// Copyright (c) 2004, 2020, Oracle and/or its affiliates. All rights reserved.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License, version 2.0, as
// published by the Free Software Foundation.
//
// This program is also distributed with certain software (including
// but not limited to OpenSSL) that is licensed under separate terms,
// as designated in a particular file or component or in included license
// documentation.  The authors of MySQL hereby grant you an
// additional permission to link the program and your derivative works
// with the separately licensed software that they have included with
// MySQL.
//
// Without limiting anything contained in the foregoing, this file,
// which is part of MySQL Connector/NET, is also subject to the
// Universal FOSS Exception, version 1.0, a copy of which can be found at
// http://oss.oracle.com/licenses/universal-foss-exception.
//
// 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, version 2.0, 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 MySql.Data.Common;
using MySql.Data.Types;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Text;
using Sog.Properties;

namespace MySql.Data.MySqlClient
{
    internal class ISSchemaProvider : SchemaProvider
    {
        public ISSchemaProvider(MySqlConnection connection)
          : base(connection)
        {
        }

        protected override MySqlSchemaCollection GetCollections()
        {
            MySqlSchemaCollection dt = base.GetCollections();

            object[][] collections = {
                new object[] {"Views", 2, 3},
                new object[] {"ViewColumns", 3, 4},
                new object[] {"Procedure Parameters", 5, 1},
                new object[] {"Procedures", 4, 3},
                new object[] {"Triggers", 2, 4}
            };

            FillTable(dt, collections);
            return dt;
        }

        protected override MySqlSchemaCollection GetRestrictions()
        {
            MySqlSchemaCollection dt = base.GetRestrictions();

            object[][] restrictions = new object[][]
                  {
                new object[] {"Procedure Parameters", "Database", "", 0},
                new object[] {"Procedure Parameters", "Schema", "", 1},
                new object[] {"Procedure Parameters", "Name", "", 2},
                new object[] {"Procedure Parameters", "Type", "", 3},
                new object[] {"Procedure Parameters", "Parameter", "", 4},
                new object[] {"Procedures", "Database", "", 0},
                new object[] {"Procedures", "Schema", "", 1},
                new object[] {"Procedures", "Name", "", 2},
                new object[] {"Procedures", "Type", "", 3},
                new object[] {"Views", "Database", "", 0},
                new object[] {"Views", "Schema", "", 1},
                new object[] {"Views", "Table", "", 2},
                new object[] {"ViewColumns", "Database", "", 0},
                new object[] {"ViewColumns", "Schema", "", 1},
                new object[] {"ViewColumns", "Table", "", 2},
                new object[] {"ViewColumns", "Column", "", 3},
                new object[] {"Triggers", "Database", "", 0},
                new object[] {"Triggers", "Schema", "", 1},
                new object[] {"Triggers", "Name", "", 2},
                new object[] {"Triggers", "EventObjectTable", "", 3},
                  };
            FillTable(dt, restrictions);
            return dt;
        }

        public override MySqlSchemaCollection GetDatabases(string[] restrictions)
        {
            string[] keys = new string[1];
            keys[0] = "SCHEMA_NAME";
            MySqlSchemaCollection dt = this.Query("SCHEMATA", "", keys, restrictions);
            dt.Columns[1].Name = "database_name";
            dt.Name = "Databases";
            return dt;
        }

        public override MySqlSchemaCollection GetTables(string[] restrictions)
        {
            string[] keys = new string[4];
            keys[0] = "TABLE_CATALOG";
            keys[1] = "TABLE_SCHEMA";
            keys[2] = "TABLE_NAME";
            keys[3] = "TABLE_TYPE";
            MySqlSchemaCollection dt = this.Query("TABLES", "TABLE_TYPE != 'VIEW'", keys, restrictions);
            dt.Name = "Tables";
            return dt;
        }

        public override MySqlSchemaCollection GetColumns(string[] restrictions)
        {
            string[] keys = new string[4];
            keys[0] = "TABLE_CATALOG";
            keys[1] = "TABLE_SCHEMA";
            keys[2] = "TABLE_NAME";
            keys[3] = "COLUMN_NAME";
            MySqlSchemaCollection dt = this.Query("COLUMNS", null, keys, restrictions);
            dt.RemoveColumn("CHARACTER_OCTET_LENGTH");
            dt.Name = "Columns";
            this.QuoteDefaultValues(dt);
            return dt;
        }

