add services logic

app/Services/School/SemesterSelectionService.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace App\Services\School;
+
+use App\Models\Configuration;
+
+class SemesterSelectionService
+{
+    public function selectedTeacherSemester(): string
+    {
+        $selected = trim((string) (session()->get('teacher_scores_selected_semester') ?? ''));
+        if ($selected !== '') {
+            return $this->normalize($selected);
+        }
+
+        $fallback = trim((string) (session()->get('semester') ?? ''));
+        if ($fallback !== '') {
+            return $this->normalize($fallback);
+        }
+
+        $configSemester = trim((string) (Configuration::getConfig('semester') ?? ''));
+        if ($configSemester !== '') {
+            return $this->normalize($configSemester);
+        }
+
+        return 'Fall';
+    }
+
+    private function normalize(string $value): string
+    {
+        return ucfirst(strtolower($value));
+    }
+}