feat(rss): add soundbites according to the podcastindex specs

Closes #83

app/Models/SoundbiteModel.php

@@ -0,0 +1,97 @@
+<?php
+
+/**
+ * Class SoundbiteModel
+ * Model for podcasts_soundbites table in database
+ *
+ * @copyright  2020 Podlibre
+ * @license    https://www.gnu.org/licenses/agpl-3.0.en.html AGPL3
+ * @link       https://castopod.org/
+ */
+
+namespace App\Models;
+
+use CodeIgniter\Model;
+
+class SoundbiteModel extends Model
+{
+    protected $table = 'soundbites';
+    protected $primaryKey = 'id';
+
+    protected $allowedFields = [
+        'podcast_id',
+        'episode_id',
+        'label',
+        'start_time',
+        'duration',
+        'created_by',
+        'updated_by',
+    ];
+
+    protected $returnType = \App\Entities\Soundbite::class;
+    protected $useSoftDeletes = false;
+
+    protected $useTimestamps = true;
+
+    protected $afterInsert = ['clearCache'];
+    protected $afterUpdate = ['clearCache'];
+    protected $beforeDelete = ['clearCache'];
+
+    public function deleteSoundbite($podcastId, $episodeId, $soundbiteId)
+    {
+        return $this->delete([
+            'podcast_id' => $podcastId,
+            'episode_id' => $episodeId,
+            'id' => $soundbiteId,
+        ]);
+    }
+
+    /**
+     * Gets all soundbites for an episode
+     *
+     * @param int $podcastId
+     * @param int $episodeId
+     *
+     * @return \App\Entities\Soundbite[]
+     */
+    public function getEpisodeSoundbites(int $podcastId, int $episodeId): array
+    {
+        if (!($found = cache("episode{$episodeId}_soundbites"))) {
+            $found = $this->where([
+                'episode_id' => $episodeId,
+                'podcast_id' => $podcastId,
+            ])
+                ->orderBy('start_time')
+                ->findAll();
+            cache()->save("episode{$episodeId}_soundbites", $found, DECADE);
+        }
+        return $found;
+    }
+
+    public function clearCache(array $data)
+    {
+        $episode = (new EpisodeModel())->find(
+            isset($data['data'])
+                ? $data['data']['episode_id']
+                : $data['id']['episode_id']
+        );
+
+        cache()->delete("episode{$episode->id}_soundbites");
+
+        // delete cache for rss feed
+        cache()->delete("podcast{$episode->id}_feed");
+        foreach (\Opawg\UserAgentsPhp\UserAgentsRSS::$db as $service) {
+            cache()->delete(
+                "podcast{$episode->podcast->id}_feed_{$service['slug']}"
+            );
+        }
+
+        $supportedLocales = config('App')->supportedLocales;
+        foreach ($supportedLocales as $locale) {
+            cache()->delete(
+                "page_podcast{$episode->podcast->id}_episode{$episode->id}_{$locale}"
+            );
+        }
+        return $data;
+    }
+}