I am trying to create a dynamic event subscription, for drupal8 commerce order state.

My use case is the following. I want to create an invoice for any order which goes into state e.g. PENDING. There is a custom state/transition yml which i have created.

Which state transition should trigger an invoice creation, i want to make this configurable.

So, the admin should be able to select specific states, in a custom settings form, and the system should only create invoices when an order enters to one of these states.

I need to create an event subscriber, which is dynamic according to the settings that the admin has entered.

In terms of code, in the event subscriber, i have the following code

public static function getSubscribedEvents() {
  $events = ['commerce_order.place.post_transition' =>'onTriggerInvoiceCreation'];
  return $events;
}

public function onTriggerInvoiceCreation(WorkflowTransitionEvent $event) {
  $invoice_creation_states = explode(",", $this->config_factory->get("my_custom_module.settings")->get("invoice_creation_states"));
  $current_state = $event->getToState()->getId();

  if(in_array($current_state, $invoice_creation_states)) {
    //create the invoice
  }
}

So, a far as i understand, i need to do one of the following

In function getSubscribedEvents, i read the my_module.settings from configuration and find a way to construct the correct event subscriber. So, instead of

$events = ['commerce_order.place.post_transition' =>'onTriggerInvoiceCreation'];

i should do something like the following

$invoice_creation_states = explode(",", $this->config_factory->get("my_custom_module.settings")->get("invoice_creation_states"));
for($i=0;$i<count($invoice_creation_states);$i++{
  $events = ['commerce_order.'.$invoice_creation_states[$i].'.post_transition' =>'onTriggerInvoiceCreation'];

As this function is static, i don't seem to be able to get hold of the config service in order to get the $invoice_creation_states.

So next thought is to create a more generic event listener, for all order state changes, and in the corresponding listener callback e.g. onTriggerInvoiceCreation i could get the custom settings and make the above condition in order to execute or not the invoice creation code.

Question: Is there a more generic transition event than commerce_order.TRANSITION_ID.TRANSITION_PHASE

something like

commerce_order.ANY_TRANSITION.ANY_PHASE ?