+=item apply_credits
+
+Applies (see L<FS::cust_credit_bill>) unapplied credits (see L<FS::cust_credit>)to outstanding invoice balances in cronological order and returns the value
+of any remaining unapplied credits available for refund (see L<FS::cust_refund>).
+
+=cut
+
+sub apply_credits {
+ my $self = shift;
+
+ return 0 unless $self->total_credited;
+
+ my @credits = sort { $b->_date <=> $a->_date} (grep { $_->credited > 0 }
+ qsearch('cust_credit', { 'custnum' => $self->custnum } ) );
+
+ my @invoices = sort { $a->_date <=> $b->_date} (grep { $_->owed > 0 }
+ qsearch('cust_bill', { 'custnum' => $self->custnum } ) );
+
+ my $credit;
+
+ foreach my $cust_bill ( @invoices ) {
+ my $amount;
+
+ if (!(defined $credit) || $credit->credited == 0) {
+ $credit = pop @credits;
+ last unless defined $credit;
+ }
+
+ if ($cust_bill->owed >= $credit->credited) {
+ $amount=$credit->credited;
+ }else{
+ $amount=$cust_bill->owed;
+ }
+
+ my $cust_credit_bill = new FS::cust_credit_bill ( {
+ 'crednum' => $credit->crednum,
+ 'invnum' => $cust_bill->invnum,
+ 'amount' => $amount,
+ '_date' => time,
+ } );
+ my $error = $cust_credit_bill->insert;
+ die $error if $error;
+
+ redo if ($cust_bill->owed > 0);
+
+ }
+
+ return $self->total_credited;
+}
+
+