// Copyright © 2004, 2011, Oracle and/or its affiliates. All rights reserved.
//
// 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.Collections;
using System.Globalization;
using System.Text;
using MySql.Data.Common;
using MySql.Data.Types;
using MySql.Data.MySqlClient.Properties;
using System.Diagnostics;
using System.Collections.Generic;
using System.Security;

namespace MySql.Data.MySqlClient
{
    /// <summary>
    /// Summary description for BaseDriver.
    /// </summary>
    internal class Driver : IDisposable
    {
        protected Encoding encoding;
        protected MySqlConnectionStringBuilder connectionString;
        protected bool isOpen;
        protected DateTime creationTime;
        protected string serverCharSet;
        protected int serverCharSetIndex;
        protected Hashtable serverProps;
        protected Hashtable charSets;
        protected long maxPacketSize;
        private DateTime idleSince;

#if !CF
        protected MySqlPromotableTransaction currentTransaction;
        protected bool inActiveUse;
#endif
        protected MySqlPool pool;
        private bool firstResult;
        protected IDriver handler;
        internal MySqlDataReader reader;
        private bool disposeInProgress;

        /// <summary>
        /// For pooled connections, time when the driver was
        /// put into idle queue
        /// </summary>
        public DateTime IdleSince
        {
            get
            {
                return idleSince;
            }
            set
            {
                idleSince = value;
            }
        }

        public Driver(MySqlConnectionStringBuilder settings)
        {
            encoding = Encoding.GetEncoding(1252);
            if (encoding == null)
                throw new MySqlException(Resources.DefaultEncodingNotFound);
            connectionString = settings;
            serverCharSet = "latin1";
            serverCharSetIndex = -1;
            maxPacketSize = 1024;
            handler = new NativeDriver(this);
        }

        ~Driver()
        {
            Dispose(false);
        }

        #region Properties

        public int ThreadID
        {
            get
            {
                return handler.ThreadId;
            }
        }

        public DBVersion Version
        {
            get
            {
                return handler.Version;
            }
        }

        public MySqlConnectionStringBuilder Settings
        {
            get
            {
                return connectionString;
            }
            set
            {
                connectionString = value;
            }
        }

        public Encoding Encoding
        {
            get
            {
                return encoding;
            }
            set
            {
                encoding = value;
            }
        }

#if !CF
        public MySqlPromotableTransaction CurrentTransaction
        {
            get
            {
                return currentTransaction;
            }
            set
            {
                currentTransaction = value;
            }
        }

        public bool IsInActiveUse
        {
            get
            {
                return inActiveUse;
            }
            set
            {
                inActiveUse = value;
            }
        }
#endif
        public bool IsOpen
        {
            get
            {
                return isOpen;
            }
        }

        public MySqlPool Pool
        {
            get
            {
                return pool;
            }
            set
            {
                pool = value;
            }
        }

        public long MaxPacketSize
        {
            get
            {
                return maxPacketSize;
            }
        }

        internal int ConnectionCharSetIndex
        {
            get
            {
                return serverCharSetIndex;
            }
            set
            {
                serverCharSetIndex = value;
            }
        }

        internal Hashtable CharacterSets
        {
            get
            {
                return charSets;
            }
        }

        public bool SupportsOutputParameters
        {
            get
            {
                return Version.isAtLeast(5, 5, 0);
            }
        }

        public bool SupportsBatch
        {
            get
            {
                return (handler.Flags & ClientFlags.MULTI_STATEMENTS) != 0;
            }
        }

        #endregion

        public string Property(string key)
        {
            return (string)serverProps[key];
        }

        public bool ConnectionLifetimeExpired()
        {
            TimeSpan ts = DateTime.Now.Subtract(creationTime);
            if (Settings.ConnectionLifeTime != 0 &&
              ts.TotalSeconds > Settings.ConnectionLifeTime)
                return true;
            return false;
        }

        public static Driver Create(MySqlConnectionStringBuilder settings)
        {
            Driver d = null;
#if !CF
            try
            {
                if (MySqlTrace.QueryAnalysisEnabled || settings.Logging || settings.UseUsageAdvisor)
                    d = new TracingDriver(settings);
            }
            catch (TypeInitializationException ex)
            {
                if (!(ex.InnerException is SecurityException))
                    throw ex;
                //Only rethrow if InnerException is not a SecurityException. If it is a SecurityException then 
                //we couldn't initialize MySqlTrace because we don't have unmanaged code permissions. 
            }
#endif
            if (d == null)
                d = new Driver(settings);

            d.Open();
            return d;
        }

        public bool HasStatus(ServerStatusFlags flag)
        {
            return (handler.ServerStatus & flag) != 0;
        }

        public virtual void Open()
        {
            creationTime = DateTime.Now;
            handler.Open();
            isOpen = true;
        }

        public virtual void Close()
        {
            Dispose();
        }

        public virtual void Configure(MySqlConnection connection)
        {
            bool firstConfigure = false;