        private MySqlSchemaCollection GetViews(string[] restrictions)
        {
            string[] keys = new string[3];
            keys[0] = "TABLE_CATALOG";
            keys[1] = "TABLE_SCHEMA";
            keys[2] = "TABLE_NAME";
            MySqlSchemaCollection dt = this.Query("VIEWS", null, keys, restrictions);
            dt.Name = "Views";
            return dt;
        }

        private MySqlSchemaCollection GetViewColumns(string[] restrictions)
        {
            StringBuilder where = new StringBuilder();
            StringBuilder sql = new StringBuilder(
                "SELECT C.* FROM information_schema.columns C");
            sql.Append(" JOIN information_schema.views V ");
            sql.Append("ON C.table_schema=V.table_schema AND C.table_name=V.table_name ");
            if (restrictions != null && restrictions.Length >= 2 &&
                restrictions[1] != null)
            {
                where.AppendFormat(CultureInfo.InvariantCulture, "C.table_schema='{0}' ", restrictions[1]);
            }

            if (restrictions != null && restrictions.Length >= 3 &&
                restrictions[2] != null)
            {
                if (where.Length > 0)
                {
                    where.Append("AND ");
                }

                where.AppendFormat(CultureInfo.InvariantCulture, "C.table_name='{0}' ", restrictions[2]);
            }

            if (restrictions != null && restrictions.Length == 4 &&
                restrictions[3] != null)
            {
                if (where.Length > 0)
                {
                    where.Append("AND ");
                }

                where.AppendFormat(CultureInfo.InvariantCulture, "C.column_name='{0}' ", restrictions[3]);
            }

            if (where.Length > 0)
            {
                sql.AppendFormat(CultureInfo.InvariantCulture, " WHERE {0}", where);
            }

            MySqlSchemaCollection dt = this.GetTable(sql.ToString());
            dt.Name = "ViewColumns";
            dt.Columns[0].Name = "VIEW_CATALOG";
            dt.Columns[1].Name = "VIEW_SCHEMA";
            dt.Columns[2].Name = "VIEW_NAME";
            this.QuoteDefaultValues(dt);
            return dt;
        }

        private MySqlSchemaCollection GetTriggers(string[] restrictions)
        {
            string[] keys = new string[4];
            keys[0] = "TRIGGER_CATALOG";
            keys[1] = "TRIGGER_SCHEMA";
            keys[2] = "EVENT_OBJECT_TABLE";
            keys[3] = "TRIGGER_NAME";
            MySqlSchemaCollection dt = this.Query("TRIGGERS", null, keys, restrictions);
            dt.Name = "Triggers";
            return dt;
        }

        /// <summary>
        /// Return schema information about procedures and functions
        /// Restrictions supported are:
        /// schema, name, type
        /// </summary>
        /// <param name="restrictions"></param>
        /// <returns></returns>
        public override MySqlSchemaCollection GetProcedures(string[] restrictions)
        {
            try
            {
                if (this.connection.Settings.HasProcAccess)
                {
                    return base.GetProcedures(restrictions);
                }
            }
            catch (MySqlException ex)
            {
                if (ex.Number == (int)MySqlErrorCode.TableAccessDenied)
                {
                    this.connection.Settings.HasProcAccess = false;
                }
                else
                {
                    throw;
                }
            }

            string[] keys = new string[4];
            keys[0] = "ROUTINE_CATALOG";
            keys[1] = "ROUTINE_SCHEMA";
            keys[2] = "ROUTINE_NAME";
            keys[3] = "ROUTINE_TYPE";

            MySqlSchemaCollection dt = this.Query("ROUTINES", null, keys, restrictions);
            dt.Name = "Procedures";
            return dt;
        }

        private MySqlSchemaCollection GetProceduresWithParameters(string[] restrictions)
        {
            MySqlSchemaCollection dt = this.GetProcedures(restrictions);
            dt.AddColumn("ParameterList", typeof(string));

            foreach (MySqlSchemaRow row in dt.Rows)
            {
                row["ParameterList"] = this.GetProcedureParameterLine(row);
            }

            return dt;
        }

        private string GetProcedureParameterLine(MySqlSchemaRow isRow)
        {
            string sql = "SHOW CREATE {0} `{1}`.`{2}`";
            sql = String.Format(sql, isRow["ROUTINE_TYPE"], isRow["ROUTINE_SCHEMA"],
                isRow["ROUTINE_NAME"]);
            MySqlCommand cmd = new MySqlCommand(sql, this.connection);
            using (MySqlDataReader reader = cmd.ExecuteReader())
            {
                reader.Read();

