<?php
/**
 * Zend Framework (http://framework.zend.com/)
 *
 * @link      http://github.com/zendframework/zend-eventmanager for the canonical source repository
 * @copyright Copyright (c) 2005-2015 Zend Technologies USA Inc. (http://www.zend.com)
 * @license   https://github.com/zendframework/zend-eventmanager/blob/master/LICENSE.md
 */

namespace Zend\EventManager;

use Traversable;

/**
 * Interface for messengers
 */
interface EventManagerInterface extends SharedEventsCapableInterface
{
    /**
     * Create and trigger an event.
     *
     * Use this method when you do not want to create an EventInterface
     * instance prior to triggering. You will be required to pass:
     *
     * - the event name
     * - the event target (can be null)
     * - any event parameters you want to provide (empty array by default)
     *
     * It will create the Event instance for you and then trigger all listeners
     * related to the event.
     *
     * @param  string $eventName
     * @param  null|object|string $target
     * @param  array|object $argv
     * @return ResponseCollection
     */
    public function trigger($eventName, $target = null, $argv = []);

    /**
     * Create and trigger an event, applying a callback to each listener result.
     *
     * Use this method when you do not want to create an EventInterface
     * instance prior to triggering. You will be required to pass:
     *
     * - the event name
     * - the event target (can be null)
     * - any event parameters you want to provide (empty array by default)
     *
     * It will create the Event instance for you, and trigger all listeners
     * related to the event.
     *
     * The result of each listener is passed to $callback; if $callback returns
     * a boolean true value, the manager must short-circuit listener execution.
     *
     * @param  callable $callback
     * @param  string $eventName
     * @param  null|object|string $target
     * @param  array|object $argv
     * @return ResponseCollection
     */
    public function triggerUntil(callable $callback, $eventName, $target = null, $argv = []);

    /**
     * Trigger an event
     *
     * Provided an EventInterface instance, this method will trigger listeners
     * based on the event name, raising an exception if the event name is missing.
     *
     * @param  EventInterface $event
     * @return ResponseCollection
     */
    public function triggerEvent(EventInterface $event);

    /**
     * Trigger an event, applying a callback to each listener result.
     *
     * Provided an EventInterface instance, this method will trigger listeners
     * based on the event name, raising an exception if the event name is missing.
     *
     * The result of each listener is passed to $callback; if $callback returns
     * a boolean true value, the manager must short-circuit listener execution.
     *
     * @param  callable $callback
     * @param  EventInterface $event
     * @return ResponseCollection
     */
    public function triggerEventUntil(callable $callback, EventInterface $event);

    /**
     * Attach a listener to an event
     *
     * The first argument is the event, and the next argument is a
     * callable that will respond to that event.
     *
     * The last argument indicates a priority at which the event should be
     * executed; by default, this value is 1; however, you may set it for any
     * integer value. Higher values have higher priority (i.e., execute first).
     *
     * You can specify "*" for the event name. In such cases, the listener will
     * be triggered for every event *that has registered listeners at the time
     * it is attached*. As such, register wildcard events last whenever possible!
     *
     * @param  string $eventName Event to which to listen.
     * @param  callable $listener
     * @param  int $priority Priority at which to register listener.
     * @return callable
     */
    public function attach($eventName, callable $listener, $priority = 1);

    /**
     * Detach a listener.
     *
     * If no $event or '*' is provided, detaches listener from all events;
     * otherwise, detaches only from the named event.
     *
     * @param callable $listener
     * @param null|string $eventName Event from which to detach; null and '*'
     *     indicate all events.
     * @return void
     */
    public function detach(callable $listener, $eventName = null);

    /**
     * Clear all listeners for a given event
     *
     * @param  string $eventName
     * @return void
     */
    public function clearListeners($eventName);

    /**
     * Provide an event prototype to use with trigger().
     *
     * When `trigger()` needs to create an event instance, it should clone the
     * prototype provided to this method.
     *
     * @param  EventInterface $prototype
     * @return void
     */
    public function setEventPrototype(EventInterface $prototype);

    /**
     * Get the identifier(s) for this EventManager
     *
     * @return array
     */
    public function getIdentifiers();

    /**
     * Set the identifiers (overrides any currently set identifiers)
     *
     * @param  string[] $identifiers
     * @return void
     */
    public function setIdentifiers(array $identifiers);

    /**
     * Add identifier(s) (appends to any currently set identifiers)
     *
     * @param  string[] $identifiers
     * @return void
     */
    public function addIdentifiers(array $identifiers);
}
