<?php

namespace Symfony\Components\EventDispatcher;

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

/**
 * Event.
 *
 * @package    Symfony
 * @subpackage Components_EventDispatcher
 * @author     Fabien Potencier <fabien.potencier@symfony-project.com>
 */
class Event implements \ArrayAccess
{
  protected $value = null;
  protected $processed = false;
  protected $subject;
  protected $name;
  protected $parameters;

  /**
   * Constructs a new Event.
   *
   * @param mixed   $subject      The subject
   * @param string  $name         The event name
   * @param array   $parameters   An array of parameters
   */
  public function __construct($subject, $name, $parameters = array())
  {
    $this->subject = $subject;
    $this->name = $name;
    $this->parameters = $parameters;
  }

  /**
   * Returns the subject.
   *
   * @return mixed The subject
   */
  public function getSubject()
  {
    return $this->subject;
  }

  /**
   * Returns the event name.
   *
   * @return string The event name
   */
  public function getName()
  {
    return $this->name;
  }

  /**
   * Sets the return value for this event.
   *
   * @param mixed $value The return value
   */
  public function setReturnValue($value)
  {
    $this->value = $value;
  }

  /**
   * Returns the return value.
   *
   * @return mixed The return value
   */
  public function getReturnValue()
  {
    return $this->value;
  }

  /**
   * Sets the processed flag.
   *
   * @param Boolean $processed The processed flag value
   */
  public function setProcessed($processed)
  {
    $this->processed = (boolean) $processed;
  }

  /**
   * Returns whether the event has been processed by a listener or not.
   *
   * @return Boolean true if the event has been processed, false otherwise
   */
  public function isProcessed()
  {
    return $this->processed;
  }

  /**
   * Returns the event parameters.
   *
   * @return array The event parameters
   */
  public function getParameters()
  {
    return $this->parameters;
  }

  /**
   * Returns true if the parameter exists.
   *
   * @param  string  $name  The parameter name
   *
   * @return Boolean true if the parameter exists, false otherwise
   */
  public function hasParameter($name)
  {
    return array_key_exists($name, $this->parameters);
  }

  /**
   * Returns a parameter value.
   *
   * @param  string  $name  The parameter name
   *
   * @return mixed  The parameter value
   *
   * @throws \InvalidArgumentException When parameter doesn't exists for this event
   */
  public function getParameter($name)
  {
    if (!array_key_exists($name, $this->parameters))
    {
      throw new \InvalidArgumentException(sprintf('The event "%s" has no "%s" parameter.', $this->name, $name));
    }

    return $this->parameters[$name];
  }

  /**
   * Sets a parameter.
   *
   * @param string  $name   The parameter name
   * @param mixed   $value  The parameter value
   */
  public function setParameter($name, $value)
  {
    $this->parameters[$name] = $value;
  }

  /**
   * Returns true if the parameter exists (implements the ArrayAccess interface).
   *
   * @param  string  $name  The parameter name
   *
   * @return Boolean true if the parameter exists, false otherwise
   */
  public function offsetExists($name)
  {
    return array_key_exists($name, $this->parameters);
  }

  /**
   * Returns a parameter value (implements the ArrayAccess interface).
   *
   * @param  string  $name  The parameter name
   *
   * @return mixed  The parameter value
   */
  public function offsetGet($name)
  {
    if (!array_key_exists($name, $this->parameters))
    {
      throw new \InvalidArgumentException(sprintf('The event "%s" has no "%s" parameter.', $this->name, $name));
    }

    return $this->parameters[$name];
  }

  /**
   * Sets a parameter (implements the ArrayAccess interface).
   *
   * @param string  $name   The parameter name
   * @param mixed   $value  The parameter value
   */
  public function offsetSet($name, $value)
  {
    $this->parameters[$name] = $value;
  }

  /**
   * Removes a parameter (implements the ArrayAccess interface).
   *
   * @param string $name    The parameter name
   */
  public function offsetUnset($name)
  {
    unset($this->parameters[$name]);
  }
}