AFK event example

lib.php

<?php
function format($text) {
	return str_replace(
		array('<pre><code>', '<hr />', '<br />'),
		array('<pre class="prettyprint"><code>', '<div class="hr"><hr></div>', '<br>'),
		SmartyPants(Markdown(render_tags($text))));
}

function render_tags($text) {
	return preg_replace_callback(
		"/{{(?<tag>[a-z0-9]+)(?<attrs>(?:\s+[a-z0-9]+=\"[^\"]+\")*)}}/",
		'render_tag', $text);
}

function parse_attrs($text) {
	$attrs = array();
	$matches = array();
	preg_match_all("/\s+(?<key>[a-z0-9]+)=\"(?<value>[^\"]+)\"/", $text, $matches, PREG_SET_ORDER);
	foreach ($matches as $m) {
		$attrs[$m['key']] = $m['value'];
	}
	return $attrs;
}

function render_tag(array $matches) {
	list($unhandled, $result) = trigger_event(
		'tag:' . $matches['tag'],
		parse_attrs($matches['attrs']));
	return $unhandled ? $matches[0] : $result;
}

function format_line($text) {
	return SmartyPants(e($text));
}

function google_fonts() {
	$fonts = func_get_args();
	foreach ($fonts as $font) {
		printf('<link href="http://fonts.googleapis.com/css?family=%s" rel="stylesheet" type="text/css">',
			htmlentities(urlencode($font)));
	}
}

function is_naked_day($now) {
	$y = gmdate('Y', $now);
	// The 7th is our fallback if neither the 5th or 9th work.
	foreach (array(5, 9, 7) as $try) {
		$day_of_week = gmdate('N', gmmktime(0, 0, 0, 4, $try, $y));
		// Best if it's a Tuesday, Wednesday, or Thursday.
		if ($day_of_week >= 2 && $day_of_week <= 4) {
			$d = $try;
			break;
		}
	}
	$start = gmmktime(-12, 0, 0, 4, $d, $y);
	$end = gmmktime(36, 0, 0, 4, $d, $y);
	return $now >= $start && $now <= $end;
}

function generate_link_embed($link) {
	list($unhandled, $result) = trigger_event('render_link', $link);
	return $unhandled ? false : $result;
}

function ts($fmt, $ts) {
	return gmdate($fmt, is_int($ts) ? $ts : strtotime($ts));
}

function dbts($ts) {
	return ts('Y-m-d H:i:s', $ts);
}

function get_via_host($url) {
	$host = parse_url($url, PHP_URL_HOST);
	if (substr($host, 0, 4) == 'www.') {
		$host = substr($host, 4);
	}
	return $host;
}

plugin.php

<?php
class FlashEmbedPlugin extends Plugin {

    protected function get_events() {
        return array(
            'render_link',
            'tag:flash' => 'render_flash_tag',
            'tag:movie' => 'render_movie_tag');
    }

    public function render_link($msg, $url) {
        $embed = $this->generate_movie_embed($url);
        return array($embed === false, $embed === false ? $url : $embed);
    }

    public function render_flash_tag($msg, array $attrs) {
        if (!isset($attrs['href'])) {
            return array(false, '');
        }
        $url = $attrs['href'];
        $width = isset($attrs['width']) ? $attrs['width'] : 640;
        $height = isset($attrs['height']) ? $attrs['height'] : 385;
        unset($attrs['href'], $attrs['width'], $attrs['height']);

        return array(false, $this->generate_flash_embed($url, $width, $height, $attrs));
    }

    public function render_movie_tag($msg, array $attrs) {
        if (!isset($attrs['href'])) {
            return array(false, '');
        }
        $url = $attrs['href'];
        $width = isset($attrs['width']) ? $attrs['width'] : null;
        $height = isset($attrs['height']) ? $attrs['height'] : null;

        $embed = $this->generate_movie_embed($url, $width, $height);
        return array($embed === false, $embed === false ? $attrs : $embed);
    }

    private function generate_flash_embed($movie_url, $width, $height, array $params) {
        $params_html = '<param name="movie" value="' . e($movie_url) . '">';
        if (count($params) > 0) {
            $params_html .= '<params name="FlashVars" value="' . e(http_build_query($params)) . '">';
            foreach ($params as $name => $value) {
                $params_html .= sprintf('<param name="%s" value="%s">', e($name), e($value));
            }
        }
        return sprintf(
            '<object type="application/x-shockwave-flash" data="%s" width="%s" height="%s">%s</object>',
            e($movie_url), $width, $height, $params_html);
    }

    private function generate_movie_embed($link, $width=null, $height=null) {
        static $patterns = array(
            'https?://(?:www\.)?youtube\.com/watch\?v=([-A-Za-z0-9_]{11,})' => array(
                'pattern' => "//www.youtube.com/v/%s&rel=1",
                'width' => 640,
                'height' => 385),
            'https?://video\.google\.com/videoplay\?docid=(-?\d+)' => array(
                'pattern' => "//video.google.com/googleplayer.swf?hl=en&docId=%s",
                'width' => 640,
                'height' => 385),
            'https?://(?:www\.)?vimeo\.com/(\d+)' => array(
                'pattern' => "//www.vimeo.com/moogaloop.swf?clip_id=%s",
                'width' => 640,
                'height' => 385),
            'https?://(?:www\.)?gametrailers\.com/video/[^/]+/(\d+)' => array(
                'pattern' => "//www.gametrailers.com/remote_wrap.php?mid=%s",
                'width' => 640,
                'height' => 385),
            'https?://(?:www\.)?dailymotion\.com/video/([a-z0-9]+)' => array(
                'pattern' => "//www.dailymotion.com/swf/%s",
                'width' => 640,
                'height' => 385));

        foreach ($patterns as $pattern => $params) {
            if (preg_match("~^$pattern~", $link, $matches)) {
                return $this->generate_flash_embed(
                    sprintf($params['pattern'], $matches[1]),
                    AFK::coalesce($width, $params['width']),
                    AFK::coalesce($height, $params['height']),
                    array());
            }
        }
        return false;
    }
}

// Instantiate an instance of this particular plugin.
new FlashEmbedPlugin();