From 57e32fed732a413d4445cc130e55304f3cd8d890 Mon Sep 17 00:00:00 2001
From: Yoga Pangestu <ypangestu976@gmail.com>
Date: Sun, 5 Apr 2026 23:52:55 +0700
Subject: [PATCH] refactor: implement null-safe operator for safer property
 access across various models and pages

---
 app/Filament/Pages/Auth/Login.php             |  6 ++---
 .../Information/CourseSchedule/Index.php      | 14 +++++-----
 .../Actions/EditStudyGroupAction.php          |  4 +--
 .../Pages/Learning/StudyGroup/Index.php       | 14 +++++-----
 app/Filament/Pages/Profile.php                |  8 +++---
 app/Filament/Pages/System/ManageSettings.php  |  2 +-
 .../Assignments/Actions/SubmitAction.php      |  2 +-
 .../Assignments/Pages/EditAssignment.php      |  6 ++---
 .../Assignments/Pages/ListAssignments.php     | 16 ++++++------
 .../Pages/SubmissionDetailPage.php            | 26 +++++++++----------
 .../Pages/SubmitAssignmentPage.php            | 22 ++++++++--------
 .../Attendances/Pages/ManageAttendances.php   | 18 ++++++-------
 .../Actions/CopyAttendanceLinkAction.php      |  2 +-
 .../Actions/GenerateSessionsAction.php        |  2 +-
 .../Actions/ShareAttendanceAction.php         |  4 +--
 .../Actions/ViewAssignmentsAction.php         |  4 +--
 .../Actions/ViewAttendanceAction.php          |  2 +-
 .../Pages/ListCourseSessions.php              | 10 +++----
 .../Pages/ManageClassSessions.php             | 12 ++++-----
 .../Materials/Tables/MaterialTable.php        |  2 +-
 .../Controllers/ShareAttendanceController.php |  2 +-
 app/Http/Middleware/DynamicFilamentTheme.php  | 10 +++----
 app/Models/Assignment.php                     |  2 +-
 app/Models/AssignmentPin.php                  |  2 +-
 app/Models/AssignmentSubmission.php           |  2 +-
 app/Models/AssignmentTarget.php               |  2 +-
 app/Models/Attendance.php                     |  2 +-
 app/Models/Changelog.php                      |  4 +--
 app/Models/ClassSession.php                   |  2 +-
 app/Models/Course.php                         |  2 +-
 app/Models/CourseSchedule.php                 |  2 +-
 app/Models/Material.php                       |  2 +-
 app/Models/Student.php                        |  2 +-
 app/Models/StudyGroup.php                     |  2 +-
 app/Models/StudyGroupMember.php               |  2 +-
 app/Models/User.php                           |  2 +-
 app/Models/UserSetting.php                    |  2 +-
 37 files changed, 110 insertions(+), 110 deletions(-)

diff --git a/app/Filament/Pages/Auth/Login.php b/app/Filament/Pages/Auth/Login.php
index 135dd92..41ec354 100644
--- a/app/Filament/Pages/Auth/Login.php
+++ b/app/Filament/Pages/Auth/Login.php
@@ -75,7 +75,7 @@ public function authenticate(): ?LoginResponse
             return null;
         }
 
-        $data = $this->form->getState();
+        $data = $this->form?->getState();
 
         $authGuard = Filament::auth();
 
@@ -105,7 +105,7 @@ public function authenticate(): ?LoginResponse
             filled($this->userUndertakingMultiFactorAuthentication) &&
             (decrypt($this->userUndertakingMultiFactorAuthentication) === $user->getAuthIdentifier())
         ) {
-            $this->multiFactorChallengeForm->validate();
+            $this->multiFactorChallengeForm?->validate();
         } else {
             foreach (Filament::getMultiFactorAuthenticationProviders() as $multiFactorAuthenticationProvider) {
                 if (! $multiFactorAuthenticationProvider->isEnabled($user)) {
@@ -122,7 +122,7 @@ public function authenticate(): ?LoginResponse
             }
 
             if (filled($this->userUndertakingMultiFactorAuthentication)) {
-                $this->multiFactorChallengeForm->fill();
+                $this->multiFactorChallengeForm?->fill();
 
                 return null;
             }
diff --git a/app/Filament/Pages/Information/CourseSchedule/Index.php b/app/Filament/Pages/Information/CourseSchedule/Index.php
index 0c9cd13..febe1c6 100644
--- a/app/Filament/Pages/Information/CourseSchedule/Index.php
+++ b/app/Filament/Pages/Information/CourseSchedule/Index.php
@@ -71,7 +71,7 @@ public static function getPagePermission(): string
 