            // if we have not already configured our server variables
            // then do so now
            if (serverProps == null)
            {
                firstConfigure = true;

                // if we are in a pool and the user has said it's ok to cache the
                // properties, then grab it from the pool
                if (Pool != null && Settings.CacheServerProperties)
                {
                    if (Pool.ServerProperties == null)
                    {
                        lock (Pool.lockServerProperties)
                        {
                            if (Pool.ServerProperties == null)
                            {
                                Pool.ServerProperties = LoadServerProperties(connection);
                                Pool.CharacterSets = LoadCharacterSets(connection);
                            }
                        }
                    }
                    serverProps = Pool.ServerProperties;
                    charSets = Pool.CharacterSets;
                }
                else
                {
                    serverProps = LoadServerProperties(connection);
                    charSets = LoadCharacterSets(connection);
                }
            }
            if (serverProps.Contains("max_allowed_packet"))
                maxPacketSize = Convert.ToInt64(serverProps["max_allowed_packet"]);

            // if the user has indicated that we are not to reset
            // the connection and this is not our first time through,
            // then we are done.
            if (!Settings.ConnectionReset && !firstConfigure)
                return;

            string charSet = connectionString.CharacterSet;
            if (charSet == null || charSet.Length == 0)
            {
                if (serverCharSetIndex >= 0)
                    charSet = (string)charSets[serverCharSetIndex];
                else
                    charSet = serverCharSet;
            }

            // now tell the server which character set we will send queries in and which charset we
            // want results in
            MySqlCommand charSetCmd = new MySqlCommand("SET character_set_results=NULL",
                              connection);
            charSetCmd.InternallyCreated = true;
            object clientCharSet = serverProps["character_set_client"];
            object connCharSet = serverProps["character_set_connection"];
            if ((clientCharSet != null && clientCharSet.ToString() != charSet) ||
              (connCharSet != null && connCharSet.ToString() != charSet))
            {
                MySqlCommand setNamesCmd = new MySqlCommand("SET NAMES " + charSet, connection);
                setNamesCmd.InternallyCreated = true;
                setNamesCmd.ExecuteNonQuery();
            }
            charSetCmd.ExecuteNonQuery();

            if (charSet != null)
                Encoding = CharSetMap.GetEncoding(Version, charSet);
            else
                Encoding = CharSetMap.GetEncoding(Version, "latin1");

            handler.Configure();
        }

        /// <summary>
        /// Loads the properties from the connected server into a hashtable
        /// </summary>
        /// <param name="connection"></param>
        /// <returns></returns>
        private Hashtable LoadServerProperties(MySqlConnection connection)
        {
            // load server properties
            Hashtable hash = new Hashtable();
            MySqlCommand cmd = new MySqlCommand("SHOW VARIABLES", connection);

            using (MySqlDataReader reader = cmd.ExecuteReader())
            {
                try
                {
                    while (reader.Read())
                    {
                        string key = reader.GetString(0);
                        string value = reader.GetString(1);
                        hash[key] = value;
                    }
                }
                catch (Exception ex)
                {
                    MySqlTrace.LogError(ThreadID, ex.Message);
                    throw;
                }
            }

            return hash;
        }

        /// <summary>
        /// Loads all the current character set names and ids for this server 
        /// into the charSets hashtable
        /// </summary>
        private Hashtable LoadCharacterSets(MySqlConnection connection)
        {
            MySqlCommand cmd = new MySqlCommand("SHOW COLLATION", connection);

            // now we load all the currently active collations
            try
            {
                using (MySqlDataReader reader = cmd.ExecuteReader())
                {
                    Hashtable chSets = new Hashtable();
                    while (reader.Read())
                    {
                        chSets[Convert.ToInt32(reader["id"], NumberFormatInfo.InvariantInfo)] =
                          reader.GetString(reader.GetOrdinal("charset"));
                    }
                    return chSets;
                }
            }
            catch (Exception ex)
            {
                MySqlTrace.LogError(ThreadID, ex.Message);
                throw;
            }
        }

        public virtual List<MySqlError> ReportWarnings(MySqlConnection connection)
        {
            List<MySqlError> warnings = new List<MySqlError>();

            MySqlCommand cmd = new MySqlCommand("SHOW WARNINGS", connection);
            cmd.InternallyCreated = true;
            using (MySqlDataReader reader = cmd.ExecuteReader())
            {
                while (reader.Read())
                {
                    warnings.Add(new MySqlError(reader.GetString(0),
                                  reader.GetInt32(1), reader.GetString(2)));
                }
            }

