// Copyright (c) 2004-2008 MySQL AB, 2008-2009 Sun Microsystems, Inc.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License version 2 as published by
// the Free Software Foundation
//
// There are special exceptions to the terms and conditions of the GPL 
// as it is applied to this software. View the full text of the 
// exception in file EXCEPTIONS in the directory of this software 
// distribution.
//
// 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 

using System;
using System.Data;
using System.Data.Common;
using System.Globalization;
using System.IO;
using System.Reflection;
using System.Text;
using MySql.Data.Common;
using MySql.Data.Types;
using System.Collections.Specialized;
using System.Collections;
using System.Text.RegularExpressions;
using MySql.Data.MySqlClient.Properties;

namespace MySql.Data.MySqlClient
{
    internal class SchemaProvider
    {
        protected MySqlConnection connection;
        public static string MetaCollection = "MetaDataCollections";

        public SchemaProvider(MySqlConnection connectionToUse)
        {
            connection = connectionToUse;
        }

        public virtual DataTable GetSchema(string collection, String[] restrictions)
        {
            if (connection.State != ConnectionState.Open)
                throw new MySqlException("GetSchema can only be called on an open connection.");

            collection = collection.ToUpper(CultureInfo.InvariantCulture);

            DataTable dt = GetSchemaInternal(collection, restrictions);

            if (dt == null)
                throw new MySqlException("Invalid collection name");
            return dt;
        }

        public virtual DataTable GetDatabases(string[] restrictions)
        {
			Regex regex = null;
			int caseSetting = Int32.Parse(connection.driver.Property("lower_case_table_names"));

            string sql = "SHOW DATABASES";

			// if lower_case_table_names is zero, then case lookup should be sensitive
			// so we can use LIKE to do the matching.
			if (caseSetting == 0)
			{
				if (restrictions != null && restrictions.Length >= 1)
					sql = sql + " LIKE '" + restrictions[0] + "'";
			}
			else if (restrictions != null && restrictions.Length >= 1 && restrictions[0] != null)
				regex = new Regex(restrictions[0], RegexOptions.IgnoreCase);

            MySqlDataAdapter da = new MySqlDataAdapter(sql, connection);
            DataTable dt = new DataTable();
            da.Fill(dt);

            DataTable table = new DataTable("Databases");
            table.Columns.Add("CATALOG_NAME", typeof (string));
            table.Columns.Add("SCHEMA_NAME", typeof (string));

            foreach (DataRow row in dt.Rows)
            {
				if (caseSetting != 0 && regex != null && 
					!regex.Match(row[0].ToString()).Success) continue;

                DataRow newRow = table.NewRow();
                newRow[1] = row[0];
                table.Rows.Add(newRow);
            }

            return table;
        }

        public virtual DataTable GetTables(string[] restrictions)
        {
            DataTable dt = new DataTable("Tables");
            dt.Columns.Add("TABLE_CATALOG", typeof (string));
            dt.Columns.Add("TABLE_SCHEMA", typeof (string));
            dt.Columns.Add("TABLE_NAME", typeof (string));
            dt.Columns.Add("TABLE_TYPE", typeof (string));
            dt.Columns.Add("ENGINE", typeof (string));
            dt.Columns.Add("VERSION", typeof (ulong));
            dt.Columns.Add("ROW_FORMAT", typeof (string));
            dt.Columns.Add("TABLE_ROWS", typeof (ulong));
            dt.Columns.Add("AVG_ROW_LENGTH", typeof (ulong));
            dt.Columns.Add("DATA_LENGTH", typeof (ulong));
            dt.Columns.Add("MAX_DATA_LENGTH", typeof (ulong));
            dt.Columns.Add("INDEX_LENGTH", typeof (ulong));
            dt.Columns.Add("DATA_FREE", typeof (ulong));
            dt.Columns.Add("AUTO_INCREMENT", typeof (ulong));
            dt.Columns.Add("CREATE_TIME", typeof (DateTime));
            dt.Columns.Add("UPDATE_TIME", typeof (DateTime));
            dt.Columns.Add("CHECK_TIME", typeof (DateTime));
            dt.Columns.Add("TABLE_COLLATION", typeof (string));
            dt.Columns.Add("CHECKSUM", typeof (ulong));
            dt.Columns.Add("CREATE_OPTIONS", typeof (string));
            dt.Columns.Add("TABLE_COMMENT", typeof (string));

            // we have to new up a new restriction array here since
            // GetDatabases takes the database in the first slot
            string[] dbRestriction = new string[4];
            if (restrictions != null && restrictions.Length >= 2)
                dbRestriction[0] = restrictions[1];
            DataTable databases = GetDatabases(dbRestriction);

            if (restrictions != null)
                Array.Copy(restrictions, dbRestriction,
                           Math.Min(dbRestriction.Length, restrictions.Length));

            foreach (DataRow db in databases.Rows)
            {
                dbRestriction[1] = db["SCHEMA_NAME"].ToString();
                FindTables(dt, dbRestriction);
            }
            return dt;
        }

        public virtual DataTable GetColumns(string[] restrictions)
        {
            DataTable dt = new DataTable("Columns");
            dt.Columns.Add("TABLE_CATALOG", typeof (string));
            dt.Columns.Add("TABLE_SCHEMA", typeof (string));
            dt.Columns.Add("TABLE_NAME", typeof (string));
            dt.Columns.Add("COLUMN_NAME", typeof (string));
            dt.Columns.Add("ORDINAL_POSITION", typeof (ulong));
            dt.Columns.Add("COLUMN_DEFAULT", typeof (string));
            dt.Columns.Add("IS_NULLABLE", typeof (string));
            dt.Columns.Add("DATA_TYPE", typeof (string));
            dt.Columns.Add("CHARACTER_MAXIMUM_LENGTH", typeof (ulong));
            dt.Columns.Add("CHARACTER_OCTET_LENGTH", typeof (ulong));
            dt.Columns.Add("NUMERIC_PRECISION", typeof (ulong));
            dt.Columns.Add("NUMERIC_SCALE", typeof (ulong));
            dt.Columns.Add("CHARACTER_SET_NAME", typeof (string));
            dt.Columns.Add("COLLATION_NAME", typeof (string));
            dt.Columns.Add("COLUMN_TYPE", typeof (string));
            dt.Columns.Add("COLUMN_KEY", typeof (string));
            dt.Columns.Add("EXTRA", typeof (string));
            dt.Columns.Add("PRIVILEGES", typeof (string));
            dt.Columns.Add("COLUMN_COMMENT", typeof (string));

