add refund and event logic

app/Services/Events/EventStudentChargeService.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace App\Services\Events;
+
+use App\Models\EventCharges;
+use App\Models\Student;
+
+class EventStudentChargeService
+{
+    public function listStudentsWithCharges(int $parentId, string $schoolYear, string $semester): array
+    {
+        $students = Student::query()
+            ->where('parent_id', $parentId)
+            ->get()
+            ->map(fn ($row) => (array) $row)
+            ->all();
+
+        $chargedIds = EventCharges::query()
+            ->where('parent_id', $parentId)
+            ->where('school_year', $schoolYear)
+            ->where('semester', $semester)
+            ->distinct()
+            ->pluck('student_id')
+            ->map(fn ($id) => (int) $id)
+            ->all();
+
+        $chargedMap = array_flip($chargedIds);
+
+        $data = [];
+        foreach ($students as $student) {
+            $data[] = [
+                'id' => (int) ($student['id'] ?? 0),
+                'name' => trim(($student['firstname'] ?? '') . ' ' . ($student['lastname'] ?? '')),
+                'charged' => isset($chargedMap[(int) ($student['id'] ?? 0)]),
+            ];
+        }
+
+        return $data;
+    }
+}