<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Bridge\Doctrine;

use Doctrine\Common\EventArgs;
use Doctrine\Common\EventManager;
use Psr\Container\ContainerInterface;

/**
 * Allows lazy loading of listener and subscriber services.
 *
 * @author Johannes M. Schmitt <schmittjoh@gmail.com>
 */
class ContainerAwareEventManager extends EventManager
{
    /**
     * Map of registered listeners.
     *
     * <event> => <listeners>
     */
    private $listeners = [];
    private $subscribers;
    private $initialized = [];
    private $initializedSubscribers = false;
    private $methods = [];
    private $container;

    public function __construct(ContainerInterface $container, array $subscriberIds = [])
    {
        $this->container = $container;
        $this->subscribers = $subscriberIds;
    }

    /**
     * {@inheritdoc}
     *
     * @return void
     */
    public function dispatchEvent($eventName, EventArgs $eventArgs = null)
    {
        if (!$this->initializedSubscribers) {
            $this->initializeSubscribers();
        }
        if (!isset($this->listeners[$eventName])) {
            return;
        }

        $eventArgs = null === $eventArgs ? EventArgs::getEmptyInstance() : $eventArgs;

        if (!isset($this->initialized[$eventName])) {
            $this->initializeListeners($eventName);
        }

        foreach ($this->listeners[$eventName] as $hash => $listener) {
            $listener->{$this->methods[$eventName][$hash]}($eventArgs);
        }
    }

    /**
     * {@inheritdoc}
     *
     * @return object[][]
     */
    public function getListeners($event = null)
    {
        if (!$this->initializedSubscribers) {
            $this->initializeSubscribers();
        }
        if (null !== $event) {
            if (!isset($this->initialized[$event])) {
                $this->initializeListeners($event);
            }

            return $this->listeners[$event];
        }

        foreach ($this->listeners as $event => $listeners) {
            if (!isset($this->initialized[$event])) {
                $this->initializeListeners($event);
            }
        }

        return $this->listeners;
    }

    /**
     * {@inheritdoc}
     *
     * @return bool
     */
    public function hasListeners($event)
    {
        if (!$this->initializedSubscribers) {
            $this->initializeSubscribers();
        }

        return isset($this->listeners[$event]) && $this->listeners[$event];
    }

    /**
     * {@inheritdoc}
     *
     * @return void
     */
    public function addEventListener($events, $listener)
    {
        $hash = $this->getHash($listener);

        foreach ((array) $events as $event) {
            // Overrides listener if a previous one was associated already
            // Prevents duplicate listeners on same event (same instance only)
            $this->listeners[$event][$hash] = $listener;

            if (\is_string($listener)) {
                unset($this->initialized[$event]);
            } else {
                $this->methods[$event][$hash] = $this->getMethod($listener, $event);
            }
        }
    }

    /**
     * {@inheritdoc}
     *
     * @return void
     */
    public function removeEventListener($events, $listener)
    {
        $hash = $this->getHash($listener);

        foreach ((array) $events as $event) {
            // Check if we actually have this listener associated
            if (isset($this->listeners[$event][$hash])) {
                unset($this->listeners[$event][$hash]);
            }

            if (isset($this->methods[$event][$hash])) {
                unset($this->methods[$event][$hash]);
            }
        }
    }

    private function initializeListeners(string $eventName)
    {
        $this->initialized[$eventName] = true;
        foreach ($this->listeners[$eventName] as $hash => $listener) {
            if (\is_string($listener)) {
                $this->listeners[$eventName][$hash] = $listener = $this->container->get($listener);

                $this->methods[$eventName][$hash] = $this->getMethod($listener, $eventName);
            }
        }
    }

    private function initializeSubscribers()
    {
        $this->initializedSubscribers = true;

        $eventListeners = $this->listeners;
        // reset eventListener to respect priority: EventSubscribers have a higher priority
        $this->listeners = [];
        foreach ($this->subscribers as $id => $subscriber) {
            if (\is_string($subscriber)) {
                parent::addEventSubscriber($this->subscribers[$id] = $this->container->get($subscriber));
            }
        }
        foreach ($eventListeners as $event => $listeners) {
            if (!isset($this->listeners[$event])) {
                $this->listeners[$event] = [];
            }
            unset($this->initialized[$event]);
            $this->listeners[$event] += $listeners;
        }
        $this->subscribers = [];
    }

    /**
     * @param string|object $listener
     */
    private function getHash($listener): string
    {
        if (\is_string($listener)) {
            return '_service_'.$listener;
        }

        return spl_object_hash($listener);
    }

    /**
     * @param object $listener
     */
    private function getMethod($listener, string $event): string
    {
        if (!method_exists($listener, $event) && method_exists($listener, '__invoke')) {
            return '__invoke';
        }

        return $event;
    }
}