            // we don't allow restricting on table type here
            string columnName = null;
            if (restrictions != null && restrictions.Length == 4)
            {
                columnName = restrictions[3];
                restrictions[3] = null;
            }
            DataTable tables = GetTables(restrictions);

            foreach (DataRow row in tables.Rows)
                LoadTableColumns(dt, row["TABLE_SCHEMA"].ToString(),
                                 row["TABLE_NAME"].ToString(), columnName);

            return dt;
        }

        private void LoadTableColumns(DataTable dt, string schema,
                                      string tableName, string columnRestriction)
        {
            string sql = String.Format("SHOW FULL COLUMNS FROM `{0}`.`{1}`",
                                       schema, tableName);
            MySqlCommand cmd = new MySqlCommand(sql, connection);

            int pos = 1;
            using (MySqlDataReader reader = cmd.ExecuteReader())
            {
                while (reader.Read())
                {
                    string colName = reader.GetString(0);
                    if (columnRestriction != null && colName != columnRestriction)
                        continue;
                    DataRow row = dt.NewRow();
                    row["TABLE_CATALOG"] = DBNull.Value;
                    row["TABLE_SCHEMA"] = schema;
                    row["TABLE_NAME"] = tableName;
                    row["COLUMN_NAME"] = colName;
                    row["ORDINAL_POSITION"] = pos++;
                    row["COLUMN_DEFAULT"] = reader.GetValue(5);
                    row["IS_NULLABLE"] = reader.GetString(3);
                    row["DATA_TYPE"] = reader.GetString(1);
                    row["CHARACTER_MAXIMUM_LENGTH"] = DBNull.Value;
                    row["CHARACTER_OCTET_LENGTH"] = DBNull.Value;
                    row["NUMERIC_PRECISION"] = DBNull.Value;
                    row["NUMERIC_SCALE"] = DBNull.Value;
                    row["CHARACTER_SET_NAME"] = reader.GetValue(2);
                    row["COLLATION_NAME"] = row["CHARACTER_SET_NAME"];
                    row["COLUMN_TYPE"] = reader.GetString(1);
                    row["COLUMN_KEY"] = reader.GetString(4);
                    row["EXTRA"] = reader.GetString(6);
                    row["PRIVILEGES"] = reader.GetString(7);
                    row["COLUMN_COMMENT"] = reader.GetString(8);
                    ParseColumnRow(row);
                    dt.Rows.Add(row);
                }
            }
        }

        private static void ParseColumnRow(DataRow row)
        {
            // first parse the character set name
            string charset = row["CHARACTER_SET_NAME"].ToString();
            int index = charset.IndexOf('_');
            if (index != -1)
                row["CHARACTER_SET_NAME"] = charset.Substring(0, index);

            // now parse the data type
            string dataType = row["DATA_TYPE"].ToString();
            index = dataType.IndexOf('(');
            if (index == -1)
                return;
            row["DATA_TYPE"] = dataType.Substring(0, index);
            int stop = dataType.IndexOf(')', index);
            string dataLen = dataType.Substring(index + 1, stop - (index + 1));
            string lowerType = row["DATA_TYPE"].ToString().ToLower();
            if (lowerType == "char" || lowerType == "varchar")
                row["CHARACTER_MAXIMUM_LENGTH"] = dataLen;
            else if (lowerType == "real" || lowerType == "decimal")
            {
                string[] lenparts = dataLen.Split(new char[] {','});
                row["NUMERIC_PRECISION"] = lenparts[0];
                if (lenparts.Length == 2)
                    row["NUMERIC_SCALE"] = lenparts[1];
            }
        }

        public virtual DataTable GetIndexes(string[] restrictions)
        {
            DataTable dt = new DataTable("Indexes");
            dt.Columns.Add("INDEX_CATALOG", typeof (string));
            dt.Columns.Add("INDEX_SCHEMA", typeof (string));
            dt.Columns.Add("INDEX_NAME", typeof (string));
            dt.Columns.Add("TABLE_NAME", typeof (string));
            dt.Columns.Add("UNIQUE", typeof (bool));
            dt.Columns.Add("PRIMARY", typeof (bool));
            dt.Columns.Add("TYPE", typeof(string));
            dt.Columns.Add("COMMENT", typeof(string));

