Koha/C4/HoldsQueue.pm
Kyle M Hall fc81ee5004 Bug 15533 - Allow patrons and librarians to select itemtype when placing hold
Some libraries would like the ability to select the itemtype to request
when placing holds. For example, if a record has 3 copies of BookA and 3
copies of BookA in large print, this feature would allow a person to
place a hold on the record, but still be able to target only the Large
Print edition so that the first Large Print copy that becomes available
is targeted, rather than forcing the patron to select a particular copy
to hold.

Test Plan:
1) Apply this patch
2) Run updatedatabase.pl
3) Create a record with items of two or more itemtypes
4) Place a record level hold on the record while choosing one particular
   itemtype
5) Check in an item from the record that is not of that itemtype
6) Notee it is not trapped for the hold
7) Check in an item from the record that does match the selected itemtype
8) Note the item is trapped for the hold

Signed-off-by: Andreas Hedström Mace <andreas.hedstrom.mace@sub.su.se>
Signed-off-by: Benjamin Rokseth <benjamin.rokseth@kul.oslo.kommune.no>

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
2016-04-29 10:26:03 +00:00

739 lines
26 KiB
Perl
Executable file

package C4::HoldsQueue;
# Copyright 2011 Catalyst IT
#
# This file is part of Koha.
#
# Koha is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# Koha is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Koha; if not, see <http://www.gnu.org/licenses>.
# FIXME: expand perldoc, explain intended logic
use strict;
use warnings;
use C4::Context;
use C4::Search;
use C4::Items;
use C4::Branch;
use C4::Circulation;
use C4::Members;
use C4::Biblio;
use Koha::DateUtils;
use List::Util qw(shuffle);
use List::MoreUtils qw(any);
use Data::Dumper;
use vars qw(@ISA @EXPORT @EXPORT_OK %EXPORT_TAGS);
BEGIN {
require Exporter;
@ISA = qw(Exporter);
@EXPORT_OK = qw(
&CreateQueue
&GetHoldsQueueItems
&TransportCostMatrix
&UpdateTransportCostMatrix
);
}
=head1 FUNCTIONS
=head2 TransportCostMatrix
TransportCostMatrix();
Returns Transport Cost Matrix as a hashref <to branch code> => <from branch code> => cost
=cut
sub TransportCostMatrix {
my $dbh = C4::Context->dbh;
my $transport_costs = $dbh->selectall_arrayref("SELECT * FROM transport_cost",{ Slice => {} });
my $today = dt_from_string();
my $calendars;
my %transport_cost_matrix;
foreach (@$transport_costs) {
my $from = $_->{frombranch};
my $to = $_->{tobranch};
my $cost = $_->{cost};
my $disabled = $_->{disable_transfer};
$transport_cost_matrix{$to}{$from} = {
cost => $cost,
disable_transfer => $disabled
};
if ( C4::Context->preference("HoldsQueueSkipClosed") ) {
$calendars->{$from} ||= Koha::Calendar->new( branchcode => $from );
$transport_cost_matrix{$to}{$from}{disable_transfer} ||=
$calendars->{$from}->is_holiday( $today );
}
}
return \%transport_cost_matrix;
}
=head2 UpdateTransportCostMatrix
UpdateTransportCostMatrix($records);
Updates full Transport Cost Matrix table. $records is an arrayref of records.
