sms credit deduction concurrency issue - php

Question

I currently writing an sms system for the end user. however, When I do the testing on the function i encounter sms credit deduction error.
There are three table in this function which are company, user and transaction.
I did many testing on this function. just cant get the credit deduction correctly.
for example there are 1000 credit in each table.
Initial value
company.sms_bal = 1000
user.user_credit_bal= 1000
transaction.transaction_balance = 1000
testing #1
deduct 1 credit on each table. it deducts correctly.
company.sms_bal = 999
user.user_credit_bal= 999
transaction.transaction_balance = 999
testing #2
deduct 2 credit on each table. it deducts incorrectly,
company.sms_bal = 997
user.user_credit_bal= 997
transaction.transaction_balance = 998 suppose to be 997.
P/S it does not always deduct incorrectly, just sometimes. Please kindly advice me. However if you are unsure my question just let me know I am willing to assist you.
Below is the function for your reference
function process_send_sms($data){
global $CONF, $Q, $OUT, $DB, $DBSH, $CODE, $LANG;
//
// check credit
//
$check_credit = check_credit($data);
if($check_credit['status'] == '100'){
//
// check credit and update credit and update track
//
// get $company_credit_bal
$DBSH->u_select('company', $company_data, array(
'company_id' => $company_id,
));
$company_credit_bal = $company_data['sms_bal'];
// get $user_credit_bal
$DBSH->u_select('user', $user_data, array(
'user_id' => $user_id,
));
$user_credit_bal = trim($user_data['user_credit_bal']);
$number_bulk_mt = trim($total_credit);
//
// update company
//
$rows = $DBSH->update(array(
'table' => 'company',
'set' => array(array('sms_bal = ?', $company_credit_bal - $number_bulk_mt),),
'where' => array(array('company_id = ?', $company_id),),));
$rows = $DBSH->update(array(
'table' => 'user',
'set' => array(array('user_credit_bal = ?', $user_credit_bal - $number_bulk_mt),),
'where' => array(array('user_id = ?', $user_id),),));
}else{
$return_data['error'] = $check_credit['error'];
}
if($check_credit['status'] == '100'){
//
// insert to the track
//
$arr = debug_backtrace();
$function_name = $arr[0]["function"];
$data = array(
'no_phones' => $total_credit,
'company_id' => $company_id,
'user_id' => $user_id,
'msg_type' => $function_name,
'track_mt_create_time' => $timestr,
'track_mt_update_date' => $timestr,
);
$DBSH->u_insert('bulk_mt_log_track', $data);
$ref_id = $DBSH->u_lastid('bulk_mt_log_track');
if($sendsmscsv == 'Y'){
foreach($phone_tem as $k => $v){
$phone_no = $v['phone'];
$message = $v['message'];
$coding = 1;
if($v['lang'] == '2'){
$coding = 3;
}
$check_credit = $credit_class->check_per_credit($phone_no,$is_intern);
$send_c_code = $check_credit['c_code' ];
$per_credit = $check_credit['per_credit'];
if($phone_no){
do{
$msgid = session_get()."_".$user_id;
$check_valid === false;
$found = $DBSH->u_count('bulk_mt_log_data', array(
'msgid' => $msgid,
));
if(!$found){
$check_valid === true;
}
$found = $DBSH->u_count('bulk_mt_log', array(
'msgid' => $msgid,));
if(!$found){
$check_valid === true;
}
}while($check_valid === false);
//
// Perform merge sms
//
$message = process_message_merge($phone_no,$user_id,$message,$company_id);
if($coding == '3'){
$len = mb_strlen($message, 'UTF-8');
$arr = array();
for( $i=0; $i<$len; $i++){
$arr[] = mb_substr($message,$i,1,'UTF-8');;
}
$message2="";
foreach($arr as $k => $substr){
$message2 .= uniord($substr);
}
$message = $message2;
}
else{
$coding = 0;
}
$data = array(
'bulk_mt_log_id' => null,
'user_id' => $user_id,
