Fix Bcc mail

CRM/Ses/Mail.php

@@ -71,13 +71,55 @@ class CRM_Ses_Mail extends Mail {
       }
     }
 
+    // Sanitize and prepare headers for transmission
+    if (!is_array($headers)) {
+      return new PEAR_Error('SES: $headers must be an array');
+    }
+
     $ses_access_key = Civi::settings()->get('ses_access_key');
     $ses_secret_key = Civi::settings()->get('ses_secret_key');
     $ses_region = Civi::settings()->get('ses_region');
 
-    // Sanitize and prepare headers for transmission
-    if (!is_array($headers)) {
-      return new PEAR_Error('SES: $headers must be an array');
+    // $headers['Bcc'] gets unset before calling this function because it assumes it won't get removed by the mailer.
+    // But SES needs the full headers and then it removes it when processing.
+    // So we have to add it back in. We can get it from the last element in the $recipients array:
+    // $recipients = [
+    // 0: To (single email)
+    // 1: Cc (comma separated string)
+    // 2: Bcc (comma separated string)
+    // ]
+    // BUT BE CAREFUL! To or Cc might not be defined so it won't always be element 2. It will always be the last element
+    //   but we don't know if we actually have any Bcc addresses without checking the To, Cc headers first.
+    // Eg. if you have To+Bcc then $recipients[0] is To and $recipients[1] is Bcc but if you have To+Cc then $recipients[1]
+    // is Cc and if $recipients[2] is not set you have no Bcc and don't need to add the header... confused yet?
+
+    // Work out which $recipients keys represent To, Cc and Bcc
+    if (array_key_exists('To', $headers)) {
+      $newRecipients['To'] = array_shift($recipients);
+    }
+    if (array_key_exists('Cc', $headers)) {
+      $newRecipients['Cc'] = array_shift($recipients);
+    }
+    $newRecipients['Bcc'] = array_shift($recipients);
+    if (!empty($newRecipients['Bcc'])) {
+      // The order of headers might not matter (I didn't check if SES cares or not).
+      // But we insert the Bcc header in the right place anyway. ie. after Cc or To or From.
+      if (array_key_exists('Cc', $headers)) {
+        $insertBccAfterHeader = 'Cc';
+      }
+      elseif (array_key_exists('To', $headers)) {
+        $insertBccAfterHeader = 'To';
+      }
+      else {
+        $insertBccAfterHeader = 'From';
+      }
+      foreach ($headers as $headerKey => $headerValue) {
+        $newHeaders[$headerKey] = $headerValue;
+        if ($headerKey === $insertBccAfterHeader) {
+          $newHeaders['Bcc'] = $newRecipients['Bcc'];
+        }
+      }
+      $headers = $newHeaders;
     }
 
     $this->_sanitizeHeaders($headers);