Records: { frombranch => <code>, tobranch => <code>, cost => <figure>, disable_transfer => <0,1> }
=cut
sub UpdateTransportCostMatrix {
my ($records) = @_;
my $dbh = C4::Context->dbh;
my $sth = $dbh->prepare("INSERT INTO transport_cost (frombranch, tobranch, cost, disable_transfer) VALUES (?, ?, ?, ?)");
$dbh->do("TRUNCATE TABLE transport_cost");
foreach (@$records) {
my $cost = $_->{cost};
my $from = $_->{frombranch};
my $to = $_->{tobranch};
if ($_->{disable_transfer}) {
$cost ||= 0;
}
elsif ( !defined ($cost) || ($cost !~ m/(0|[1-9][0-9]*)(\.[0-9]*)?/o) ) {
warn "Invalid $from -> $to cost $cost - must be a number >= 0, disablig";
$cost = 0;
$_->{disable_transfer} = 1;
}
$sth->execute( $from, $to, $cost, $_->{disable_transfer} ? 1 : 0 );
}
}
=head2 GetHoldsQueueItems
GetHoldsQueueItems($branch);
Returns hold queue for a holding branch. If branch is omitted, then whole queue is returned
=cut
sub GetHoldsQueueItems {
my ($branchlimit) = @_;
my $dbh = C4::Context->dbh;
my @bind_params = ();
my $query = q/SELECT tmp_holdsqueue.*, biblio.author, items.ccode, items.itype, biblioitems.itemtype, items.location, items.enumchron, items.cn_sort, biblioitems.publishercode,biblio.copyrightdate,biblioitems.publicationyear,biblioitems.pages,biblioitems.size,biblioitems.publicationyear,biblioitems.isbn,items.copynumber
FROM tmp_holdsqueue
JOIN biblio USING (biblionumber)
LEFT JOIN biblioitems USING (biblionumber)
LEFT JOIN items USING ( itemnumber)
/;
if ($branchlimit) {
$query .=" WHERE tmp_holdsqueue.holdingbranch = ?";
push @bind_params, $branchlimit;
}
$query .= " ORDER BY ccode, location, cn_sort, author, title, pickbranch, reservedate";
my $sth = $dbh->prepare($query);
$sth->execute(@bind_params);
my $items = [];
while ( my $row = $sth->fetchrow_hashref ){
my $record = GetMarcBiblio($row->{biblionumber});
if ($record){
$row->{subtitle} = [ map { $_->{subfield} } @{ GetRecordValue( 'subtitle', $record, '' ) } ];
$row->{parts} = GetRecordValue('parts',$record,'')->[0]->{subfield};
$row->{numbers} = GetRecordValue('numbers',$record,'')->[0]->{subfield};
}
# return the bib-level or item-level itype per syspref
if (!C4::Context->preference('item-level_itypes')) {
$row->{itype} = $row->{itemtype};
}
delete $row->{itemtype};
push @$items, $row;
}
return $items;
}
=head2 CreateQueue
CreateQueue();
Top level function that turns reserves into tmp_holdsqueue and hold_fill_targets.
=cut
sub CreateQueue {
my $dbh = C4::Context->dbh;
$dbh->do("DELETE FROM tmp_holdsqueue"); # clear the old table for new info
$dbh->do("DELETE FROM hold_fill_targets");
my $total_bibs = 0;
my $total_requests = 0;
my $total_available_items = 0;
my $num_items_mapped = 0;
my $branches_to_use;
my $transport_cost_matrix;
my $use_transport_cost_matrix = C4::Context->preference("UseTransportCostMatrix");
if ($use_transport_cost_matrix) {
$transport_cost_matrix = TransportCostMatrix();
unless (keys %$transport_cost_matrix) {
warn "UseTransportCostMatrix set to yes, but matrix not populated";
undef $transport_cost_matrix;
}
}
unless ($transport_cost_matrix) {
$branches_to_use = load_branches_to_pull_from();
}
my $bibs_with_pending_requests = GetBibsWithPendingHoldRequests();
foreach my $biblionumber (@$bibs_with_pending_requests) {
$total_bibs++;
my $hold_requests = GetPendingHoldRequestsForBib($biblionumber);
my $available_items = GetItemsAvailableToFillHoldRequestsForBib($biblionumber, $branches_to_use);
$total_requests += scalar(@$hold_requests);
$total_available_items += scalar(@$available_items);
my $item_map = MapItemsToHoldRequests($hold_requests, $available_items, $branches_to_use, $transport_cost_matrix);
$item_map or next;
my $item_map_size = scalar(keys %$item_map)
or next;
$num_items_mapped += $item_map_size;
CreatePicklistFromItemMap($item_map);
AddToHoldTargetMap($item_map);
if (($item_map_size < scalar(@$hold_requests )) and
($item_map_size < scalar(@$available_items))) {
# DOUBLE CHECK, but this is probably OK - unfilled item-level requests
# FIXME
#warn "unfilled requests for $biblionumber";
#warn Dumper($hold_requests), Dumper($available_items), Dumper($item_map);
}
}
}
=head2 GetBibsWithPendingHoldRequests
my $biblionumber_aref = GetBibsWithPendingHoldRequests();
Return an arrayref of the biblionumbers of all bibs
that have one or more unfilled hold requests.
