Dashboard Widget showing Download Stats for all Download Monitor Downloads in Wordpress

DownloadStats.php

<?php
/**
 * Created by PhpStorm.
 * User: fredbradley
 * Date: 05/10/2017
 * Time: 11:43
 */

namespace FredBradley\CranleighWPAdmin;

/**
 * Class DownloadStats
 *
 * @package FredBradley\CranleighWPAdmin
 */
class DownloadStats {

	/**
	 * DownloadStats constructor.
	 */
	public function __construct() {
		add_action( 'wp_dashboard_setup', [ $this, 'add_widget' ], 109999 );
	}

	/**
	 * Function: add_widget
	 *
	 * This is the function that is called in the constructor.
	 * This in turn calls the `add_meta_box` function IF Download monitor is found as an active plugin
	 */
	public function add_widget() {
		if (is_plugin_active('download-monitor/download-monitor.php')) {

			add_meta_box(
				'cs_dlm_download_stats',
				"Last Month's Download Stats",
				[ $this, 'cs_show_dlm_download_stats_widget' ],
				'dashboard',
				'side',
				'high'
			);

		}
	}

	/**
	 * Function: getDifference
	 *
	 * This works out how the difference between this month and last month.
	 * (Yes I developed this function in September, and didn't change the variable names!)
	 *
	 * @param int  $september
	 * @param int  $august
	 * @param bool $format
	 *
	 * @return int|string
	 */
	private function getDifference(int $september, int $august, $format = false) {

		$difference = $september - $august;

		if ($format===false) {
			return $difference;
		}

		if ($format==="%") {
			$difference = $difference."%";
		}

		if ($difference > 0) {
			return '<span style="color:green;">+'.$difference.'</span>';
		} elseif ($difference == 0) {
			return '<span>'.$difference.'</span>';
		} else {
			return '<span style="color:red;">'.$difference.'</span>';
		}
	}

	/**
	 * Function: cs_show_dlm_download_stats_widget
	 *
	 * This is the function that actually display content on the dashboard widget.
	 * For now, everything is written all in this function (except the `getDifference` function)
	 * For clarity I could separate this out later.
	 */
	public function cs_show_dlm_download_stats_widget() {
		global $wpdb;

		// Get the names of the month from SQL rather than PHP as that's what we'll be using in a query further down.
		$month = $wpdb->get_row("SELECT MONTHNAME(CURRENT_DATE - INTERVAL 1 MONTH) as curr_month, MONTHNAME(CURRENT_DATE - INTERVAL 2 MONTH) as prev_month");

		// Do the SQL query on Wordpress database.
		$downloads = $wpdb->get_results("
			SELECT 
				download_id
				,sum(case when (MONTH(download_date) = MONTH(CURRENT_DATE - INTERVAL 1 MONTH) AND download_status='completed' ) then 1 else 0 end) as curr_month
				,sum(case when (MONTH(download_date) = MONTH(CURRENT_DATE - INTERVAL 2 MONTH) AND download_status='completed' ) then 1 else 0 end) as prev_month
			FROM {$wpdb->prefix}download_log
			GROUP BY download_id
			ORDER BY curr_month DESC
		");

		echo '<p><strong>Showing all download logs for '.$month->curr_month.':</strong></p>';
		echo '<table class="table" style="display:block;max-height:375px;overflow-y: scroll;">';
		echo '<thead style="font-weight: bolder">';
		echo '<td>Item</td>';
		echo '<td style="text-align: center">'.$month->curr_month.'</td>';
//		echo '<td style="text-align: center">'.$month->prev_month.'</td>';
		echo '<td style="text-align:center">Diff ('.substr($month->prev_month, 0, 3).')</td>';
		echo '</thead>';

		// Set current totals to Zero!
		$total = [
			"curr_month" => 0,
			"prev_month" => 0
		];

		foreach ($downloads as $download):
			$post = get_post($download->download_id);
			echo '<tr>';
			echo '<td><a href="'.get_edit_post_link($download->download_id).'">'.$post->post_title.'</a></td>';
			echo '<td style="text-align: center"><code>'.$download->curr_month.'</code></td>';
		//	echo '<td style="text-align: center"><code>'.$download->prev_month.'</code></td>';
			echo '<td style="text-align: center"><code>'.$this->getDifference($download->curr_month, $download->prev_month, true).'</code></td>';
			echo '</tr>';
			$total['curr_month'] = $total['curr_month'] + $download->curr_month;
			$total['prev_month'] = $total['prev_month'] + $download->prev_month;
		endforeach;
		echo '</table>';
		echo '<hr />';
		echo '<table>';
		echo '<thead style="font-weight: bolder">';
		echo '<td></td>';
		echo '<td>'.$month->curr_month.'</td>';
		echo '<td>'.$month->prev_month.'</td>';
		echo '<td>Diff</td>';
		echo '</thead>';
		echo '<tfoot style="font-style:italic;">';
		echo '<td><strong>Total Downloads</strong></td>';
		echo '<td style="text-align: center"><code>'.$total['curr_month'].'</code></td>';
		echo '<td style="text-align: center"><code>'.$total['prev_month'].'</code></td>';
		echo '<td style="text-align: center"><code>'.$this->getDifference($total['curr_month'], $total['prev_month'], true).'</code></td>';
		echo '</tfoot>';
		echo '</table>';

	}
}

Here's an example of it in action...