feat: enhance admin ui with responsive design and ux improvements

- add podcast sidebar navigation
- add podcast dashboard with latest episodes
- add pagination to podcast episodes
- add components helper to reuse ui components (button, data_table, etc.)
- enhance podcast and episode forms by splitting them into form sections
- add hint tooltips to podcast and episode forms
- transform radio inputs as buttons for better ux
- replace explicit field by parental_advisory
- replace author field by publisher
- add podcasts_categories table to set multiple categories
- use choices.js to enhance multiselect fields
- update Language files
- update js dependencies to latest versions

closes #31, #9

app/Models/CategoryModel.php

@@ -53,4 +53,72 @@ class CategoryModel extends Model
 
         return $options;
     }
+
+    /**
+     * Sets categories for a given podcast
+     *
+     * @param int $podcastId
+     * @param array $categories
+     *
+     * @return integer|false Number of rows inserted or FALSE on failure
+     */
+    public function setPodcastCategories($podcastId, $categories)
+    {
+        cache()->delete("podcasts{$podcastId}_categories");
+
+        // Remove already previously set categories to overwrite them
+        $this->db
+            ->table('podcasts_categories')
+            ->delete(['podcast_id' => $podcastId]);
+
+        if (!empty($categories)) {
+            // prepare data for `podcasts_categories` table
+            $data = array_reduce(
+                $categories,
+                function ($result, $categoryId) use ($podcastId) {
+                    $result[] = [
+                        'podcast_id' => $podcastId,
+                        'category_id' => $categoryId,
+                    ];
+
+                    return $result;
+                },
+                []
+            );
+
+            // Set podcast categories
+            return $this->db->table('podcasts_categories')->insertBatch($data);
+        }
+
+        // no row has been inserted after deletion
+        return 0;
+    }
+
+    /**
+     * Gets all the podcast categories
+     *
+     * @param int $podcastId
+     *
+     * @return \App\Entities\Category[]
+     */
+    public function getPodcastCategories($podcastId)
+    {
+        if (!($categories = cache("podcasts{$podcastId}_categories"))) {
+            $categories = $this->select('categories.*')
+                ->join(
+                    'podcasts_categories',
+                    'podcasts_categories.category_id = categories.id'
+                )
+                ->where('podcasts_categories.podcast_id', $podcastId)
+                ->findAll();
+
+            cache()->save(
+                "podcasts{$podcastId}_categories",
+                $categories,
+                DECADE
+            );
+        }
+
+        return $categories;
+    }
 }