'company_id' => $company_id,
'mt_to' => $phone_no,
'campaign' => $campaign_name,
'mt_status' => 'P',
'mt_text' => $message,
'coding' => $coding,
'msgid' => $msgid,
'is_intern' => $is_intern?$is_intern:'NOT',
'per_credit' => $per_credit ? $per_credit:'0',
'mt_from' => $mt_from?$mt_from:'',
'send_c_code' => $send_c_code,
'mt_create_date' => $timestr,
'mt_update_date' => $timestr,
'ref_id' => $ref_id,
'gateway_id' => $gateway_id,
);
$DBSH->u_insert('bulk_mt_log', $data);
$rows = $DBSH->select(array(
'field' => array('*'),
'table' => 'transaction',
'where' => array(array('company_id = ?', $company_id),
array('transaction_balance > ?', 0),
array('transaction_sms_expire_date > ?', $timestr),),
'order' => 'transaction_sms_expire_date ASC',
));
$data_transaction_id = array();
while($row = $DBSH->fetchRow(DB_FETCHMODE_ASSOC)){
$data_transaction_id[] = $row[transaction_id];
}
$transaction_id = $data_transaction_id[0];
if($transaction_id){
$rows = $DBSH->update(array(
'table' => 'transaction',
'set' => array(array('transaction_balance = transaction_balance - '.$per_credit),),
'where' => array(array('company_id = ?', $company_id),
array('transaction_id = ?', $transaction_id),),
));
}
}
}
}else{
if ($phone){
foreach($phone as $k => $phone_no){
foreach($sms_message as $km => $message){
$check_credit = $credit_class->check_per_credit($phone_no,$is_intern);
$send_c_code = $check_credit['c_code' ];
$per_credit = $check_credit['per_credit'];
if($phone_no){
do{
$msgid = session_get()."_".$user_id;
$check_valid === false;
$found = $DBSH->u_count('bulk_mt_log_data', array(
'msgid' => $msgid,
));
if(!$found){
$check_valid === true;
}
$found = $DBSH->u_count('bulk_mt_log', array(
'msgid' => $msgid,));
if(!$found){
$check_valid === true;
}
}while($check_valid === false);
//
// Perform merge sms
//
$message = process_message_merge($phone_no,$user_id,$message,$company_id);
if($message_type == 'unicode'){
$coding = 3;
$len = mb_strlen($message, 'UTF-8');
$arr = array();
for( $i=0; $i<$len; $i++){
$arr[] = mb_substr($message,$i,1,'UTF-8');;
}
$message2="";
foreach($arr as $k => $substr){
$message2 .= uniord($substr);
}
$message = $message2;
}
else{
$coding = 0;
}
$data = array(
'bulk_mt_log_id' => null,
'user_id' => $user_id,
'company_id' => $company_id,
'mt_to' => $phone_no,
'campaign' => $campaign_name,
'mt_status' => 'P',
'mt_text' => $message,
'coding' => $coding,
'msgid' => $msgid,
'is_intern' => $is_intern?$is_intern:'NOT',
'per_credit' => $per_credit ? $per_credit:'0',
'send_c_code' => $send_c_code,
'mt_create_date' => $timestr,
'mt_update_date' => $timestr,
'ref_id' => $ref_id,
'mt_from' => $mt_from?$mt_from:'',
'gateway_id' => $gateway_id,
);
$DBSH->u_insert('bulk_mt_log', $data);
$rows = $DBSH->select(array(
'field' => array('*'),
'table' => 'transaction',
'where' => array(array('company_id = ?', $company_id),
array('transaction_balance > ?', 0),
array('transaction_sms_expire_date > ?', $timestr),
),
'order' => 'transaction_sms_expire_date ASC',
));
$data_transaction_id = array();
while($row = $DBSH->fetchRow(DB_FETCHMODE_ASSOC)){
$data_transaction_id[] = $row[transaction_id];
}
$transaction_id = $data_transaction_id[0];
if($transaction_id){
$rows = $DBSH->update(array(
'table' => 'transaction',
'set' => array(array('transaction_balance = transaction_balance - '.$per_credit),),
'where' => array(array('company_id = ?', $company_id),
array('transaction_id = ?', $transaction_id),),
));
}
}
}
}
}
}
}else{
$return_data['error'] = $check_credit['error'];
}
if($return_data){
$return_data['status'] ='102';
}else{
$return_data['status'] ='100';
}
return $return_data;
}