Stats admin: consolidate the dashboard registration decision in Main

Main::maybe_register_dashboard() is now the single place deciding when
the Odyssey dashboard owns the Stats screen: always for unconnected
sites (so Odyssey's pricing grid is reachable before connecting), and
for connected sites when the stats module is active, Odyssey is
enabled, and the request isn't a noheader chart image. The stats module
just falls back to the old interface when it declines.

Author: kangzj

projects/packages/stats-admin/changelog/stats-366-pricing-grid

@@ -1,4 +1,4 @@
 Significance: minor
 Type: added
 
-Register the Stats dashboard before the site connects, so eligible new installations without a Stats plan can reach the pricing grid rendered by Odyssey.
+Register the Stats dashboard before the site connects, so new installations can reach the Stats pricing grid rendered by Odyssey.

projects/packages/stats-admin/src/class-main.php

@@ -8,6 +8,7 @@
 namespace Automattic\Jetpack\Stats_Admin;
 
 use Automattic\Jetpack\Connection\Manager;
+use Automattic\Jetpack\Modules;
 use Automattic\Jetpack\Stats\Options as Stats_Options;
 use Automattic\Jetpack\Tracking;
 
@@ -52,16 +53,9 @@ public static function init() {
 	 */
 	private function __construct() {
 		add_action( 'rest_api_init', array( REST_Controller::class, 'register' ) );
-		add_action( 'jetpack_site_registered', array( Pricing_Grid\Eligibility::class, 'record_connection_time' ) );
-
-		// The stats module normally registers the Stats menu, but modules only
-		// load once the site is connected. Register the dashboard here for
-		// unconnected sites only, so eligible new sites see the pricing grid
-		// before connecting. Connected sites go exclusively through the stats
-		// module (modules/stats.php), which also owns the noheader chart-image
-		// paths used by the adminbar and the dashboard widget.
-		if ( is_admin() && ! ( new Manager() )->is_connected() && Pricing_Grid\Eligibility::is_eligible_site() ) {
-			Dashboard::init();
+
+		if ( is_admin() ) {
+			self::maybe_register_dashboard();
 		}
 
 		// Disable JITM assets on the Stats page.
@@ -82,6 +76,43 @@ function ( $show, $screen_id ) {
 		add_filter( 'jetpack_stats_transient_cleanup_prefixes', array( $this, 'register_transient_cleanup_prefix' ) );
 	}
 
+	/**
+	 * Register the Odyssey dashboard as the Stats menu when it should own the
+	 * Stats screen, and report whether it did.
+	 *
+	 * Called from two entry points covering disjoint cases: this package's
+	 * constructor for sites that haven't connected yet (the stats module,
+	 * which normally registers the menu, only loads once connected), and the
+	 * stats module's stats_admin_menu() for connected sites, which falls back
+	 * to the old Stats interface when this declines.
+	 *
+	 * @return bool Whether the dashboard was registered.
+	 */
+	public static function maybe_register_dashboard() {
+		// Unconnected sites can't load the stats module; register the
+		// dashboard so Odyssey — which hosts the Stats pricing grid and owns
+		// its eligibility — is reachable before connecting.
+		if ( ! ( new Manager() )->is_connected() ) {
+			Dashboard::init();
+			return true;
+		}
+
+		// On connected sites the stats module owns the screen: respect the
+		// Odyssey opt-out, and leave noheader chart-image requests (the
+		// adminbar sparkline and dashboard widget) to the legacy interface.
+		if (
+			! ( new Modules() )->is_active( 'stats' )
+			|| ! Stats_Options::get_option( 'enable_odyssey_stats' )
+			// phpcs:ignore WordPress.Security.NonceVerification.Recommended
+			|| isset( $_GET['noheader'] )
+		) {
+			return false;
+		}
+
+		Dashboard::init();
+		return true;
+	}
+
 	/**
 	 * Register the stats-admin transient prefix for cleanup.
 	 *

projects/packages/stats-admin/src/pricing-grid/class-eligibility.php

@@ -0,0 +1,62 @@
+<?php
+/**
+ * Unit tests for the Main class.
+ *
+ * @package automattic/jetpack-stats-admin
+ */
+
+namespace Automattic\Jetpack\Stats_Admin;
+
+use Automattic\Jetpack\Connection\Manager as Connection_Manager;
+
+/**
+ * Unit tests for the Main class.
+ */
+class Main_Test extends TestCase {
+	/**
+	 * Setting up the test.
+	 */
+	public function setUp(): void {
+		parent::setUp();
+		( new Connection_Manager() )->reset_connection_status();
+	}
+
+	/**
+	 * Returning the environment into its initial state.
+	 */
+	public function tearDown(): void {
+		parent::tearDown();
+		( new Connection_Manager() )->reset_connection_status();
+	}
+
+	/**
+	 * An unconnected site registers the dashboard, so Odyssey (and its
+	 * pricing grid) is reachable before connecting.
+	 */
+	public function test_maybe_register_dashboard_for_unconnected_site() {
+		remove_filter( 'jetpack_options', array( $this, 'mock_jetpack_site_connection_options' ) );
+		( new Connection_Manager() )->reset_connection_status();
+
+		$this->assertTrue( Main::maybe_register_dashboard() );
+	}
+
+	/**
+	 * A connected site without the stats module active declines, leaving the
+	 * screen to the module's own registration.
+	 */
+	public function test_maybe_register_dashboard_declines_for_connected_site_without_module() {
+		$this->assertFalse( Main::maybe_register_dashboard() );
+	}
+
+	/**
+	 * A noheader chart-image request declines, so the legacy interface can
+	 * serve the raw image.
+	 */
+	public function test_maybe_register_dashboard_declines_for_noheader_request() {
+		$_GET['noheader'] = '';
+
+		$this->assertFalse( Main::maybe_register_dashboard() );
+
+		unset( $_GET['noheader'] );
+	}
+}