tax engine refactoring for Avalara and Billsoft tax vendors, #25718

1 files changed, 318 insertions, 0 deletions

diff --git a/FS/FS/TaxEngine/internal.pm b/FS/FS/TaxEngine/internal.pm
new file mode 100644
index 0000000..60f7aad
--- /dev/null
+++ b/FS/FS/TaxEngine/internal.pm
@@ -0,0 +1,318 @@
+package FS::TaxEngine::internal;
+
+use strict;
+use base 'FS::TaxEngine';
+use FS::Record qw(dbh qsearch qsearchs);
+
+=head1 SUMMARY
+
+FS::TaxEngine::internal: the classic Freeside "internal tax engine".
+Uses tax rates and localities defined in L<FS::cust_main_county>.
+
+=cut
+
+my %part_pkg_cache;
+
+sub add_sale {
+  my ($self, $cust_bill_pkg) = @_;
+  my $cust_pkg = $cust_bill_pkg->cust_pkg;
+  my $pkgpart = $cust_bill_pkg->pkgpart_override || $cust_pkg->pkgpart;
+  my $part_pkg = $part_pkg_cache{$pkgpart} ||= FS::part_pkg->by_key($pkgpart)
+    or die "pkgpart $pkgpart not found";
+  push @{ $self->{items} }, $cust_bill_pkg;
+
+  my $location = $cust_pkg->tax_location; # cacheable?
+
+  my @loc_keys = qw( district city county state country );
+  my %taxhash = map { $_ => $location->get($_) } @loc_keys;
+
+  $taxhash{'taxclass'} = $part_pkg->taxclass;
+
+  my @taxes = (); # entries are cust_main_county objects
+  my %taxhash_elim = %taxhash;
+  my @elim = qw( district city county state );
+  do {
+
+    #first try a match with taxclass
+    @taxes = qsearch( 'cust_main_county', \%taxhash_elim );
+
+    if ( !scalar(@taxes) && $taxhash_elim{'taxclass'} ) {
+      #then try a match without taxclass
+      my %no_taxclass = %taxhash_elim;
+      $no_taxclass{ 'taxclass' } = '';
+      @taxes = qsearch( 'cust_main_county', \%no_taxclass );
+    }
+
+    $taxhash_elim{ shift(@elim) } = '';
+  } while ( !scalar(@taxes) && scalar(@elim) );
+
+  foreach (@taxes) {
+    my $taxnum = $_->taxnum;
+    $self->{taxes}->{$taxnum} ||= [ $_ ];
+    push @{ $self->{taxes}->{$taxnum} }, $cust_bill_pkg;
+  }
+}
+
+sub taxline {
+  my ($self, %opt) = @_;
+  my $tax_object = $opt{tax};
+  my $taxables = $opt{sales};
+  my $taxnum = $tax_object->taxnum;
+  my $exemptions = $self->{exemptions}->{$taxnum} ||= [];
+  
+  my $name = $tax_object->taxname || 'Tax';
+  my $taxable_cents = 0;
+  my $tax_cents = 0;
+
+  my $cust_main = $self->{cust_main};
+  my $custnum   = $cust_main->custnum;
+  my $invoice_time = $self->{invoice_time};
+
+  # set a flag if the customer is tax-exempt
+  my $exempt_cust;
+  my $conf = FS::Conf->new;
+  if ( $conf->exists('cust_class-tax_exempt') ) {
+    my $cust_class = $cust_main->cust_class;
+    $exempt_cust = $cust_class->tax if $cust_class;
+  } else {
+    $exempt_cust = $cust_main->tax;
+  }
+  # set a flag if the customer is exempt from this tax here
+  my $exempt_cust_taxname = $cust_main->tax_exemption($tax_object->taxname)
+    if $tax_object->taxname;
+
+  # Gather any exemptions that are already attached to these cust_bill_pkgs
+  # so that we can deduct them from the customer's monthly limit.
