Implement WordPress Hooks in a Custom Pure PHP Code - php

Question

I'm creating a really huge system in PHP and I would like to make things simpler for me and probably for the future developers.
I'm looking to achieve a functionality where when a certain action is triggered in the system, a custom function is called, just the same idea used by WordPress add_action();
This is exactly what I mean,
For example in WordPress, if one needs to execute code in the header section, a hook called wp_head is used, that's
function add_script_to_header(){
echo "this one will be print in the header";
}
add_action( 'wp_head', 'add_script_to_header' );
function another_script_on_header(){
echo "this onather script on the header";
}
add_action( 'wp_head', 'another_script_on_header' );
Now that was just an example, I would like to implement the same thing with custom PHP completely independent of WordPress, which means, my code is not in any way related to WordPress.
I've tried to use callable functions in PHP, but at some point, it gets tongue-twisting
In my case, I have a class called Orders that records, payments, shift orders from one state to another, and a lot more things, I would like to have a hook or way of triggering action with a function when certain actions are triggered.
The following code indicates some of my trials
function next_order($orderId, $status, $autoApprove = 0){
// this is function that is responsible for shifting orders from one status to another
// or from one state to another
// I would like add_action() function to be linked here, so that I can track
// order status with external functions
}
function add_action( $action_name, $function_name ){
if( $action_name == "order_next" ){
call_user_func( $function_name, $action_name);
}
if( $action_name == 'order_placed' ){
// here we can place an action for that
}
if( $action_name == 'order_paid' ){
}
}
function benson_karue( $orderId ){
echo "This is the order id ".$orderId;
}
add_action( 'order_next', 'benson_karue' );