            // Get the list of tables first
            int max = restrictions == null ? 4 : restrictions.Length;
            string[] tableRestrictions = new string[Math.Max(max, 4)];
            if (restrictions != null)
                restrictions.CopyTo(tableRestrictions, 0);
            tableRestrictions[3] = "BASE TABLE";
            DataTable tables = GetTables(tableRestrictions);

            foreach (DataRow table in tables.Rows)
            {
                string sql = String.Format("SHOW INDEX FROM `{0}`.`{1}`",
                    MySqlHelper.DoubleQuoteString((string)table["TABLE_SCHEMA"]), 
                    MySqlHelper.DoubleQuoteString((string)table["TABLE_NAME"]));
                MySqlDataAdapter da = new MySqlDataAdapter(sql, connection);
                DataTable indexes = new DataTable();
                da.Fill(indexes);
                foreach (DataRow index in indexes.Rows)
                {
                    long seq_index = (long) index["SEQ_IN_INDEX"];
                    if (seq_index != 1) continue;
                    if (restrictions != null && restrictions.Length == 4 &&
                        restrictions[3] != null &&
                        !index["KEY_NAME"].Equals(restrictions[3])) continue;
                    DataRow row = dt.NewRow();
                    row["INDEX_CATALOG"] = null;
                    row["INDEX_SCHEMA"] = table["TABLE_SCHEMA"];
                    row["INDEX_NAME"] = index["KEY_NAME"];
                    row["TABLE_NAME"] = index["TABLE"];
                    row["UNIQUE"] = (long) index["NON_UNIQUE"] == 0;
                    row["PRIMARY"] = index["KEY_NAME"].Equals("PRIMARY");
                    row["TYPE"] = index["INDEX_TYPE"];
                    row["COMMENT"] = index["COMMENT"];
                    dt.Rows.Add(row);
                }
            }

            return dt;
        }

        public virtual DataTable GetIndexColumns(string[] restrictions)
        {
            DataTable dt = new DataTable("IndexColumns");
            dt.Columns.Add("INDEX_CATALOG", typeof (string));
            dt.Columns.Add("INDEX_SCHEMA", typeof (string));
            dt.Columns.Add("INDEX_NAME", typeof (string));
            dt.Columns.Add("TABLE_NAME", typeof (string));
            dt.Columns.Add("COLUMN_NAME", typeof (string));
            dt.Columns.Add("ORDINAL_POSITION", typeof (int));
            dt.Columns.Add("SORT_ORDER", typeof(string));

            int max = restrictions == null ? 4 : restrictions.Length;
            string[] tableRestrictions = new string[Math.Max(max, 4)];
            if (restrictions != null)
                restrictions.CopyTo(tableRestrictions, 0);
            tableRestrictions[3] = "BASE TABLE";
            DataTable tables = GetTables(tableRestrictions);

            foreach (DataRow table in tables.Rows)
            {
                string sql = String.Format("SHOW INDEX FROM `{0}`.`{1}`",
                                           table["TABLE_SCHEMA"], table["TABLE_NAME"]);
                MySqlCommand cmd = new MySqlCommand(sql, connection);
                using (MySqlDataReader reader = cmd.ExecuteReader())
                {
                    while (reader.Read())
                    {
                        string key_name = GetString(reader, reader.GetOrdinal("KEY_NAME"));
                        string col_name = GetString(reader, reader.GetOrdinal("COLUMN_NAME"));

                        if (restrictions != null)
                        {
                            if (restrictions.Length >= 4 && restrictions[3] != null &&
                                key_name != restrictions[3]) continue;
                            if (restrictions.Length >= 5 && restrictions[4] != null &&
                                col_name != restrictions[4]) continue;
                        }
                        DataRow row = dt.NewRow();
                        row["INDEX_CATALOG"] = null;
                        row["INDEX_SCHEMA"] = table["TABLE_SCHEMA"];
                        row["INDEX_NAME"] = key_name;
                        row["TABLE_NAME"] = GetString(reader, reader.GetOrdinal("TABLE"));
                        row["COLUMN_NAME"] = col_name;
                        row["ORDINAL_POSITION"] = reader.GetValue(reader.GetOrdinal("SEQ_IN_INDEX"));
                        row["SORT_ORDER"] = reader.GetString("COLLATION");
                        dt.Rows.Add(row);
                    }
                }
            }

            return dt;
        }

        public virtual DataTable GetForeignKeys(string[] restrictions)
        {
            DataTable dt = new DataTable("Foreign Keys");
            dt.Columns.Add("CONSTRAINT_CATALOG", typeof (string));
            dt.Columns.Add("CONSTRAINT_SCHEMA", typeof (string));
            dt.Columns.Add("CONSTRAINT_NAME", typeof (string));
            dt.Columns.Add("TABLE_CATALOG", typeof(string));
            dt.Columns.Add("TABLE_SCHEMA", typeof (string));
            dt.Columns.Add("TABLE_NAME", typeof (string));
            dt.Columns.Add("MATCH_OPTION", typeof(string));
            dt.Columns.Add("UPDATE_RULE", typeof(string));
            dt.Columns.Add("DELETE_RULE", typeof(string));
            dt.Columns.Add("REFERENCED_TABLE_CATALOG", typeof (string));
            dt.Columns.Add("REFERENCED_TABLE_SCHEMA", typeof (string));
            dt.Columns.Add("REFERENCED_TABLE_NAME", typeof (string));

            // first we use our restrictions to get a list of tables that should be
            // consulted.  We save the keyname restriction since GetTables doesn't 
            // understand that.
            string keyName = null;
            if (restrictions != null && restrictions.Length >= 4)
            {
                keyName = restrictions[3];
                restrictions[3] = null;
            }

            DataTable tables = GetTables(restrictions);

            // now for each table retrieved, we call our helper function to
            // parse it's foreign keys
            foreach (DataRow table in tables.Rows)
                GetForeignKeysOnTable(dt, table, keyName, false);

            return dt;
        }

        public virtual DataTable GetForeignKeyColumns(string[] restrictions)
        {
            DataTable dt = new DataTable("Foreign Keys");
            dt.Columns.Add("CONSTRAINT_CATALOG", typeof(string));
            dt.Columns.Add("CONSTRAINT_SCHEMA", typeof(string));
            dt.Columns.Add("CONSTRAINT_NAME", typeof(string));
            dt.Columns.Add("TABLE_CATALOG", typeof(string));
            dt.Columns.Add("TABLE_SCHEMA", typeof(string));
            dt.Columns.Add("TABLE_NAME", typeof(string));
            dt.Columns.Add("COLUMN_NAME", typeof(string));
            dt.Columns.Add("ORDINAL_POSITION", typeof(int));
            dt.Columns.Add("REFERENCED_TABLE_CATALOG", typeof(string));
            dt.Columns.Add("REFERENCED_TABLE_SCHEMA", typeof(string));
            dt.Columns.Add("REFERENCED_TABLE_NAME", typeof(string));
            dt.Columns.Add("REFERENCED_COLUMN_NAME", typeof(string));

