I need to create a task for a cron job that exports data to a csv file, saves it and then emails it to a given email address. What I have done so far is...

if(!empty($data)){
				//create CSV
				$filename = 'ProductsOrdered-'.$today.'.csv';
				$separator = $this->csvSeparator;
				$csvColumns = array('ProductID', 'Product Title', 'MYOB Code', 'Order Date', 'Quantity', 'Total Value');
				$fileData = '';

				if($this->csvHasHeader) {
					$headers = array();
		
					// determine the CSV headers. If a field is callable (e.g. anonymous function) then use the
					// source name as the header instead
					foreach($csvColumns as $columnSource => $columnHeader) {
						$headers[] = (!is_string($columnHeader) && is_callable($columnHeader)) ? $columnSource : $columnHeader;
					}
		
					$fileData .= "\"" . implode("\"{$separator}\"", array_values($headers)) . "\"";
					$fileData .= "\n";
				}
				$items = $data;
				
				foreach($items as $item) {
					
						$columnData = array();
		
						foreach($item as $e) {
							
							$value = str_replace(array("\r", "\n"), "\n", $e);
							$columnData[] = '"' . str_replace('"', '""', $value) . '"';
						}
		
						$fileData .= implode($separator, $columnData);
						$fileData .= "\n";
						
				}
				
				$csv = SS_HTTPRequest::send_file($fileData, $filename, 'text/csv');
				$f = new File();
				$f->ClassName = 'File';
				$f->Name = $filename;
				$f->Title = $filename;
				$f->Filename = 'assets/Uploads/Reports'.$filename;
				$f->write();
				//email the report
				$to = 'email@somewhere.com.au';
				$subject = 'Products Ordered Yesterday';
				$from = 'email@somewhere.com.au';
				$email = new Email($from, $to, $subject);
				$email->setTemplate('ReportEmail');
				$email->attachFile('/assets/Uploads/Reports/'.$filename.'');
				$email->send();
			}

Which I have mostly borrowed from the GridFieldExportButton class. Unfortunately it is not working. The file neither downloads automatically or saves in the assets folder. The data is def not empty as I can print it out to the screen, its just not doing anything.

Any pointers would be fabulous.