👾 bug fix: don't call APIWrapper twice

no more double soft credits

twinglecampaign.php

@@ -15,18 +15,32 @@ function twinglecampaign_civicrm_config(&$config) {
   _twinglecampaign_civix_civicrm_config($config);
 
   // This dispatchers add event listeners to TwingleDonation.submit
-  // (de.systopia.twingle) and call an API-Wrapper which maps incoming Twingle
+  // (de.systopia.twingle) to call an API-Wrapper which maps incoming Twingle
   // donations to TwingleCampaigns and create soft credits for event initiators.
-  Civi::dispatcher()->addListener(
-    'civi.api.prepare',
-    ['CRM_TwingleCampaign_Utils_APIWrapper', 'PREPARE'],
-    -100
-  );
-  Civi::dispatcher()->addListener(
-    'civi.api.respond',
-    ['CRM_TwingleCampaign_Utils_APIWrapper', 'RESPOND'],
-    -100
-  );
+
+  // Do only add listeners once
+  if (!in_array(
+    ["CRM_TwingleCampaign_Utils_APIWrapper", "PREPARE"],
+    Civi::dispatcher()->getListeners('civi.api.prepare'))
+  ) {
+    Civi::dispatcher()->addListener(
+      'civi.api.prepare',
+      ['CRM_TwingleCampaign_Utils_APIWrapper', 'PREPARE'],
+      -100
+    );
+  }
+
+  // Do only add listeners once
+  if (!in_array(
+    ["CRM_TwingleCampaign_Utils_APIWrapper", "RESPOND"],
+    Civi::dispatcher()->getListeners('civi.api.respond')
+  )) {
+    Civi::dispatcher()->addListener(
+      'civi.api.respond',
+      ['CRM_TwingleCampaign_Utils_APIWrapper', 'RESPOND'],
+      -100
+    );
+  }
 }