PMPro fallback: Try to fix the wp_insert_user failure that is about to happen because PayPal Express gateway lost the session for any reason

pmpro-optimize-checkout-insert-user.php

<?php
/**
 * Test:
 * - Go to checkout page
 * - Click on proceed (with PayPal Express)
 * - Copy the paypal.com link and complete the checkout in anonymous mode (session is empty for sure)
 * - Check the CREATED USER! :)
 *
 * Added a cookie fallback for session lost, when payment completed after a long time.
 * Doesn't cover the case above though.
 *
 * Just with some notices in logs.
 * @see https://github.com/strangerstudios/paid-memberships-pro/issues/1341
 *
 * DISCUSSION ABOUT THIS:
 * @see https://github.com/strangerstudios/paid-memberships-pro/issues/1338
 */
/*
add_action('init', function(){
    $new_user_array = [
        'user_login' => '',
        'user_email' => '',
        'user_pass' => '',
        'first_name' => '',
        'first_name' => '',
    ];

    $new_user_array = apply_filters( 'pmpro_checkout_new_user_array', $new_user_array );
    var_dump( $new_user_array );
});
*/

/**
 * Save paypalexpress session user data to cookie as well.
 * Should last more than sessions, at least until the browser is closed.
 */
add_action( 'pmpro_paypalexpress_session_vars', function(){
    global $current_user;

    if( ! $current_user->ID ){
        // without expiration, the cookie will expire at the end of the session
        // so when the browser closes. should last more than the session though
        setcookie( "pmpro_signup_username", $_SESSION['pmpro_signup_username'] );
        setcookie( "pmpro_signup_password", $_SESSION['pmpro_signup_password'] );
        setcookie( "pmpro_signup_email",    $_SESSION['pmpro_signup_email'] );

        /* to simulate issue with session */
        if( $simulate_issue_with_session = false ){
            $_SESSION['pmpro_signup_username'] = '';
            $_SESSION['pmpro_signup_password'] = '';
            $_SESSION['pmpro_signup_email']    = '';
        }
    }

}, 10 );

/**
 * Try to fix the wp_insert_user failure that is about to happen
 * because PayPal Express gateway lost the session for any reason
 * @see https://github.com/strangerstudios/paid-memberships-pro/issues/1338
 */
add_filter( 'pmpro_checkout_new_user_array', function( $new_user_array ){
    global $current_user;

    $send_debug_email = false;

    $before_new_user_array = $new_user_array;

    // if we are reviewing an order
    if( isset( $_REQUEST['review'] ) ) {
        $order_code = $_REQUEST['review'];
        $order = new MemberOrder( $order_code );
    }

    // check: if we are using paypalexpress for this order (not needed I think)
    // because paypal express is the only one acting this way, isn't it?
    // if( $order->gateway === 'paypalexpress' )

    // check: if we dont already have a user for this order AND the user is not logged in
    if( $order->user_id == 0 && ! $current_user->ID ){

        /**
         * FALLBACK IF USER_LOGIN IS MISSING
         */
        // if we will not be able to create user
        if( empty( $new_user_array['user_login'] ) ){

            // debug = true
            $send_debug_email = true;

            // try to fetch fallback from cookies
            if( isset( $_COOKIE['pmpro_signup_username'] ) ){
                $fallback_username = $_COOKIE['pmpro_signup_username'];
                $fallback_password = $_COOKIE['pmpro_signup_password'];
                $fallback_email    = $_COOKIE['pmpro_signup_email'];

                // now get rid of insecure cookies
                unset( $_COOKIE['pmpro_signup_username'] ); setcookie( 'pmpro_signup_username', '', time() - 3600, '/' );
                unset( $_COOKIE['pmpro_signup_password'] ); setcookie( 'pmpro_signup_password', '', time() - 3600, '/' );
                unset( $_COOKIE['pmpro_signup_email'] );    setcookie( 'pmpro_signup_email', '', time() - 3600, '/' );
            }else{
                // generate a fallbacks
                $fallback_username = wp_help__generate_unique_username( "$order->FirstName $order->LastName", 'pmpro' );
                $fallback_password = wp_generate_password();
                $fallback_email    = "mirco+$fallback_username@sedweb.it";
            }

            /** avoid other warning, @see https://github.com/strangerstudios/paid-memberships-pro/issues/1341 */
            $_SESSION['pmpro_signup_username'] = $fallback_username;
            $_SESSION['pmpro_signup_password'] = $fallback_password;
            $_SESSION['pmpro_signup_email']    = $fallback_email;

            /** fix the new_user_array data */
            $new_user_array['user_login'] = $fallback_username;
            $new_user_array['user_email'] = $fallback_email;
            $new_user_array['user_pass']  = $fallback_password;
        }


        /**
         * FALLBACK IF USER_LOGIN IS INVALID (incomplete)
         */
        // if the username is longer then 60 chars
        if( $new_user_array['user_login'] > 60 ){
            // !! can be moved to PMPro checks BEFORE checkout
            // hard force, user never get noticed... tricky.
            $new_user_array['user_login'] = wp_help__generate_unique_username( substr( $new_user_array['user_login'], 0, 15 ) );
        }

        // if the username is listed in illegals
        $illegal_logins = (array) apply_filters( 'illegal_user_logins', array() );
        if( in_array( strtolower( $new_user_array['user_login'] ), array_map( 'strtolower', $illegal_logins ) ) ){
            // !! can be moved to PMPro checks BEFORE checkout
            // hard force, user never get noticed... tricky.
            $new_user_array['user_login'] = wp_help__generate_unique_username( '');
        }

        // if the username already exists
        if( username_exists( $new_user_array['user_login'] ) ){
            // !! can be moved to PMPro checks BEFORE checkout
            // hard force, user never get noticed... tricky.
            $new_user_array['user_login'] = wp_help__generate_unique_username( '' );
        }


        /**
         * Complete user profiles from order data
         */
        // if first_name not assigned automatically from order
        if( empty( $new_user_array['first_name'] ) ){
            $new_user_array['first_name'] = $order->FirstName;
        }

        // if last_name not assigned automatically from order
        if( empty( $new_user_array['last_name'] ) ){
            $new_user_array['last_name'] = $order->LastName;
        }
    }

    // log
    if( $send_debug_email && function_exists( 'debug__extended' ) ){
        debug__extended( [
            'where'        => str_replace( ABSPATH, '', __FILE__ ) . ':' . __LINE__,
            'user_array_1' => $before_new_user_array,
            'user_array_2' => $new_user_array,
        ] );
    }

    return $new_user_array;
}, 11 );

/**
 * Generate a unique username based on the string passed.
 * If the string is empty, uses the fallback_usrename_base plus a suffix (-1, -2...)
 *
 * @param $string_name
 * @param string $fallback_username_base
 * @return string
 */
function wp_help__generate_unique_username( $string_name, $fallback_username_base = 'pmpro-user' ){
    // any string to a valid username
    $username_base = sanitize_user( $string_name, true );

    // only lower chars, numbers and hyphens
    $username_base = sanitize_title( $username_base );

    // ensure it's still valid (may be empty)
    if( ! validate_username( $username_base ) ){
        $username_base = $fallback_username_base;
    }

    // append a suffix until it's valid
    $suffix = 1;
    while( $suffix < 100000 ){ // dont like infinite loops, avoid using while( true )
        $username = "$username_base-$suffix";

        if( ! username_exists( $username ) ){
            return $username;
        }

        $suffix++;
    }

    // since I dont like infinite loops and used a limited loops above,
    // it may be unable to generate a new unique username... amen.
    return false;
}