Implement Phase 9: Prometheus Metrics (v0.9.0)

- Add Prometheus metrics integration via wp-prometheus hooks
- Create Grafana dashboard JSON with 24 panels
- Add metrics settings tab with enable/disable toggle
- Expose inventory, booking, occupancy, revenue, and guest metrics

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/Plugin.php

@@ -19,6 +19,7 @@ use Magdev\WpBnb\Booking\EmailNotifier;
 use Magdev\WpBnb\Frontend\Search;
 use Magdev\WpBnb\Frontend\Shortcodes;
 use Magdev\WpBnb\Integration\CF7;
+use Magdev\WpBnb\Integration\Prometheus;
 use Magdev\WpBnb\Frontend\Widgets\AvailabilityCalendar;
 use Magdev\WpBnb\Frontend\Widgets\BuildingRooms;
 use Magdev\WpBnb\Frontend\Widgets\SimilarRooms;
@@ -142,6 +143,9 @@ final class Plugin {
 			CF7::init();
 		}
 
+		// Initialize Prometheus metrics integration.
+		Prometheus::init();
+
 		// Initialize admin components.
 		if ( is_admin() ) {
 			$this->init_admin();
@@ -610,6 +614,10 @@ final class Plugin {
 				   class="nav-tab <?php echo 'updates' === $active_tab ? 'nav-tab-active' : ''; ?>">
 					<?php esc_html_e( 'Updates', 'wp-bnb' ); ?>
 				</a>
+				<a href="<?php echo esc_url( admin_url( 'admin.php?page=wp-bnb-settings&tab=metrics' ) ); ?>"
+				   class="nav-tab <?php echo 'metrics' === $active_tab ? 'nav-tab-active' : ''; ?>">
+					<?php esc_html_e( 'Metrics', 'wp-bnb' ); ?>
+				</a>
 			</nav>
 
 			<div class="tab-content">
@@ -624,6 +632,9 @@ final class Plugin {
 					case 'updates':
 						$this->render_updates_settings();
 						break;
+					case 'metrics':
+						$this->render_metrics_settings();
+						break;
 					default:
 						$this->render_general_settings();
 						break;
@@ -1265,6 +1276,163 @@ final class Plugin {
 		<?php
 	}
 