                // if we are not the owner of this proc or have permissions
                // then we will get null for the body
                if (reader.IsDBNull(2))
                {
                    return null;
                }

                string sqlMode = reader.GetString(1);

                string body = reader.GetString(2);
                MySqlTokenizer tokenizer = new MySqlTokenizer(body);
                tokenizer.AnsiQuotes = sqlMode.IndexOf("ANSI_QUOTES") != -1;
                tokenizer.BackslashEscapes = sqlMode.IndexOf("NO_BACKSLASH_ESCAPES") == -1;

                string token = tokenizer.NextToken();
                while (token != "(")
                {
                    token = tokenizer.NextToken();
                }

                int start = tokenizer.StartIndex + 1;
                token = tokenizer.NextToken();
                while (token != ")" || tokenizer.Quoted)
                {
                    token = tokenizer.NextToken();

                    // if we see another ( and we are not quoted then we
                    // are in a size element and we need to look for the closing paren
                    if (token == "(" && !tokenizer.Quoted)
                    {
                        while (token != ")" || tokenizer.Quoted)
                        {
                            token = tokenizer.NextToken();
                        }

                        token = tokenizer.NextToken();
                    }
                }

                return body.Substring(start, tokenizer.StartIndex - start);
            }
        }

        private MySqlSchemaCollection GetParametersForRoutineFromIS(string[] restrictions)
        {
            string[] keys = new string[5];
            keys[0] = "SPECIFIC_CATALOG";
            keys[1] = "SPECIFIC_SCHEMA";
            keys[2] = "SPECIFIC_NAME";
            keys[3] = "ROUTINE_TYPE";
            keys[4] = "PARAMETER_NAME";

            StringBuilder sql = new StringBuilder(@"SELECT * FROM INFORMATION_SCHEMA.PARAMETERS");

            // now get our where clause and append it if there is one
            string where = GetWhereClause(null, keys, restrictions);
            if (!String.IsNullOrEmpty(where))
            {
                sql.AppendFormat(CultureInfo.InvariantCulture, " WHERE {0}", where);
            }

            MySqlSchemaCollection coll = this.QueryCollection("parameters", sql.ToString());

            if ((coll.Rows.Count != 0) && ((string)coll.Rows[0]["routine_type"] == "FUNCTION"))
            {
                // update missing data for the first row (function return value).
                // (using sames valus than GetParametersFromShowCreate).
                coll.Rows[0]["parameter_mode"] = "IN";
                coll.Rows[0]["parameter_name"] = "return_value"; // "FUNCTION";
            }

            return coll;
        }

        private MySqlSchemaCollection GetParametersFromIS(string[] restrictions, MySqlSchemaCollection routines)
        {
            MySqlSchemaCollection parms = null;

            if (routines == null || routines.Rows.Count == 0)
            {
                if (restrictions == null)
                {
                    parms = this.QueryCollection("parameters", "SELECT * FROM INFORMATION_SCHEMA.PARAMETERS WHERE 1=2");
                }
                else
                {
                    parms = this.GetParametersForRoutineFromIS(restrictions);
                }
            }
            else
            {
                foreach (MySqlSchemaRow routine in routines.Rows)
                {
                    if (restrictions != null && restrictions.Length >= 3)
                    {
                        restrictions[2] = routine["ROUTINE_NAME"].ToString();
                    }

                    parms = this.GetParametersForRoutineFromIS(restrictions);
                }
            }

            parms.Name = "Procedure Parameters";
            return parms;
        }

        internal MySqlSchemaCollection CreateParametersTable()
        {
            MySqlSchemaCollection dt = new MySqlSchemaCollection("Procedure Parameters");
            dt.AddColumn("SPECIFIC_CATALOG", typeof(string));
            dt.AddColumn("SPECIFIC_SCHEMA", typeof(string));
            dt.AddColumn("SPECIFIC_NAME", typeof(string));
            dt.AddColumn("ORDINAL_POSITION", typeof(Int32));
            dt.AddColumn("PARAMETER_MODE", typeof(string));
            dt.AddColumn("PARAMETER_NAME", typeof(string));
            dt.AddColumn("DATA_TYPE", typeof(string));
            dt.AddColumn("CHARACTER_MAXIMUM_LENGTH", typeof(Int32));
            dt.AddColumn("CHARACTER_OCTET_LENGTH", typeof(Int32));
            dt.AddColumn("NUMERIC_PRECISION", typeof(byte));
            dt.AddColumn("NUMERIC_SCALE", typeof(Int32));
            dt.AddColumn("CHARACTER_SET_NAME", typeof(string));
            dt.AddColumn("COLLATION_NAME", typeof(string));
            dt.AddColumn("DTD_IDENTIFIER", typeof(string));
            dt.AddColumn("ROUTINE_TYPE", typeof(string));
            return dt;
        }