     public function mount(): void
     {
-        $this->form->fill();
+        $this->form?->fill();
     }
 
     public function form(Schema $schema): Schema
@@ -132,15 +132,15 @@ public function getSchedules(): Collection
             ->map(function ($daySchedules) {
                 return $daySchedules->map(fn ($schedule) => (object) [
                     'id' => $schedule->id,
-                    'course_code' => $schedule->course->code ?? 'MATKUL',
-                    'course_name' => $schedule->course->name ?? 'Mata Kuliah Tidak Diketahui',
-                    'lecturer' => $schedule->course->lecturer ?? 'Dosen Belum Ditentukan',
-                    'semester' => $schedule->course->semester,
-                    'credit' => $schedule->course->credit ?? '-',
+                    'course_code' => $schedule->course?->code ?? 'MATKUL',
+                    'course_name' => $schedule->course?->name ?? 'Mata Kuliah Tidak Diketahui',
+                    'lecturer' => $schedule->course?->lecturer ?? 'Dosen Belum Ditentukan',
+                    'semester' => $schedule->course?->semester,
+                    'credit' => $schedule->course?->credit ?? '-',
                     'room' => $schedule->room,
                     'mode_label' => $schedule->mode?->getLabel(),
                     'mode_color' => $schedule->mode?->getColor(),
-                    'time_range' => $schedule->start_time->format('H:i').' – '.$schedule->end_time->format('H:i'),
+                    'time_range' => $schedule->start_time?->format('H:i').' – '.$schedule->end_time?->format('H:i'),
                 ]);
             });
     }
diff --git a/app/Filament/Pages/Learning/StudyGroup/Actions/EditStudyGroupAction.php b/app/Filament/Pages/Learning/StudyGroup/Actions/EditStudyGroupAction.php
index d11dec6..d390008 100644
--- a/app/Filament/Pages/Learning/StudyGroup/Actions/EditStudyGroupAction.php
+++ b/app/Filament/Pages/Learning/StudyGroup/Actions/EditStudyGroupAction.php
@@ -33,8 +33,8 @@ protected function setUp(): void
                 return [
                     'name' => $record->name,
                     'leader_id' => $record->leader_id,
-                    'course_id' => $record->courses->pluck('id')->toArray(),
-                    'students' => $record->students->pluck('id')->toArray(),
+                    'course_id' => $record->courses?->pluck('id')->toArray(),
+                    'students' => $record->students?->pluck('id')->toArray(),
                 ];
             })
             ->after(function (StudyGroup $record, array $data) {
diff --git a/app/Filament/Pages/Learning/StudyGroup/Index.php b/app/Filament/Pages/Learning/StudyGroup/Index.php
index 08cd7e2..7012316 100644
--- a/app/Filament/Pages/Learning/StudyGroup/Index.php
+++ b/app/Filament/Pages/Learning/StudyGroup/Index.php
@@ -81,7 +81,7 @@ public function emptyDescription(): string
 
     public function mount(): void
     {
-        $this->form->fill([
+        $this->form?->fill([
             'course_id' => $this->course_id,
         ]);
     }
@@ -141,20 +141,20 @@ public function studyGroups(): Collection
         $studentId = auth()->user()?->student?->id;
 
         return $query->orderBy('name', 'asc')->get()->map(function ($record) use ($studentId) {
-            $isMyGroup = ($studentId && ($record->leader_id === $studentId || $record->students->contains($studentId)));
+            $isMyGroup = ($studentId && ($record->leader_id === $studentId || $record->students?->contains($studentId)));
 
             return (object) [
                 'id' => $record->id,
                 'name' => $record->name,
                 'is_my_group' => $isMyGroup,
                 'leader_avatar' => $record->leader?->user?->facehash_avatar_url,
-                'leader_name' => $record->leader->full_name ?? 'Belum Ditentukan',
+                'leader_name' => $record->leader?->full_name ?? 'Belum Ditentukan',
                 'is_leader' => $studentId && $record->leader_id === $studentId,
-                'courses' => $record->courses->map(fn ($c) => (object) [
+                'courses' => $record->courses?->map(fn ($c) => (object) [
                     'name' => $c->name,
                 ]),
-                'students_count' => $record->students->count(),
-                'students' => $record->students->map(fn ($s) => (object) [
+                'students_count' => $record->students?->count() ?? 0,
+                'students' => $record->students?->map(fn ($s) => (object) [
                     'id' => $s->id,
                     'full_name' => $s->full_name,
                     'is_me' => $studentId && $s->id === $studentId,
@@ -177,7 +177,7 @@ public function isMyGroup(StudyGroup $record): bool
             return false;
         }
 