            // first we use our restrictions to get a list of tables that should be
            // consulted.  We save the keyname restriction since GetTables doesn't 
            // understand that.
            string keyName = null;
            if (restrictions != null && restrictions.Length >= 4)
            {
                keyName = restrictions[3];
                restrictions[3] = null;
            }

            DataTable tables = GetTables(restrictions);

            // now for each table retrieved, we call our helper function to
            // parse it's foreign keys
            foreach (DataRow table in tables.Rows)
                GetForeignKeysOnTable(dt, table, keyName, true); 
            return dt;
        }


        private string GetSqlMode()
        {
            MySqlCommand cmd = new MySqlCommand("SELECT @@SQL_MODE", connection);
            return cmd.ExecuteScalar().ToString();
        }

        #region Foreign Key routines

        /// <summary>
        /// GetForeignKeysOnTable retrieves the foreign keys on the given table.
        /// Since MySQL supports foreign keys on versions prior to 5.0, we can't  use
        /// information schema.  MySQL also does not include any type of SHOW command
        /// for foreign keys so we have to resort to use SHOW CREATE TABLE and parsing
        /// the output.
        /// </summary>
        /// <param name="fkTable">The table to store the key info in.</param>
        /// <param name="tableToParse">The table to get the foeign key info for.</param>
        /// <param name="filterName">Only get foreign keys that match this name.</param>
		/// <param name="includeColumns">Should column information be included in the table.</param>
        private void GetForeignKeysOnTable(DataTable fkTable, DataRow tableToParse,
                                           string filterName, bool includeColumns)
        {
            string sqlMode = GetSqlMode();

            if (filterName != null)
                filterName = filterName.ToLower(CultureInfo.InvariantCulture);

            string sql = string.Format("SHOW CREATE TABLE `{0}`.`{1}`",
                                       tableToParse["TABLE_SCHEMA"], tableToParse["TABLE_NAME"]);
            string lowerBody = null, body = null;
            MySqlCommand cmd = new MySqlCommand(sql, connection);
            using (MySqlDataReader reader = cmd.ExecuteReader())
            {
                reader.Read();
                body = reader.GetString(1);
                lowerBody = body.ToLower(CultureInfo.InvariantCulture);
            }

            MySqlTokenizer tokenizer = new MySqlTokenizer(lowerBody);
            tokenizer.AnsiQuotes = sqlMode.IndexOf("ANSI_QUOTES") != -1;
            tokenizer.BackslashEscapes = sqlMode.IndexOf("NO_BACKSLASH_ESCAPES") != -1;
            
            while (true)
            {
                string token = tokenizer.NextToken();
                // look for a starting contraint
                while (token != null && (token != "constraint" || tokenizer.Quoted))
                    token = tokenizer.NextToken();
                if (token == null) break;

                ParseConstraint(fkTable, tableToParse, tokenizer, includeColumns);
            }
        }

        private static void ParseConstraint(DataTable fkTable, DataRow table, 
            MySqlTokenizer tokenizer, bool includeColumns)
        {
            string name = tokenizer.NextToken();
            DataRow row = fkTable.NewRow();

            // make sure this constraint is a FK
            string token = tokenizer.NextToken();
            if (token != "foreign" || tokenizer.Quoted)
                return;
            tokenizer.NextToken(); // read off the 'KEY' symbol
            tokenizer.NextToken(); // read off the '(' symbol

            row["CONSTRAINT_CATALOG"] = table["TABLE_CATALOG"];
            row["CONSTRAINT_SCHEMA"] = table["TABLE_SCHEMA"];
            row["TABLE_CATALOG"] = table["TABLE_CATALOG"];
            row["TABLE_SCHEMA"] = table["TABLE_SCHEMA"];
            row["TABLE_NAME"] = table["TABLE_NAME"];
            row["REFERENCED_TABLE_CATALOG"] = null;
            row["CONSTRAINT_NAME"] = name.Trim(new char[] { '\'', '`' });

            ArrayList srcColumns = includeColumns ? ParseColumns(tokenizer) : null;

            // now look for the references section
            while (token != "references" || tokenizer.Quoted)
                token = tokenizer.NextToken();
            string target1 = tokenizer.NextToken();
            string target2 = tokenizer.NextToken();
            if (target2.StartsWith("."))
            {
                row["REFERENCED_TABLE_SCHEMA"] = target1;
                row["REFERENCED_TABLE_NAME"] = target2.Substring(1).Trim(new char[] { '\'', '`' });
                tokenizer.NextToken();  // read off the '('
            }
            else
            {
                row["REFERENCED_TABLE_SCHEMA"] = table["TABLE_SCHEMA"];
                row["REFERENCED_TABLE_NAME"] = target1.Substring(1).Trim(new char[] { '\'', '`' }); ;
            }

