///////////////////////////////////////////////////////////
//  Bool.cs
//  Implementation of Class UnitLastMeterReadingFetcher
//  CSLA type: Read-only object
//  Created on: 25-Sept-2007
//  Object design: John 
//	Coded: 25-Sept-2007
///////////////////////////////////////////////////////////

using System;
using System.Data;
using CSLA.Data;
using GZTW.Data;
using CSLA;
using System.Threading;
using CSLA.Security;
using System.ComponentModel;



namespace GZTW.AyaNova.BLL
{
    //case 500
    /// <summary>
    ///Gets the last meter reading for a unit
    ///in the AyaNova database
    /// </summary>
    [Serializable, EditorBrowsable(EditorBrowsableState.Never)]
    internal class UnitLastMeterReadingFetcher : ReadOnlyBase
    {

        #region Attributes
        private long _Meter = 0;
        //private Guid _ID;
        #endregion

        #region Constructor

        /// <summary>
        /// Private constructor to prevent direct instantiation
        /// </summary>
        private UnitLastMeterReadingFetcher()
        {

        }
        #endregion


        #region Static methods




        internal static long LastMeterReading(Guid ID)
        {

            return ((UnitLastMeterReadingFetcher)DataPortal.Fetch(new Criteria(ID)))._Meter;

        }


        #endregion

        #region DAL DATA ACCESS
        /// 
        /// <param Bool="Criteria"></param>
        protected override void DataPortal_Fetch(object Criteria)
        {
            Criteria crit = (Criteria)Criteria;
            switch (DBUtil.DB.DBType)
            {
                case DataBaseType.FireBird:
                    {
                        this._Meter = DBUtil.ScalarToLong(
                            DBUtil.GetScalarFromSQLString(
                            "SELECT FIRST 1 aMeter FROM aUnitMeterReading WHERE " +
                            "(aUnitMeterReading.aUnitID = @ID) " +
                            "ORDER BY aCreated DESC ", crit.ID)
                            );
                    }
                    break;

                case DataBaseType.MSSQL:
                    {
                        this._Meter = DBUtil.ScalarToLong(
                            DBUtil.GetScalarFromSQLString(
                            "SELECT TOP 1 aMeter FROM aUnitMeterReading WHERE " +
                            "(aUnitMeterReading.aUnitID = @ID) " +
                            "ORDER BY aCreated DESC ", crit.ID)
                            );
                    }
                    break;

                default:
                    throw new ApplicationException("UNKNOWN DB TYPE IN Unit.MeterHelper");

            }

        }



        #endregion

        #region criteria
        /// <summary>
        /// Criteria for identifying existing object
        /// </summary>
        [Serializable]
        private class Criteria
        {

            public Guid ID;
            
            public Criteria(Guid _ID)
            {
                ID = _ID;
               

            }

        }
        #endregion

    }//end class

}//end namespace GZTW.AyaNova.BLL