Bug 13098: Make _FixAccountForLostAndReturned refund the right thing

This patch changes the logic inside the method, to make it match the
behaviour described on the tests.

It uses the existing offsets on the account_offsets table to gather
information about the right things to refund.

To test:
- Run:
  $ kshell
 k$ prove t/db_dependent/Circulation.t
=> FAIL: Tests don't pass!
- Apply this patch
- Run
 k$ prove t/db_dependent/Circulation.t
=> SUCCESS: Tests pass!
- Sign off :-D

Followed test plan, patch works as described. All three patches pass QA
test tool
Signed-off-by: Alex Buckley <alexbuckley@catalyst.net.nz>

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>

C4/Circulation.pm

@@ -2392,8 +2392,10 @@ sub _FixAccountForLostAndReturned {
     my $borrowernumber = @_ ? shift : undef;
     my $item_id        = @_ ? shift : $itemnumber;  # Send the barcode if you want that logged in the description
 
+    my $credit;
+
     # check for charge made for lost book
-    my $accountline = Koha::Account::Lines->search(
+    my $accountlines = Koha::Account::Lines->search(
         {
             itemnumber  => $itemnumber,
             accounttype => { -in => [ 'L', 'Rep', 'W' ] },
@@ -2401,29 +2403,49 @@ sub _FixAccountForLostAndReturned {
         {
             order_by => { -desc => [ 'date', 'accountno' ] }
         }
-    )->next();
-
-    return unless $accountline;
-    return if $accountline->accounttype eq 'W';    # Written off
-
-    $accountline->accounttype('LR');
-    $accountline->store();
-
-    my $account = Koha::Account->new( { patron_id => $accountline->borrowernumber } );
-    my $credit_id = $account->pay(
-        {
-            amount       => $accountline->amount,
-            description  => "Item Returned " . $item_id,
-            account_type => 'CR',
-            offset_type  => 'Lost Item Return',
-            lines        => [$accountline],
-
-        }
     );
 
-    ModItem( { paidfor => '' }, undef, $itemnumber, { log_action => 0 } );
+    return unless $accountlines->count > 0;
+    my $accountline = $accountlines->next;
 
-    return $credit_id;
+    # Use cases
+    if ( $accountline->amount > $accountline->amountoutstanding ) {
+        # some amount has been cancelled. collect the offsets that are not writeoffs
+        # this works because the only way to subtract from a debt is
+        # using the UI buttons 'Pay' and 'Write off'
+        my $credits_offsets = Koha::Account::Offsets->search({
+            debit_id  => $accountline->id,
+            credit_id => { '!=' => undef }, # it is not the debit itself
+            type      => { '!=' => 'Writeoff' },
+            amount    => { '<'  => 0 } # credits are negative on the DB
+        });
+
+        my $total_to_refund = ( $credits_offsets->count > 0 )
+                                ? $credits_offsets->total * -1 # credits are negative on the DB
+                                : 0;
+
+        if ( $total_to_refund > 0 ) {
+            my $account = Koha::Patrons->find( $accountline->borrowernumber )->account;
+            $credit = $account->add_credit(
+                {
+                    amount      => $total_to_refund,
+                    description => 'Item Returned ' . $item_id,
+                    type        => 'lost_item_return'
+                }
+            );
+        }
+
+        ModItem( { paidfor => '' }, undef, $itemnumber, { log_action => 0 } );
+    }
+    # else {
+        # $accountline->amount == $accountline->amountoutstanding
+    #}
+
+    $accountline->accounttype('LR');
+    $accountline->amountoutstanding(0);
+    $accountline->store();
+
+    return ($credit) ? $credit->id : undef;
 }
 
 =head2 _GetCircControlBranch