<?php
/**************************************************************
 *                                                            *
 *   Provides a notification to the user everytime            *
 *   your WordPress theme is updated                          *
 *                                                            *
 *   Author: Joao Araujo                                      *
 *   Profile: http://themeforest.net/user/unisphere           *
 *   Follow me: http://twitter.com/unispheredesign            *
 *                                                            *
 **************************************************************/
 
 

// Constants for the theme name, folder and remote XML url
define( 'NOTIFIER_THEME_NAME', YIW_THEME_NAME ); // The theme name
define( 'NOTIFIER_THEME_FOLDER_NAME', YIW_THEME_FOLDER_NAME ); // The theme folder name
define( 'NOTIFIER_CACHE_INTERVAL', 21600 ); // The time interval for the remote XML cache in the database (21600 seconds = 6 hours)


// Adds an update notification to the WordPress Dashboard menu
function update_notifier_menu() {  
    if (function_exists('simplexml_load_string')) { // Stop if simplexml_load_string funtion isn't available
        $xml = get_latest_theme_version(NOTIFIER_CACHE_INTERVAL); // Get the latest remote XML file on our server
        
        // get version
        if ( function_exists( 'wp_get_theme' ) ) {
            $theme_data = wp_get_theme();
            $version = $theme_data->version;    
        } else {
            $theme_data = get_theme_data(TEMPLATEPATH . '/style.css');
            $version = $theme_data['Version'];
        }
        
        if ( ! is_object( $xml ) )
            return;

        if( version_compare($xml->latest, $version, '>') ) { // Compare current theme version with the remote XML version
                add_dashboard_page( NOTIFIER_THEME_NAME . ' Theme Updates', NOTIFIER_THEME_NAME . ' <span class="update-plugins count-1"><span class="update-count">1 Update</span></span>', 'administrator', 'theme-update-notifier', 'update_notifier');
        }
    }   
}
add_action('admin_menu', 'update_notifier_menu');  



// Adds an update notification to the WordPress 3.1+ Admin Bar
function update_notifier_bar_menu() {
    if (function_exists('simplexml_load_string')) { // Stop if simplexml_load_string funtion isn't available
        global $wp_admin_bar, $wpdb;
    
        if ( !is_super_admin() || !is_admin_bar_showing() ) // Don't display notification in admin bar if it's disabled or the current user isn't an administrator
        return;
        
        $xml = get_latest_theme_version(NOTIFIER_CACHE_INTERVAL); // Get the latest remote XML file on our server
        
        // get version
        if ( function_exists( 'wp_get_theme' ) ) {
            $theme_data = wp_get_theme();
            $version = $theme_data->version;    
        } else {
            $theme_data = get_theme_data(TEMPLATEPATH . '/style.css');
            $version = $theme_data['Version'];
        }  
        
        if ( ! is_object( $xml ) )
            return;
    
        if( version_compare($xml->latest, $version, '>') ) { // Compare current theme version with the remote XML version
            $wp_admin_bar->add_menu( array( 'id' => 'update_notifier', 'title' => '<span>' . NOTIFIER_THEME_NAME . ' <span id="ab-updates">1 Update</span></span>', 'href' => get_admin_url() . 'index.php?page=theme-update-notifier' ) );
        }
    }
}
add_action( 'admin_bar_menu', 'update_notifier_bar_menu', 1000 );



// The notifier page
function update_notifier() { 
    $xml = get_latest_theme_version(NOTIFIER_CACHE_INTERVAL); // Get the latest remote XML file on our server
        
    // get version
    if ( function_exists( 'wp_get_theme' ) ) {
        $theme_data = wp_get_theme();
        $version = $theme_data->version;    
    } else {
        $theme_data = get_theme_data(TEMPLATEPATH . '/style.css');
        $version = $theme_data['Version'];
    } ?>
    
    <style>
        .update-nag { display: none; }
        #instructions {max-width: 670px;}
        h3.title {margin: 30px 0 0 0; padding: 30px 0 0 0; border-top: 1px solid #ddd;}
    </style>

