#if MYSQL_6_10

// Copyright ?2004, 2018, 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.Data;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace Externals.MySql.Data.MySqlClient
{
    /// <summary>
    /// Helper class that makes it easier to work with the provider.
    /// </summary>
    internal sealed partial class MySqlHelper
    {
        enum CharClass : byte
        {
            None,
            Quote,
            Backslash
        }

        private static string stringOfBackslashChars = "\u005c\u00a5\u0160\u20a9\u2216\ufe68\uff3c";
        private static string stringOfQuoteChars =
            "\u0022\u0027\u0060\u00b4\u02b9\u02ba\u02bb\u02bc\u02c8\u02ca\u02cb\u02d9\u0300\u0301\u2018\u2019\u201a\u2032\u2035\u275b\u275c\uff07";

        private static CharClass[] charClassArray = MakeCharClassArray();

        // this class provides only static methods
        private MySqlHelper()
        {
        }

        #region ExecuteNonQuery

        /// <summary>
        /// Executes a single command against a MySQL database.  The <see cref="MySqlConnection"/> is assumed to be
        /// open when the method is called and remains open after the method completes.
        /// </summary>
        /// <param name="connection">The <see cref="MySqlConnection"/> object to use</param>
        /// <param name="commandText">The SQL command to be executed.</param>
        /// <param name="commandParameters">An array of <see cref="MySqlParameter"/> objects to use with the command.</param>
        /// <returns>The number of affected records.</returns>
        public static int ExecuteNonQuery(MySqlConnection connection, string commandText, params MySqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            MySqlCommand cmd = new MySqlCommand();
            cmd.Connection = connection;
            cmd.CommandText = commandText;
            cmd.CommandType = CommandType.Text;

            if (commandParameters != null)
                foreach (MySqlParameter p in commandParameters)
                    cmd.Parameters.Add(p);

            int result = cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();

            return result;
        }

        /// <summary>
        /// Executes a single command against a MySQL database.
        /// </summary>
        /// <param name="connectionString"><see cref="MySqlConnection.ConnectionString"/> to use.</param>
        /// <param name="commandText">The SQL command to be executed.</param>
        /// <param name="parms">An rray of <see cref="MySqlParameter"/> objects to use with the command.</param>
        /// <returns>The number of affected records.</returns>
        /// <remarks>A new <see cref="MySqlConnection"/> is created using the <see cref="MySqlConnection.ConnectionString"/> given.</remarks>
        public static int ExecuteNonQuery(string connectionString, string commandText, params MySqlParameter[] parms)
        {
            //create & open a SqlConnection, and dispose of it after we are done.
            using (MySqlConnection cn = new MySqlConnection(connectionString))
            {
                cn.Open();

                //call the overload that takes a connection in place of the connection string
                return ExecuteNonQuery(cn, commandText, parms);
            }
        }
        #endregion

        #region ExecuteDataReader

        /// <summary>
        /// Executes a single command against a MySQL database, possibly inside an existing transaction.
        /// </summary>
        /// <param name="connection"><see cref="MySqlConnection"/> object to use for the command</param>
        /// <param name="transaction"><see cref="MySqlTransaction"/> object to use for the command</param>
        /// <param name="commandText">Command text to use</param>
        /// <param name="commandParameters">Array of <see cref="MySqlParameter"/> objects to use with the command</param>
        /// <param name="externalConn">True if the connection should be preserved, false if not</param>
        /// <returns><see cref="MySqlDataReader"/> object ready to read the results of the command</returns>
        private static MySqlDataReader ExecuteReader(MySqlConnection connection, MySqlTransaction transaction, string commandText, MySqlParameter[] commandParameters, bool externalConn)
        {
            //create a command and prepare it for execution
            MySqlCommand cmd = new MySqlCommand();
            cmd.Connection = connection;
            cmd.Transaction = transaction;
            cmd.CommandText = commandText;
            cmd.CommandType = CommandType.Text;

            if (commandParameters != null)
                foreach (MySqlParameter p in commandParameters)
                    cmd.Parameters.Add(p);

