xobotyi / emittr

src/EventEmitter.php

<?php
/**
 * @Author : a.zinovyev
 * @Package: emittr
 * @License: http://www.opensource.org/licenses/mit-license.php
 */

namespace xobotyi\emittr;

class EventEmitter implements Interfaces\EventEmitter
{
    public const EVENT_LISTENER_ADDED   = 'listenerAdded';
    public const EVENT_LISTENER_REMOVED = 'listenerRemoved';

    /**
     * @var Interfaces\GlobalEventHandler;
     */
    private $eventEmitterGlobal;

    /**
     * @var array
     */
    private $eventListeners = [];

    /**
     * @var int
     */
    private $maxListenersCount = 10;

    /**
     * EventEmitter constructor.
     *
     * @param null|\xobotyi\emittr\Interfaces\GlobalEventHandler $emitterGlobal
     */
    public function __construct(?Interfaces\GlobalEventHandler $emitterGlobal = null) {
        $this->setGlobalEmitter($emitterGlobal ?: GlobalEventHandler::getInstance());
    }

    /**
     * @inheritdoc
     *
     * @param string|\xobotyi\emittr\Event $event
     * @param null                         $payload
     *
     * @return \xobotyi\emittr\EventEmitter
     */
    public function emit($event, $payload = null) :self {
        if (is_string($event)) {
            $event = new Event($event, $payload, get_called_class(), $this);
        }
        else if (!($event instanceof Event)) {

$event is always a sub-type of xobotyi\emittr\Event.

            throw new \TypeError('first parameter has to be of type string or \xobotyi\emittr\Event instance, got ' . gettype($event));
        }

        if (empty($this->eventListeners) || $this->eventEmitterGlobal::propagateEvent($event, $this->eventListeners)) {
            $this->eventEmitterGlobal->propagateEventGlobal($event);
        }

        return $this;
    }

    /**
     * @inheritdoc
     *
     * @param string                $eventName
     * @param array|callable|string $callback
     *
     * @return \xobotyi\emittr\EventEmitter
     */
    public function on(string $eventName, $callback) :self {
        $this->eventEmitterGlobal::storeCallback($this->eventListeners, $eventName, $callback, $this->maxListenersCount, false, false);
        $this->emit(self::EVENT_LISTENER_ADDED, ['callback' => &$callback]);

        return $this;
    }

    /**
     * @inheritdoc
     *
     * @param string                $eventName
     * @param array|callable|string $callback
     *
     * @return \xobotyi\emittr\EventEmitter
     */
    public function once(string $eventName, $callback) :self {
        $this->eventEmitterGlobal::storeCallback($this->eventListeners, $eventName, $callback, $this->maxListenersCount, true, false);
        $this->emit(self::EVENT_LISTENER_ADDED, ['callback' => &$callback]);

        return $this;
    }

    /**
     * @inheritdoc
     *
     * @param string                $eventName
     * @param array|callable|string $callback
     *
     * @return \xobotyi\emittr\EventEmitter
     */
    public function prependListener(string $eventName, $callback) :self {
        $this->eventEmitterGlobal::storeCallback($this->eventListeners, $eventName, $callback, $this->maxListenersCount, false, true);
        $this->emit(self::EVENT_LISTENER_ADDED, ['callback' => &$callback]);

        return $this;
    }

    /**
     * @inheritdoc
     *
     * @param string                $eventName
     * @param array|callable|string $callback
     *
     * @return \xobotyi\emittr\EventEmitter
     */
    public function prependOnceListener(string $eventName, $callback) :self {
        $this->eventEmitterGlobal::storeCallback($this->eventListeners, $eventName, $callback, $this->maxListenersCount, true, true);
        $this->emit(self::EVENT_LISTENER_ADDED, ['callback' => &$callback]);

        return $this;
    }

    /**
     * @inheritdoc
     *
     * @param string                $eventName
     * @param array|callable|string $callback
     *
     * @return \xobotyi\emittr\EventEmitter
     */
    public function off(string $eventName, $callback) :self {
        if (empty($this->eventListeners[$eventName])) {
            return $this;
        }

        $this->eventListeners[$eventName] = \array_values(\array_filter($this->eventListeners[$eventName], function ($item) use (&$callback) { return $item[1] !== $callback; }));
        $this->emit(self::EVENT_LISTENER_REMOVED, ['eventName' => $eventName, 'callback' => &$callback]);

        if (empty($this->eventListeners[$eventName])) {
            unset($this->eventListeners[$eventName]);
        }

        return $this;
    }

    /**
     * @inheritdoc
     *
     * @param null|string $eventName
     *
     * @return \xobotyi\emittr\EventEmitter
     */
    public function removeAllListeners(?string $eventName = null) :self {
        if ($eventName === null) {
            foreach ($this->eventListeners as $eventName => $callbacks) {
                foreach ($callbacks as &$callback) {
                    $this->emit(self::EVENT_LISTENER_REMOVED, [
                        'eventName' => $eventName,
                        'callback'  => &$callback[1],
                    ]);
                }
            }

            $this->eventListeners = [];

            return $this;
        }

        if (empty($this->eventListeners[$eventName])) {
            return $this;
        }

        foreach ($this->eventListeners[$eventName] as $callback) {
            $this->emit(self::EVENT_LISTENER_REMOVED, ['eventName' => $eventName, 'callback' => &$callback[1]]);
        }

        unset($this->eventListeners[$eventName]);

        return $this;
    }

    /**
     * @inheritdoc
     *
     * @return array
     */
    public function getEventNames() :array {
        return empty($this->eventListeners) ? [] : \array_keys($this->eventListeners);
    }

    /**
     * @inheritdoc
     *
     * @param null|string $eventName
     *
     * @return array
     */
    public function getListeners(?string $eventName = null) :array {
        return $eventName ? $this->eventListeners[$eventName] ?? [] : $this->eventListeners;
    }

    /**
     * @inheritdoc
     *
     * @return int
     */
    public function getMaxListenersCount() :int {
        return $this->maxListenersCount;
    }

    /**
     * @inheritdoc
     *
     * @param int $maxListenersCount
     *
     * @return \xobotyi\emittr\EventEmitter
     */
    public function setMaxListenersCount(int $maxListenersCount) :self {
        if ($maxListenersCount < 0) {
            throw new \InvalidArgumentException('Listeners count must be greater or equal 0, got ' . $maxListenersCount);
        }

        $this->maxListenersCount = $maxListenersCount;

        return $this;
    }

    /**
     * @inheritdoc
     *
     * @return \xobotyi\emittr\Interfaces\GlobalEventHandler
     */
    public function getGlobalEmitter() :Interfaces\GlobalEventHandler {
        return $this->eventEmitterGlobal;
    }

    /**
     * @inheritdoc
     *
     * @param \xobotyi\emittr\Interfaces\GlobalEventHandler $emitterGlobal
     *
     * @return \xobotyi\emittr\EventEmitter
     */
    public function setGlobalEmitter(Interfaces\GlobalEventHandler $emitterGlobal) :self {
        $this->eventEmitterGlobal = $emitterGlobal;

        return $this;
    }
}