    <div class="wrap">
    
        <div id="icon-tools" class="icon32"></div>
        <h2><?php echo NOTIFIER_THEME_NAME ?> Theme Updates</h2>
        <div id="message" class="updated below-h2"><p><strong>There is a new version of the <?php echo NOTIFIER_THEME_NAME; ?> theme available.</strong> You have version <?php echo $version; ?> installed. Update to version <?php echo $xml->latest; ?>.</p></div>

        <img style="float: left; margin: 0 20px 20px 0; border: 1px solid #ddd;" src="<?php echo get_template_directory_uri() . '/screenshot.png'; ?>" />
        
        <div id="instructions">
            <h3>Update Download and Instructions</h3>
            <p><strong>Please note:</strong> make a <strong>backup</strong> of the Theme inside your WordPress installation folder <strong>/wp-content/themes/<?php echo NOTIFIER_THEME_FOLDER_NAME; ?>/</strong>. I also encourage you to make a full backup your site and database before performing an update.</p>
            <p>To get the latest update of the Theme, go to <a href="http://yithemes.com/">YIThemes.com</a>, head over to your <strong>orders</strong> page and download the theme again.</p>
<p>If you bought the theme on Theme Forest, go on our <a href="http://support.yithemes.com/">support forum</a> and ask in the <a href="http://support.yithemes.com/viewtopic.php?f=8&t=13758">apposite topic</a> to enable the theme for you on <a href="http://yithemes.com/">YIThemes.com</a>.</p>
            <p>Extract the contents of the zip file, look for the extracted theme folder, and after you have all the new files upload them using FTP to the <strong>/wp-content/themes/<?php echo NOTIFIER_THEME_FOLDER_NAME; ?>/</strong> folder overwriting the old ones (this is why it's important to backup any changes you've made to the theme files).</p>
            <p>If you didn't make any changes to the theme files, you are free to overwrite them with the new ones without the risk of losing theme settings, pages, posts, slider images, etc.</p>
            <p>Now if you have modified files like CSS or some php files and you haven't kept track of your changes then you can use some 'diff' tools to compare the two versions' files and folders. That way you'd know exactly what files to update and where, line by line. Otherwise you'll loose your customizations.</p>
        </div>

        <h3 class="title">Changelog</h3>
        <?php echo $xml->changelog; ?>

    </div>
    
<?php } 



// Get the remote XML file contents and return its data (Version and Changelog)
// Uses the cached version if available and inside the time interval defined
function get_latest_theme_version($interval) {
    $notifier_file_url = NOTIFIER_XML_FILE; 
    $db_cache_field = 'yiw-notifier-cache';
    $db_cache_field_last_updated = 'yiw-notifier-cache-last-updated';
    $last = get_option( $db_cache_field_last_updated );
    $now = time();
    // check the cache
    if ( !$last || (( $now - $last ) > $interval) ) {
        // cache doesn't exist, or is old, so refresh it
        if( function_exists('curl_init') ) { // if cURL is available, use it...
            $ch = curl_init($notifier_file_url);
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
            curl_setopt($ch, CURLOPT_HEADER, 0);
            curl_setopt($ch, CURLOPT_TIMEOUT, 10);
            $cache = curl_exec($ch);
            curl_close($ch);
        } else {
            $cache = @file_get_contents($notifier_file_url); // ...if not, use the common file_get_contents()
        }
        
        if ($cache) {           
            // we got good results  
            update_option( $db_cache_field, $cache );
            update_option( $db_cache_field_last_updated, time() );
        } 
        // read from the cache file
        $notifier_data = get_option( $db_cache_field );
    }
    else {
        // cache file is fresh enough, so read from it
        $notifier_data = get_option( $db_cache_field );
    }
    
    // Let's see if the $xml data was returned as we expected it to.
    // If it didn't, use the default 1.0.0 as the latest version so that we don't have problems when the remote server hosting the XML file is down
    if( strpos((string)$notifier_data, '<notifier>') === false ) {
        $notifier_data = file_get_contents( dirname(__FILE__) . '/default.xml' );
    }
    
    // Load the remote XML data into a variable and return it
    $xml = @simplexml_load_string($notifier_data); 
    
    return $xml;
}

?>