        /// <summary>
        /// Return schema information about parameters for procedures and functions
        /// Restrictions supported are:
        /// schema, name, type, parameter name
        /// </summary>
        public virtual MySqlSchemaCollection GetProcedureParameters(
            string[] restrictions,
            MySqlSchemaCollection routines)
        {
            bool is55 = this.connection.driver.Version.isAtLeast(5, 5, 3);

            try
            {
                // we want to avoid using IS if  we can as it is painfully slow
                MySqlSchemaCollection dt = this.CreateParametersTable();
                this.GetParametersFromShowCreate(dt, restrictions, routines);
                return dt;
            }
            catch (Exception)
            {
                if (!is55)
                {
                    throw;
                }

                // we get here by not having access and we are on 5.5 or later so just use IS
                return this.GetParametersFromIS(restrictions, routines);
            }
        }

        protected override MySqlSchemaCollection GetSchemaInternal(string collection, string[] restrictions)
        {
            MySqlSchemaCollection dt = base.GetSchemaInternal(collection, restrictions);
            if (dt != null)
            {
                return dt;
            }

            switch (collection)
            {
                case "VIEWS":
                    return this.GetViews(restrictions);
                case "PROCEDURES":
                    return this.GetProcedures(restrictions);
                case "PROCEDURES WITH PARAMETERS":
                    return this.GetProceduresWithParameters(restrictions);
                case "PROCEDURE PARAMETERS":
                    return this.GetProcedureParameters(restrictions, null);
                case "TRIGGERS":
                    return this.GetTriggers(restrictions);
                case "VIEWCOLUMNS":
                    return this.GetViewColumns(restrictions);
            }

            return null;
        }

        private static string GetWhereClause(string initial_where, string[] keys, string[] values)
        {
            StringBuilder where = new StringBuilder(initial_where);
            if (values != null)
            {
                for (int i = 0; i < keys.Length; i++)
                {
                    if (i >= values.Length)
                    {
                        break;
                    }

                    if (values[i] == null || values[i] == String.Empty)
                    {
                        continue;
                    }

                    if (where.Length > 0)
                    {
                        where.Append(" AND ");
                    }

                    where.AppendFormat(
                        CultureInfo.InvariantCulture,
                        "{0} LIKE '{1}'", keys[i], values[i]);
                }
            }

            return where.ToString();
        }

        private MySqlSchemaCollection Query(string tableName, string initialWhere,
            string[] keys, string[] values)
        {
            StringBuilder query = new StringBuilder("SELECT * FROM INFORMATION_SCHEMA.");
            query.Append(tableName);

            string where = GetWhereClause(initialWhere, keys, values);

            if (where.Length > 0)
            {
                query.AppendFormat(CultureInfo.InvariantCulture, " WHERE {0}", where);
            }

            if (tableName.Equals("COLUMNS", StringComparison.OrdinalIgnoreCase))
            {
                query.Append(" ORDER BY ORDINAL_POSITION");
            }

            return this.GetTable(query.ToString());
        }

        private MySqlSchemaCollection GetTable(string sql)
        {
            MySqlSchemaCollection c = new MySqlSchemaCollection();
            MySqlCommand cmd = new MySqlCommand(sql, this.connection);
            MySqlDataReader reader = cmd.ExecuteReader();

