Fix https://github.com/firefly-iii/firefly-iii/issues/8352

app/Services/Internal/Support/CreditRecalculateService.php

@@ -33,6 +33,7 @@ use FireflyIII\Models\TransactionGroup;
 use FireflyIII\Models\TransactionJournal;
 use FireflyIII\Models\TransactionType;
 use FireflyIII\Repositories\Account\AccountRepositoryInterface;
+use Illuminate\Support\Facades\Log;
 
 /**
  * Class CreditRecalculateService
@@ -195,8 +196,7 @@ class CreditRecalculateService
         $transactions = $account->transactions()
                                 ->leftJoin('transaction_journals', 'transaction_journals.id', '=', 'transactions.transaction_journal_id')
                                 ->orderBy('transaction_journals.date', 'ASC')
-            ->get(['transactions.*'])
+                                ->get(['transactions.*']);
-        ;
         $total        = $transactions->count();
         app('log')->debug(sprintf('Found %d transaction(s) to process.', $total));
 
@@ -267,6 +267,7 @@ class CreditRecalculateService
 
             return $leftOfDebt;
         }
+        Log::debug(sprintf('Liability direction is "%s"', $direction));
 
         // amount to use depends on the currency:
         $usedAmount    = $this->getAmountToUse($transaction, $accountCurrency, $foreignCurrency);
@@ -334,6 +335,20 @@ class CreditRecalculateService
             return $result;
         }
 
+        if ($isSameAccount && $isDebit && $this->isTransferIn($usedAmount, $type)) { // case 9
+            $usedAmount = app('steam')->positive($usedAmount);
+            $result     = bcadd($leftOfDebt, $usedAmount);
+            app('log')->debug(sprintf('Case 9 (transfer into debit liability, means you owe more): %s + %s = %s', app('steam')->bcround($leftOfDebt, 2), app('steam')->bcround($usedAmount, 2), app('steam')->bcround($result, 2)));
+            return $result;
+        }
+        if ($isSameAccount && $isDebit && $this->isTransferOut($usedAmount, $type)) { // case 10
+            $usedAmount = app('steam')->positive($usedAmount);
+            $result     = bcsub($leftOfDebt, $usedAmount);
+            app('log')->debug(sprintf('Case 5 (transfer out of debit liability, means you owe less): %s - %s = %s', app('steam')->bcround($leftOfDebt, 2), app('steam')->bcround($usedAmount, 2), app('steam')->bcround($result, 2)));
+
+            return $result;
+        }
+
         // in any other case, remove amount from left of debt.
         if (in_array($type, [TransactionType::WITHDRAWAL, TransactionType::DEPOSIT, TransactionType::TRANSFER], true)) {
             $usedAmount = app('steam')->negative($usedAmount);
@@ -400,7 +415,7 @@ class CreditRecalculateService
      * because the person is paying us back.
      *
      * case 7
-     * if it's a credit ("I am owed") this increases the amount due.
+     * if it's a debit ("I owe") this increases the amount due.
      * because we are borrowing more money.
      */
     private function isDepositOut(string $amount, string $transactionType): bool
@@ -423,9 +438,25 @@ class CreditRecalculateService
      * case 5: transfer into loan (from other loan).
      * if it's a credit ("I am owed") this increases the amount due,
      * because the person has to pay more back.
+     *
+     * case 8: transfer into loan (from other loan).
+     * if it's a debit ("I owe") this decreases the amount due.
+     * because the person has to pay more back.
      */
     private function isTransferIn(string $amount, string $transactionType): bool
     {
         return TransactionType::TRANSFER === $transactionType && 1 === bccomp($amount, '0');
     }
+
+    /**
+     * it's a transfer out of loan (from other loan)
+     *
+     * case 9
+     * if it's a debit ("I owe") this decreases the amount due.
+     * because we remove money from the amount left to owe
+     */
+    private function isTransferOut(string $amount, string $transactionType): bool
+    {
+        return TransactionType::DEPOSIT === $transactionType && -1 === bccomp($amount, '0');
+    }
 }