Checkbox implementation and refactor naming structure

[MAILPOET-3920]

lib/PostEditorBlocks/MarketingOptinBlock.php

@@ -0,0 +1,83 @@
+<?php
+
+namespace MailPoet\PostEditorBlocks;
+
+use Automattic\WooCommerce\Blocks\Integrations\IntegrationInterface;
+use MailPoet\Config\Env;
+
+/**
+ * Class MarketingOptinBlock
+ *
+ * Class for integrating marketing optin block with WooCommerce Checkout.
+ */
+class MarketingOptinBlock implements IntegrationInterface {
+  /** @var array */
+  private $options;
+
+  public function __construct(
+    array $options
+  ) {
+    $this->options = $options;
+  }
+
+  /**
+   * The name of the integration.
+   *
+   * @return string
+   */
+  public function get_name() { // phpcs:ignore
+    return 'mailpoet';
+  }
+
+  /**
+   * Register block scripts and assets.
+   */
+  public function initialize() {
+    $script_asset_path = Env::$assetsUrl . '/dist/js/marketing_optin_block/marketing-optin-block-frontend.asset.php';
+    $script_asset      = file_exists($script_asset_path)
+      ? require $script_asset_path
+      : [
+        'dependencies' => [],
+        'version'      => Env::$version,
+      ];
+    wp_register_script(
+      'mailpoet-marketing-optin-block-frontend',
+      Env::$assetsUrl . '/dist/js/marketing_optin_block/marketing-optin-block-frontend.js',
+      $script_asset['dependencies'],
+      $script_asset['version'],
+      true
+    );
+    wp_set_script_translations(
+      'mailpoet-marketing-optin-block-frontend',
+      'mailpoet',
+      Env::$languagesPath
+    );
+  }
+
+  /**
+   * Returns an array of script handles to enqueue in the frontend context.
+   *
+   * @return string[]
+   */
+  public function get_script_handles() { // phpcs:ignore
+    return ['mailpoet-marketing-optin-block-frontend'];
+  }
+
+  /**
+   * Returns an array of script handles to enqueue in the editor context.
+   *
+   * @return string[]
+   */
+  public function get_editor_script_handles() { // phpcs:ignore
+    return [];
+  }
+
+  /**
+   * An array of key, value pairs of data made available to the block on the client side.
+   *
+   * @return array
+   */
+  public function get_script_data() { // phpcs:ignore
+    return $this->options;
+  }
+}