includes/classes/class-wp-ulike-activator.php
<?php
/**
 * WP ULike Activator
 * // @echo HEADER
 */

// If this file is called directly, abort.
if ( ! defined( 'ABSPATH' ) ) {
	exit; // Exit if accessed directly.
}

class wp_ulike_activator {

	/**
	 * Instance of this class.
	 *
	 * @var object
	 */
	protected static $instance = null;

	/**
	 * Other variables
	 */
	protected $tables, $database;

	public function __construct(){
		global $wpdb;

		$this->database = $wpdb;
		$this->tables   = array(
			'posts'      => $this->database->prefix . "ulike",
			'comments'   => $this->database->prefix . "ulike_comments",
			'activities' => $this->database->prefix . "ulike_activities",
			'forums'     => $this->database->prefix . "ulike_forums",
			'meta'       => $this->database->prefix . "ulike_meta"
		);
	}


	public function activate() {
		$this->install_tables();
	}

	public function install_tables(){

		$max_index_length = 191;

		$charset_collate = '';

		if ( $this->database->has_cap( 'collation' ) ) {
			$charset_collate = $this->database->get_charset_collate();
		}

		if( ! function_exists('maybe_create_table') ){
			// Add one library admin function for next function
			require_once( ABSPATH . 'wp-admin/includes/upgrade.php' );
		}

		// Extract array to variables
		extract( $this->tables );

		// Posts table
		maybe_create_table( $posts, "CREATE TABLE `{$posts}` (
			`id` bigint(20) NOT NULL AUTO_INCREMENT,
			`post_id` bigint(20) NOT NULL,
			`date_time` datetime NOT NULL,
			`ip` varchar(100) NOT NULL,
			`user_id` varchar(100) NOT NULL,
			`status` varchar(30) NOT NULL,
			PRIMARY KEY (`id`),
			KEY `post_id` (`post_id`),
			KEY `date_time` (`date_time`),
			KEY `user_id` (`user_id`),
			KEY `status` (`status`)
		) $charset_collate AUTO_INCREMENT=1;" );

		// Comments table
		maybe_create_table( $comments, "CREATE TABLE `{$comments}` (
			`id` bigint(20) NOT NULL AUTO_INCREMENT,
			`comment_id` bigint(20) NOT NULL,
			`date_time` datetime NOT NULL,
			`ip` varchar(100) NOT NULL,
			`user_id` varchar(100) NOT NULL,
			`status` varchar(30) NOT NULL,
			PRIMARY KEY (`id`),
			KEY `comment_id` (`comment_id`),
			KEY `date_time` (`date_time`),
			KEY `user_id` (`user_id`),
			KEY `status` (`status`)
		) $charset_collate AUTO_INCREMENT=1;" );

		// Activities table
		maybe_create_table( $activities, "CREATE TABLE `{$activities}` (
			`id` bigint(20) NOT NULL AUTO_INCREMENT,
			`activity_id` bigint(20) NOT NULL,
			`date_time` datetime NOT NULL,
			`ip` varchar(100) NOT NULL,
			`user_id` varchar(100) NOT NULL,
			`status` varchar(30) NOT NULL,
			PRIMARY KEY (`id`),
			KEY `activity_id` (`activity_id`),
			KEY `date_time` (`date_time`),
			KEY `user_id` (`user_id`),
			KEY `status` (`status`)
		) $charset_collate AUTO_INCREMENT=1;" );

		// Forums table
		maybe_create_table( $forums, "CREATE TABLE `{$forums}` (
			`id` bigint(20) NOT NULL AUTO_INCREMENT,
			`topic_id` bigint(20) NOT NULL,
			`date_time` datetime NOT NULL,
			`ip` varchar(100) NOT NULL,
			`user_id` varchar(100) NOT NULL,
			`status` varchar(30) NOT NULL,
			PRIMARY KEY (`id`),
			KEY `topic_id` (`topic_id`),
			KEY `date_time` (`date_time`),
			KEY `user_id` (`user_id`),
			KEY `status` (`status`)
		) $charset_collate AUTO_INCREMENT=1;" );


