Making My Own WordPress Chartbeat Plugin

<?php
/*
Plugin Name: Ct Most Popular
Plugin URI: http://www.craiget.com
Description: Display most viewed posts using the Chartbeat API, exposes one function: ct_most_popular_plugin_widget(); 
Version: 0.1
Author: Craige
Author URI: http://craiget.com
License: For example and testing purposes. Not suggested for use on a real site.
*/
 
$ct_most_popular_plugin_version = "0.1";
 
$ct_most_popular_plugin_data = array();
 
// create a most_popular option
register_activation_hook(__FILE__, 'ct_most_popular_plugin_install');
function ct_most_popular_plugin_install()
{
	add_option("ct_most_popular_plugin_data", $ct_most_popular_data);
	add_option("ct_most_popular_plugin_version", $ct_most_popular_plugin_version);
	// schedule hourly update
	wp_schedule_event(time(), 'hourly', 'ct_most_popular_plugin_update_event');
}
 
// delete the most_popular option
register_deactivation_hook(__FILE__, 'ct_most_popular_plugin_uninstall');
function ct_most_popular_plugin_uninstall()
{
	delete_option("ct_most_popular_plugin_data");
	delete_option("ct_most_popular_plugin_version");
	// un-schedule hourly update
	wp_clear_scheduled_hook('ct_most_popular_plugin_update_event');
}
 
// appear under "Settings" on the admin page
add_action('admin_menu', 'ct_most_popular_plugin_menu');
function ct_most_popular_plugin_menu() {
	add_options_page('Ct Most Popular', 'Ct Most Popular', 'manage_options', '', 'ct_most_popular_plugin_options');
}
 
// init option values in db
add_action('admin_init', 'ct_most_popular_plugin_options_init' );
function ct_most_popular_plugin_options_init(){
	register_setting('ct_most_popular_plugin_options', 'ct_most_popular_plugin', 'ct_most_popular_plugin_validate' );
}
 
// sanitize and validate input
function ct_most_popular_plugin_validate($input) {
	$input['host'] =  wp_filter_nohtml_kses($input['host']);
	$input['chartbeat_api_key'] =  wp_filter_nohtml_kses($input['chartbeat_api_key']);
	$input['limit'] =  (int)($input['limit']);
	if($input['limit'] == 0) $input['limit'] = 10;
	return $input;
}
 
// display options page html
function ct_most_popular_plugin_options() {
	if (!current_user_can('manage_options'))  {
		wp_die(__('You do not have sufficient permissions to access this page.') );
	}
?>
<div class="wrap">
	<h2>Ct Most Popular Plugin Options Title</h2>
	<form method="post" action="options.php">
		<?php settings_fields('ct_most_popular_plugin_options'); ?>
		<?php $options = get_option('ct_most_popular_plugin'); ?>
		<table class="form-table">
		<tr valign="top">
			<th scope="row">Host</th>
			<td><input type="text" name="ct_most_popular_plugin[host]" value="<?php echo $options['host']; ?>" /></td>
			<td><i>ie, example.com</i></td>
		</tr>
		<tr valign="top">
			<th scope="row">Chartbeat API Key</th>
			<td><input type="text" name="ct_most_popular_plugin[chartbeat_api_key]" value="<?php echo $options['chartbeat_api_key']; ?>" /></td>
			<td><i><a href="http://chartbeat.com/apikeys/">http://chartbeat.com/apikeys/</a></i></td>
		</tr>
		<tr valign="top">
			<th scope="row">Limit</th>
			<td><input type="text" name="ct_most_popular_plugin[limit]" value="<?php echo $options['limit']; ?>" /></td>
			<td><i>number of items to show, 10</i></td>
		</tr>
		</table>
		<p class="submit">
			<input type="submit" class="button-primary" value="<?php _e('Save Changes') ?>" />
		</p>
		<p>
		This plugin uses the <a href="http://chartbeat.pbworks.com/">Chartbeat API</a> to show the most popular pages on your site, updated hourly.
		</p>
		<p>
		This plugin was created for my own amusement and to practice creating Wordpress plugins, it is <strong>NOT RECOMMENDED</strong> for use.
		</p>
		<p>
		Chartbeat has released a perfectly good plugin that does this and more: <a href="http://wordpress.org/extend/plugins/chartbeat/">http://wordpress.org/extend/plugins/chartbeat/</a>
		</p>
		<p>
		This plugin fetches new data once every hour using Wordpress's built-in <a href="http://codex.wordpress.org/Function_Reference/wp_schedule_event">scheduling hooks</a> to update the list of popular posts hourly.
		This keeps things self-contained, but doesn't provide much flexibility. You may want to use cron instead, which would require a little hacking.
		</p>
	</form>
</div>
<?php
}
 
// get popularity data from chartbeat, store in db
add_action('ct_most_popular_plugin_update_event', 'ct_most_popular_plugin_update_chartbeat');
function ct_most_popular_plugin_update_chartbeat() {
	// construct chartbeat call
	$options = get_option('ct_most_popular_plugin');
	$host = $options['host'];
	$apikey = $options['chartbeat_api_key'];
	$limit = $options['limit'];
	// build url
	$url = 'http://api.chartbeat.com/toppages/?host=HOST&limit=LIMIT&apikey=APIKEY';
	$url = str_replace('HOST', $host, $url);
	$url = str_replace('APIKEY', $apikey, $url);
	$url = str_replace('LIMIT', $limit, $url);
	// fetch data
	$data = file_get_contents($url);
	$data = json_decode($data, true);
	// exit if not enough results back
	if(count($data) < $limit)
		return;
	$result = array();
	for($i=0; $i<count($data); $i++) {
		if($data[$i]['path'] == "/")
			continue;
		$result[] = $data[$i];
	}
	$result = array_slice($result, 0, $limit);
	// store in db
	update_option("ct_most_popular_plugin_data", $result);
}
 
// add this function in your sidebar
function ct_most_popular_plugin_widget() {
	$data = get_option("ct_most_popular_plugin_data");
	echo('<ul>');
	foreach ($data as $post) {
		echo('<li>');
		echo('<a href="'.$post['path'].'">'.$post['visitors'].'-'.$post['i'].'</a>');
		echo('</li>');
	}
	echo('</ul>');
}