+  my @existing_exemptions = @{ $exemptions };
+  push @existing_exemptions, @{ $_->cust_tax_exempt_pkg }
+    foreach @$taxables;
+
+  my $tax_item = FS::cust_bill_pkg->new({
+      'pkgnum'    => 0,
+      'recur'     => 0,
+      'sdate'     => '',
+      'edate'     => '',
+      'itemdesc'  => $name,
+  });
+  my @tax_location;
+
+  foreach my $cust_bill_pkg (@$taxables) {
+
+    my $cust_pkg  = $cust_bill_pkg->cust_pkg;
+    my $part_pkg  = $cust_bill_pkg->part_pkg;
+    my @new_exemptions;
+    my $taxable_charged = $cust_bill_pkg->setup + $cust_bill_pkg->recur
+      or next; # don't create zero-amount exemptions
+
+    # XXX the following procedure should probably be in cust_bill_pkg
+
+    if ( $exempt_cust ) {
+
+      push @new_exemptions, FS::cust_tax_exempt_pkg->new({
+          amount => $taxable_charged,
+          exempt_cust => 'Y',
+        });
+      $taxable_charged = 0;
+
+    } elsif ( $exempt_cust_taxname ) {
+
+      push @new_exemptions, FS::cust_tax_exempt_pkg->new({
+          amount => $taxable_charged,
+          exempt_cust_taxname => 'Y',
+        });
+      $taxable_charged = 0;
+
+    }
+
+    if ( ($part_pkg->setuptax eq 'Y' or $tax_object->setuptax eq 'Y')
+        and $cust_bill_pkg->setup > 0 and $taxable_charged > 0 ) {
+
+      push @new_exemptions, FS::cust_tax_exempt_pkg->new({
+          amount => $cust_bill_pkg->setup,
+          exempt_setup => 'Y'
+      });
+      $taxable_charged -= $cust_bill_pkg->setup;
+
+    }
+    if ( ($part_pkg->recurtax eq 'Y' or $tax_object->recurtax eq 'Y')
+        and $cust_bill_pkg->recur > 0 and $taxable_charged > 0 ) {
+
+      push @new_exemptions, FS::cust_tax_exempt_pkg->new({
+          amount => $cust_bill_pkg->recur,
+          exempt_recur => 'Y'
+      });
+       $taxable_charged -= $cust_bill_pkg->recur;
+
+    }
+
+    if ( $tax_object->exempt_amount && $tax_object->exempt_amount > 0
+      and $taxable_charged > 0 ) {
+      # If the billing period extends across multiple calendar months, 
+      # there may be several months of exemption available.
+      my $sdate = $cust_bill_pkg->sdate || $invoice_time;
+      my $start_month = (localtime($sdate))[4] + 1;
+      my $start_year  = (localtime($sdate))[5] + 1900;
+      my $edate = $cust_bill_pkg->edate || $invoice_time;
+      my $end_month   = (localtime($edate))[4] + 1;
+      my $end_year    = (localtime($edate))[5] + 1900;
+
+      # If the partial last month + partial first month <= one month,
+      # don't use the exemption in the last month
+      # (unless the last month is also the first month, e.g. one-time
+      # charges)
+      if ( (localtime($sdate))[3] >= (localtime($edate))[3]
+           and ($start_month != $end_month or $start_year != $end_year)
+     ) {
+        $end_month--;
+        if ( $end_month == 0 ) {
+          $end_year--;
+          $end_month = 12;
+        }
+      }
+
+      # number of months of exemption available
+      my $freq = ($end_month - $start_month) +
+                 ($end_year  - $start_year) * 12 +
+                 1;
+
+      # divide equally among all of them
+      my $permonth = sprintf('%.2f', $taxable_charged / $freq);
+
+      #call the whole thing off if this customer has any old
+      #exemption records...
+      my @cust_tax_exempt =
+        qsearch( 'cust_tax_exempt' => { custnum=> $custnum } );
+      if ( @cust_tax_exempt ) {
+        return
+          'this customer still has old-style tax exemption records; '.
+          'run bin/fs-migrate-cust_tax_exempt?';
+      }
+
+      my ($mon, $year) = ($start_month, $start_year);
+      while ($taxable_charged > 0.005 and
+             ($year < $end_year or
+               ($year == $end_year and $mon <= $end_month)
+             )
+      ) {
+
+        # find the sum of the exemption used by this customer, for this tax,
+        # in this month
+        my $sql = "
+          SELECT SUM(amount)
+            FROM cust_tax_exempt_pkg
+              LEFT JOIN cust_bill_pkg USING ( billpkgnum )
+              LEFT JOIN cust_bill     USING ( invnum     )
+            WHERE custnum = ?
