<?php
/**
 * AJAX handler for user search (Select2 remote source).
 *
 * Replaces the static get_users() approach in metabox, category,
 * and bulk-actions screens with a live, paginated AJAX search.
 *
 * Endpoint : wp_ajax_aisp_search_users
 * Params   : term (string), page (int, optional, default 1)
 * Returns  : { results: [{id, text}], pagination: {more: bool} }
 *
 * @package AISP_User_Exclusive_Products
 */

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

if ( ! class_exists( 'AISP_Exclusive_Products_Ajax_User_Search' ) ) :

final class AISP_Exclusive_Products_Ajax_User_Search {

	/**
	 * Number of users returned per page.
	 *
	 * @var int
	 */
	const PER_PAGE = 20;

	private static $instance = null;

	public static function instance() {
		if ( null === self::$instance ) {
			self::$instance = new self();
		}
		return self::$instance;
	}

	private function __construct() {
		add_action( 'wp_ajax_aisp_search_users', array( $this, 'handle_search' ) );
	}

	/**
	 * Handle the AJAX request and output JSON.
	 */
	public function handle_search() {

		// Capability check — only shop managers / admins.
		if ( ! current_user_can( 'manage_woocommerce' ) ) {
			wp_send_json_error( array( 'message' => __( 'Unauthorized.', 'aisp-user-exclusive-products' ) ), 403 );
		}

		// Nonce verification.
		if (
			! isset( $_GET['_ajax_nonce'] )
			|| ! wp_verify_nonce(
				sanitize_text_field( wp_unslash( $_GET['_ajax_nonce'] ) ),
				'aisp_search_users_nonce'
			)
		) {
			wp_send_json_error( array( 'message' => __( 'Invalid nonce.', 'aisp-user-exclusive-products' ) ), 403 );
		}

		$term = isset( $_GET['term'] ) ? sanitize_text_field( wp_unslash( $_GET['term'] ) ) : '';
		$page = isset( $_GET['page'] ) ? max( 1, (int) $_GET['page'] ) : 1;

		$args = array(
			'number'  => self::PER_PAGE,
			'paged'   => $page,
			'orderby' => 'display_name',
			'order'   => 'ASC',
			'fields'  => array( 'ID', 'display_name', 'user_email' ),
		);

		// Search by display_name, login, or email when a term is given.
		if ( ! empty( $term ) ) {
			$args['search']         = '*' . $term . '*';
			$args['search_columns'] = array( 'display_name', 'user_login', 'user_email' );
		}

		$user_query = new WP_User_Query( $args );
		$users      = $user_query->get_results();
		$total      = (int) $user_query->get_total();

		$results = array();
		foreach ( $users as $user ) {
			$results[] = array(
				'id'   => (int) $user->ID,
				'text' => $user->display_name . ' (' . $user->user_email . ')',
			);
		}

		$has_more = ( $page * self::PER_PAGE ) < $total;

		wp_send_json(
			array(
				'results'    => $results,
				'pagination' => array( 'more' => $has_more ),
			)
		);
	}
}

endif;