+=item desc
+
+Returns a description for this line item. For typical line items, this is the
+I<pkg> field of the corresponding B<FS::part_pkg> object (see L<FS::part_pkg>).
+For one-shot line items and named taxes, it is the I<itemdesc> field of this
+line item, and for generic taxes, simply returns "Tax".
+
+=cut
+
+sub desc {
+ my $self = shift;
+
+ if ( $self->pkgnum > 0 ) {
+ $self->itemdesc || $self->part_pkg->pkg;
+ } else {
+ $self->itemdesc || 'Tax';
+ }
+}
+
+=item owed_setup
+
+Returns the amount owed (still outstanding) on this line item's setup fee,
+which is the amount of the line item minus all payment applications (see
+L<FS::cust_bill_pay_pkg> and credit applications (see
+L<FS::cust_credit_bill_pkg>).
+
+=cut
+
+sub owed_setup {
+ my $self = shift;
+ $self->owed('setup', @_);
+}
+
+=item owed_recur
+
+Returns the amount owed (still outstanding) on this line item's recurring fee,
+which is the amount of the line item minus all payment applications (see
+L<FS::cust_bill_pay_pkg> and credit applications (see
+L<FS::cust_credit_bill_pkg>).
+
+=cut
+
+sub owed_recur {
+ my $self = shift;
+ $self->owed('recur', @_);
+}
+
+# modeled after cust_bill::owed...
+sub owed {
+ my( $self, $field ) = @_;
+ my $balance = $self->$field();
+ $balance -= $_->amount foreach ( $self->cust_bill_pay_pkg($field) );
+ $balance -= $_->amount foreach ( $self->cust_credit_bill_pkg($field) );
+ $balance = sprintf( '%.2f', $balance );
+ $balance =~ s/^\-0\.00$/0.00/; #yay ieee fp
+ $balance;
+}
+
+sub cust_bill_pay_pkg {
+ my( $self, $field ) = @_;
+ qsearch( 'cust_bill_pay_pkg', { 'billpkgnum' => $self->billpkgnum,
+ 'setuprecur' => $field,
+ }
+ );
+}
+
+sub cust_credit_bill_pkg {
+ my( $self, $field ) = @_;
+ qsearch( 'cust_credit_bill_pkg', { 'billpkgnum' => $self->billpkgnum,
+ 'setuprecur' => $field,
+ }
+ );
+}
+
+=item units
+
+Returns the number of billing units (for tax purposes) represented by this,
+line item.
+
+=cut
+
+sub units {
+ my $self = shift;
+ $self->pkgnum ? $self->part_pkg->calc_units($self->cust_pkg) : 0; # 1?
+}
+
+=item quantity
+
+=cut
+
+sub quantity {
+ my( $self, $value ) = @_;
+ if ( defined($value) ) {
+ $self->setfield('quantity', $value);
+ }
+ $self->getfield('quantity') || 1;
+}
+
+=item unitsetup
+
+=cut
+
+sub unitsetup {
+ my( $self, $value ) = @_;
+ if ( defined($value) ) {
+ $self->setfield('unitsetup', $value);
+ }
+ $self->getfield('unitsetup') eq ''
+ ? $self->getfield('setup')
+ : $self->getfield('unitsetup');
+}
+
+=item unitrecur
+
+=cut
+
+sub unitrecur {
+ my( $self, $value ) = @_;
+ if ( defined($value) ) {
+ $self->setfield('unitrecur', $value);
+ }
+ $self->getfield('unitrecur') eq ''
+ ? $self->getfield('recur')
+ : $self->getfield('unitrecur');
+}
+
+=item usage CLASSNUM
+
+Returns the amount of the charge associated with usage class CLASSNUM if
+CLASSNUM is defined. Otherwise returns the total charge associated with
+usage.
+
+=cut
+
+sub usage {
+ my( $self, $classnum ) = @_;
+ my $sum = 0;
+ my @values = ();
+
+ if ( $self->get('details') ) {
+
+ @values =
+ map { $_->[2] }
+ grep { ref($_) && ( defined($classnum) ? $_->[3] eq $classnum : 1 ) }
+ @{ $self->get('details') };
+
+ }else{
+
+ my $hashref = { 'billpkgnum' => $self->billpkgnum };
+ $hashref->{ 'classnum' } = $classnum if defined($classnum);
+ @values = map { $_->amount } qsearch('cust_bill_pkg_detail', $hashref);
+
+ }
+
+ foreach ( @values ) {
+ $sum += $_ if $_;
+ }
+ $sum;
+}
+
+=item usage_classes
+
+Returns a list of usage classnums associated with this invoice line's
+details.
+
+=cut
+
+sub usage_classes {
+ my( $self ) = @_;
+
+ if ( $self->get('details') ) {
+
+ my %seen = ();
+ foreach my $detail ( grep { ref($_) } @{$self->get('details')} ) {
+ $seen{ $detail->[3] } = 1;
+ }
+ keys %seen;
+
+ }else{
+
+ map { $_->classnum }
+ qsearch({ table => 'cust_bill_pkg_detail',
+ hashref => { billpkgnum => $self->billpkgnum },
+ select => 'DISTINCT classnum',
+ });
+
+ }
+
+}
+