+             AND taxnum  = ?
+              AND year    = ?
+              AND month   = ?
+              AND exempt_monthly = 'Y'
+        ";
+        my $sth = dbh->prepare($sql) or
+          return "fatal: can't lookup existing exemption: ". dbh->errstr;
+        $sth->execute(
+          $custnum,
+          $tax_object->taxnum,
+          $year,
+          $mon,
+        ) or
+          return "fatal: can't lookup existing exemption: ". dbh->errstr;
+        my $existing_exemption = $sth->fetchrow_arrayref->[0] || 0;
+
+        # add any exemption we're already using for another line item
+       foreach ( grep { $_->taxnum == $tax_object->taxnum &&
+                         $_->exempt_monthly eq 'Y'   &&
+                         $_->month  == $mon          &&
+                         $_->year   == $year
+                       } @existing_exemptions
+                )
+        {
+          $existing_exemption += $_->amount;
+        }
+
+        my $remaining_exemption =
+          $tax_object->exempt_amount - $existing_exemption;
+        if ( $remaining_exemption > 0 ) {
+          my $addl = $remaining_exemption > $permonth
+            ? $permonth
+            : $remaining_exemption;
+          $addl = $taxable_charged if $addl > $taxable_charged;
+
+          push @new_exemptions, FS::cust_tax_exempt_pkg->new({
+              amount          => sprintf('%.2f', $addl),
+              exempt_monthly  => 'Y',
+              year            => $year,
+              month           => $mon,
+            });
+          $taxable_charged -= $addl;
+        }
+        # if they're using multiple months of exemption for a multi-month
+        # package, then record the exemptions in separate months
+        $mon++;
+        if ( $mon > 12 ) {
+          $mon -= 12;
+          $year++;
+        }
+
+      }
+    } # if exempt_amount
+
+    $_->taxnum($tax_object->taxnum) foreach @new_exemptions;
+
+    # attach them to the line item
+    push @{ $cust_bill_pkg->cust_tax_exempt_pkg }, @new_exemptions;
+    push @existing_exemptions, @new_exemptions;
+
+    $taxable_charged = sprintf( "%.2f", $taxable_charged);
+    next if $taxable_charged == 0;
+
+    my $this_tax_cents = int($taxable_charged * $tax_object->tax);
+    my $location = FS::cust_bill_pkg_tax_location->new({
+        'taxnum'      => $tax_object->taxnum,
+        'taxtype'     => ref($tax_object),
+        'cents'       => $this_tax_cents,
+        'pkgnum'      => $cust_bill_pkg->pkgnum,
+        'locationnum' => $cust_bill_pkg->cust_pkg->tax_locationnum,
+        'taxable_cust_bill_pkg' => $cust_bill_pkg,
+        'tax_cust_bill_pkg'     => $tax_item,
+    });
+    push @tax_location, $location;
+
+    $taxable_cents += $taxable_charged;
+    $tax_cents += $this_tax_cents;
+  } #foreach $cust_bill_pkg
+
+  # now round and distribute
+  my $extra_cents = sprintf('%.2f', $taxable_cents * $tax_object->tax / 100)
+                            * 100 - $tax_cents;
+  # make sure we have an integer
+  $extra_cents = sprintf('%.0f', $extra_cents);
+  if ( $extra_cents < 0 ) {
+    die "nonsense extra_cents value $extra_cents";
+  }
+  $tax_cents += $extra_cents;
+  my $i = 0;
+  foreach (@tax_location) { # can never require more than a single pass, yes?
+    my $cents = $_->get('cents');
+    if ( $extra_cents > 0 ) {
+      $cents++;
+      $extra_cents--;
+    }
+    $_->set('amount', sprintf('%.2f', $cents/100));
+  }
+  $tax_item->set('setup' => sprintf('%.2f', $tax_cents / 100));
+  $tax_item->set('cust_bill_pkg_tax_location', \@tax_location);
+
+  return $tax_item;
+}
+
+sub info {
+ +{
+    batch       => 0,
+    override    => 0,
+    rate_table  => 'cust_main_county',
+    link_table  => 'cust_bill_pkg_tax_location',
+  }
+}
+
+1;