=cut
sub GetBibsWithPendingHoldRequests {
my $dbh = C4::Context->dbh;
my $bib_query = "SELECT DISTINCT biblionumber
FROM reserves
WHERE found IS NULL
AND priority > 0
AND reservedate <= CURRENT_DATE()
AND suspend = 0
";
my $sth = $dbh->prepare($bib_query);
$sth->execute();
my $biblionumbers = $sth->fetchall_arrayref();
return [ map { $_->[0] } @$biblionumbers ];
}
=head2 GetPendingHoldRequestsForBib
my $requests = GetPendingHoldRequestsForBib($biblionumber);
Returns an arrayref of hashrefs to pending, unfilled hold requests
on the bib identified by $biblionumber. The following keys
are present in each hashref:
biblionumber
borrowernumber
itemnumber
priority
branchcode
reservedate
reservenotes
borrowerbranch
The arrayref is sorted in order of increasing priority.
=cut
sub GetPendingHoldRequestsForBib {
my $biblionumber = shift;
my $dbh = C4::Context->dbh;
my $request_query = "SELECT biblionumber, borrowernumber, itemnumber, priority, reserves.branchcode,
reservedate, reservenotes, borrowers.branchcode AS borrowerbranch, itemtype
FROM reserves
JOIN borrowers USING (borrowernumber)
WHERE biblionumber = ?
AND found IS NULL
AND priority > 0
AND reservedate <= CURRENT_DATE()
AND suspend = 0
ORDER BY priority";
my $sth = $dbh->prepare($request_query);
$sth->execute($biblionumber);
my $requests = $sth->fetchall_arrayref({});
return $requests;
}
=head2 GetItemsAvailableToFillHoldRequestsForBib
my $available_items = GetItemsAvailableToFillHoldRequestsForBib($biblionumber, $branches_ar);
Returns an arrayref of items available to fill hold requests
for the bib identified by C<$biblionumber>. An item is available
to fill a hold request if and only if:
* it is not on loan
* it is not withdrawn
* it is not marked notforloan
* it is not currently in transit
* it is not lost
* it is not sitting on the hold shelf
* it is not damaged (unless AllowHoldsOnDamagedItems is on)
=cut
sub GetItemsAvailableToFillHoldRequestsForBib {
my ($biblionumber, $branches_to_use) = @_;
my $dbh = C4::Context->dbh;
my $items_query = "SELECT itemnumber, homebranch, holdingbranch, itemtypes.itemtype AS itype
FROM items ";
if (C4::Context->preference('item-level_itypes')) {
$items_query .= "LEFT JOIN itemtypes ON (itemtypes.itemtype = items.itype) ";
} else {
$items_query .= "JOIN biblioitems USING (biblioitemnumber)
LEFT JOIN itemtypes USING (itemtype) ";
}
$items_query .= "WHERE items.notforloan = 0
AND holdingbranch IS NOT NULL
AND itemlost = 0
AND withdrawn = 0";
$items_query .= " AND damaged = 0" unless C4::Context->preference('AllowHoldsOnDamagedItems');
$items_query .= " AND items.onloan IS NULL
AND (itemtypes.notforloan IS NULL OR itemtypes.notforloan = 0)
AND itemnumber NOT IN (
SELECT itemnumber
FROM reserves
WHERE biblionumber = ?
AND itemnumber IS NOT NULL
AND (found IS NOT NULL OR priority = 0)
)
AND items.biblionumber = ?";
my @params = ($biblionumber, $biblionumber);
if ($branches_to_use && @$branches_to_use) {
$items_query .= " AND holdingbranch IN (" . join (",", map { "?" } @$branches_to_use) . ")";
push @params, @$branches_to_use;
}
my $sth = $dbh->prepare($items_query);
$sth->execute(@params);
my $itm = $sth->fetchall_arrayref({});
my @items = grep { ! scalar GetTransfers($_->{itemnumber}) } @$itm;
return [ grep {
my $rule = GetBranchItemRule($_->{homebranch}, $_->{itype});
$_->{holdallowed} = $rule->{holdallowed};
$_->{hold_fulfillment_policy} = $rule->{hold_fulfillment_policy};
} @items ];
}
=head2 MapItemsToHoldRequests
MapItemsToHoldRequests($hold_requests, $available_items, $branches, $transport_cost_matrix)
=cut
sub MapItemsToHoldRequests {
my ($hold_requests, $available_items, $branches_to_use, $transport_cost_matrix) = @_;
# handle trival cases
return unless scalar(@$hold_requests) > 0;
return unless scalar(@$available_items) > 0;
# identify item-level requests
my %specific_items_requested = map { $_->{itemnumber} => 1 }
grep { defined($_->{itemnumber}) }
@$hold_requests;
# group available items by itemnumber
my %items_by_itemnumber = map { $_->{itemnumber} => $_ } @$available_items;
# items already allocated
my %allocated_items = ();
# map of items to hold requests
my %item_map = ();
# figure out which item-level requests can be filled
my $num_items_remaining = scalar(@$available_items);
foreach my $request (@$hold_requests) {
last if $num_items_remaining == 0;