+	/**
+	 * Render metrics settings tab.
+	 *
+	 * @return void
+	 */
+	private function render_metrics_settings(): void {
+		$metrics_enabled     = Prometheus::is_enabled();
+		$prometheus_active   = class_exists( '\Magdev\WpPrometheus\Plugin' ) || defined( 'WP_PROMETHEUS_VERSION' );
+		$dashboard_file      = WP_BNB_PATH . 'assets/grafana/wp-bnb-dashboard.json';
+		$dashboard_available = file_exists( $dashboard_file );
+		?>
+		<form method="post" action="">
+			<?php wp_nonce_field( 'wp_bnb_save_settings', 'wp_bnb_settings_nonce' ); ?>
+
+			<h2><?php esc_html_e( 'Prometheus Metrics', 'wp-bnb' ); ?></h2>
+
+			<?php if ( ! $prometheus_active ) : ?>
+				<div class="notice notice-warning inline" style="margin: 0 0 20px 0;">
+					<p>
+						<span class="dashicons dashicons-warning" style="color: #dba617;"></span>
+						<strong><?php esc_html_e( 'WP Prometheus not detected', 'wp-bnb' ); ?></strong><br>
+						<?php
+						printf(
+							/* translators: %s: Plugin URL */
+							esc_html__( 'The WP Prometheus plugin is required to expose metrics. Please install and activate it from %s.', 'wp-bnb' ),
+							'<a href="https://src.bundespruefstelle.ch/magdev/wp-prometheus" target="_blank">wp-prometheus</a>'
+						);
+						?>
+					</p>
+				</div>
+			<?php else : ?>
+				<div class="notice notice-success inline" style="margin: 0 0 20px 0;">
+					<p>
+						<span class="dashicons dashicons-yes-alt" style="color: #00a32a;"></span>
+						<strong><?php esc_html_e( 'WP Prometheus is active', 'wp-bnb' ); ?></strong>
+						<?php esc_html_e( 'Metrics will be exposed via the /metrics/ endpoint.', 'wp-bnb' ); ?>
+					</p>
+				</div>
+			<?php endif; ?>
+
+			<table class="form-table" role="presentation">
+				<tr>
+					<th scope="row"><?php esc_html_e( 'Enable Metrics', 'wp-bnb' ); ?></th>
+					<td>
+						<label>
+							<input type="checkbox" name="wp_bnb_metrics_enabled"
+								   value="yes" <?php checked( $metrics_enabled ); ?>>
+							<?php esc_html_e( 'Expose BnB metrics via Prometheus', 'wp-bnb' ); ?>
+						</label>
+						<p class="description">
+							<?php esc_html_e( 'When enabled, occupancy, booking, revenue, and guest metrics will be available for Prometheus scraping.', 'wp-bnb' ); ?>
+						</p>
+					</td>
+				</tr>
+			</table>
+
+			<h2><?php esc_html_e( 'Available Metrics', 'wp-bnb' ); ?></h2>
+			<p class="description"><?php esc_html_e( 'The following metrics are exposed when enabled:', 'wp-bnb' ); ?></p>
+
+			<table class="widefat striped" style="max-width: 800px; margin-top: 10px;">
+				<thead>
+					<tr>
+						<th><?php esc_html_e( 'Metric', 'wp-bnb' ); ?></th>
+						<th><?php esc_html_e( 'Type', 'wp-bnb' ); ?></th>
+						<th><?php esc_html_e( 'Description', 'wp-bnb' ); ?></th>
+					</tr>
+				</thead>
+				<tbody>
+					<tr>
+						<td><code>wp_bnb_buildings_total</code></td>
+						<td><?php esc_html_e( 'Gauge', 'wp-bnb' ); ?></td>
+						<td><?php esc_html_e( 'Total number of buildings', 'wp-bnb' ); ?></td>
+					</tr>
+					<tr>
+						<td><code>wp_bnb_rooms_total</code></td>
+						<td><?php esc_html_e( 'Gauge', 'wp-bnb' ); ?></td>
+						<td><?php esc_html_e( 'Total rooms by status (available, occupied, maintenance, inactive)', 'wp-bnb' ); ?></td>
+					</tr>
+					<tr>
+						<td><code>wp_bnb_bookings_total</code></td>
+						<td><?php esc_html_e( 'Gauge', 'wp-bnb' ); ?></td>
+						<td><?php esc_html_e( 'Total bookings by status (pending, confirmed, checked_in, checked_out, cancelled)', 'wp-bnb' ); ?></td>
+					</tr>
+					<tr>
+						<td><code>wp_bnb_occupancy_rate_current</code></td>
+						<td><?php esc_html_e( 'Gauge', 'wp-bnb' ); ?></td>
+						<td><?php esc_html_e( 'Current room occupancy rate (percentage)', 'wp-bnb' ); ?></td>