            // if we are supposed to include columns, read the target columns
            ArrayList targetColumns = includeColumns ? ParseColumns(tokenizer) : null;

            if (includeColumns)
                ProcessColumns(fkTable, row, srcColumns, targetColumns);
            else
                fkTable.Rows.Add(row);
        }

        private static ArrayList ParseColumns(MySqlTokenizer tokenizer)
        {
            ArrayList sc = new ArrayList();
            string token = tokenizer.NextToken();
            while (token != ")")
            {
                if (token != ",")
                    sc.Add(token);
                token = tokenizer.NextToken();
            }
            return sc;
        }

        private static void ProcessColumns(DataTable fkTable, DataRow row,
            ArrayList srcColumns, ArrayList targetColumns)
        {
            for (int i = 0; i < srcColumns.Count; i++)
            {
                DataRow newRow = fkTable.NewRow();
                newRow.ItemArray = row.ItemArray;
                newRow["COLUMN_NAME"] = (string)srcColumns[i];
                newRow["ORDINAL_POSITION"] = i;
                newRow["REFERENCED_COLUMN_NAME"] = (string)targetColumns[i];
                fkTable.Rows.Add(newRow);
            }
        }

        #endregion

        public virtual DataTable GetUsers(string[] restrictions)
        {
            StringBuilder sb = new StringBuilder("SELECT Host, User FROM mysql.user");
            if (restrictions != null && restrictions.Length > 0)
                sb.AppendFormat(CultureInfo.InvariantCulture, " WHERE User LIKE '{0}'", restrictions[0]);

            MySqlDataAdapter da = new MySqlDataAdapter(sb.ToString(), connection);
            DataTable dt = new DataTable();
            da.Fill(dt);
            dt.TableName = "Users";
            dt.Columns[0].ColumnName = "HOST";
            dt.Columns[1].ColumnName = "USERNAME";

            return dt;
        }

        public virtual DataTable GetProcedures(string[] restrictions)
        {
            DataTable dt = new DataTable("Procedures");
            dt.Columns.Add(new DataColumn("SPECIFIC_NAME", typeof(string)));
            dt.Columns.Add(new DataColumn("ROUTINE_CATALOG", typeof(string)));
            dt.Columns.Add(new DataColumn("ROUTINE_SCHEMA", typeof(string)));
            dt.Columns.Add(new DataColumn("ROUTINE_NAME", typeof(string)));
            dt.Columns.Add(new DataColumn("ROUTINE_TYPE", typeof(string)));
            dt.Columns.Add(new DataColumn("DTD_IDENTIFIER", typeof(string)));
            dt.Columns.Add(new DataColumn("ROUTINE_BODY", typeof(string)));
            dt.Columns.Add(new DataColumn("ROUTINE_DEFINITION", typeof(string)));
            dt.Columns.Add(new DataColumn("EXTERNAL_NAME", typeof(string)));
            dt.Columns.Add(new DataColumn("EXTERNAL_LANGUAGE", typeof(string)));
            dt.Columns.Add(new DataColumn("PARAMETER_STYLE", typeof(string)));
            dt.Columns.Add(new DataColumn("IS_DETERMINISTIC", typeof(string)));
            dt.Columns.Add(new DataColumn("SQL_DATA_ACCESS", typeof(string)));
            dt.Columns.Add(new DataColumn("SQL_PATH", typeof(string)));
            dt.Columns.Add(new DataColumn("SECURITY_TYPE", typeof(string)));
            dt.Columns.Add(new DataColumn("CREATED", typeof(DateTime)));
            dt.Columns.Add(new DataColumn("LAST_ALTERED", typeof(DateTime)));
            dt.Columns.Add(new DataColumn("SQL_MODE", typeof(string)));
            dt.Columns.Add(new DataColumn("ROUTINE_COMMENT", typeof(string)));
            dt.Columns.Add(new DataColumn("DEFINER", typeof(string)));

            StringBuilder sql = new StringBuilder("SELECT * FROM mysql.proc WHERE 1=1");
            if (restrictions != null)
            {
                if (restrictions.Length >= 2 && restrictions[1] != null)
                    sql.AppendFormat(CultureInfo.InvariantCulture, 
                        " AND db LIKE '{0}'", restrictions[1]);
                if (restrictions.Length >= 3 && restrictions[2] != null)
                    sql.AppendFormat(CultureInfo.InvariantCulture, 
                        " AND name LIKE '{0}'", restrictions[2]);
                if (restrictions.Length >= 4 && restrictions[3] != null)
                    sql.AppendFormat(CultureInfo.InvariantCulture, 
                        " AND type LIKE '{0}'", restrictions[3]);
            }

            MySqlCommand cmd = new MySqlCommand(sql.ToString(), connection);
            using (MySqlDataReader reader = cmd.ExecuteReader())
            {
                while (reader.Read())
                {
                    DataRow row = dt.NewRow();
                    row["SPECIFIC_NAME"] = reader.GetString("specific_name");
                    row["ROUTINE_CATALOG"] = DBNull.Value;
                    row["ROUTINE_SCHEMA"] = reader.GetString("db");
                    row["ROUTINE_NAME"] = reader.GetString("name");
                    string routineType = reader.GetString("type");
                    row["ROUTINE_TYPE"] = routineType;
                    row["DTD_IDENTIFIER"] = routineType.ToLower(CultureInfo.InvariantCulture) == "function" ?
                        (object)reader.GetString("returns") : DBNull.Value;
                    row["ROUTINE_BODY"] = "SQL";
                    row["ROUTINE_DEFINITION"] = reader.GetString("body");
                    row["EXTERNAL_NAME"] = DBNull.Value;
                    row["EXTERNAL_LANGUAGE"] = DBNull.Value;
                    row["PARAMETER_STYLE"] = "SQL";
                    row["IS_DETERMINISTIC"] = reader.GetString("is_deterministic");
                    row["SQL_DATA_ACCESS"] = reader.GetString("sql_data_access");
                    row["SQL_PATH"] = DBNull.Value;
                    row["SECURITY_TYPE"] = reader.GetString("security_type");
                    row["CREATED"] = reader.GetDateTime("created");
                    row["LAST_ALTERED"] = reader.GetDateTime("modified");
                    row["SQL_MODE"] = reader.GetString("sql_mode");
                    row["ROUTINE_COMMENT"] = reader.GetString("comment");
                    row["DEFINER"] = reader.GetString("definer");
                    dt.Rows.Add(row);
                }
            }

