<?php

/**
 * BB code to BB code formatter that automatically links URLs and emails using
 * [url] and [email] tags.
 *
 * @package XenForo_BbCode
 */
class XenForo_BbCode_Formatter_BbCode_AutoLink extends XenForo_BbCode_Formatter_BbCode_Abstract
{
	/**
	 * Callback for all tags.
	 *
	 * @var callback
	 */
	protected $_generalTagCallback = array('$this', 'autoLinkTag');

	/**
	 * The tags that disable autolinking.
	 *
	 * @var array
	 */
	protected $_disableAutoLink = array('url', 'email', 'img', 'code', 'php', 'html', 'plain', 'media');

	/**
	 * Auto embed media settings.
	 *
	 * @var array
	 */
	protected $_autoEmbed = array();

	/**
	 * Amount of media embeds that can be automatically applied.
	 *
	 * @var integer 0 will disable auto embed
	 */
	protected $_autoEmbedRemaining = 0;

	protected $_enableAutoEmbed = true;

	public function __construct()
	{
		parent::__construct();

		$options = XenForo_Application::get('options');

		// TODO: end-user ability to disable auto-embedding on a per-post basis
		$this->_autoEmbed = $options->autoEmbedMedia;
		$this->_autoEmbedRemaining = ($options->messageMaxMedia ? $options->messageMaxMedia : PHP_INT_MAX);
	}

	public function addCustomTags(array $tags)
	{
		parent::addCustomTags($tags);

		foreach ($tags AS $tagName => $tag)
		{
			if ($tag['disable_autolink'] || $tag['plain_children'])
			{
				$this->_disableAutoLink[] = $tagName;
			}
		}
	}

	public function renderTree(array $tree, array $extraStates = array())
	{
		$this->_subtractMediaTagsRemaining($tree);
		return parent::renderTree($tree, $extraStates);
	}

	public function setAutoEmbed($enable)
	{
		$this->_enableAutoEmbed = $enable;
	}

	protected function _subtractMediaTagsRemaining(array $tree)
	{
		foreach ($tree AS $element)
		{
			if (is_array($element))
			{
				// tag
				if (strtolower($element['tag']) == 'media')
				{
					$this->_autoEmbedRemaining--;
				}
				$this->_subtractMediaTagsRemaining($element['children']);
			}
		}
	}

	/**
	 * Callback that all tags with go through. Changes the rendering state to disable
	 * URL parsing if necessary.
	 *
	 * @param array $tag
	 * @param array $rendererStates

	 * @return string
	 */
	public function autoLinkTag(array $tag, array $rendererStates)
	{
		if (in_array($tag['tag'], $this->_disableAutoLink))
		{
			$rendererStates['stopAutoLink'] = true;
		}

		if ($tag['tag'] == 'url'
			&& $this->_autoEmbed['embedType'] != XenForo_Helper_Media::AUTO_EMBED_MEDIA_DISABLED
			&& $this->_enableAutoEmbed
		)
		{
			$childText = $this->stringifyTree($tag['children'], $rendererStates);
			if (empty($tag['option']) || $tag['option'] == $childText)
			{
				return $this->_autoLinkUrl($childText);
			}
		}

		$text = $this->renderSubTree($tag['children'], $rendererStates);

		if (!empty($tag['original']) && is_array($tag['original']))
		{
			list($prepend, $append) = $tag['original'];
		}
		else
		{
			$prepend = '';
			$append = '';
		}

		// note: necessary to return prepend/append unfiltered to keep them unchanged
		return $prepend . $text . $append;
	}

	/**
	 * String filter that does link parsing if not disabled.
	 *
	 * @param string $string
	 * @param array $rendererStates List of states the renderer may be in
	 *
	 * @return string Filtered/escaped string
	 */
	public function filterString($string, array $rendererStates)
	{
		if (empty($rendererStates['stopAutoLink']))
		{
			$string = preg_replace_callback(
				'#(?<=[^a-z0-9@-]|^)(https?://|ftp://|www\.)[^\s"]+#iu',
				array($this, '_autoLinkUrlCallback'),
				$string
			);

			if (strpos($string, '@') !== false)
			{
				// assertion to prevent matching email in url matched above (user:pass@example.com)
				$string = preg_replace(
					'#[a-z0-9.+_-]+@[a-z0-9-]+(\.[a-z]+)+(?![^\s"]*\[/url\])#iu',
					'[email]$0[/email]',
					$string
				);
			}
		}

		return $string;
	}

	/**
	 * Callback for the auto-linker regex.
	 *
	 * @param array $match
	 *
	 * @return string
	 */
	protected function _autoLinkUrlCallback(array $match)
	{
		return $this->_autoLinkUrl($match[0]);
	}

	/**
	 * Handles autolinking the given URL.
	 *
	 * @param string $url
	 *
	 * @return string
	 */
	protected function _autoLinkUrl($url)
	{
		$link = XenForo_Helper_String::prepareAutoLinkedUrl($url);

		if ($link['url'] === $link['linkText'])
		{
			if ($this->_autoEmbed['embedType'] != XenForo_Helper_Media::AUTO_EMBED_MEDIA_DISABLED
				&& $this->_autoEmbedRemaining > 0
				&& $this->_enableAutoEmbed
				&& ($mediaTag = XenForo_Helper_Media::convertMediaLinkToEmbedHtml($link['url'], $this->_autoEmbed))
			)
			{
				$tag = $mediaTag;
				$this->_autoEmbedRemaining--;
			}
			else
			{
				$tag = '[url]' . $link['url'] . '[/url]';
			}
		}
		else
		{
			$tag = '[url="' . $link['url'] . '"]' . $link['linkText'] . '[/url]';
		}

		return $tag . $link['suffixText'];
	}
}