+					</tr>
+					<tr>
+						<td><code>wp_bnb_occupancy_rate_this_month</code></td>
+						<td><?php esc_html_e( 'Gauge', 'wp-bnb' ); ?></td>
+						<td><?php esc_html_e( 'Room occupancy rate for current month (percentage)', 'wp-bnb' ); ?></td>
+					</tr>
+					<tr>
+						<td><code>wp_bnb_checkins_today</code></td>
+						<td><?php esc_html_e( 'Gauge', 'wp-bnb' ); ?></td>
+						<td><?php esc_html_e( 'Number of check-ins scheduled for today', 'wp-bnb' ); ?></td>
+					</tr>
+					<tr>
+						<td><code>wp_bnb_checkouts_today</code></td>
+						<td><?php esc_html_e( 'Gauge', 'wp-bnb' ); ?></td>
+						<td><?php esc_html_e( 'Number of check-outs scheduled for today', 'wp-bnb' ); ?></td>
+					</tr>
+					<tr>
+						<td><code>wp_bnb_revenue_this_month</code></td>
+						<td><?php esc_html_e( 'Gauge', 'wp-bnb' ); ?></td>
+						<td><?php esc_html_e( 'Total revenue for current month', 'wp-bnb' ); ?></td>
+					</tr>
+					<tr>
+						<td><code>wp_bnb_revenue_ytd</code></td>
+						<td><?php esc_html_e( 'Gauge', 'wp-bnb' ); ?></td>
+						<td><?php esc_html_e( 'Total revenue year to date', 'wp-bnb' ); ?></td>
+					</tr>
+					<tr>
+						<td><code>wp_bnb_booking_avg_value</code></td>
+						<td><?php esc_html_e( 'Gauge', 'wp-bnb' ); ?></td>
+						<td><?php esc_html_e( 'Average booking value', 'wp-bnb' ); ?></td>
+					</tr>
+					<tr>
+						<td><code>wp_bnb_guests_total</code></td>
+						<td><?php esc_html_e( 'Gauge', 'wp-bnb' ); ?></td>
+						<td><?php esc_html_e( 'Total number of registered guests', 'wp-bnb' ); ?></td>
+					</tr>
+					<tr>
+						<td><code>wp_bnb_guests_repeat</code></td>
+						<td><?php esc_html_e( 'Gauge', 'wp-bnb' ); ?></td>
+						<td><?php esc_html_e( 'Number of repeat guests (more than one booking)', 'wp-bnb' ); ?></td>
+					</tr>
+				</tbody>
+			</table>
+
+			<h2 style="margin-top: 30px;"><?php esc_html_e( 'Grafana Dashboard', 'wp-bnb' ); ?></h2>
+
+			<?php if ( $dashboard_available ) : ?>
+				<p>
+					<?php esc_html_e( 'A pre-configured Grafana dashboard is available for visualizing WP BnB metrics.', 'wp-bnb' ); ?>
+				</p>
+				<p>
+					<strong><?php esc_html_e( 'Dashboard file:', 'wp-bnb' ); ?></strong>
+					<code>assets/grafana/wp-bnb-dashboard.json</code>
+				</p>
+				<p class="description">
+					<?php esc_html_e( 'If WP Prometheus is installed, this dashboard will be automatically registered and available for export in the Prometheus settings.', 'wp-bnb' ); ?>
+				</p>
+			<?php else : ?>
+				<div class="notice notice-warning inline">
+					<p><?php esc_html_e( 'Grafana dashboard file not found.', 'wp-bnb' ); ?></p>
+				</div>
+			<?php endif; ?>
+
+			<p class="submit">
+				<?php submit_button( __( 'Save Metrics Settings', 'wp-bnb' ), 'primary', 'submit', false ); ?>
+			</p>
+		</form>
+		<?php
+	}
+
 	/**
 	 * Render license status badge.
 	 *
@@ -1336,6 +1504,9 @@ final class Plugin {
 			case 'updates':
 				$this->save_updates_settings();
 				break;
+			case 'metrics':
+				$this->save_metrics_settings();
+				break;
 			default:
 				$this->save_general_settings();
 				break;
@@ -1465,6 +1636,19 @@ final class Plugin {
 		settings_errors( 'wp_bnb_settings' );
 	}
 
+	/**
+	 * Save metrics settings.
+	 *
+	 * @return void
+	 */
+	private function save_metrics_settings(): void {
+		$metrics_enabled = isset( $_POST['wp_bnb_metrics_enabled'] ) ? 'yes' : 'no';
+		update_option( Prometheus::OPTION_ENABLED, $metrics_enabled );
+
+		add_settings_error( 'wp_bnb_settings', 'settings_saved', __( 'Metrics settings saved.', 'wp-bnb' ), 'success' );
+		settings_errors( 'wp_bnb_settings' );
+	}
+
 	/**
 	 * AJAX handler for checking room availability.
 	 *