Add feature flags API

[MAILPOET-2008]

lib/API/JSON/v1/FeatureFlags.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace MailPoet\API\JSON\v1;
+
+use MailPoet\API\JSON\Endpoint as APIEndpoint;
+use MailPoet\API\JSON\Error as APIError;
+use MailPoet\Config\AccessControl;
+use MailPoet\Features\FeatureFlagsController;
+use MailPoet\Features\FeaturesController;
+
+if (!defined('ABSPATH')) exit;
+
+class FeatureFlags extends APIEndpoint {
+
+  /** @var FeatureFlagsController */
+  private $feature_flags_controller;
+
+  public $permissions = [
+    'global' => AccessControl::PERMISSION_MANAGE_FEATURES,
+  ];
+
+  function __construct(FeatureFlagsController $feature_flags) {
+    $this->feature_flags_controller = $feature_flags;
+  }
+
+  function getAll() {
+    $feature_flags = $this->feature_flags_controller->getAll();
+    return $this->successResponse($feature_flags);
+  }
+
+  function set(array $flags) {
+    foreach ($flags as $name => $value) {
+      if (!isset(FeaturesController::$defaults[$name])) {
+        return $this->badRequest([
+          APIError::BAD_REQUEST => "Feature '$name' does not exist'",
+        ]);
+      }
+    }
+
+    foreach ($flags as $name => $value) {
+      $this->feature_flags_controller->set($name, (bool)$value);
+    }
+    return $this->successResponse([]);
+  }
+}