-        return $record->leader_id === $studentId || $record->students->contains($studentId);
+        return $record->leader_id === $studentId || $record->students?->contains($studentId);
     }
 
     public function studyGroupFormSchema(): array
diff --git a/app/Filament/Pages/Profile.php b/app/Filament/Pages/Profile.php
index 0c3b524..ed24a0a 100644
--- a/app/Filament/Pages/Profile.php
+++ b/app/Filament/Pages/Profile.php
@@ -243,7 +243,7 @@ public function save(): void
 
             $this->callHook('beforeValidate');
 
-            $data = $this->form->getState();
+            $data = $this->form?->getState();
 
             $this->callHook('afterValidate');
 
@@ -311,13 +311,13 @@ protected function handleRecordUpdate(Model $record, array $data): Model
 
         /** @var User $record */
         if ($studentData && $record->student()->exists()) {
-            $record->student->update($studentData);
+            $record->student?->update($studentData);
         } elseif ($studentData) {
             $record->student()->create($studentData);
         }
 
         if ($settingsData && $record->settings()->exists()) {
-            $record->settings->update($settingsData);
+            $record->settings?->update($settingsData);
         } elseif ($settingsData) {
             $record->settings()->create($settingsData);
         }
@@ -330,7 +330,7 @@ protected function afterSave(): void
         SystemNotification::send('profile_updated')
             ->send();
 
-        if (filled($this->form->getState()['password'] ?? null)) {
+        if (filled($this->form?->getState()['password'] ?? null)) {
             filament()->auth()->logout();
             session()->invalidate();
             session()->regenerateToken();
diff --git a/app/Filament/Pages/System/ManageSettings.php b/app/Filament/Pages/System/ManageSettings.php
index 052ca7e..68b78e4 100644
--- a/app/Filament/Pages/System/ManageSettings.php
+++ b/app/Filament/Pages/System/ManageSettings.php
@@ -92,7 +92,7 @@ protected function afterSave(): void
             $student = Student::find($kosmaId);
 
             if ($student?->user) {
-                $student->user->assignRole(RoleEnum::Kosma);
+                $student->user?->assignRole(RoleEnum::Kosma);
             }
         }
     }
diff --git a/app/Filament/Resources/Learning/Assignments/Actions/SubmitAction.php b/app/Filament/Resources/Learning/Assignments/Actions/SubmitAction.php
index e28d05d..3d9cd27 100644
--- a/app/Filament/Resources/Learning/Assignments/Actions/SubmitAction.php
+++ b/app/Filament/Resources/Learning/Assignments/Actions/SubmitAction.php
@@ -30,7 +30,7 @@ protected function setUp(): void
 
                 if ($record->type === AssignmentType::Group) {
                     return $record->studyGroups()
-                        ->where('leader_id', auth()->user()->student->id)
+                        ->where('leader_id', auth()->user()?->student?->id)
                         ->exists();
                 }
 
diff --git a/app/Filament/Resources/Learning/Assignments/Pages/EditAssignment.php b/app/Filament/Resources/Learning/Assignments/Pages/EditAssignment.php
index 6f14598..c9fbc6b 100644
--- a/app/Filament/Resources/Learning/Assignments/Pages/EditAssignment.php
+++ b/app/Filament/Resources/Learning/Assignments/Pages/EditAssignment.php
@@ -41,17 +41,17 @@ protected function getSavedNotification(): ?Notification
 
     protected function mutateFormDataBeforeFill(array $data): array
     {
-        $data['student_ids'] = $this->record->assignmentTargets()
+        $data['student_ids'] = $this->record?->assignmentTargets()
             ->whereNotNull('student_id')
             ->pluck('student_id')
             ->toArray();
 
-        $data['study_group_ids'] = $this->record->assignmentTargets()
+        $data['study_group_ids'] = $this->record?->assignmentTargets()
             ->whereNotNull('study_group_id')
             ->pluck('study_group_id')
             ->toArray();
 
-        $media = $this->record->getMedia('assignments')->last();
+        $media = $this->record?->getMedia('assignments')->last();
         $relativePath = $media ? $media->getPathRelativeToRoot() : null;
 
