Add workaround for translations for of opt-in block in editor

We currently don't have tooling for passing translations from scripts to wp.i18n.
This solution provides a temporary way of passing translated strings to wp.i18n for scripts that are
used outside admin pages that are handled via MailPoet.
[MAILPOET-3920]

assets/js/src/marketing_optin_block/edit.tsx

@@ -20,14 +20,11 @@ const { optinEnabled, defaultText } = getSetting('mailpoet_data');
 const EmptyState = (): JSX.Element => (
   <Placeholder
     icon={<Icon icon={megaphone} />}
-    label={__('Marketing opt-in', 'mailpoet')}
+    label={__('marketing-opt-in-label', 'mailpoet')}
     className="wp-block-mailpoet-newsletter-block-placeholder"
   >
     <span className="wp-block-mailpoet-newsletter-block-placeholder__description">
-      {__(
-        'MailPoet marketing opt-in would be shown here if enabled. You can enable from the settings page.',
-        'mailpoet'
-      )}
+      {__('marketing-opt-in-not-shown', 'mailpoet')}
     </span>
     <Button
       isPrimary
@@ -36,7 +33,7 @@ const EmptyState = (): JSX.Element => (
       rel="noopener noreferrer"
       className="wp-block-mailpoet-newsletter-block-placeholder__button"
     >
-      {__('Enable opt-in for Checkout', 'mailpoet')}
+      {__('marketing-opt-in-enable', 'mailpoet')}
     </Button>
   </Placeholder>
 );

lib/PostEditorBlocks/MarketingOptinBlock.php

@@ -48,6 +48,7 @@ class MarketingOptinBlock implements IntegrationInterface {
       $script_asset['version'],
       true
     );
+    $this->registerEditorTranslations();
   }
 
   /**
@@ -76,4 +77,27 @@ class MarketingOptinBlock implements IntegrationInterface {
   public function get_script_data() { // phpcs:ignore
     return $this->options;
   }
+
+  /**
+   * Workaround for registering script translations.
+   * Currently, we don't generate translation files for scripts. This method enqueues an inline script
+   * that renders same output as a script translation file would render, when rendered via wp_scripts()->print_translations.
+   * Note that keys need to match strings in JS files
+   */
+  private function registerEditorTranslations() {
+    $handle = 'mailpoet-marketing-optin-block-editor-script';
+    $editorTranslations = $this->wp->getWpScripts()->print_translations($handle, false);
+    // mailpoet-marketing-optin-block-editor-script is not enqueued
+    if ($editorTranslations === false) {
+      return;
+    }
+    $translations = [
+      '' => ['domain' => 'messages'],
+      'marketing-opt-in-label' => [__('Marketing opt-in', 'mailpoet')],
+      'marketing-opt-in-not-shown' => [__('MailPoet marketing opt-in would be shown here if enabled. You can enable from the settings page.', 'mailpoet')],
+      'marketing-opt-in-enable' => [__('Enable opt-in for Checkout', 'mailpoet')],
+    ];
+    $editorTranslations = str_replace('{ "messages": { "": {} }', '{ "messages": ' . json_encode($translations), $editorTranslations);
+    $this->wp->wpAddInlineScript($handle, $editorTranslations, 'before');
+  }
 }

lib/WP/Functions.php

@@ -752,4 +752,11 @@ class Functions {
   public function wpSetScriptTranslations(string $handle, string $domain = 'default', string $path = null): bool {
     return wp_set_script_translations($handle, $domain, $path);
   }
+
+  /**
+   * @return \WP_Scripts
+   */
+  public function getWpScripts() {
+    return wp_scripts();
+  }
 }