Rock.Model.AttendanceQryExtensions.GetAttendanceWithSummaryDateTime C# (CSharp) Method

        public static IQueryable<AttendanceService.AttendanceWithSummaryDateTime> GetAttendanceWithSummaryDateTime( this IQueryable<Attendance> qryAttendance, ChartGroupBy summarizeBy )
        {
            IQueryable<AttendanceService.AttendanceWithSummaryDateTime> qryAttendanceGroupedBy;

            if ( summarizeBy == ChartGroupBy.Week )
            {
                qryAttendanceGroupedBy = qryAttendance.Select( a => new AttendanceService.AttendanceWithSummaryDateTime
                {
                    SummaryDateTime = a.SundayDate,
                    Attendance = a
                } );
            }
            else if ( summarizeBy == ChartGroupBy.Month )
            {
                qryAttendanceGroupedBy = qryAttendance.Select( a => new AttendanceService.AttendanceWithSummaryDateTime
                {
                    SummaryDateTime = (DateTime)SqlFunctions.DateAdd( "day", -SqlFunctions.DatePart( "day", a.SundayDate ) + 1, a.SundayDate ),
                    Attendance = a
                } );
            }
            else if ( summarizeBy == ChartGroupBy.Year )
            {
                qryAttendanceGroupedBy = qryAttendance.Select( a => new AttendanceService.AttendanceWithSummaryDateTime
                {
                    SummaryDateTime = (DateTime)SqlFunctions.DateAdd( "day", -SqlFunctions.DatePart( "dayofyear", a.SundayDate ) + 1, a.SundayDate ),
                    Attendance = a
                } );
            }
            else
            {
                // shouldn't happen
                qryAttendanceGroupedBy = qryAttendance.Select( a => new AttendanceService.AttendanceWithSummaryDateTime
                {
                    SummaryDateTime = a.SundayDate,
                    Attendance = a
                } );
            }

            return qryAttendanceGroupedBy;
        }