# is this an item-level request?
if (defined($request->{itemnumber})) {
# fill it if possible; if not skip it
if (
exists $items_by_itemnumber{ $request->{itemnumber} }
and not exists $allocated_items{ $request->{itemnumber} }
and ( # Don't fill item level holds that contravene the hold pickup policy at this time
( $items_by_itemnumber{ $request->{itemnumber} }->{hold_fulfillment_policy} eq 'any' )
|| ( $request->{branchcode} eq $items_by_itemnumber{ $request->{itemnumber} }->{ $items_by_itemnumber{ $request->{itemnumber} }->{hold_fulfillment_policy} } )
and ( !$request->{itemtype} # If hold itemtype is set, item's itemtype must match
|| $items_by_itemnumber{ $request->{itemnumber} }->{itype} eq $request->{itemtype} )
)
)
{
$item_map{ $request->{itemnumber} } = {
borrowernumber => $request->{borrowernumber},
biblionumber => $request->{biblionumber},
holdingbranch => $items_by_itemnumber{ $request->{itemnumber} }->{holdingbranch},
pickup_branch => $request->{branchcode} || $request->{borrowerbranch},
item_level => 1,
reservedate => $request->{reservedate},
reservenotes => $request->{reservenotes},
};
$allocated_items{ $request->{itemnumber} }++;
$num_items_remaining--;
}
} else {
# it's title-level request that will take up one item
$num_items_remaining--;
}
}
# group available items by branch
my %items_by_branch = ();
foreach my $item (@$available_items) {
next unless $item->{holdallowed};
push @{ $items_by_branch{ $item->{holdingbranch} } }, $item
unless exists $allocated_items{ $item->{itemnumber} };
}
return \%item_map unless keys %items_by_branch;
# now handle the title-level requests
$num_items_remaining = scalar(@$available_items) - scalar(keys %allocated_items);
my $pull_branches;
foreach my $request (@$hold_requests) {
last if $num_items_remaining == 0;
next if defined($request->{itemnumber}); # already handled these
# look for local match first
my $pickup_branch = $request->{branchcode} || $request->{borrowerbranch};
my ($itemnumber, $holdingbranch);
my $holding_branch_items = $items_by_branch{$pickup_branch};
if ( $holding_branch_items ) {
foreach my $item (@$holding_branch_items) {
if (
$request->{borrowerbranch} eq $item->{homebranch}
&& ( ( $item->{hold_fulfillment_policy} eq 'any' ) # Don't fill item level holds that contravene the hold pickup policy at this time
|| $request->{branchcode} eq $item->{ $item->{hold_fulfillment_policy} } )
&& ( !$request->{itemtype} # If hold itemtype is set, item's itemtype must match
|| $items_by_itemnumber{ $request->{itemnumber} }->{itype} eq $request->{itemtype} )
)
{
$itemnumber = $item->{itemnumber};
last;
}
}
$holdingbranch = $pickup_branch;
}
elsif ($transport_cost_matrix) {
$pull_branches = [keys %items_by_branch];
$holdingbranch = least_cost_branch( $pickup_branch, $pull_branches, $transport_cost_matrix );
if ( $holdingbranch ) {
my $holding_branch_items = $items_by_branch{$holdingbranch};
foreach my $item (@$holding_branch_items) {
next if $request->{borrowerbranch} ne $item->{homebranch};
# Don't fill item level holds that contravene the hold pickup policy at this time
next unless $item->{hold_fulfillment_policy} eq 'any'
|| $request->{branchcode} eq $item->{ $item->{hold_fulfillment_policy} };
# If hold itemtype is set, item's itemtype must match
next unless ( !$request->{itemtype}
|| $item->{itype} eq $request->{itemtype} );
$itemnumber = $item->{itemnumber};
last;
}
}
else {
next;
}
}
unless ($itemnumber) {
# not found yet, fall back to basics
if ($branches_to_use) {
