index.php

<?php
/**
 * Plugin Name: Woocommerce Random Order Numbers
 * Description: Generates large hyphenated random order numbers (e.g. 13124234-2343423-32423423-333) and uses them as the public order number.
 * Version:     1.0
 * Author:      P4UL
 */

if ( ! defined( 'ABSPATH' ) ) exit;

class P4UL_Random_Order_Numbers {
	const META_KEY = '_p4ul_random_order_number';

	public function __construct() {
		// Create number during checkout/order creation
		add_action( 'woocommerce_checkout_create_order', [ $this, 'maybe_assign_number_on_checkout' ], 20, 1 );
		add_action( 'woocommerce_new_order', [ $this, 'maybe_assign_number_on_new_order' ], 20, 1 );

		// Display the custom number everywhere
		add_filter( 'woocommerce_order_number', [ $this, 'filter_public_order_number' ], 10, 2 );

		// Make it searchable in admin
		add_filter( 'woocommerce_shop_order_search_fields', [ $this, 'add_searchable_meta' ] );

		// Show in admin order meta box (read-only)
		add_action( 'add_meta_boxes', [ $this, 'add_admin_metabox' ] );
	}

	/**
	 * Generate a hyphenated random numeric string like 13124234-2343423-32423423-333.
	 * Pattern is filterable via 'p4ul_random_order_number_pattern'.
	 */
	public function generate_number(): string {
		// Default group lengths. Example output: 8-7-8-3 digits
		$pattern = apply_filters( 'p4ul_random_order_number_pattern', [8, 7, 8, 3] );

		$groups = [];
		foreach ( $pattern as $len ) {
			$groups[] = $this->random_digits( max(1, (int) $len ) );
		}
		return implode( '-', $groups );
	}

	private function random_digits( int $length ): string {
		// wp_generate_password with only digits
		return wp_generate_password( $length, false, false, '0123456789' );
	}

	/**
	 * Ensure uniqueness across orders.
	 */
	public function generate_unique_number(): string {
		global $wpdb;

		$meta_key = self::META_KEY;
		$tries    = 0;

		do {
			$number = $this->generate_number();
			$exists = (int) $wpdb->get_var( $wpdb->prepare(
				"SELECT COUNT(1) FROM {$wpdb->postmeta} WHERE meta_key = %s AND meta_value = %s LIMIT 1",
				$meta_key,
				$number
			) );
			$tries++;
			if ( $tries > 25 ) {
				// Safety net: append 4 digits to drastically reduce collision risk
				$number .= '-' . $this->random_digits(4);
				$exists = 0;
			}
		} while ( $exists > 0 );

		return $number;
	}

	/**
	 * Assign number when creating order during checkout (WC 3.0+).
	 */
	public function maybe_assign_number_on_checkout( WC_Order $order ) {
		if ( ! $order->get_meta( self::META_KEY, true ) ) {
			$order->update_meta_data( self::META_KEY, $this->generate_unique_number() );
		}
	}

	/**
	 * Assign number for programmatically created orders that bypass checkout hook.
	 */
	public function maybe_assign_number_on_new_order( $order_id ) {
		$order = wc_get_order( $order_id );
		if ( $order && ! $order->get_meta( self::META_KEY, true ) ) {
			$order->update_meta_data( self::META_KEY, $this->generate_unique_number() );
			$order->save();
		}
	}

	/**
	 * Replace displayed order number with our custom one.
	 */
	public function filter_public_order_number( $order_number, $order ) {
		if ( $order instanceof WC_Order ) {
			$custom = $order->get_meta( self::META_KEY, true );
			if ( $custom ) {
				return $custom;
			}
		}
		return $order_number;
	}

	/**
	 * Allow searching orders by the random number in admin.
	 */
	public function add_searchable_meta( $fields ) {
		$fields[] = self::META_KEY;
		return $fields;
	}

	/**
	 * Small metabox in admin > single order showing the random number.
	 */
	public function add_admin_metabox() {
		add_meta_box(
			'p4ul-random-order-number',
			__( 'Random Order Number', 'p4ul' ),
			function( $post ) {
				$order = wc_get_order( $post->ID );
				if ( ! $order ) return;
				$number = $order->get_meta( self::META_KEY, true );
				if ( ! $number ) {
					echo '<p>' . esc_html__( 'No random order number assigned.', 'p4ul' ) . '</p>';
					return;
				}
				echo '<code style="font-size:14px;">' . esc_html( $number ) . '</code>';
				echo '<p style="margin-top:8px;color:#666;">' . esc_html__( 'This value is used wherever WooCommerce displays the order number and can be searched from the orders list.', 'p4ul' ) . '</p>';
			},
			'shop_order',
			'side',
			'core'
		);
	}
}

add_action( 'plugins_loaded', function() {
	// Only run if WooCommerce active
	if ( class_exists( 'WooCommerce' ) ) {
		new P4UL_Random_Order_Numbers();
	}
} );

/**
 * Optional: change the pattern of digit groups.
 * Example below produces 10-10 (uncomment to use).
 */
// add_filter( 'p4ul_random_order_number_pattern', function( $pattern ) {
// 	return [10, 10];
// } );