Woocommerce custom checkout

global $woocommerce;
 $items = $woocommerce->cart->get_cart();
 $data = $_REQUEST;
 
 $payment_first_name = $data['payment_first_name'];
 $payment_last_name = $data['payment_last_name'];
 
 
 $billing_adress_same = $data['billing_adress_same'];
 
 
 $billing_address = $data['billing_address'];
 $billing_city = $data['billing_city'];
 $billing_state = $data['billing_state'];
 $billing_post_code = $data['billing_post_code'];
 
 
 $payment_method = $data['payment_method'];
 
 $creadit_card_first_name = $data['creadit_card_first_name'];
 $creadit_card_last_name = $data['creadit_card_last_name'];
 
 $eway_payments_card_number = $data['eway_payments-card-number'];
 $eway_payments_card_expiry_year = $data['eway_payments-card-expiry-year'];
 $eway_payments_card_expiry_month = $data['eway_payments-card-expiry-month'];
 $eway_payments_card_cvc = $data['eway_payments-card-cvc'];
 
 $desktop_terms_condition = $data['desktop_terms_condition'];
 
 
 $shipping = array(            
 'first_name' =>$_SESSION['book_first_name'],            
 'last_name'  =>$_SESSION['book_last_name'],            
 'company'    =>'',            
 'email'      =>$_SESSION['book_email'],            
 'phone'      =>$_SESSION['book_mobile_number'],            
 'address_1'  =>$_SESSION['book_address'],            
 'address_2'  =>'',             
 'city'       =>$_SESSION['book_city'],            
 'state'      =>$_SESSION['book_state'],            
 'postcode'   =>$_SESSION['book_post_code'],            
 'country'    =>'AUS'       
 );
 
 if(isset($data['billing_adress_same']) && $data['billing_adress_same'] ==  1){
 $address = array(            
 'first_name' =>$data['payment_first_name'],            
 'last_name'  =>$data['payment_last_name'],            
 'company'    =>'',            
 'email'      =>$_SESSION['book_email'],            
 'phone'      =>$_SESSION['book_mobile_number'],            
 'address_1'  =>$_SESSION['book_address'],            
 'address_2'  =>'',             
 'city'       =>$_SESSION['book_city'],            
 'state'      =>$_SESSION['book_state'],            
 'postcode'   =>$_SESSION['book_post_code'],            
 'country'    =>'AUS'       
 );
 } else {
 $address = array(            
 'first_name' => $data['payment_first_name'],            
 'last_name'  => $data['payment_last_name'],            
 'company'    =>'',            
 'email'      =>$_SESSION['book_email'],            
 'phone'      =>$_SESSION['book_mobile_number'],            
 'address_1'  =>$data['billing_address'],            
 'address_2'  =>'',             
 'city'       =>$data['billing_city'],            
 'state'      =>$data['billing_state'],            
 'postcode'   =>$data['billing_post_code'],            
 'country'    =>'AUS'       
 );
 }
 
 if(!isset($_SESSION['current_order_seeion']) || $_SESSION['current_order_seeion'] == ""){
 $order = wc_create_order();
 
 
 if(!empty($items)){
 foreach($items as $item => $values) {  
 $order->add_product( get_product($values['product_id']),$values['quantity']);
 }
 } 
 
 $order->set_address( $address, 'billing' );
 $order->set_address( $shipping, 'shipping' );
 $order->calculate_totals();
 
 $order_id = $order->id;
 
 if($_SESSION['for_gift'] == "yes"){
 add_post_meta($order_id,'gift_data',$varDataArr = array('for_gift' =>$_SESSION['for_gift'],'gift_first_name'=>$_SESSION['gift_first_name'],'gift_last_name'=>$_SESSION['gift_last_name'],'gift_mobile_number'=>$_SESSION['gift_mobile_number'],'gift_email'=>$_SESSION['gift_email'],'gift_address'=>$_SESSION['gift_address'],'gift_city'=>$_SESSION['gift_city'],'gift_state'=>$_SESSION['gift_state'],'gift_post_code'=>$_SESSION['gift_post_code'])); 
 }
 
 update_post_meta( $order_id, 'book_start_month', sanitize_text_field( $_SESSION['book_start_session'] ) );
 update_post_meta( $order_id, 'book_session_time', sanitize_text_field( $_SESSION['book_session'] ) );
 
 } else {
 $order_id = $_SESSION['current_order_seeion'];
 }
 define( 'WOOCOMMERCE_CHECKOUT', true );
 $available_gateways = WC()->payment_gateways->get_available_payment_gateways();
 if($payment_method == "paypal"){
 $result = $available_gateways['paypal']->process_payment($order_id);
 
 if($result['result'] == 'failure'){
 $_SESSION['current_order_seeion'] = $order_id;
 echo json_encode(array('result' => 'fail', 'message' => 'Please enter valid Creadit Card Information'));
 } else {
 echo json_encode(array('result' => 'success', 'redirect' => $result['redirect']));
 }
 } else {
 $result = $available_gateways['eway_payments']->process_payment($order_id);
 
 if($result['result'] == 'failure'){
 $_SESSION['current_order_seeion'] = $order_id;
 echo json_encode(array('result' => 'fail', 'message' => 'Please enter valid Creadit Card Information'));
 } else {
 echo json_encode(array('result' => 'success', 'redirect' => $result['redirect']));
 }
 }
 
 die();