            // add columns
            for (int i = 0; i < reader.FieldCount; i++)
            {
                c.AddColumn(reader.GetName(i), reader.GetFieldType(i));
            }

            using (reader)
            {
                while (reader.Read())
                {
                    MySqlSchemaRow row = c.AddRow();
                    for (int i = 0; i < reader.FieldCount; i++)
                    {
                        row[i] = reader.GetValue(i);
                    }
                }
            }

            return c;
        }

        public override MySqlSchemaCollection GetForeignKeys(string[] restrictions)
        {
            if (!this.connection.driver.Version.isAtLeast(5, 1, 16))
            {
                return base.GetForeignKeys(restrictions);
            }

            string sql = @"SELECT rc.constraint_catalog, rc.constraint_schema,
                rc.constraint_name, kcu.table_catalog, kcu.table_schema, rc.table_name,
                rc.match_option, rc.update_rule, rc.delete_rule, 
                NULL as referenced_table_catalog,
                kcu.referenced_table_schema, rc.referenced_table_name 
                FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS rc
                LEFT JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE kcu ON 
                kcu.constraint_catalog <=> rc.constraint_catalog AND
                kcu.constraint_schema <=> rc.constraint_schema AND 
                kcu.constraint_name <=> rc.constraint_name 
                WHERE 1=1 AND kcu.ORDINAL_POSITION=1";

            StringBuilder where = new StringBuilder();
            if (restrictions.Length >= 2 && !String.IsNullOrEmpty(restrictions[1]))
            {
                where.AppendFormat(
                    CultureInfo.InvariantCulture,
            " AND rc.constraint_schema LIKE '{0}'", restrictions[1]);
            }

            if (restrictions.Length >= 3 && !String.IsNullOrEmpty(restrictions[2]))
            {
                where.AppendFormat(
                    CultureInfo.InvariantCulture,
            " AND rc.table_name LIKE '{0}'", restrictions[2]);
            }

            if (restrictions.Length >= 4 && !String.IsNullOrEmpty(restrictions[3]))
            {
                where.AppendFormat(
                    CultureInfo.InvariantCulture,
            " AND rc.constraint_name LIKE '{0}'", restrictions[2]);
            }

            sql += where.ToString();

            return this.GetTable(sql);
        }

        public override MySqlSchemaCollection GetForeignKeyColumns(string[] restrictions)
        {
            if (!this.connection.driver.Version.isAtLeast(5, 0, 6))
            {
                return base.GetForeignKeyColumns(restrictions);
            }

            string sql = @"SELECT kcu.* FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE kcu
                WHERE kcu.referenced_table_name IS NOT NULL";

            StringBuilder where = new StringBuilder();
            if (restrictions.Length >= 2 && !String.IsNullOrEmpty(restrictions[1]))
            {
                where.AppendFormat(
                    CultureInfo.InvariantCulture,
            " AND kcu.constraint_schema LIKE '{0}'", restrictions[1]);
            }

            if (restrictions.Length >= 3 && !String.IsNullOrEmpty(restrictions[2]))
            {
                where.AppendFormat(
                    CultureInfo.InvariantCulture,
            " AND kcu.table_name LIKE '{0}'", restrictions[2]);
            }

            if (restrictions.Length >= 4 && !String.IsNullOrEmpty(restrictions[3]))
            {
                where.AppendFormat(
                    CultureInfo.InvariantCulture,
            " AND kcu.constraint_name LIKE '{0}'", restrictions[3]);
            }

            sql += where.ToString();

            return this.GetTable(sql);
        }

        #region Procedures Support Rouines

        internal void GetParametersFromShowCreate(
            MySqlSchemaCollection parametersTable,
            string[] restrictions, MySqlSchemaCollection routines)
        {
            // this allows us to pass in a pre-populated routines table
            // and avoid the querying for them again.
            // we use this when calling a procedure or function
            if (routines == null)
            {
                routines = this.GetSchema("procedures", restrictions);
            }

            MySqlCommand cmd = this.connection.CreateCommand();

            foreach (MySqlSchemaRow routine in routines.Rows)
            {
                string showCreateSql = String.Format(
                    "SHOW CREATE {0} `{1}`.`{2}`",
                    routine["ROUTINE_TYPE"], routine["ROUTINE_SCHEMA"],
                    routine["ROUTINE_NAME"]);
                cmd.CommandText = showCreateSql;
                try
                {
                    string nameToRestrict = null;
                    if (restrictions != null && restrictions.Length == 5 &&
                        restrictions[4] != null)
                    {
                        nameToRestrict = restrictions[4];
                    }

