Display an error message informing the user to subscribe through the hosted form if they were previously unsubscribed.

Author: iamdharmesh

lib/mailchimp/mailchimp.php

@@ -190,6 +190,28 @@ public function post( $endpoint, $body, $method = 'POST', $list_id = '' ) {
 				$merges = get_option( 'mailchimp_sf_merge_fields_' . $list_id );
 			}
 
+			// Check if the email address is in compliance state.
+			if ( ! isset( $body['errors'] ) && isset( $body['status'] ) && isset( $body['title'] ) && 400 === $body['status'] && 'Member In Compliance State' === $body['title'] ) {
+				$url     = mailchimp_sf_signup_form_url( $list_id );
+				$message = wp_kses(
+					sprintf(
+						/* translators: %s: Hosted form Url */
+						__(
+							'The email address cannot be subscribed because it was previously unsubscribed, bounced, or is under review. Please <a href="%s" target="_blank">sign up here.</a>',
+							'mailchimp'
+						),
+						esc_url( $url )
+					),
+					[
+						'a' => [
+							'href'   => [],
+							'target' => [],
+						],
+					]
+				);
+				return new WP_Error( 'mc-subscribe-error-compliance', $message );
+			}
+
 			$field_name = '';
 			foreach ( $merges as $merge ) {
 				if ( empty( $body['errors'] ) ) {

mailchimp.php

@@ -1224,13 +1224,16 @@ function mailchimp_sf_update_profile_url( $email ) {
 /**
  * Get signup form URL.
  *
+ * @param string $list_id List ID
  * @return string
  */
-function mailchimp_sf_signup_form_url() {
-	$dc      = get_option( 'mc_datacenter' );
-	$user    = get_option( 'mc_user' );
-	$list_id = get_option( 'mc_list_id' );
-	$url     = 'http://' . $dc . '.list-manage.com/subscribe?u=' . $user['account_id'] . '&id=' . $list_id;
+function mailchimp_sf_signup_form_url( $list_id = '' ) {
+	$dc   = get_option( 'mc_datacenter' );
+	$user = get_option( 'mc_user' );
+	if ( empty( $list_id ) ) {
+		$list_id = get_option( 'mc_list_id' );
+	}
+	$url = 'http://' . $dc . '.list-manage.com/subscribe?u=' . $user['account_id'] . '&id=' . $list_id;
 	return $url;
 }
 

views/css/frontend.php

@@ -6,7 +6,7 @@
  */
 
 ?>
-.mc_error_msg {
+.mc_error_msg, .mc_error_msg a {
 	color: red;
 	margin-bottom: 1.0em;
 }