		// Meta values table
		maybe_create_table( $meta, "CREATE TABLE `{$meta}` (
			`meta_id` bigint(20) unsigned NOT NULL auto_increment,
			`item_id` bigint(20) unsigned NOT NULL default '0',
			`meta_group` varchar(100) default NULL,
			`meta_key` varchar(255) default NULL,
			`meta_value` longtext,
			PRIMARY KEY  (`meta_id`),
			KEY `item_id` (`item_id`),
			KEY `meta_group` (`meta_group`),
			KEY `meta_key` (`meta_key`($max_index_length))
		) $charset_collate AUTO_INCREMENT=1;" );

		// Update db version
		if( get_option( 'wp_ulike_dbVersion' ) === false ){
			update_option( 'wp_ulike_dbVersion', WP_ULIKE_DB_VERSION );
		}
	}

	public function upgrade_0(){
		// Extract array to variables
		extract( $this->tables );

		// Posts ugrades
		$this->database->query( "
			ALTER TABLE $posts
			ADD INDEX( `post_id`, `date_time`, `user_id`, `status`),
			CHANGE `user_id` `user_id` VARCHAR(100) NOT NULL,
			CHANGE `ip` `ip` VARCHAR(100) NOT NULL;
		" );
		// Comments ugrades
		$this->database->query( "
			ALTER TABLE $comments
			ADD INDEX( `comment_id`, `date_time`, `user_id`, `status`),
			CHANGE `user_id` `user_id` VARCHAR(100) NOT NULL,
			CHANGE `ip` `ip` VARCHAR(100) NOT NULL;
		" );
		// BuddyPress ugrades
		$this->database->query( "
			ALTER TABLE $activities
			ADD INDEX( `activity_id`, `date_time`, `user_id`, `status`),
			CHANGE `user_id` `user_id` VARCHAR(100) NOT NULL,
			CHANGE `ip` `ip` VARCHAR(100) NOT NULL;
		" );
		// bbPress upgrades
		$this->database->query( "
			ALTER TABLE $forums
			ADD INDEX( `topic_id`, `date_time`, `user_id`, `status`),
			CHANGE `user_id` `user_id` VARCHAR(100) NOT NULL,
			CHANGE `ip` `ip` VARCHAR(100) NOT NULL;
		" );

		// Update db version
		update_option( 'wp_ulike_dbVersion', '2.1' );
	}

	public function upgrade_1(){
		// Extract array to variables
		extract( $this->tables );

		// Posts ugrades
		$this->database->query( "
			ALTER TABLE $meta
			CHANGE `item_id` `item_id` VARCHAR(100) NOT NULL;
		" );
		// Update db version
		update_option( 'wp_ulike_dbVersion', '2.2' );
	}

	public function upgrade_2(){
		// Extract array to variables
		extract( $this->tables );

		// Maybe not installed meta table
		$this->install_tables();

		// Posts ugrades
		$this->database->query( "
			ALTER TABLE $meta
			CHANGE `item_id` `item_id` bigint(20) unsigned NOT NULL;
		" );

		// Update db version
		update_option( 'wp_ulike_dbVersion', '2.3' );
	}

	public function upgrade_3(){
		// Extract table names
		extract( $this->tables );

		// Add 'fingerprint' column to posts table
		$this->database->query( "
			ALTER TABLE $posts
			ADD COLUMN `fingerprint` VARCHAR(64) DEFAULT NULL AFTER `user_id`;
		" );

		// Add 'fingerprint' column to comments table
		$this->database->query( "
			ALTER TABLE $comments
			ADD COLUMN `fingerprint` VARCHAR(64) DEFAULT NULL AFTER `user_id`;
		" );

		// Add 'fingerprint' column to activities table
		$this->database->query( "
			ALTER TABLE $activities
			ADD COLUMN `fingerprint` VARCHAR(64) DEFAULT NULL AFTER `user_id`,
			ADD INDEX (`fingerprint`);
		" );

		// Add 'fingerprint' column to forums table
		$this->database->query( "
			ALTER TABLE $forums
			ADD COLUMN `fingerprint` VARCHAR(64) DEFAULT NULL AFTER `user_id`;
		" );

		// Update db version
		update_option( 'wp_ulike_dbVersion', '2.4' );
	}


    /**
    * Return an instance of this class.
    *
    * @return    object    A single instance of this class.
    */
    public static function get_instance() {
      // If the single instance hasn't been set, set it now.
      if ( null == self::$instance ) {
        self::$instance = new self;
      }

      return self::$instance;
    }
}