                    using (MySqlDataReader reader = cmd.ExecuteReader())
                    {
                        reader.Read();
                        string body = reader.GetString(2);
                        reader.Close();
                        this.ParseProcedureBody(parametersTable, body, routine, nameToRestrict);
                    }
                }
                catch (System.Data.SqlTypes.SqlNullValueException snex)
                {
                    throw new InvalidOperationException(
                        String.Format(Resources.UnableToRetrieveParameters, routine["ROUTINE_NAME"]), snex);
                }
            }
        }

        private void ParseProcedureBody(MySqlSchemaCollection parametersTable, string body,
            MySqlSchemaRow row, string nameToRestrict)
        {
            List<string> modes = new List<string>(new string[3] { "IN", "OUT", "INOUT" });

            string sqlMode = row["SQL_MODE"].ToString();

            int pos = 1;
            MySqlTokenizer tokenizer = new MySqlTokenizer(body);
            tokenizer.AnsiQuotes = sqlMode.IndexOf("ANSI_QUOTES") != -1;
            tokenizer.BackslashEscapes = sqlMode.IndexOf("NO_BACKSLASH_ESCAPES") == -1;
            tokenizer.ReturnComments = false;
            string token = tokenizer.NextToken();

            // this block will scan for the opening paren while also determining
            // if this routine is a function.  If so, then we need to add a
            // parameter row for the return parameter since it is ordinal position
            // 0 and should appear first.
            while (token != "(")
            {
                if (String.Compare(token, "FUNCTION", StringComparison.OrdinalIgnoreCase) == 0 &&
                    nameToRestrict == null)
                {
                    parametersTable.AddRow();
                    InitParameterRow(row, parametersTable.Rows[0]);
                }

                token = tokenizer.NextToken();
            }

            token = tokenizer.NextToken();  // now move to the next token past the (

            while (token != ")")
            {
                MySqlSchemaRow parmRow = parametersTable.NewRow();
                InitParameterRow(row, parmRow);
                parmRow["ORDINAL_POSITION"] = pos++;

                // handle mode and name for the parameter
                string mode = StringUtility.ToUpperInvariant(token);
                if (!tokenizer.Quoted && modes.Contains(mode))
                {
                    parmRow["PARAMETER_MODE"] = mode;
                    token = tokenizer.NextToken();
                }

                if (tokenizer.Quoted)
                {
                    token = token.Substring(1, token.Length - 2);
                }

                parmRow["PARAMETER_NAME"] = token;

                // now parse data type
                token = this.ParseDataType(parmRow, tokenizer);
                if (token == ",")
                {
                    token = tokenizer.NextToken();
                }

                // now determine if we should include this row after all
                // we need to parse it before this check so we are correctly
                // positioned for the next parameter
                if (nameToRestrict == null ||
                    String.Compare(parmRow["PARAMETER_NAME"].ToString(), nameToRestrict, StringComparison.OrdinalIgnoreCase) == 0)
                {
                    parametersTable.Rows.Add(parmRow);
                }
            }

            // now parse out the return parameter if there is one.
            token = StringUtility.ToUpperInvariant(tokenizer.NextToken());
            if (String.Compare(token, "RETURNS", StringComparison.OrdinalIgnoreCase) == 0)
            {
                MySqlSchemaRow parameterRow = parametersTable.Rows[0];
                parameterRow["PARAMETER_NAME"] = "RETURN_VALUE";
                this.ParseDataType(parameterRow, tokenizer);
            }
        }

        /// <summary>
        /// Initializes a new row for the procedure parameters table.
        /// </summary>
        private static void InitParameterRow(MySqlSchemaRow procedure, MySqlSchemaRow parameter)
        {
            parameter["SPECIFIC_CATALOG"] = null;
            parameter["SPECIFIC_SCHEMA"] = procedure["ROUTINE_SCHEMA"];
            parameter["SPECIFIC_NAME"] = procedure["ROUTINE_NAME"];
            parameter["PARAMETER_MODE"] = "IN";
            parameter["ORDINAL_POSITION"] = 0;
            parameter["ROUTINE_TYPE"] = procedure["ROUTINE_TYPE"];
        }

