refactor: Split FrontController into multiple classes

Closes #177

controllers/JsonController.php

@@ -0,0 +1,44 @@
+<?php
+/**
+ * JsonController class.
+ */
+
+namespace Alltube\Controller;
+
+use Alltube\Video;
+use Exception;
+use Slim\Http\Request;
+use Slim\Http\Response;
+
+/**
+ * Controller that returns JSON.
+ */
+class JsonController extends BaseController
+{
+    /**
+     * Return the JSON object generated by youtube-dl.
+     *
+     * @param Request  $request  PSR-7 request
+     * @param Response $response PSR-7 response
+     *
+     * @return Response HTTP response
+     */
+    public function json(Request $request, Response $response)
+    {
+        $url = $request->getQueryParam('url');
+
+        if (isset($url)) {
+            try {
+                $this->video = new Video($url, $this->getFormat($request), $this->getPassword($request));
+
+                return $response->withJson($this->video->getJson());
+            } catch (Exception $e) {
+                return $response->withJson(['error' => $e->getMessage()])
+                    ->withStatus(500);
+            }
+        } else {
+            return $response->withJson(['error' => 'You need to provide the url parameter'])
+                ->withStatus(400);
+        }
+    }
+}