Top Spam Mail Domains WordPress plugin for a dashboard widget

top-spam-mail-domains.php

<?php # -*- coding: utf-8 -*-
namespace WPSE;
/**
 * Plugin Name: Top Mail Domains
 * Description: List the most used domain names from spammers and users in two dashboard widgets.
 * Version:     2013.06.02
 * Author:      Thomas Scholz
 * Author URI:  http://wpkrauts.com
 * License:     MIT
 */

\is_admin() && \add_action(
	'wp_dashboard_setup',
	array (
		Top_Spam_Mail_Domains::get_instance(),
		'setup'
	)
);

class Top_Spam_Mail_Domains
{
	protected static $instance;

	public static function get_instance()
	{
		if ( NULL === self::$instance )
			self::$instance = new self;

		return self::$instance;
	}

	public function setup()
	{
		$comment_model  = new Comment_Data;
		$comment_widget = new Widget( $comment_model );

		\wp_add_dashboard_widget(
			'top_comment_spam_domains',
			'Top Comment Mail Domains',
			array ( $comment_widget, 'display' )
		);

		$user_model  = new User_Data;
		$user_widget = new Widget( $user_model );

		\wp_add_dashboard_widget(
			'top_user_spam_domains',
			'Top User Mail Domains',
			array ( $user_widget, 'display' )
		);
	}
}

class Widget
{
	protected $source;

	public function __construct( Data $source )
	{
		$this->source = $source;
	}

	public function display()
	{
		$data = $this->source->get_domains(1);

		if ( empty ( $data ) )
			return print 'No domains found.';

		print $this->data_to_table( $data );
	}

	protected function data_to_table( Array $data )
	{
		$table  = '<table class="widefat">';
		$header = '<tr><th>Domain</th><th>Amount</th></tr>';
		$table .= "<thead>$header</thead><tfoot>$header</tfoot>";

		foreach ( $data as $result )
			$table .= sprintf(
				'<tr class="%1$s"><td>%2$s</td><td>%3$s</td></tr>',
				$this->row_class(),
				\esc_html( $result->domain ),
				\esc_html( $result->amount )
			);

		return "$table</table>";
	}

	protected function row_class()
	{
		static $count = 1;

		return ( $count++ % 2 ) ? '' : 'alt';
	}
}

abstract class Data
{
	public function get_domains( $min = 5 )
	{
		global $wpdb;

		$sql = $this->get_sql( absint( $min ) );
		return $wpdb->get_results( $sql );
	}

	abstract protected function get_sql( $min );
}

class Comment_Data extends Data
{
	protected function get_sql( $min )
	{
		global $wpdb;

		return "
SELECT (
	SUBSTR(
		`comment_author_email`,
		INSTR( `comment_author_email`, '@' ) + 1,
		LENGTH( `comment_author_email` ) - INSTR( `comment_author_email`, '@' )
	)
) AS domain,
COUNT(*) AS amount
FROM        `$wpdb->comments`
WHERE       `comment_approved` = 'spam'
GROUP BY    domain
HAVING      amount > $min
ORDER BY    amount DESC
LIMIT 0, 150
		";
	}
}


class User_Data extends Data
{
	protected function get_sql( $min )
	{
		global $wpdb;

		return "
		SELECT (
		SUBSTR(
		`user_email`,
		INSTR( `user_email`, '@' ) + 1,
		LENGTH( `user_email` ) - INSTR( `user_email`, '@' )
		)
		) AS domain,
		COUNT(*) AS amount
		FROM        `$wpdb->users`
		GROUP BY    domain
		HAVING      amount > $min
		ORDER BY    amount DESC
		LIMIT 0, 150
		";
	}
}