$pull_branches = $branches_to_use;
} else {
$pull_branches = [keys %items_by_branch];
}
# Try picking items where the home and pickup branch match first
PULL_BRANCHES:
foreach my $branch (@$pull_branches) {
my $holding_branch_items = $items_by_branch{$branch}
or next;
$holdingbranch ||= $branch;
foreach my $item (@$holding_branch_items) {
next if $pickup_branch ne $item->{homebranch};
next if ( $item->{holdallowed} == 1 && $item->{homebranch} ne $request->{borrowerbranch} );
# Don't fill item level holds that contravene the hold pickup policy at this time
next unless $item->{hold_fulfillment_policy} eq 'any'
|| $request->{branchcode} eq $item->{ $item->{hold_fulfillment_policy} };
# If hold itemtype is set, item's itemtype must match
next unless ( !$request->{itemtype}
|| $item->{itype} eq $request->{itemtype} );
$itemnumber = $item->{itemnumber};
$holdingbranch = $branch;
last PULL_BRANCHES;
}
}
# Now try items from the least cost branch based on the transport cost matrix or StaticHoldsQueueWeight
unless ( $itemnumber ) {
foreach my $current_item ( @{ $items_by_branch{$holdingbranch} } ) {
if ( $holdingbranch && ( $current_item->{holdallowed} == 2 || $request->{borrowerbranch} eq $current_item->{homebranch} ) ) {
# Don't fill item level holds that contravene the hold pickup policy at this time
next unless $current_item->{hold_fulfillment_policy} eq 'any'
|| $request->{branchcode} eq $current_item->{ $current_item->{hold_fulfillment_policy} };
# If hold itemtype is set, item's itemtype must match
next unless ( !$request->{itemtype}
|| $current_item->{itype} eq $request->{itemtype} );
$itemnumber = $current_item->{itemnumber};
last; # quit this loop as soon as we have a suitable item
}
}
}
# Now try for items for any item that can fill this hold
unless ( $itemnumber ) {
PULL_BRANCHES2:
foreach my $branch (@$pull_branches) {
my $holding_branch_items = $items_by_branch{$branch}
or next;
foreach my $item (@$holding_branch_items) {
next if ( $item->{holdallowed} == 1 && $item->{homebranch} ne $request->{borrowerbranch} );
# Don't fill item level holds that contravene the hold pickup policy at this time
next unless $item->{hold_fulfillment_policy} eq 'any'
|| $request->{branchcode} eq $item->{ $item->{hold_fulfillment_policy} };
# If hold itemtype is set, item's itemtype must match
next unless ( !$request->{itemtype}
|| $item->{itype} eq $request->{itemtype} );
$itemnumber = $item->{itemnumber};
$holdingbranch = $branch;
last PULL_BRANCHES2;
}
}
}
}
if ($itemnumber) {
my $holding_branch_items = $items_by_branch{$holdingbranch}
or die "Have $itemnumber, $holdingbranch, but no items!";
@$holding_branch_items = grep { $_->{itemnumber} != $itemnumber } @$holding_branch_items;
delete $items_by_branch{$holdingbranch} unless @$holding_branch_items;
$item_map{$itemnumber} = {
borrowernumber => $request->{borrowernumber},
biblionumber => $request->{biblionumber},
holdingbranch => $holdingbranch,
pickup_branch => $pickup_branch,
item_level => 0,
reservedate => $request->{reservedate},
reservenotes => $request->{reservenotes},
};
$num_items_remaining--;
}
}
return \%item_map;
}
=head2 CreatePickListFromItemMap
=cut
sub CreatePicklistFromItemMap {
my $item_map = shift;
my $dbh = C4::Context->dbh;
my $sth_load=$dbh->prepare("
INSERT INTO tmp_holdsqueue (biblionumber,itemnumber,barcode,surname,firstname,phone,borrowernumber,
cardnumber,reservedate,title, itemcallnumber,
holdingbranch,pickbranch,notes, item_level_request)
VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)