            //create a reader
            MySqlDataReader dr;

            // call ExecuteReader with the appropriate CommandBehavior
            if (externalConn)
            {
                dr = cmd.ExecuteReader();
            }
            else
            {
                dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
            }

            // detach the SqlParameters from the command object, so they can be used again.
            cmd.Parameters.Clear();

            return dr;
        }

        /// <summary>
        /// Executes a single command against a MySQL database.
        /// </summary>
        /// <param name="connectionString">Settings to use for this command</param>
        /// <param name="commandText">Command text to use</param>
        /// <returns><see cref="MySqlDataReader"/> object ready to read the results of the command</returns>
        public static MySqlDataReader ExecuteReader(string connectionString, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteReader(connectionString, commandText, null);
        }

        /// <summary>
        /// Executes a single command against a MySQL database.
        /// </summary>
        /// <param name="connection"><see cref="MySqlConnection"/> object to use for the command</param>
        /// <param name="commandText">Command text to use</param>
        /// <returns><see cref="MySqlDataReader"/> object ready to read the results of the command</returns>
        public static MySqlDataReader ExecuteReader(MySqlConnection connection, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteReader(connection, null, commandText, null, true);
        }

        /// <summary>
        /// Executes a single command against a MySQL database.
        /// </summary>
        /// <param name="connectionString">Settings to use for this command</param>
        /// <param name="commandText">Command text to use</param>
        /// <param name="commandParameters">Array of <see cref="MySqlParameter"/> objects to use with the command</param>
        /// <returns><see cref="MySqlDataReader"/> object ready to read the results of the command</returns>
        public static MySqlDataReader ExecuteReader(string connectionString, string commandText, params MySqlParameter[] commandParameters)
        {
            //create & open a SqlConnection
            MySqlConnection cn = new MySqlConnection(connectionString);
            cn.Open();

            //call the private overload that takes an internally owned connection in place of the connection string
            return ExecuteReader(cn, null, commandText, commandParameters, false);
        }

        /// <summary>
        /// Executes a single command against a MySQL database.
        /// </summary>
        /// <param name="connection">Connection to use for the command</param>
        /// <param name="commandText">Command text to use</param>
        /// <param name="commandParameters">Array of <see cref="MySqlParameter"/> objects to use with the command</param>
        /// <returns><see cref="MySqlDataReader"/> object ready to read the results of the command</returns>
        public static MySqlDataReader ExecuteReader(MySqlConnection connection, string commandText, params MySqlParameter[] commandParameters)
        {
            //call the private overload that takes an internally owned connection in place of the connection string
            return ExecuteReader(connection, null, commandText, commandParameters, true);
        }


        #endregion

        #region ExecuteScalar

        /// <summary>
        /// Execute a single command against a MySQL database.
        /// </summary>
        /// <param name="connectionString">Settings to use for the update</param>
        /// <param name="commandText">Command text to use for the update</param>
        /// <returns>The first column of the first row in the result set, or a null reference if the result set is empty.</returns>
        public static object ExecuteScalar(string connectionString, string commandText)
        {
            //pass through the call providing null for the set of MySqlParameters
            return ExecuteScalar(connectionString, commandText, null);
        }

        /// <summary>
        /// Execute a single command against a MySQL database.
        /// </summary>
        /// <param name="connectionString">Settings to use for the command</param>
        /// <param name="commandText">Command text to use for the command</param>
        /// <param name="commandParameters">Parameters to use for the command</param>
        /// <returns>The first column of the first row in the result set, or a null reference if the result set is empty.</returns>
        public static object ExecuteScalar(string connectionString, string commandText, params MySqlParameter[] commandParameters)
        {
            //create & open a SqlConnection, and dispose of it after we are done.
            using (MySqlConnection cn = new MySqlConnection(connectionString))
            {
                cn.Open();

                //call the overload that takes a connection in place of the connection string
                return ExecuteScalar(cn, commandText, commandParameters);
            }
        }

