/**
Page for adding/editing invoices. When first opened, displays the user selection form
Also checks that all proper tables and settings are stup.
*/
function page_manage_invoice() {
global $wpi_settings;
WPI_Functions::check_tables();
WPI_Functions::check_settings();
if (isset($_REQUEST['wpi']['new_invoice']) || isset($_REQUEST['wpi']['existing_invoice'])) {
include($wpi_settings['admin']['ui_path'] . '/manage_invoice.php');
} else {
include($wpi_settings['admin']['ui_path'] . '/blocks/postbox_user_selection_form.php');
}
}