From d55ff327b09875a213821b2ccdc6860cd4323812 Mon Sep 17 00:00:00 2001
From: Seamus Lee <seamuslee001@gmail.com>
Date: Mon, 13 Jul 2020 14:38:20 +1000
Subject: [PATCH] [REF] permit negative payments to be made against completed
 payments

---
 CRM/Financial/BAO/Payment.php        | 11 +++++++++--
 tests/phpunit/api/v3/PaymentTest.php |  1 +
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/CRM/Financial/BAO/Payment.php b/CRM/Financial/BAO/Payment.php
index f841363f141f..1dabc550e504 100644
--- a/CRM/Financial/BAO/Payment.php
+++ b/CRM/Financial/BAO/Payment.php
@@ -486,6 +486,9 @@ protected static function getPayableLineItems($params): array {
     if ($outstandingBalance !== 0.0) {
       $ratio = $params['total_amount'] / $outstandingBalance;
     }
+    elseif ($params['total_amount'] < 0) {
+      $ratio = $params['total_amount'] / (float) CRM_Core_BAO_FinancialTrxn::getTotalPayments($params['contribution_id'], TRUE);
+    }
     else {
       // Help we are making a payment but no money is owed. We won't allocate the overpayment to any line item.
       $ratio = 0;
@@ -495,12 +498,16 @@ protected static function getPayableLineItems($params): array {
       $lineItems[$lineItemID]['id'] = $lineItemID;
       $lineItems[$lineItemID]['paid'] = self::getAmountOfLineItemPaid($lineItemID);
       $lineItems[$lineItemID]['balance'] = $lineItem['subTotal'] - $lineItems[$lineItemID]['paid'];
-
       if (!empty($lineItemOverrides)) {
         $lineItems[$lineItemID]['allocation'] = $lineItemOverrides[$lineItemID] ?? NULL;
       }
       else {
-        $lineItems[$lineItemID]['allocation'] = $lineItems[$lineItemID]['balance'] * $ratio;
+        if (empty($lineItems[$lineItemID]['balance']) && !empty($ratio) && $params['total_amount'] < 0) {
+          $lineItems[$lineItemID]['allocation'] = $lineItem['subTotal'] * $ratio;
+        }
+        else {
+          $lineItems[$lineItemID]['allocation'] = $lineItems[$lineItemID]['balance'] * $ratio;
+        }
       }
     }
     return $lineItems;
diff --git a/tests/phpunit/api/v3/PaymentTest.php b/tests/phpunit/api/v3/PaymentTest.php
index 046f1f6058df..2d3da04872e1 100644
--- a/tests/phpunit/api/v3/PaymentTest.php
+++ b/tests/phpunit/api/v3/PaymentTest.php
@@ -183,6 +183,7 @@ public function testGetPaymentWithTrxnID() {
       ],
     ];
     $this->checkPaymentResult($payment, $expectedResult);
+    $this->callAPISuccess('Payment', 'create', ['total_amount' => '-20', 'contribution_id' => $contributionID2]);
     $this->validateAllPayments();
   }