        /// <summary>
        /// Execute a single command against a MySQL database.
        /// </summary>
        /// <param name="connection"><see cref="MySqlConnection"/> object to use</param>
        /// <param name="commandText">Command text to use for the command</param>
        /// <returns>The first column of the first row in the result set, or a null reference if the result set is empty.</returns>
        public static object ExecuteScalar(MySqlConnection connection, string commandText)
        {
            //pass through the call providing null for the set of MySqlParameters
            return ExecuteScalar(connection, commandText, null);
        }

        /// <summary>
        /// Execute a single command against a MySQL database.
        /// </summary>
        /// <param name="connection"><see cref="MySqlConnection"/> object to use</param>
        /// <param name="commandText">Command text to use for the command</param>
        /// <param name="commandParameters">Parameters to use for the command</param>
        /// <returns>The first column of the first row in the result set, or a null reference if the result set is empty.</returns>
        public static object ExecuteScalar(MySqlConnection connection, string commandText, params MySqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            MySqlCommand cmd = new MySqlCommand();
            cmd.Connection = connection;
            cmd.CommandText = commandText;
            cmd.CommandType = CommandType.Text;

            if (commandParameters != null)
                foreach (MySqlParameter p in commandParameters)
                    cmd.Parameters.Add(p);

            //execute the command & return the results
            object retval = cmd.ExecuteScalar();

            // detach the SqlParameters from the command object, so they can be used again.
            cmd.Parameters.Clear();
            return retval;

        }

        #endregion

        #region Utility methods
        private static CharClass[] MakeCharClassArray()
        {

            CharClass[] a = new CharClass[65536];
            foreach (char c in stringOfBackslashChars)
            {
                a[c] = CharClass.Backslash;
            }
            foreach (char c in stringOfQuoteChars)
            {
                a[c] = CharClass.Quote;
            }
            return a;
        }

        private static bool NeedsQuoting(string s)
        {
            return s.Any(c => charClassArray[c] != CharClass.None);
        }

        /// <summary>
        /// Escapes the string.
        /// </summary>
        /// <param name="value">The string to escape.</param>
        /// <returns>The string with all quotes escaped.</returns>
        public static string EscapeString(string value)
        {
            if (!NeedsQuoting(value))
                return value;

            StringBuilder sb = new StringBuilder();

            foreach (char c in value)
            {
                CharClass charClass = charClassArray[c];
                if (charClass != CharClass.None)
                {
                    sb.Append("\\");
                }
                sb.Append(c);
            }
            return sb.ToString();
        }

        /// <summary>
        /// Replaces quotes with double quotes.
        /// </summary>
        /// <param name="value">The string to modidify.</param>
        /// <returns>A string containing double quotes instead of single quotes.</returns>
        public static string DoubleQuoteString(string value)
        {
            if (!NeedsQuoting(value))
                return value;

            StringBuilder sb = new StringBuilder();
            foreach (char c in value)
            {
                CharClass charClass = charClassArray[c];
                if (charClass == CharClass.Quote)
                    sb.Append(c);
                else if (charClass == CharClass.Backslash)
                    sb.Append("\\");
                sb.Append(c);
            }
            return sb.ToString();
        }

        #endregion

        #region Async

        #region NonQuery
        /// <summary>
        /// Async version of ExecuteNonQuery
        /// </summary>
        /// <param name="connection"><see cref="MySqlConnection"/> object to use</param>
        /// <param name="commandText">SQL command to be executed</param>
        /// <param name="commandParameters">Array of <see cref="MySqlParameter"/> objects to use with the command.</param>
        /// <returns>Rows affected</returns>
        public static Task<int> ExecuteNonQueryAsync(MySqlConnection connection, string commandText, params MySqlParameter[] commandParameters)
        {
            return ExecuteNonQueryAsync(connection, commandText, CancellationToken.None, commandParameters);
        }

        public static Task<int> ExecuteNonQueryAsync(MySqlConnection connection, string commandText, CancellationToken cancellationToken, params MySqlParameter[] commandParameters)
        {
            var result = new TaskCompletionSource<int>();
            if (cancellationToken == CancellationToken.None || !cancellationToken.IsCancellationRequested)
            {
                try
                {
                    var queryResult = ExecuteNonQuery(connection, commandText, commandParameters);
                    result.SetResult(queryResult);
                }
                catch (Exception ex)
                {
                    result.SetException(ex);
                }
            }
            else
            {
                result.SetCanceled();
            }
            return result.Task;
        }

