Example of how to restrict certain users from withdrawing certain coins in Bitcoin and Altcoin Wallets for WordPress

wallets-withdraw-block.php

<?php
/*
 * Plugin Name: Bitcoin and Altcoin Wallets: Fine-grained withdrawals blocking
 * Description: Example of how to restrict certain users from withdrawing certain coins.
 * Version: 1.0.0
 * Plugin URI: https://gist.github.com/alex-georgiou/f063dd0565e562eb47c037cdf2d17547
 * Author: Alexandros Georgiou <info@dashed-slug.net>
 * Author URI: http://dashed-slug.net
 * License: GPLv2 or later
 *
 */

/**
 * Restrict user1 from withdrawing BTC and user2 from withdrawing LTC.
 */
function block_withdrawals( $args ) {
	$block = array(
		array(
			'user_login' => 'user1',
			'symbol' => 'BTC',
		),
		array(
			'user_login' => 'user2',
			'symbol' => 'LTC',
		),
	);

	if ( ! $args['from_user_id'] ) {
		$args['from_user_id'] = get_current_user_id();
	}

	$user = get_user_by( 'ID', $args['from_user_id'] );

	foreach ( $block as $b ) {

		if ( $b['user_login'] == $user['user_login'] && $b['symbol'] == $args['symbol'] ) {

			throw new Exception(
				sprintf(
					'User %s is not allowed to withdraw %s!',
					$user['user_login'],
					$b['symbol']
				)
			);
		}
	}
}