            return dt;
        }

        protected virtual DataTable GetCollections()
        {
            object[][] collections = new object[][]
                {
                    new object[] {"MetaDataCollections", 0, 0},
                    new object[] {"DataSourceInformation", 0, 0},
                    new object[] {"DataTypes", 0, 0},
                    new object[] {"Restrictions", 0, 0},
                    new object[] {"ReservedWords", 0, 0},
                    new object[] {"Databases", 1, 1},
                    new object[] {"Tables", 4, 2},
                    new object[] {"Columns", 4, 4},
                    new object[] {"Users", 1, 1},
                    new object[] {"Foreign Keys", 4, 3},
                    new object[] {"IndexColumns", 5, 4},
                    new object[] {"Indexes", 4, 3},
                    new object[] {"Foreign Key Columns", 4, 3},
                    new object[] {"UDF", 1, 1}
                };

            DataTable dt = new DataTable("MetaDataCollections");
            dt.Columns.Add(new DataColumn("CollectionName", typeof (string)));
            dt.Columns.Add(new DataColumn("NumberOfRestrictions", typeof(int)));
            dt.Columns.Add(new DataColumn("NumberOfIdentifierParts", typeof (int)));

            FillTable(dt, collections);

            return dt;
        }

        private DataTable GetDataSourceInformation()
        {
#if CF
            throw new NotSupportedException();
#else
            DataTable dt = new DataTable("DataSourceInformation");
            dt.Columns.Add("CompositeIdentifierSeparatorPattern", typeof (string));
            dt.Columns.Add("DataSourceProductName", typeof (string));
            dt.Columns.Add("DataSourceProductVersion", typeof (string));
            dt.Columns.Add("DataSourceProductVersionNormalized", typeof (string));
            dt.Columns.Add("GroupByBehavior", typeof (GroupByBehavior));
            dt.Columns.Add("IdentifierPattern", typeof (string));
            dt.Columns.Add("IdentifierCase", typeof (IdentifierCase));
            dt.Columns.Add("OrderByColumnsInSelect", typeof (bool));
            dt.Columns.Add("ParameterMarkerFormat", typeof (string));
            dt.Columns.Add("ParameterMarkerPattern", typeof (string));
            dt.Columns.Add("ParameterNameMaxLength", typeof (int));
            dt.Columns.Add("ParameterNamePattern", typeof (string));
            dt.Columns.Add("QuotedIdentifierPattern", typeof (string));
            dt.Columns.Add("QuotedIdentifierCase", typeof (IdentifierCase));
            dt.Columns.Add("StatementSeparatorPattern", typeof (string));
            dt.Columns.Add("StringLiteralPattern", typeof (string));
            dt.Columns.Add("SupportedJoinOperators", typeof (SupportedJoinOperators));

            DBVersion v = connection.driver.Version;
            string ver = String.Format("{0:0}.{1:0}.{2:0}",
                                       v.Major, v.Minor, v.Build);

            DataRow row = dt.NewRow();
            row["CompositeIdentifierSeparatorPattern"] = "\\.";
            row["DataSourceProductName"] = "MySQL";
            row["DataSourceProductVersion"] = connection.ServerVersion;
            row["DataSourceProductVersionNormalized"] = ver;
            row["GroupByBehavior"] = GroupByBehavior.Unrelated;
            row["IdentifierPattern"] =
                @"(^\`\p{Lo}\p{Lu}\p{Ll}_@#][\p{Lo}\p{Lu}\p{Ll}\p{Nd}@$#_]*$)|(^\`[^\`\0]|\`\`+\`$)|(^\"" + [^\""\0]|\""\""+\""$)";
            row["IdentifierCase"] = IdentifierCase.Insensitive;
            row["OrderByColumnsInSelect"] = false;
            row["ParameterMarkerFormat"] = "{0}";
            row["ParameterMarkerPattern"] = "(@[A-Za-z0-9_$#]*)";
            row["ParameterNameMaxLength"] = 128;
            row["ParameterNamePattern"] =
                @"^[\p{Lo}\p{Lu}\p{Ll}\p{Lm}_@#][\p{Lo}\p{Lu}\p{Ll}\p{Lm}\p{Nd}\uff3f_@#\$]*(?=\s+|$)";
            row["QuotedIdentifierPattern"] = @"(([^\`]|\`\`)*)";
            row["QuotedIdentifierCase"] = IdentifierCase.Sensitive;
            row["StatementSeparatorPattern"] = ";";
            row["StringLiteralPattern"] = "'(([^']|'')*)'";
            row["SupportedJoinOperators"] = 15;
            dt.Rows.Add(row);

