feat: add premium podcasts to manage subscriptions for premium episodes

closes #193

modules/Analytics/Models/AnalyticsPodcastBySubscriptionModel.php

@@ -0,0 +1,61 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright  2022 Ad Aures
+ * @license    https://www.gnu.org/licenses/agpl-3.0.en.html AGPL3
+ * @link       https://castopod.org/
+ */
+
+namespace Modules\Analytics\Models;
+
+use CodeIgniter\Model;
+use Modules\Analytics\Entities\AnalyticsPodcastsBySubscription;
+
+class AnalyticsPodcastBySubscriptionModel extends Model
+{
+    /**
+     * @var string
+     */
+    protected $table = 'analytics_podcasts_by_subscription';
+
+    /**
+     * @var string
+     */
+    protected $returnType = AnalyticsPodcastsBySubscription::class;
+
+    /**
+     * @var bool
+     */
+    protected $useSoftDeletes = false;
+
+    /**
+     * @var bool
+     */
+    protected $useTimestamps = false;
+
+    public function getNumberOfDownloadsLast3Months(int $podcastId, int $subscriptionId): int
+    {
+        $cacheName = "{$podcastId}_{$subscriptionId}_analytics_podcast_by_subscription";
+
+        if (
+            ! ($found = cache($cacheName))
+        ) {
+            $found = (int) ($this->builder()
+                ->selectSum('hits', 'total_hits')
+                ->where([
+                    'podcast_id' => $podcastId,
+                    'subscription_id' => $subscriptionId,
+                ])
+                ->where('`date` >= UTC_TIMESTAMP() - INTERVAL 3 month', null, false)
+                ->get()
+                ->getResultArray())[0]['total_hits'];
+
+            cache()
+                ->save($cacheName, $found, 600);
+        }
+
+        return $found;
+    }
+}