        /// <summary>
        /// Asynchronous version of the ExecuteNonQuery method.
        /// </summary>
        /// <param name="connectionString"><see cref="MySqlConnection.ConnectionString"/> to use.</param>
        /// <param name="commandText">The SQL command to be executed.</param>
        /// <param name="commandParameters">An array of <see cref="MySqlParameter"/> objects to use with the command.</param>
        /// <returns>The number of rows affected.</returns>
        public static Task<int> ExecuteNonQueryAsync(string connectionString, string commandText, params MySqlParameter[] commandParameters)
        {
            return ExecuteNonQueryAsync(connectionString, commandText, CancellationToken.None, commandParameters);
        }

        /// <summary>
        /// Asynchronous version of the ExecuteNonQuery method.
        /// </summary>
        /// <param name="connectionString"><see cref="MySqlConnection.ConnectionString"/> to use.</param>
        /// <param name="commandText">The SQL command to be executed.</param>
        /// <param name="cancellationToken">The cancellation token.</param>
        /// <param name="commandParameters">An array of <see cref="MySqlParameter"/> objects to use with the command.</param>
        /// <returns>The number of rows affected.</returns>
        public static Task<int> ExecuteNonQueryAsync(string connectionString, string commandText, CancellationToken cancellationToken, params MySqlParameter[] commandParameters)
        {
            var result = new TaskCompletionSource<int>();
            if (cancellationToken == CancellationToken.None || !cancellationToken.IsCancellationRequested)
            {
                try
                {
                    var queryResult = ExecuteNonQuery(connectionString, commandText, commandParameters);
                    result.SetResult(queryResult);
                }
                catch (Exception ex)
                {
                    result.SetException(ex);
                }
            }
            else
            {
                result.SetCanceled();
            }
            return result.Task;
        }

        #endregion


        #region DataReader
        /// <summary>
        /// Async version of ExecuteReader
        /// </summary>
        /// <param name="connection"><see cref="MySqlConnection"/> object to use for the command</param>
        /// <param name="transaction"><see cref="MySqlTransaction"/> object to use for the command</param>
        /// <param name="commandText">Command text to use</param>
        /// <param name="commandParameters">Array of <see cref="MySqlParameter"/> objects to use with the command</param>
        /// <param name="ExternalConn">True if the connection should be preserved, false if not</param>
        /// <returns><see cref="MySqlDataReader"/> object ready to read the results of the command</returns>
        private static Task<MySqlDataReader> ExecuteReaderAsync(MySqlConnection connection, MySqlTransaction transaction, string commandText, MySqlParameter[] commandParameters, bool ExternalConn)
        {
            return ExecuteReaderAsync(connection, transaction, commandText, commandParameters, ExternalConn, CancellationToken.None);
        }

        private static Task<MySqlDataReader> ExecuteReaderAsync(MySqlConnection connection, MySqlTransaction transaction, string commandText, MySqlParameter[] commandParameters, bool ExternalConn, CancellationToken cancellationToken)
        {
            var result = new TaskCompletionSource<MySqlDataReader>();
            if (cancellationToken == CancellationToken.None || !cancellationToken.IsCancellationRequested)
            {
                try
                {
                    var reader = ExecuteReader(connection, transaction, commandText, commandParameters, ExternalConn);
                    result.SetResult(reader);
                }
                catch (Exception ex)
                {
                    result.SetException(ex);
                }
            }
            else
            {
                result.SetCanceled();
            }
            return result.Task;
        }

