fix gitignore & add assets registration functionality.

modules/ppcp-order-tracking/.gitignore

@@ -1,2 +1,2 @@
 node_modules
-assets
+/assets

modules/ppcp-order-tracking/src/Assets/OrderEditPageAssets.php

@@ -0,0 +1,100 @@
+<?php
+/**
+ * Register and configure assets for order edit page.
+ *
+ * @package WooCommerce\PayPalCommerce\OrderTracking\Assets
+ */
+
+declare(strict_types=1);
+
+namespace WooCommerce\PayPalCommerce\OrderTracking\Assets;
+
+use WooCommerce\PayPalCommerce\OrderTracking\Endpoint\OrderTrackingEndpoint;
+
+/**
+ * Class OrderEditPageAssets
+ */
+class OrderEditPageAssets {
+
+	/**
+	 * The URL to the module.
+	 *
+	 * @var string
+	 */
+	private $module_url;
+
+	/**
+	 * The assets version.
+	 *
+	 * @var string
+	 */
+	private $version;
+
+	/**
+	 * WebhooksStatusPageAssets constructor.
+	 *
+	 * @param string $module_url                         The URL to the module.
+	 * @param string $version                            The assets version.
+	 */
+	public function __construct(
+		string $module_url,
+		string $version
+	) {
+		$this->module_url = $module_url;
+		$this->version    = $version;
+	}
+
+	/**
+	 * Registers the scripts and styles.
+	 *
+	 * @return void
+	 */
+	public function register(): void {
+		wp_register_style(
+			'ppcp-webhooks-order-edit-page-style',
+			untrailingslashit( $this->module_url ) . '/assets/css/order-edit-page.css',
+			array(),
+			$this->version
+		);
+
+		wp_register_script(
+			'ppcp-tracking',
+			untrailingslashit( $this->module_url ) . '/assets/js/order-edit-page.js',
+			array( 'jquery' ),
+			$this->version,
+			true
+		);
+
+		wp_localize_script(
+			'ppcp-tracking',
+			'PayPalCommerceGatewayOrderTrackingInfo',
+			$this->get_script_data()
+		);
+	}
+
+	/**
+	 * Returns the data for the script.
+	 *
+	 * @return array a map of script data.
+	 */
+	public function get_script_data(): array {
+		return array(
+			'ajax' => array(
+				'tracking_info' => array(
+					'endpoint' => \WC_AJAX::get_endpoint( OrderTrackingEndpoint::ENDPOINT ),
+					'nonce'    => wp_create_nonce( OrderTrackingEndpoint::nonce() ),
+				),
+			),
+		);
+	}
+
+	/**
+	 * Enqueues the necessary scripts.
+	 *
+	 * @return void
+	 */
+	public function enqueue(): void {
+		wp_enqueue_style( 'ppcp-webhooks-order-edit-page-style' );
+		wp_enqueue_script( 'ppcp-tracking' );
+	}
+}