using System;
using System.Data;
using System.IO;
using Common.Library.SQL.Base;
using MySql.Data.MySqlClient;

namespace Common.Library.SQL.MySQL
{
    public class MySQL : SQLBase
    {
        protected MySqlConnection DBConnection {get;set;}
        protected MySqlCommand DBCommand {get;set;}
        protected MySqlDataReader DBReader {get;set;}

        public MySQL(string server, string database, string username, string password)
        {
            DBConnectionInfo = new DBConnectionInformation()
            {
                DBHost = server,
                DBUserName = username,
                DBName = database,
                DBPassword = password,
                DBType = DBType.MYSQL
            };
        }
    
        protected override void InitConnection()
        {
            DBConnection = new MySqlConnection(DBConnectionInfo.GetConnectionString());
            DBConnection.Open();
            DBCommand = DBConnection.CreateCommand();
        }

        protected override void DisposeConnection()
        {
            if(DBConnection.State == ConnectionState.Open)
            {
                DBConnection.Close();
            }
        }

        protected override int GetOrdinal(string columnName)
        {
            return DBReader.GetOrdinal(columnName);
        }

        protected override int? GetInt(int columnID)
        {
            int? rv = null;

            if(!DBReader.IsDBNull(columnID))
            {
                rv = DBReader.GetInt32(columnID);
            }

            return rv;
        }

        protected override int? GetInt(string columnName)
        {
            return GetInt(GetOrdinal(columnName));
        }

        protected override byte? GetByte(int columnID)
        {
            byte? rv = null;

            if(!DBReader.IsDBNull(columnID))
            {
                rv = DBReader.GetByte(columnID);
            }

            return rv;
        }

        protected override byte? GetByte(string columnName)
        {
            return GetByte(GetOrdinal(columnName));
        }

        protected override byte[] GetBytes(int columnID)
        {
            byte[] rv = null;

            if (!DBReader.IsDBNull(columnID))
            {
                const int CHUNK_SIZE = 2 * 1024;
                byte[] buffer = new byte[CHUNK_SIZE];
                long bytesRead;
                long fieldOffset = 0;

                using (var stream = new MemoryStream())
                {
                    while ((bytesRead = DBReader.GetBytes(columnID, fieldOffset, buffer, 0, buffer.Length)) == buffer.Length)
                    {
                        stream.Write(buffer, 0, (int)bytesRead);
                        fieldOffset += bytesRead;
                    }
                    rv = stream.ToArray();
                }
            }

            return rv;
        }

        protected override byte[] GetBytes(string columnName)
        {
            return GetBytes(GetOrdinal(columnName));
        }

        protected override decimal? GetDecimal(int columnID)
        {
            decimal? rv = null;

            if(!DBReader.IsDBNull(columnID))
            {
                rv = DBReader.GetDecimal(columnID);
            }

            return rv;
        }

        protected override decimal? GetDecimal(string columnName)
        {
            return GetDecimal(GetOrdinal(columnName));
        }

        protected override long? GetLong(int columnID)
        {
            long? rv = null;

            if(!DBReader.IsDBNull(columnID))
            {
                rv = DBReader.GetInt64(columnID);
            }

            return rv;
        }

        protected override long? GetLong(string columnName)
        {
            return GetLong(GetOrdinal(columnName));
        }

        protected override short? GetShort(int columnID)
        {
            short? rv = null;

            if(!DBReader.IsDBNull(columnID))
            {
                rv = DBReader.GetInt16(columnID);
            }

            return rv;
        }

        protected override short? GetShort(string columnName)
        {
            return GetShort(GetOrdinal(columnName));
        }

        protected override string GetString(int columnID)
        {
            string rv = string.Empty;

            if(!DBReader.IsDBNull(columnID))
            {
                rv = DBReader.GetString(columnID);
            }

            return rv;
        }

        protected override string GetString(string columnName)
        {
            return GetString(GetOrdinal(columnName));
        }

        protected override bool? GetBool(int columnID)
        {
            bool? rv = null;

            if(!DBReader.IsDBNull(columnID))
            {
                rv = DBReader.GetBoolean(columnID);
            }

            return rv;
        }

        protected override bool? GetBool(string columnName)
        {
            return GetBool(GetOrdinal(columnName));
        }

        protected override DateTime? GetDateTime(int columnID)
        {
            DateTime? rv = null;

            if(!DBReader.IsDBNull(columnID))
            {
                rv = GetDateTime(columnID);
            }

            return rv;
        }

        protected override DateTime? GetDateTime(string columnName)
        {
            return GetDateTime(GetOrdinal(columnName));
        }
    }
}