        /// <summary>
        ///  Parses out the elements of a procedure parameter data type.
        /// </summary>
        private string ParseDataType(MySqlSchemaRow row, MySqlTokenizer tokenizer)
        {
            StringBuilder dtd = new StringBuilder(
                StringUtility.ToUpperInvariant(tokenizer.NextToken()));
            row["DATA_TYPE"] = dtd.ToString();
            string type = row["DATA_TYPE"].ToString();

            string token = tokenizer.NextToken();
            if (token == "(")
            {
                token = tokenizer.ReadParenthesis();
                dtd.AppendFormat(CultureInfo.InvariantCulture, "{0}", token);
                if (type != "ENUM" && type != "SET")
                {
                    ParseDataTypeSize(row, token);
                }

                token = tokenizer.NextToken();
            }
            else
            {
                dtd.Append(GetDataTypeDefaults(type, row));
            }

            while (token != ")" &&
                   token != "," &&
                   String.Compare(token, "begin", StringComparison.OrdinalIgnoreCase) != 0 &&
                   String.Compare(token, "return", StringComparison.OrdinalIgnoreCase) != 0)
            {
                if (String.Compare(token, "CHARACTER", StringComparison.OrdinalIgnoreCase) == 0 ||
                    String.Compare(token, "BINARY", StringComparison.OrdinalIgnoreCase) == 0)
                { }  // we don't need to do anything with this
                else if (String.Compare(token, "SET", StringComparison.OrdinalIgnoreCase) == 0 ||
                         String.Compare(token, "CHARSET", StringComparison.OrdinalIgnoreCase) == 0)
                {
                    row["CHARACTER_SET_NAME"] = tokenizer.NextToken();
                }
                else if (String.Compare(token, "ASCII", StringComparison.OrdinalIgnoreCase) == 0)
                {
                    row["CHARACTER_SET_NAME"] = "latin1";
                }
                else if (String.Compare(token, "UNICODE", StringComparison.OrdinalIgnoreCase) == 0)
                {
                    row["CHARACTER_SET_NAME"] = "ucs2";
                }
                else if (String.Compare(token, "COLLATE", StringComparison.OrdinalIgnoreCase) == 0)
                {
                    row["COLLATION_NAME"] = tokenizer.NextToken();
                }
                else
                {
                    dtd.AppendFormat(CultureInfo.InvariantCulture, " {0}", token);
                }

                token = tokenizer.NextToken();
            }

            if (dtd.Length > 0)
            {
                row["DTD_IDENTIFIER"] = dtd.ToString();
            }

            // now default the collation if one wasn't given
            if (string.IsNullOrEmpty((string)row["COLLATION_NAME"]) &&
                !string.IsNullOrEmpty((string)row["CHARACTER_SET_NAME"]))
            {
                row["COLLATION_NAME"] = CharSetMap.GetDefaultCollation(
            row["CHARACTER_SET_NAME"].ToString(), this.connection);
            }

            // now set the octet length
            if (row["CHARACTER_MAXIMUM_LENGTH"] != null)
            {
                if (row["CHARACTER_SET_NAME"] == null)
                {
                    row["CHARACTER_SET_NAME"] = "";
                }

                row["CHARACTER_OCTET_LENGTH"] =
                    CharSetMap.GetMaxLength((string)row["CHARACTER_SET_NAME"], this.connection) *
                    (int)row["CHARACTER_MAXIMUM_LENGTH"];
            }

            return token;
        }

        private static string GetDataTypeDefaults(string type, MySqlSchemaRow row)
        {
            string format = "({0},{1})";
            object precision = row["NUMERIC_PRECISION"];
            if (MetaData.IsNumericType(type) &&
                string.IsNullOrEmpty((string)row["NUMERIC_PRECISION"]))
            {
                row["NUMERIC_PRECISION"] = 10;
                row["NUMERIC_SCALE"] = 0;
                if (!MetaData.SupportScale(type))
                {
                    format = "({0})";
                }

                return String.Format(format, row["NUMERIC_PRECISION"],
                    row["NUMERIC_SCALE"]);
            }

            return String.Empty;
        }

        private static void ParseDataTypeSize(MySqlSchemaRow row, string size)
        {
            size = size.Trim('(', ')');
            string[] parts = size.Split(',');

            if (!MetaData.IsNumericType(row["DATA_TYPE"].ToString()))
            {
                row["CHARACTER_MAXIMUM_LENGTH"] = Int32.Parse(parts[0], CultureInfo.InvariantCulture);

                // will set octet length in a minute
            }
            else
            {
                row["NUMERIC_PRECISION"] = Int32.Parse(parts[0], CultureInfo.InvariantCulture);
                if (parts.Length == 2)
                {
                    row["NUMERIC_SCALE"] = Int32.Parse(parts[1], CultureInfo.InvariantCulture);
                }
            }
        }

        #endregion

    }
}