Event.php

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<?php

namespace Rsi\Fred;

/**
 *  Event handler component.
 */
class Event extends Component{

  protected $_events = [];
  protected $_counts = [];

  /**
   * Start listening to an event.
   * @param string $name  Name of the event (usually with a class name prefix).
   * @param function $callback  Callback function (first parameter must be the sender; others are event specific).
   * @param int $prio  Callbacks with a lower prio value are called before ones with higher values. Otherwise callbacks are
   *   called in the order in which they where added.
   */
  public function listen($name,$callback,$prio = 50){
    \Rsi\Record::add($this->_events,[$name,$prio],[]);
    $this->_events[$name][$prio][] = $callback;
    ksort($this->_events[$name]);
  }
  /**
   * Trigger an event.
   * @param string $name  Name of the event (usually with a class name prefix).
   * @param object $sender,...  The initiator of the event, and other parameters for the callback function.
   * @return mixed  Return value if one of the callbacks returned something other than null (this will also directly stop the
   *   chain). Returns null if none of the callbacks functions (if any) returned anything other than null.
   */
  public function trigger($name,$sender = null){
    if($log = $this->component('log')) $log->debug(__CLASS__ . "::trigger('$name',...)",__FILE__,__LINE__);
    if(array_key_exists($name,$this->_events)){
      $this->_counts[$name] = $this->count($name) + 1;
      $params = array_slice(func_get_args(),1);
      foreach($this->_events[$name] as $events) foreach($events as $callback){
        if(is_array($callback) && is_string($name = \Rsi\Record::value($callback))) $callback = [$this->component($name),array_pop($callback)];
        if(($result = call_user_func_array($callback,$params)) !== null) return $result;
      }
    }
    return null;
  }
  /**
   * Number of times an event has been triggered.
   * @param string $name  Name of the event (usually with a class name prefix).
   * @return int  Counter (false if event does not exist).
   */
  public function count($name){
    return $this->_counts[$name] ?? (array_key_exists($name,$this->_events) ? 0 : false);
  }

}