refactor(analytics): move all analytics files to a new Libraries/Analytics folder

- add page hit on podcast activity page
- update development docs

app/Libraries/Analytics/Controllers/EpisodeAnalyticsController.php

@@ -0,0 +1,83 @@
+<?php
+
+/**
+ * @copyright  2020 Podlibre
+ * @license    https://www.gnu.org/licenses/agpl-3.0.en.html AGPL3
+ * @link       https://castopod.org/
+ */
+
+namespace Analytics\Controllers;
+
+use CodeIgniter\Controller;
+
+class EpisodeAnalyticsController extends Controller
+{
+    /**
+     * An array of helpers to be loaded automatically upon
+     * class instantiation. These helpers will be available
+     * to all other controllers that extend Analytics.
+     *
+     * @var array
+     */
+    protected $helpers = ['analytics'];
+
+    /**
+     * @var \Analytics\Config\Analytics
+     */
+    protected $config;
+    /**
+     * Constructor.
+     */
+    public function initController(
+        \CodeIgniter\HTTP\RequestInterface $request,
+        \CodeIgniter\HTTP\ResponseInterface $response,
+        \Psr\Log\LoggerInterface $logger
+    ) {
+        // Do Not Edit This Line
+        parent::initController($request, $response, $logger);
+
+        //--------------------------------------------------------------------
+        // Preload any models, libraries, etc, here.
+        //--------------------------------------------------------------------
+        // E.g.:
+        // $this->session = \Config\Services::session();
+
+        set_user_session_deny_list_ip();
+        set_user_session_location();
+        set_user_session_player();
+
+        $this->config = config('Analytics');
+    }
+
+    // Add one hit to this episode:
+    public function hit($base64EpisodeData, ...$enclosureUri)
+    {
+        $session = \Config\Services::session();
+        $session->start();
+        $serviceName = '';
+        if (isset($_GET['_from'])) {
+            $serviceName = $_GET['_from'];
+        } elseif (!empty($session->get('embeddable_player_domain'))) {
+            $serviceName = $session->get('embeddable_player_domain');
+        } elseif ($session->get('referer') !== '- Direct -') {
+            $serviceName = parse_url($session->get('referer'), PHP_URL_HOST);
+        }
+
+        $episodeData = unpack(
+            'IpodcastId/IepisodeId/IbytesThreshold/IfileSize/Iduration/IpublicationDate',
+            base64_url_decode($base64EpisodeData),
+        );
+
+        podcast_hit(
+            $episodeData['podcastId'],
+            $episodeData['episodeId'],
+            $episodeData['bytesThreshold'],
+            $episodeData['fileSize'],
+            $episodeData['duration'],
+            $episodeData['publicationDate'],
+            $serviceName,
+        );
+
+        return redirect()->to($this->config->getEnclosureUrl($enclosureUri));
+    }
+}