refacto: clean up a little

user/plugins/m3-p2/m3-p2.php

@@ -7,6 +7,7 @@ use Grav\Common\Plugin;
 use Grav\Common\Uri;
 use Symfony\Component\EventDispatcher\Event;
 
+
 /**
  * Features:
  * - /sync   Cheap git-sync (did not knew about it at the time)
@@ -222,6 +223,7 @@ class M3P2Plugin extends Plugin
         $uri = $this->grav['uri'];
 //        var_dump($uri); // best doc ftw
 
+        // GRAV's routing makes use hook 404 pages and do the URL match ourselves
         if ("lessons" != $uri->paths(0)) {
             return; // perhaps not
         }
@@ -247,8 +249,6 @@ class M3P2Plugin extends Plugin
             }
 
             foreach ($page_config->lessons as $lesson) {
-//                print("Checking lesson".print_r($lesson, true)."<br>\n");
-//                if ($lesson_slug == $lesson) {
                 if ($lesson_slug == $lesson['slug']) {
                     return true; // yay, this page is part of the lesson
                 }
@@ -265,18 +265,21 @@ class M3P2Plugin extends Plugin
             $hb = $b->header();
 
             $fdp = function ($lesson) use ($lesson_slug) {
-                return $lesson["slug"] == $lesson_slug;
+                return trim($lesson["slug"]) === $lesson_slug;
             };
 
-            // We're assuming the config exists (it should)
-            // NOOOOPE IT DOES NOT THERE IS A BUG TO HUNT HERE FIXME
-            $ma = @array_filter($ha->lessons, $fdp)[0];
-            $mb = @array_filter($hb->lessons, $fdp)[0];
+            $mar = array_filter($ha->lessons, $fdp);
+            assert($mar && !empty($mar), "No lesson found for $lesson_slug in page ".$a->url());
+            $ma = array_shift($mar);
+
+            $mbr = array_filter($hb->lessons, $fdp);
+            assert($mbr && !empty($mbr), "No lesson found for $lesson_slug in page ".$b->url());
+            $mb = array_shift($mbr);
 
-            if (isset($ma['order'])) {
+            if ($ma && isset($ma['order'])) {
                 $la = floor($ma['order']);
             }
-            if (isset($mb['order'])) {
+            if ($mb && isset($mb['order'])) {
                 $lb = floor($mb['order']);
             }