            MySqlInfoMessageEventArgs args = new MySqlInfoMessageEventArgs();
            args.errors = warnings.ToArray();
            if (connection != null)
                connection.OnInfoMessage(args);
            return warnings;
        }

        public virtual void SendQuery(MySqlPacket p)
        {
            handler.SendQuery(p);
            firstResult = true;
        }

        public virtual ResultSet NextResult(int statementId, bool force)
        {
            if (!force && !firstResult && !HasStatus(ServerStatusFlags.AnotherQuery | ServerStatusFlags.MoreResults))
                return null;
            firstResult = false;

            int affectedRows = -1, insertedId = -1, warnings = 0;
            int fieldCount = GetResult(statementId, ref affectedRows, ref insertedId);
            if (fieldCount == -1)
                return null;
            if (fieldCount > 0)
                return new ResultSet(this, statementId, fieldCount);
            else
                return new ResultSet(affectedRows, insertedId);
        }

        protected virtual int GetResult(int statementId, ref int affectedRows, ref int insertedId)
        {
            return handler.GetResult(ref affectedRows, ref insertedId);
        }

        public virtual bool FetchDataRow(int statementId, int columns)
        {
            return handler.FetchDataRow(statementId, columns);
        }

        public virtual bool SkipDataRow()
        {
            return FetchDataRow(-1, 0);
        }

        public virtual void ExecuteDirect(string sql)
        {
            MySqlPacket p = new MySqlPacket(Encoding);
            p.WriteString(sql);
            SendQuery(p);
            NextResult(0, false);
        }

        public MySqlField[] GetColumns(int count)
        {
            MySqlField[] fields = new MySqlField[count];
            for (int i = 0; i < count; i++)
                fields[i] = new MySqlField(this);
            handler.GetColumnsData(fields);

            return fields;
        }

        public virtual int PrepareStatement(string sql, ref MySqlField[] parameters)
        {
            return handler.PrepareStatement(sql, ref parameters);
        }

        public IMySqlValue ReadColumnValue(int index, MySqlField field, IMySqlValue value)
        {
            return handler.ReadColumnValue(index, field, value);
        }

        public void SkipColumnValue(IMySqlValue valObject)
        {
            handler.SkipColumnValue(valObject);
        }

        public void ResetTimeout(int timeoutMilliseconds)
        {
            handler.ResetTimeout(timeoutMilliseconds);
        }

        public bool Ping()
        {
            return handler.Ping();
        }

        public virtual void SetDatabase(string dbName)
        {
            handler.SetDatabase(dbName);
        }

        public virtual void ExecuteStatement(MySqlPacket packetToExecute)
        {
            handler.ExecuteStatement(packetToExecute);
        }


        public virtual void CloseStatement(int id)
        {
            handler.CloseStatement(id);
        }

        public virtual void Reset()
        {
            handler.Reset();
        }

        public virtual void CloseQuery(MySqlConnection connection, int statementId)
        {
            if (handler.WarningCount > 0)
                ReportWarnings(connection);
        }

        #region IDisposable Members

        protected virtual void Dispose(bool disposing)
        {
            // Avoid cyclic calls to Dispose.
            if (disposeInProgress)
                return;

            disposeInProgress = true;

            try
            {
                ResetTimeout(1000);
                if (disposing)
                    handler.Close(isOpen);
                // if we are pooling, then release ourselves
                if (connectionString.Pooling)
                    MySqlPoolManager.RemoveConnection(this);
            }
            catch (Exception)
            {
                if (disposing)
                    throw;
            }
            finally
            {
                reader = null;
                isOpen = false;
                disposeInProgress = false;
            }
        }

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        #endregion
    }

    internal interface IDriver
    {
        int ThreadId
        {
            get;
        }
        DBVersion Version
        {
            get;
        }
        ServerStatusFlags ServerStatus
        {
            get;
        }
        ClientFlags Flags
        {
            get;
        }
        void Configure();
        void Open();
        void SendQuery(MySqlPacket packet);
        void Close(bool isOpen);
        bool Ping();
        int GetResult(ref int affectedRows, ref int insertedId);
        bool FetchDataRow(int statementId, int columns);
        int PrepareStatement(string sql, ref MySqlField[] parameters);
        void ExecuteStatement(MySqlPacket packet);
        void CloseStatement(int statementId);
        void SetDatabase(string dbName);
        void Reset();
        IMySqlValue ReadColumnValue(int index, MySqlField field, IMySqlValue valObject);
        void SkipColumnValue(IMySqlValue valueObject);
        void GetColumnsData(MySqlField[] columns);
        void ResetTimeout(int timeout);
        int WarningCount
        {
            get;
        }
    }
}