Bug 29346: Refactor loop code into a subroutine

The CreateQueue() method deletes the holds queue data, fetches some
configuration (branches to use, transport cost matrix) and then loops
through a list of biblionumbers, generating the tmp_holdsqueue and
hold_fill_targets rows for the specified biblio.

This patch simply moves that last bit that is run inside the biblios
loop into a separate sub.

The update_queue_for_biblio sub is designed so it does the exact same
thing it did inside the loop, but also gets added the capability of
querying those parameters if not passed, and it also gets a 'delete'
parameter so it deletes the biblio-specific holds queue rows before
starting to work.

This way, it can be reused to write a background job for real-time holds
queue update :-D

To test:
1. Run:
   $ kshell
  k$ prove t/db_dependent/HoldsQueue.t
=> SUCCESS: Tests pass!
2. Apply this patch
3. Repeat 1
=> SUCCESS: Tests still pass! Behavior is kept!
4. Sign off :-D

Sponsored-by: Montgomery County Public Libraries
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>

C4/HoldsQueue.pm

@@ -44,6 +44,8 @@ BEGIN {
         TransportCostMatrix
         UpdateTransportCostMatrix
         GetPendingHoldRequestsForBib
+        load_branches_to_pull_from
+        update_queue_for_biblio
      );
 }
 
@@ -204,27 +206,19 @@ sub CreateQueue {
     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;
+        my $result = update_queue_for_biblio(
+            {   biblio_id             => $biblionumber,
+                branches_to_use       => $branches_to_use,
+                transport_cost_matrix => $transport_cost_matrix,
+            }
+        );
 
-        $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);
-        }
+        $total_requests        += $result->{requests};
+        $total_available_items += $result->{available_items};
+        $num_items_mapped      += $result->{mapped_items};
     }
 }
 
@@ -855,5 +849,90 @@ sub least_cost_branch {
     # return $branch[0] if @branch == 1;
 }
 
+=head3 update_queue_for_biblio
+
+    my $result = update_queue_for_biblio(
+        {
+            biblio_id             => $biblio_id,
+          [ branches_to_use       => $branches_to_use,
+            transport_cost_matrix => $transport_cost_matrix,
+            delete                => $delete, ]
+        }
+    );
+
+Given a I<biblio_id>, this method calculates and sets the holds queue entries
+for the biblio's holds, and the hold fill targets (items).
+
+=head4 Return value
+
+It return a hashref containing:
+
+=over
+
+=item I<requests>: the pending holds count for the biblio.
+
+=item I<available_items> the count of items that are available to fill holds for the biblio.
+
+=item I<mapped_items> the total items that got mapped.
+
+=back
+
+=head4 Optional parameters
+
+=over
+
+=item I<branches_to_use> a list of branchcodes to be used to restrict which items can be used.
+
+=item I<transport_cost_matrix> is the output of C<TransportCostMatrix>.
+
+=item I<delete> tells the method to delete prior entries on the related tables for the biblio_id.
+
+=back
+
+Note: All the optional parameters will be calculated in the method if omitted. They
+are allowed to be passed to avoid calculating them many times inside loops.
+
+=cut
+
+sub update_queue_for_biblio {
+    my ($args) = @_;
+
+    my $biblio_id = $args->{biblio_id};
+
+    my $branches_to_use = $args->{branches_to_use} // load_branches_to_pull_from( C4::Context->preference('UseTransportCostMatrix') );
+    my $transport_cost_matrix;
+
+    if ( !exists $args->{transport_cost_matrix}
+        && C4::Context->preference('UseTransportCostMatrix') ) {
+        $transport_cost_matrix = TransportCostMatrix();
+    } else {
+        $transport_cost_matrix = $args->{transport_cost_matrix};
+    }
+
+    if ( $args->{delete} ) {
+        my $dbh = C4::Context->dbh;
+
+        $dbh->do("DELETE FROM tmp_holdsqueue WHERE biblionumber=$biblio_id");
+        $dbh->do("DELETE FROM hold_fill_targets WHERE biblionumber=$biblio_id");
+    }
+
+    my $hold_requests   = GetPendingHoldRequestsForBib($biblio_id);
+    my $available_items = GetItemsAvailableToFillHoldRequestsForBib( $biblio_id, $branches_to_use );
+
+    my $result = {
+        requests        => scalar( @{$hold_requests} ),
+        available_items => scalar( @{$available_items} ),
+    };
+
+    my $item_map = MapItemsToHoldRequests( $hold_requests, $available_items, $branches_to_use, $transport_cost_matrix );
+    $result->{mapped_items} = scalar( keys %{$item_map} );
+
+    if ($item_map) {
+        CreatePicklistFromItemMap($item_map);
+        AddToHoldTargetMap($item_map);
+    }
+
+    return $result;
+}
 
 1;