");
foreach my $itemnumber (sort keys %$item_map) {
my $mapped_item = $item_map->{$itemnumber};
my $biblionumber = $mapped_item->{biblionumber};
my $borrowernumber = $mapped_item->{borrowernumber};
my $pickbranch = $mapped_item->{pickup_branch};
my $holdingbranch = $mapped_item->{holdingbranch};
my $reservedate = $mapped_item->{reservedate};
my $reservenotes = $mapped_item->{reservenotes};
my $item_level = $mapped_item->{item_level};
my $item = GetItem($itemnumber);
my $barcode = $item->{barcode};
my $itemcallnumber = $item->{itemcallnumber};
my $borrower = GetMember('borrowernumber'=>$borrowernumber);
my $cardnumber = $borrower->{'cardnumber'};
my $surname = $borrower->{'surname'};
my $firstname = $borrower->{'firstname'};
my $phone = $borrower->{'phone'};
my $bib = GetBiblioData($biblionumber);
my $title = $bib->{title};
$sth_load->execute($biblionumber, $itemnumber, $barcode, $surname, $firstname, $phone, $borrowernumber,
$cardnumber, $reservedate, $title, $itemcallnumber,
$holdingbranch, $pickbranch, $reservenotes, $item_level);
}
}
=head2 AddToHoldTargetMap
=cut
sub AddToHoldTargetMap {
my $item_map = shift;
my $dbh = C4::Context->dbh;
my $insert_sql = q(
INSERT INTO hold_fill_targets (borrowernumber, biblionumber, itemnumber, source_branchcode, item_level_request)
VALUES (?, ?, ?, ?, ?)
);
my $sth_insert = $dbh->prepare($insert_sql);
foreach my $itemnumber (keys %$item_map) {
my $mapped_item = $item_map->{$itemnumber};
$sth_insert->execute($mapped_item->{borrowernumber}, $mapped_item->{biblionumber}, $itemnumber,
$mapped_item->{holdingbranch}, $mapped_item->{item_level});
}
}
# Helper functions, not part of any interface
sub _trim {
return $_[0] unless $_[0];
$_[0] =~ s/^\s+//;
$_[0] =~ s/\s+$//;
$_[0];
}
sub load_branches_to_pull_from {
my @branches_to_use;
my $static_branch_list = C4::Context->preference("StaticHoldsQueueWeight");
@branches_to_use = map { _trim($_) } split( /,/, $static_branch_list )
if $static_branch_list;
@branches_to_use =
Koha::Database->new()->schema()->resultset('Branch')
->get_column('branchcode')->all()
unless (@branches_to_use);
@branches_to_use = shuffle(@branches_to_use)
if C4::Context->preference("RandomizeHoldsQueueWeight");
my $today = dt_from_string();
if ( C4::Context->preference('HoldsQueueSkipClosed') ) {
@branches_to_use = grep {
!Koha::Calendar->new( branchcode => $_ )
->is_holiday( $today )
} @branches_to_use;
}
return \@branches_to_use;
}
sub least_cost_branch {
#$from - arrayref
my ($to, $from, $transport_cost_matrix) = @_;
# Nothing really spectacular: supply to branch, a list of potential from branches
# and find the minimum from - to value from the transport_cost_matrix
return $from->[0] if ( @$from == 1 && $transport_cost_matrix->{$to}{$from->[0]}->{disable_transfer} != 1 );
# If the pickup library is in the list of libraries to pull from,
# return that library right away, it is obviously the least costly
return ($to) if any { $_ eq $to } @$from;
my ($least_cost, @branch);
foreach (@$from) {
my $cell = $transport_cost_matrix->{$to}{$_};
next if $cell->{disable_transfer};
my $cost = $cell->{cost};
next unless defined $cost; # XXX should this be reported?
unless (defined $least_cost) {
$least_cost = $cost;
push @branch, $_;
next;
}
next if $cost > $least_cost;
if ($cost == $least_cost) {
push @branch, $_;
next;
}
@branch = ($_);
$least_cost = $cost;
}
return $branch[0];
# XXX return a random @branch with minimum cost instead of the first one;
# return $branch[0] if @branch == 1;
}
1;