        /// <summary>
        /// Async version of ExecuteReader
        /// </summary>
        /// <param name="connectionString">Settings to use for this command</param>
        /// <param name="commandText">Command text to use</param>
        /// <returns><see cref="MySqlDataReader"/> object ready to read the results of the command</returns>
        public static Task<MySqlDataReader> ExecuteReaderAsync(string connectionString, string commandText)
        {
            return ExecuteReaderAsync(connectionString, commandText, CancellationToken.None, (MySqlParameter[])null);
        }

        public static Task<MySqlDataReader> ExecuteReaderAsync(string connectionString, string commandText, CancellationToken cancellationToken)
        {
            return ExecuteReaderAsync(connectionString, commandText, cancellationToken, (MySqlParameter[])null);
        }

        /// <summary>
        /// Async version of ExecuteReader
        /// </summary>
        /// <param name="connection"><see cref="MySqlConnection"/> object to use for the command</param>
        /// <param name="commandText">Command text to use</param>
        /// <returns><see cref="MySqlDataReader"/> object ready to read the results of the command</returns>
        public static Task<MySqlDataReader> ExecuteReaderAsync(MySqlConnection connection, string commandText)
        {
            return ExecuteReaderAsync(connection, null, commandText, (MySqlParameter[])null, true, CancellationToken.None);
        }

        public static Task<MySqlDataReader> ExecuteReaderAsync(MySqlConnection connection, string commandText, CancellationToken cancellationToken)
        {
            return ExecuteReaderAsync(connection, null, commandText, (MySqlParameter[])null, true, cancellationToken);
        }

        /// <summary>
        /// Async version of ExecuteReader
        /// </summary>
        /// <param name="connectionString">Settings to use for this command</param>
        /// <param name="commandText">Command text to use</param>
        /// <param name="commandParameters">Array of <see cref="MySqlParameter"/> objects to use with the command</param>
        /// <returns><see cref="MySqlDataReader"/> object ready to read the results of the command</returns>
        public static Task<MySqlDataReader> ExecuteReaderAsync(string connectionString, string commandText, params MySqlParameter[] commandParameters)
        {
            return ExecuteReaderAsync(connectionString, commandText, CancellationToken.None, commandParameters);
        }

        public static Task<MySqlDataReader> ExecuteReaderAsync(string connectionString, string commandText, CancellationToken cancellationToken, params MySqlParameter[] commandParameters)
        {
            var result = new TaskCompletionSource<MySqlDataReader>();
            if (cancellationToken == CancellationToken.None || !cancellationToken.IsCancellationRequested)
            {
                try
                {
                    var reader = ExecuteReader(connectionString, commandText, commandParameters);
                    result.SetResult(reader);
                }
                catch (Exception ex)
                {
                    result.SetException(ex);
                }
            }
            else
            {
                result.SetCanceled();
            }
            return result.Task;
        }

        /// <summary>
        /// Async version of ExecuteReader
        /// </summary>
        /// <param name="connection">Connection to use for the command</param>
        /// <param name="commandText">Command text to use</param>
        /// <param name="commandParameters">Array of <see cref="MySqlParameter"/> objects to use with the command</param>
        /// <returns><see cref="MySqlDataReader"/> object ready to read the results of the command</returns>
        public static Task<MySqlDataReader> ExecuteReaderAsync(MySqlConnection connection, string commandText, params MySqlParameter[] commandParameters)
        {
            return ExecuteReaderAsync(connection, null, commandText, commandParameters, true, CancellationToken.None);
        }

        public static Task<MySqlDataReader> ExecuteReaderAsync(MySqlConnection connection, string commandText, CancellationToken cancellationToken, params MySqlParameter[] commandParameters)
        {
            return ExecuteReaderAsync(connection, null, commandText, commandParameters, true, cancellationToken);
        }