         $data['pdf'] = $relativePath ? [$relativePath] : [];
diff --git a/app/Filament/Resources/Learning/Assignments/Pages/ListAssignments.php b/app/Filament/Resources/Learning/Assignments/Pages/ListAssignments.php
index e4da2dc..76d4474 100644
--- a/app/Filament/Resources/Learning/Assignments/Pages/ListAssignments.php
+++ b/app/Filament/Resources/Learning/Assignments/Pages/ListAssignments.php
@@ -46,7 +46,7 @@ public static function getPagePermission(): string
 
     public function mount(): void
     {
-        $this->form->fill([
+        $this->form?->fill([
             'search' => $this->search,
             'course_id' => $this->course_id,
         ]);
@@ -221,7 +221,7 @@ public function assignments(): Collection
 
     private function getAssignmentPriority($assignment): int
     {
-        $isSubmitted = $assignment->assignmentSubmissions->isNotEmpty();
+        $isSubmitted = $assignment->assignmentSubmissions?->isNotEmpty();
         $isOverdue = now()->isAfter($assignment->due_date);
 
         if (! $isOverdue) {
@@ -244,14 +244,14 @@ public function assignmentCards()
         $pinnedIds = $this->pinnedIds;
 
         return $this->assignments()->map(function ($assignment) use ($studentProfile, $pinnedIds) {
-            $submission = $assignment->assignmentSubmissions->first();
+            $submission = $assignment->assignmentSubmissions?->first();
             $isSubmitted = $submission !== null;
             $isGroup = $assignment->type === AssignmentType::Group;
 
             $isLeader = false;
             if ($isGroup) {
-                $userGroup = $assignment->studyGroups->first(function ($g) use ($studentProfile) {
-                    return $g->leader_id === $studentProfile->id || $g->students->contains($studentProfile->id);
+                $userGroup = $assignment->studyGroups?->first(function ($g) use ($studentProfile) {
+                    return $g->leader_id === $studentProfile->id || $g->students?->contains($studentProfile->id);
                 });
                 $isLeader = $userGroup && $userGroup->leader_id === $studentProfile->id;
             }
@@ -263,7 +263,7 @@ public function assignmentCards()
             $canSubmitActual = $canSubmit && $canSubmitByRole;
 
             $isUrgent = ! $isSubmitted && $canSubmitActual && now()->diffInHours($assignment->due_date) <= 48;
-            $isNew = $assignment->created_at->diffInDays(now()) <= 3;
+            $isNew = $assignment->created_at?->diffInDays(now()) <= 3;
             $isPinned = in_array($assignment->id, $pinnedIds);
 
             $statusLabel = SystemNotification::getByKey('labels.assignment_status.not_submitted');
@@ -288,8 +288,8 @@ public function assignmentCards()
                 'id' => $assignment->id,
                 'title' => $assignment->title,
                 'course_name' => $assignment->course?->name ?? '-',
-                'due_date_formatted' => $assignment->due_date->translatedFormat('l, d F Y H:i'),
-                'submitted_at_formatted' => ($isSubmitted && $submission->submitted_at) ? $submission->submitted_at->translatedFormat('l, d F Y H:i') : null,
+                'due_date_formatted' => $assignment->due_date?->translatedFormat('l, d F Y H:i'),
+                'submitted_at_formatted' => ($isSubmitted && $submission->submitted_at) ? $submission->submitted_at?->translatedFormat('l, d F Y H:i') : null,
                 'is_submitted' => $isSubmitted,
                 'is_group' => $isGroup,
                 'is_leader' => $isLeader,
diff --git a/app/Filament/Resources/Learning/Assignments/Pages/SubmissionDetailPage.php b/app/Filament/Resources/Learning/Assignments/Pages/SubmissionDetailPage.php
index 1f9db13..11403e0 100644
--- a/app/Filament/Resources/Learning/Assignments/Pages/SubmissionDetailPage.php
+++ b/app/Filament/Resources/Learning/Assignments/Pages/SubmissionDetailPage.php
@@ -30,7 +30,7 @@ public function statCards(): array
     {
         return [
             [
-                'label' => $this->record->type === AssignmentType::Individual ? 'Total Mahasiswa' : 'Total Kelompok',
+                'label' => $this->record?->type === AssignmentType::Individual ? 'Total Mahasiswa' : 'Total Kelompok',
                 'value' => $this->totalCount,
                 'icon' => 'heroicon-o-user-group',
                 'color_classes' => 'bg-gray-100 dark:bg-gray-700 text-gray-600 dark:text-gray-900',
@@ -65,11 +65,11 @@ public function progressColorClass(): string
     #[Computed]
     public function submissionSummary(): Collection
     {
-        $assignment = $this->record->load(['students', 'studyGroups', 'course']);
+        $assignment = $this->record?->load(['students', 'studyGroups', 'course']);
         $isIndividual = $assignment->type === AssignmentType::Individual;
 
         if ($isIndividual) {
-            $targets = $assignment->students->keyBy('id');
+            $targets = $assignment->students?->keyBy('id') ?? collect();
 
