/************************************************************************************
 * 
 *  Umbraco Data Layer
 *  MIT Licensed work
 *  ©2008 Ruben Verborgh
 * 
 ***********************************************************************************/

using System;
using System.Data;
using System.Data.SqlClient;
using System.Xml;
using MSC = MySql.Data.MySqlClient;

namespace umbraco.DataLayer.SqlHelpers.MySql
{
    /// <summary>
    /// Sql Helper for a MySQL 5.0 database.
    /// </summary>
    public class MySqlHelper : SqlHelper<MSC.MySqlParameter>
    {
        /// <summary>SQL parser that replaces the SQL-Server specific tokens by their MySQL equivalent.</summary>
        private MySqlParser m_SqlParser = new MySqlParser();

        /// <summary>Initializes a new instance of the <see cref="MySqlHelper"/> class.</summary>
        /// <param name="connectionString">The connection string.</param>
        public MySqlHelper(string connectionString)
            : base(connectionString)
        {
            m_Utility = new MySqlUtility(this);
        }

        /// <summary>
        /// Creates a new parameter for use with this specific implementation of ISqlHelper.
        /// </summary>
        /// <param name="parameterName">Name of the parameter.</param>
        /// <param name="value">Value of the parameter.</param>
        /// <returns>A new parameter of the correct type.</returns>
        /// <remarks>Abstract factory pattern</remarks>
        public override IParameter CreateParameter(string parameterName, object value)
        {
            return new MySqlParameter(parameterName, value);
        }

        /// <summary>Converts a the command before executing.</summary>
        /// <param name="commandText">The command text.</param>
        /// <returns>The original command text.</returns>
        protected override string ConvertCommand(string commandText)
        {
            return m_SqlParser.Parse(commandText);
        }

        /// <summary>Executes a command that returns a single value.</summary>
        /// <param name="commandText">The command text.</param>
        /// <param name="parameters">The parameters.</param>
        /// <returns>The return value of the command.</returns>
        protected override object ExecuteScalar(string commandText, MSC.MySqlParameter[] parameters)
        {
            return MSC.MySqlHelper.ExecuteScalar(ConnectionString, commandText, parameters);
        }

        /// <summary>Executes a command and returns the number of rows affected.</summary>
        /// <param name="commandText">The command text.</param>
        /// <param name="parameters">The parameters.</param>
        /// <returns>
        /// The number of rows affected by the command.
        /// </returns>
        protected override int ExecuteNonQuery(string commandText, MSC.MySqlParameter[] parameters)
        {
            return MSC.MySqlHelper.ExecuteNonQuery(ConnectionString, commandText, parameters);
        }

        /// <summary>Executes a command and returns a records reader containing the results.</summary>
        /// <param name="commandText">The command text.</param>
        /// <param name="parameters">The parameters.</param>
        /// <returns>
        /// A data reader containing the results of the command.
        /// </returns>
        protected override IRecordsReader ExecuteReader(string commandText, MSC.MySqlParameter[] parameters)
        {
            return new MySqlDataReader(MSC.MySqlHelper.ExecuteReader(ConnectionString, commandText, parameters));
        }

        /// <summary>Converts the scalar value to the given type.</summary>
        /// <typeparam name="T">Desired type of the value.</typeparam>
        /// <param name="scalar">A scalar returned by ExecuteScalar.</param>
        /// <returns>The scalar, converted to type T.</returns>
        protected override T ConvertScalar<T>(object scalar)
        {
            if (scalar == null)
                return default(T);

            switch (typeof(T).FullName)
            {
                case "System.Boolean": return (T)(object)((1).Equals(scalar));
                default: return base.ConvertScalar<T>(scalar);
            }
        }
    }
}