        #endregion

        #region Scalar
        /// <summary>
        /// Async version of ExecuteScalar
        /// </summary>
        /// <param name="connectionString">Settings to use for the update</param>
        /// <param name="commandText">Command text to use for the update</param>
        /// <returns>The first column of the first row in the result set, or a null reference if the result set is empty.</returns>
        public static Task<object> ExecuteScalarAsync(string connectionString, string commandText)
        {
            return ExecuteScalarAsync(connectionString, commandText, CancellationToken.None, (MySqlParameter[])null);
        }

        public static Task<object> ExecuteScalarAsync(string connectionString, string commandText, CancellationToken cancellationToken)
        {
            return ExecuteScalarAsync(connectionString, commandText, cancellationToken, (MySqlParameter[])null);
        }

        /// <summary>
        /// Async version of ExecuteScalar
        /// </summary>
        /// <param name="connectionString">Settings to use for the command</param>
        /// <param name="commandText">Command text to use for the command</param>
        /// <param name="commandParameters">Parameters to use for the command</param>
        /// <returns>The first column of the first row in the result set, or a null reference if the result set is empty.</returns>
        public static Task<object> ExecuteScalarAsync(string connectionString, string commandText, params MySqlParameter[] commandParameters)
        {
            return ExecuteScalarAsync(connectionString, commandText, CancellationToken.None, commandParameters);
        }

        public static Task<object> ExecuteScalarAsync(string connectionString, string commandText, CancellationToken cancellationToken, params MySqlParameter[] commandParameters)
        {
            var result = new TaskCompletionSource<object>();
            if (cancellationToken == CancellationToken.None || !cancellationToken.IsCancellationRequested)
            {
                try
                {
                    var scalarResult = ExecuteScalar(connectionString, commandText, commandParameters);
                    result.SetResult(scalarResult);
                }
                catch (Exception ex)
                {
                    result.SetException(ex);
                }
            }
            else
            {
                result.SetCanceled();
            }
            return result.Task;
        }

        /// <summary>
        /// Async version of ExecuteScalar
        /// </summary>
        /// <param name="connection"><see cref="MySqlConnection"/> object to use</param>
        /// <param name="commandText">Command text to use for the command</param>
        /// <returns>The first column of the first row in the result set, or a null reference if the result set is empty.</returns>
        public static Task<object> ExecuteScalarAsync(MySqlConnection connection, string commandText)
        {
            return ExecuteScalarAsync(connection, commandText, CancellationToken.None, (MySqlParameter[])null);
        }

        public static Task<object> ExecuteScalarAsync(MySqlConnection connection, string commandText, CancellationToken cancellationToken)
        {
            return ExecuteScalarAsync(connection, commandText, cancellationToken, (MySqlParameter[])null);
        }

        /// <summary>
        /// Async version of ExecuteScalar
        /// </summary>
        /// <param name="connection"><see cref="MySqlConnection"/> object to use</param>
        /// <param name="commandText">Command text to use for the command</param>
        /// <param name="commandParameters">Parameters to use for the command</param>
        /// <returns>The first column of the first row in the result set, or a null reference if the result set is empty.</returns>
        public static Task<object> ExecuteScalarAsync(MySqlConnection connection, string commandText, params MySqlParameter[] commandParameters)
        {
            return ExecuteScalarAsync(connection, commandText, CancellationToken.None, commandParameters);
        }

        public static Task<object> ExecuteScalarAsync(MySqlConnection connection, string commandText, CancellationToken cancellationToken, params MySqlParameter[] commandParameters)
        {
            var result = new TaskCompletionSource<object>();
            if (cancellationToken == CancellationToken.None || !cancellationToken.IsCancellationRequested)
            {
                try
                {
                    var scalarResult = ExecuteScalar(connection, commandText, commandParameters);
                    result.SetResult(scalarResult);
                }
                catch (Exception ex)
                {
                    result.SetException(ex);
                }
            }
            else
            {
                result.SetCanceled();
            }
            return result.Task;
        }
        #endregion
        #endregion
    }
}

#endif