, ex.Message);
                throw ex;
            }
        }

        public override ResultSet NextResult(int statementId, bool force)
        {
            // first let's see if we already have a resultset on this statementId
            if (activeResult != null)
            {
                //oldRS = activeResults[statementId];
                if (Settings.UseUsageAdvisor)
                    ReportUsageAdvisorWarnings(statementId, activeResult);
                MySqlTrace.TraceEvent(TraceEventType.Information, MySqlTraceEventType.ResultClosed, 
                    Resources.TraceResultClosed, driverId, activeResult.TotalRows, activeResult.SkippedRows, 
                    rowSizeInBytes);
                rowSizeInBytes = 0;
                activeResult = null;
            }

            activeResult = base.NextResult(statementId, force);
            return activeResult;
        }

        public override int PrepareStatement(string sql, ref MySqlField[] parameters)
        {
            int statementId = base.PrepareStatement(sql, ref parameters);
            MySqlTrace.TraceEvent(TraceEventType.Information, MySqlTraceEventType.StatementPrepared,
                Resources.TraceStatementPrepared, driverId, sql, statementId);
            return statementId;
        }

        public override void CloseStatement(int id)
        {
            base.CloseStatement(id);
            MySqlTrace.TraceEvent(TraceEventType.Information, MySqlTraceEventType.StatementClosed,
                Resources.TraceStatementClosed, driverId, id);
        }

        public override void SetDatabase(string dbName)
        {
            base.SetDatabase(dbName);
            MySqlTrace.TraceEvent(TraceEventType.Information, MySqlTraceEventType.NonQuery, 
                Resources.TraceSetDatabase, driverId, dbName);
        }

        public override void ExecuteStatement(MySqlPacket packetToExecute)
        {
            base.ExecuteStatement(packetToExecute);
            int pos = packetToExecute.Position;
            packetToExecute.Position = 1;
            int statementId = packetToExecute.ReadInteger(4);
            packetToExecute.Position = pos;

            MySqlTrace.TraceEvent(TraceEventType.Information, MySqlTraceEventType.StatementExecuted,
                Resources.TraceStatementExecuted, driverId, statementId, ThreadID);
        }

        public override bool FetchDataRow(int statementId, int columns)
        {
            try
            {
                bool b = base.FetchDataRow(statementId, columns);
                if (b)
                    rowSizeInBytes += (handler as NativeDriver).Packet.Length;
                return b;
            }
            catch (MySqlException ex)
            {
                MySqlTrace.TraceEvent(TraceEventType.Error, MySqlTraceEventType.Error, 
                    Resources.TraceFetchError, driverId, ex.Number, ex.Message);
                throw ex;
            }
        }

        public override void CloseQuery(MySqlConnection connection, int statementId)
        {
            base.CloseQuery(connection, statementId);

            MySqlTrace.TraceEvent(TraceEventType.Information, MySqlTraceEventType.QueryClosed, 
                Resources.TraceQueryDone, driverId);
        }

        public override List<MySqlError> ReportWarnings(MySqlConnection connection)
        {
            List<MySqlError> warnings = base.ReportWarnings(connection);
            foreach (MySqlError warning in warnings)
                MySqlTrace.TraceEvent(TraceEventType.Warning, MySqlTraceEventType.Warning, 
                    Resources.TraceWarning, driverId, warning.Level, warning.Code, warning.Message);
            return warnings;
        }

        private bool AllFieldsAccessed(ResultSet rs)
        {
            if (rs.Fields == null || rs.Fields.Length == 0) return true;

            for (int i = 0; i < rs.Fields.Length; i++)
                if (!rs.FieldRead(i)) return false;
            return true;
        }

        private void ReportUsageAdvisorWarnings(int statementId, ResultSet rs)
        {
            if (!Settings.UseUsageAdvisor) return;

            if (HasStatus(ServerStatusFlags.NoIndex))
                MySqlTrace.TraceEvent(TraceEventType.Warning, MySqlTraceEventType.UsageAdvisorWarning, 
                    Resources.TraceUAWarningNoIndex, driverId, UsageAdvisorWarningFlags.NoIndex);
            else if (HasStatus(ServerStatusFlags.BadIndex))
                MySqlTrace.TraceEvent(TraceEventType.Warning, MySqlTraceEventType.UsageAdvisorWarning, 
                    Resources.TraceUAWarningBadIndex, driverId, UsageAdvisorWarningFlags.BadIndex);

            // report abandoned rows
            if (rs.SkippedRows > 0)
                MySqlTrace.TraceEvent(TraceEventType.Warning, MySqlTraceEventType.UsageAdvisorWarning, 
                    Resources.TraceUAWarningSkippedRows, driverId, UsageAdvisorWarningFlags.SkippedRows, rs.SkippedRows);

            // report not all fields accessed
            if (!AllFieldsAccessed(rs))
            {
                StringBuilder notAccessed = new StringBuilder("");
                string delimiter = "";
                for (int i = 0; i < rs.Size; i++)
                    if (!rs.FieldRead(i))
                    {
                        notAccessed.AppendFormat("{0}{1}", delimiter, rs.Fields[i].ColumnName);
                        delimiter = ",";
                    }
                MySqlTrace.TraceEvent(TraceEventType.Warning, MySqlTraceEventType.UsageAdvisorWarning, 
                    Resources.TraceUAWarningSkippedColumns, driverId, UsageAdvisorWarningFlags.SkippedColumns, 
                        notAccessed.ToString());
            }

            // report type conversions if any
            if (rs.Fields != null)
            {
                foreach (MySqlField f in rs.Fields)
                {
                    StringBuilder s = new StringBuilder();
                    string delimiter = "";
                    foreach (Type t in f.TypeConversions)
                    {
                        s.AppendFormat("{0}{1}", delimiter, t.Name);
                        delimiter = ",";
                    }
                    if (s.Length > 0)
                        MySqlTrace.TraceEvent(TraceEventType.Warning, MySqlTraceEventType.UsageAdvisorWarning, 
                            Resources.TraceUAWarningFieldConversion, driverId, UsageAdvisorWarningFlags.FieldConversion,
                            f.ColumnName, s.ToString());
                }
            }
        }
    }
}