            return dt;
#endif
        }

        private static DataTable GetDataTypes()
        {
            DataTable dt = new DataTable("DataTypes");
            dt.Columns.Add(new DataColumn("TypeName", typeof (string)));
            dt.Columns.Add(new DataColumn("ProviderDbType", typeof (int)));
            dt.Columns.Add(new DataColumn("ColumnSize", typeof (long)));
            dt.Columns.Add(new DataColumn("CreateFormat", typeof (string)));
            dt.Columns.Add(new DataColumn("CreateParameters", typeof (string)));
            dt.Columns.Add(new DataColumn("DataType", typeof (string)));
            dt.Columns.Add(new DataColumn("IsAutoincrementable", typeof (bool)));
            dt.Columns.Add(new DataColumn("IsBestMatch", typeof (bool)));
            dt.Columns.Add(new DataColumn("IsCaseSensitive", typeof (bool)));
            dt.Columns.Add(new DataColumn("IsFixedLength", typeof (bool)));
            dt.Columns.Add(new DataColumn("IsFixedPrecisionScale", typeof (bool)));
            dt.Columns.Add(new DataColumn("IsLong", typeof (bool)));
            dt.Columns.Add(new DataColumn("IsNullable", typeof (bool)));
            dt.Columns.Add(new DataColumn("IsSearchable", typeof (bool)));
            dt.Columns.Add(new DataColumn("IsSearchableWithLike", typeof (bool)));
            dt.Columns.Add(new DataColumn("IsUnsigned", typeof (bool)));
            dt.Columns.Add(new DataColumn("MaximumScale", typeof (short)));
            dt.Columns.Add(new DataColumn("MinimumScale", typeof (short)));
            dt.Columns.Add(new DataColumn("IsConcurrencyType", typeof (bool)));
            dt.Columns.Add(new DataColumn("IsLiteralSupported", typeof (bool)));
            dt.Columns.Add(new DataColumn("LiteralPrefix", typeof (string)));
            dt.Columns.Add(new DataColumn("LiteralSuffix", typeof (string)));
            dt.Columns.Add(new DataColumn("NativeDataType", typeof (string)));

            // have each one of the types contribute to the datatypes collection
            MySqlBit.SetDSInfo(dt);
            MySqlBinary.SetDSInfo(dt);
            MySqlDateTime.SetDSInfo(dt);
            MySqlTimeSpan.SetDSInfo(dt);
            MySqlString.SetDSInfo(dt);
            MySqlDouble.SetDSInfo(dt);
            MySqlSingle.SetDSInfo(dt);
            MySqlByte.SetDSInfo(dt);
            MySqlInt16.SetDSInfo(dt);
            MySqlInt32.SetDSInfo(dt);
            MySqlInt64.SetDSInfo(dt);
            MySqlDecimal.SetDSInfo(dt);
            MySqlUByte.SetDSInfo(dt);
            MySqlUInt16.SetDSInfo(dt);
            MySqlUInt32.SetDSInfo(dt);
            MySqlUInt64.SetDSInfo(dt);

            return dt;
        }

        protected virtual DataTable GetRestrictions()
        {
            object[][] restrictions = new object[][]
                {
                    new object[] {"Users", "Name", "", 0},
                    new object[] {"Databases", "Name", "", 0},
                    new object[] {"Tables", "Database", "", 0},
                    new object[] {"Tables", "Schema", "", 1},
                    new object[] {"Tables", "Table", "", 2},
                    new object[] {"Tables", "TableType", "", 3},
                    new object[] {"Columns", "Database", "", 0},
                    new object[] {"Columns", "Schema", "", 1},
                    new object[] {"Columns", "Table", "", 2},
                    new object[] {"Columns", "Column", "", 3},
                    new object[] {"Indexes", "Database", "", 0},
                    new object[] {"Indexes", "Schema", "", 1},
                    new object[] {"Indexes", "Table", "", 2},
                    new object[] {"Indexes", "Name", "", 3},
                    new object[] {"IndexColumns", "Database", "", 0},
                    new object[] {"IndexColumns", "Schema", "", 1},
                    new object[] {"IndexColumns", "Table", "", 2},
                    new object[] {"IndexColumns", "ConstraintName", "", 3},
                    new object[] {"IndexColumns", "Column", "", 4},
                    new object[] {"Foreign Keys", "Database", "", 0},
                    new object[] {"Foreign Keys", "Schema", "", 1},
                    new object[] {"Foreign Keys", "Table", "", 2},
                    new object[] {"Foreign Keys", "Constraint Name", "", 3},
                    new object[] {"Foreign Key Columns", "Catalog", "", 0},
                    new object[] {"Foreign Key Columns", "Schema", "", 1},
                    new object[] {"Foreign Key Columns", "Table", "", 2},
                    new object[] {"Foreign Key Columns", "Constraint Name", "", 3},
                    new object[] {"UDF", "Name", "", 0}
                };

            DataTable dt = new DataTable("Restrictions");
            dt.Columns.Add(new DataColumn("CollectionName", typeof (string)));
            dt.Columns.Add(new DataColumn("RestrictionName", typeof (string)));
            dt.Columns.Add(new DataColumn("RestrictionDefault", typeof (string)));
            dt.Columns.Add(new DataColumn("RestrictionNumber", typeof (int)));

            FillTable(dt, restrictions);

            return dt;
        }

        private static DataTable GetReservedWords()
        {
            DataTable dt = new DataTable("ReservedWords");
            dt.Columns.Add(new DataColumn(DbMetaDataColumnNames.ReservedWord, typeof(string)));

            Stream str = Assembly.GetExecutingAssembly().GetManifestResourceStream(
                "MySql.Data.MySqlClient.Properties.ReservedWords.txt");
            StreamReader sr = new StreamReader(str);
            string line = sr.ReadLine();
            while (line != null)
            {
                string[] keywords = line.Split(new char[] {' '});
                foreach (string s in keywords)
                {
                    if (String.IsNullOrEmpty(s)) continue;
                    DataRow row = dt.NewRow();
                    row[0] = s;
                    dt.Rows.Add(row);
                }
                line = sr.ReadLine();
            }
            sr.Close();
            str.Close();

            return dt;
        }

        protected static void FillTable(DataTable dt, object[][] data)
        {
            foreach (object[] dataItem in data)
            {
                DataRow row = dt.NewRow();
                for (int i = 0; i < dataItem.Length; i++)
                    row[i] = dataItem[i];
                dt.Rows.Add(row);
            }
        }

        private void FindTables(DataTable schemaTable, string[] restrictions)
        {
            StringBuilder sql = new StringBuilder();
            StringBuilder where = new StringBuilder();
            sql.AppendFormat(CultureInfo.InvariantCulture,
                             "SHOW TABLE STATUS FROM `{0}`", restrictions[1]);
            if (restrictions != null && restrictions.Length >= 3 &&
                restrictions[2] != null)
                where.AppendFormat(CultureInfo.InvariantCulture,
                                   " LIKE '{0}'", restrictions[2]);
            sql.Append(where.ToString());

            string table_type = restrictions[1].ToLower() == "information_schema"
                                    ?
                                "SYSTEM VIEW"
                                    : "BASE TABLE";

