Bank Salary Slip Generation for Payroll Management System

Today I completed, one more section of Payroll Management System and that is Generation of Bank Salary Slip. As I am making this Web Based payroll software for a contract based firm working at Trident Group, dhaula, they need an individual slip which they ll give to Bank for payment of their employees. So, I did the same.

Here is the code for the bankslip.php to generate odt

<?php
session_start();
if($_SESSION['user']!='admin') {
    header('location:../checklogin/error.php');
}
require_once('../library/odf.php');
include '../dbfiles/config.php';
class bankslip {
    private $op;
    private $query;
    public function download_slip() {
        $odf = new odf("bankslip.odt");
        if($_POST['month']!='' && $_POST['year']=='') {
            echo "<script>alert('You forgot to submit year'); window.location='bankslip.php';</script>";
        }
        elseif ($_POST['month']=='' && $_POST['year']!='') {
            echo "<script>alert('You forgot to enter month'); window.location='bankslip.php';</script>";
        }
        elseif (($_POST['month']!='' && $_POST['year']!='') && $_POST['current']!='') {
            echo "<script>alert('Hello!! I didnt told you to select all options'); window.location='bankslip.php';</script>";
        }
        elseif (($_POST['month']=='' && $_POST['year']=='') && $_POST['current']=='') {
            echo "<script>alert('Hello!! I told you to select one option'); window.location='bankslip.php';</script>";
        }
        elseif ($_POST['month']!=''&& $_POST['year']!='') {
            $this->op= 'defined';
            $month= $_POST['month'];
            $year= $_POST['year'];

        }
        elseif ($_POST['current']!='') {
            $this->op= 'current';
            $month= date('n')-1;
            $year= date('Y');
        }
        switch ($month) {
            case 1:
                $monthname= 'January';
                break;
            case 2:
                $monthname= 'February';
                break;
            case 3:
                $monthname= 'March';
                break;
            case 4:
                $monthname= 'April';
                break;
            case 5:
                $monthname= 'May';
                break;
            case 6:
                $monthname= 'June';
                break;
            case 7:
                $monthname= 'July';
                break;
            case 8:
                $monthname= 'August';
                break;
            case 9:
                $monthname= 'September';
                break;
            case 10:
                $monthname= 'October';
                break;
            case 11:
                $monthname= 'November';
                break;
            case 12:
                $monthname= 'December';
                break;
        }
        $odf->setVars('month', $monthname);
        $odf->setVars('year', $year);
        $this->query= mysql_query("Select workers.id as id, worker_fname, worker_lname, gross, hra, rate, workdays, pf, esi, advance, accno from workers, worker_fixeds, worker_varys, worker_acc where workers.id=worker_fixeds.worker_id and workers.id=worker_varys.id and workers.id=worker_acc.id and month='$month' and year='$year'");
        $bank = $odf->setSegment('emp');
        $s=1;
        while($result= mysql_fetch_array($this->query)) {
            if(!$result) {
                header('location:qerror.php?op='.mysql_error());
            }
            $cal= sprintf('%.2f',($result['rate'])*($result['workdays']));
            $ded= $result['pf']+$result['esi']+$result['advance'];
            if($result['workdays']<20) {
                $wages= sprintf('%.2f',(($result['rate'])*($result['workdays']))+0);
                $netpay= sprintf('%.0f', ($wages-$ded));
                $total= sprintf('%.0f', ($total+$netpay));
            }
            else {
                $wages= sprintf('%.2f',(($result['rate'])*($result['workdays']))+$result['hra']);
                $netpay= sprintf('%.0f', ($wages-$ded));
                $total= sprintf('%.0f', ($total+$netpay));
            }
            $bank->s($s);
            $bank->accno($result['accno']);
            $bank->name($result['worker_fname'].' '.$result['worker_lname']);
            $bank->amount($netpay);
            $bank->merge();
            $s=$s+1;
        }
        $odf->mergeSegment($bank);
        $odf->setVars('total', $total);
        $odf->exportAsAttachedFile('Bankslip.odt');
    }
}
$bank_slip= new bankslip();
$bank_slip->download_slip();
?>