Piwik for Multisite

gistfile1.php

<?php
/*
 Plugin name: Piwik Stats
 Description: Implement Piwik tracking code
 Version: 1.0
 Author: Erick Hitter
 Author URI: http://www.ethitter.com
 License: GPLv2
*/

/*
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

/**
 * Add Piwik tracking code to page footer
 *
 * @uses is_user_logged_in, get_current_blog_id
 * @action wp_footer
 * @return string or null
 */
function eth_piwik_tracking_code() {
  // Don't let me screw up the Analytics
	if ( is_user_logged_in() )
		return;

	// Map of blog ID to Piwik ID
	$tracking_ids = array(
		1 => 3,
		2 => 1,
		3 => 2,
		4 => 5,
		5 => 6,
		7 => 4,
		8 => 7,
		9 => 11
	);

	$current_blog_id = get_current_blog_id();

	if ( array_key_exists( $current_blog_id, $tracking_ids ) ) :
		$tracking_id = (int) $tracking_ids[ $current_blog_id ];
	?>

<!-- Piwik -->
<script type="text/javascript">
	var pkBaseURL = (("https:" == document.location.protocol) ? "https://stats.erick.me/" : "http://stats.erick.me/");
	document.write(unescape("%3Cscript src='" + pkBaseURL + "piwik.js' type='text/javascript'%3E%3C/script%3E"));
</script>
<script type="text/javascript">
	try {
		var piwikTracker = Piwik.getTracker(pkBaseURL + "piwik.php", <?php echo $tracking_id; ?>);
		<?php if ( is_404() ) : ?>piwikTracker.setDocumentTitle('404/URL = '+String(document.location.href).replace(/\//g,"%2f") + '/From = ' + String(document.referrer).replace(/\//g,"%2f"));<?php echo "\n"; endif; ?>
		piwikTracker.trackPageView();
		piwikTracker.enableLinkTracking();
	} catch( err ) {}
</script>
<noscript><p><img src="http://stats.erick.me/piwik.php?idsite=<?php echo $tracking_id; ?>" style="border:0" alt="" /></p></noscript>
<!-- End Piwik Tracking Code -->

	<?php endif;
}
add_action( 'wp_footer', 'eth_piwik_tracking_code', 9999 );