            MySqlCommand cmd = new MySqlCommand(sql.ToString(), connection);
            using (MySqlDataReader reader = cmd.ExecuteReader())
            {
                while (reader.Read())
                {
                    DataRow row = schemaTable.NewRow();
                    row["TABLE_CATALOG"] = null;
                    row["TABLE_SCHEMA"] = restrictions[1];
                    row["TABLE_NAME"] = reader.GetString(0);
                    row["TABLE_TYPE"] = table_type;
                    row["ENGINE"] = GetString(reader, 1);
                    row["VERSION"] = reader.GetValue(2);
                    row["ROW_FORMAT"] = GetString(reader, 3);
                    row["TABLE_ROWS"] = reader.GetValue(4);
                    row["AVG_ROW_LENGTH"] = reader.GetValue(5);
                    row["DATA_LENGTH"] = reader.GetValue(6);
                    row["MAX_DATA_LENGTH"] = reader.GetValue(7);
                    row["INDEX_LENGTH"] = reader.GetValue(8);
                    row["DATA_FREE"] = reader.GetValue(9);
                    row["AUTO_INCREMENT"] = reader.GetValue(10);
                    row["CREATE_TIME"] = reader.GetValue(11);
                    row["UPDATE_TIME"] = reader.GetValue(12);
                    row["CHECK_TIME"] = reader.GetValue(13);
                    row["TABLE_COLLATION"] = GetString(reader, 14);
                    row["CHECKSUM"] = reader.GetValue(15);
                    row["CREATE_OPTIONS"] = GetString(reader, 16);
                    row["TABLE_COMMENT"] = GetString(reader, 17);
                    schemaTable.Rows.Add(row);
                }
            }
        }

        private static string GetString(MySqlDataReader reader, int index)
        {
            if (reader.IsDBNull(index))
                return null;
            return reader.GetString(index);
        }

        public virtual DataTable GetUDF(string[] restrictions)
        {
            string sql = "SELECT name,ret,dl FROM mysql.func";
            if (restrictions != null)
            {
                if (restrictions.Length >= 1 && !String.IsNullOrEmpty(restrictions[0]))
                    sql += String.Format(" WHERE name LIKE '{0}'", restrictions[0]);
            }

            DataTable dt = new DataTable("User-defined Functions");
            dt.Columns.Add("NAME", typeof(string));
            dt.Columns.Add("RETURN_TYPE", typeof(int));
            dt.Columns.Add("LIBRARY_NAME", typeof(string));

            MySqlCommand cmd = new MySqlCommand(sql, connection);
            try
            {
                using (MySqlDataReader reader = cmd.ExecuteReader())
                {
                    while (reader.Read())
                    {
                        DataRow row = dt.NewRow();
                        row[0] = reader.GetString(0);
                        row[1] = reader.GetInt32(1);
                        row[2] = reader.GetString(2);
                        dt.Rows.Add(row);
                    }
                }
            }
            catch (MySqlException ex)
            {
                if (ex.Number != (int)MySqlErrorCode.TableAccessDenied)
                    throw;
                throw new MySqlException(Resources.UnableToEnumerateUDF, ex);
            }

            return dt;
        }

        protected virtual DataTable GetSchemaInternal(string collection, string[] restrictions)
        {
            switch (collection)
            {
                    // common collections
                case "METADATACOLLECTIONS":
                    return GetCollections();
                case "DATASOURCEINFORMATION":
                    return GetDataSourceInformation();
                case "DATATYPES":
                    return GetDataTypes();
                case "RESTRICTIONS":
                    return GetRestrictions();
                case "RESERVEDWORDS":
                    return GetReservedWords();

                    // collections specific to our provider
                case "USERS":
                    return GetUsers(restrictions);
                case "DATABASES":
                    return GetDatabases(restrictions);
                case "UDF":
                    return GetUDF(restrictions);
            }

            // if we have a current database and our users have
            // not specified a database, then default to the currently
            // selected one.
            if (restrictions == null)
                restrictions = new string[2];
            if (connection != null &&
                connection.Database != null &&
                connection.Database.Length > 0 &&
                restrictions.Length > 1 &&
                restrictions[1] == null)
                restrictions[1] = connection.Database;

            switch (collection)
            {
                case "TABLES":
                    return GetTables(restrictions);
                case "COLUMNS":
                    return GetColumns(restrictions);
                case "INDEXES":
                    return GetIndexes(restrictions);
                case "INDEXCOLUMNS":
                    return GetIndexColumns(restrictions);
                case "FOREIGN KEYS":
                    return GetForeignKeys(restrictions);
                case "FOREIGN KEY COLUMNS":
                    return GetForeignKeyColumns(restrictions);
            } 
            return null;
        }

        internal string[] CleanRestrictions(string[] restrictionValues)
        {
            string[] restrictions = null;
            if (restrictionValues != null)
            {
                restrictions = (string[])restrictionValues.Clone();

                for (int x = 0; x < restrictions.Length; x++)
                {
                    string s = restrictions[x];
                    if (s == null) continue;
                    restrictions[x] = s.Trim('`');
                }
            }
            return restrictions;
        }
    }
}