Markup per currency

This snippet will change the markup of various currencies on a per-currency basis.

/**
	@brief		Mark up various currencies.
	@since		2019-01-30 15:23:20
**/
function mcc_mycryptocheckout_markup_amount( $action )
{
	switch( $action->currency_id )
	{
		case 'BTC':
			// BTC is 10% more expensive to use
			$action->marked_up_amount = $action->marked_up_amount * 1.10; 
		break;
		case 'ETH':
			// ETH is 10% cheaper.
			$action->marked_up_amount = $action->marked_up_amount * 0.90;
		break;
	}
}
add_action( 'mycryptocheckout_markup_amount', 'mcc_mycryptocheckout_markup_amount' );