<?php
/**
 * Billing phone pre-fill.
 *
 * @package Rahkar\WP
 */

declare( strict_types = 1 );

namespace Rahkar\WP\Modules\OtpAuth;

use Rahkar\WP\Notifications\PhoneNumber;

defined( 'ABSPATH' ) || exit;

/**
 * Puts the number a customer verified into the checkout's phone field.
 *
 * Asking someone to type the number they proved ownership of ninety seconds
 * earlier is the kind of friction that loses orders. WooCommerce already reads
 * `billing_phone` from user meta, so this only covers the gap: an account that
 * has a verified number but no billing phone yet, which is every account created
 * through the code login.
 *
 * This used to share a class with the checkout gate. The gate is a paid module
 * now and lives in the pro add-on; the pre-fill stays here because it belongs to
 * signing in by code, whether or not anything gates the checkout.
 */
final class PhonePrefill {

	/**
	 * Fill `billing_phone` with the verified number when WooCommerce has none.
	 *
	 * @param mixed  $value Value WooCommerce resolved, or null.
	 * @param string $input Field name.
	 *
	 * @return mixed
	 *
	 * @internal Hooked callback.
	 */
	public function fillPhone( $value, string $input ) {
		if ( 'billing_phone' !== $input || ! empty( $value ) ) {
			return $value;
		}

		$userId = get_current_user_id();

		if ( $userId <= 0 ) {
			return $value;
		}

		$canonical = (string) get_user_meta( $userId, 'rahkar_phone', true );

		if ( '' === $canonical ) {
			return $value;
		}

		$phone = PhoneNumber::parse( $canonical );

		// Shown in the national form the customer recognises — `09123456789`,
		// not the `989123456789` the database stores.
		return null !== $phone ? $phone->national() : $value;
	}
}