<?php
defined( 'ABSPATH' ) || exit;

/**
 * Certificate Verification Handler for display
 *
 * @package ACCEVE_Certificate_Verification
 * @since 1.0.0
 */
class ACCEVE_Certificate_Verification {

    /**
     * Singleton instance.
     *
     * @var ACCEVE_Certificate_Verification|null
     */
    private static $instance = null;

    /**
     * Get singleton instance.
     *
     * @return ACCEVE_Certificate_Verification
     */
    public static function get_instance() {
        if (null === self::$instance) {
            self::$instance = new self();
        }
        return self::$instance;
    }

    /**
     * Constructor.
     */
    private function __construct() {

    }

    /**
     * Verify certificate status for display.
     *
     * Checks whether a certificate exists and determines its current status:
     * - Returns the certificate object if it is valid and active
     * - Returns 'expired' if the certificate has passed its expiry date
     * - Returns 'inactive' if the certificate is disabled
     * - Returns false if the certificate does not exist or verification fails
     *
     * @since 1.0.0
     *
     * @param string|int $certificate_id     Certificate ID to verify.
     * @param string     $verification_code  Optional verification code.
     *
     * @return object|string|false Certificate object on success,
     *                             'expired' if expired,
     *                             'inactive' if inactive,
     *                             false if not found or invalid.
     */
    public function verify_certificate($certificate_id, $verification_code = '') {
        $db          = ACCEVE_Certificate_Verification_Database::get_instance();
        $certificate = $db->get_certificate($certificate_id, $verification_code);

        if (!$certificate) {
            return false;
        }

        if ($certificate->expiry_date && strtotime($certificate->expiry_date) < time()) {
            return 'expired';
        }

        if (!$certificate->is_active) {
            return 'inactive';
        }

        return $certificate;
    }
}