             $submissions = AssignmentSubmission::with('student')
                 ->where('assignment_id', $assignment->id)
@@ -87,7 +87,7 @@ public function submissionSummary(): Collection
                     'secondary_info' => $student->student_number,
                     'submission_id' => $submission?->id,
                     'submitted' => $isSubmitted,
-                    'submitted_at_formatted' => $isSubmitted ? $submission->submitted_at?->translatedFormat('l, d F Y H:i') : '-',
+                    'submitted_at_formatted' => $isSubmitted ? $submission?->submitted_at?->translatedFormat('l, d F Y H:i') : '-',
                     'has_file' => $isSubmitted && $submission->hasMedia('submission'),
                     'status_classes' => Arr::toCssClasses([
                         'inline-flex items-center gap-1 rounded-full px-2.5 py-0.5 text-xs font-medium',
@@ -98,7 +98,7 @@ public function submissionSummary(): Collection
                 ];
             })->sortBy('secondary_info')->values();
         } else {
-            $targets = $assignment->studyGroups->keyBy('id');
+            $targets = $assignment->studyGroups?->keyBy('id') ?? collect();
 
             $submissions = AssignmentSubmission::with(['studyGroup', 'student'])
                 ->where('assignment_id', $assignment->id)
@@ -113,7 +113,7 @@ public function submissionSummary(): Collection
                     'id' => $group->id,
                     'is_individual' => false,
                     'primary_name' => $group->name,
-                    'secondary_info' => $isSubmitted ? $submission->student->full_name : '-',
+                    'secondary_info' => $isSubmitted ? $submission?->student?->full_name : '-',
                     'submission_id' => $submission?->id,
                     'submitted' => $isSubmitted,
                     'submitted_at_formatted' => $isSubmitted ? $submission->submitted_at?->translatedFormat('l, d F Y H:i') : '-',
@@ -132,13 +132,13 @@ public function submissionSummary(): Collection
     #[Computed]
     public function totalCount(): int
     {
-        return $this->submissionSummary->count();
+        return $this->submissionSummary?->count();
     }
 
     #[Computed]
     public function doneCount(): int
     {
-        return $this->submissionSummary->where('submitted', true)->count();
+        return $this->submissionSummary?->where('submitted', true)->count();
     }
 
     #[Computed]
@@ -152,17 +152,17 @@ public function percentage(): int
     #[Computed]
     public function isOverdue(): bool
     {
-        return now()->isAfter($this->record->due_date);
+        return now()->isAfter($this->record?->due_date);
     }
 
     #[Computed]
     public function assignmentSummary(): array
     {
         return [
-            'title' => $this->record->title,
-            'course' => $this->record->course?->name ?? '-',
-            'due_date' => $this->record->due_date?->translatedFormat('l, d F Y H:i'),
-            'type' => $this->record->type->value,
+            'title' => $this->record?->title,
+            'course' => $this->record?->course?->name ?? '-',
+            'due_date' => $this->record?->due_date?->translatedFormat('l, d F Y H:i'),
+            'type' => $this->record?->type->value,
             'is_overdue' => $this->isOverdue,
         ];
     }
diff --git a/app/Filament/Resources/Learning/Assignments/Pages/SubmitAssignmentPage.php b/app/Filament/Resources/Learning/Assignments/Pages/SubmitAssignmentPage.php
index 2289bb5..6fe3b4c 100644
--- a/app/Filament/Resources/Learning/Assignments/Pages/SubmitAssignmentPage.php
+++ b/app/Filament/Resources/Learning/Assignments/Pages/SubmitAssignmentPage.php
@@ -42,7 +42,7 @@ public function mount(Assignment $record): void
     {
         $this->record = $record;
 
-        $this->form->fill([
+        $this->form?->fill([
             'is_resubmit' => $this->isResubmit,
         ]);
     }
@@ -59,7 +59,7 @@ public function statusCards(): array
         return [
             [
                 'label' => 'Batas Waktu',
-                'value' => $this->record->due_date?->translatedFormat('l, d F Y H:i'),
+                'value' => $this->record?->due_date?->translatedFormat('l, d F Y H:i'),
                 'icon' => 'heroicon-o-clock',
                 'is_danger' => $this->isOverdue,
                 'badge' => $this->isOverdue ? '(Terlewat)' : null,
@@ -98,7 +98,7 @@ public function currentGroup(): ?StudyGroup
     {
         $student = $this->student;
 
-        return $this->record->studyGroups()
+        return $this->record?->studyGroups()
             ->where(fn ($q) => $q->where('leader_id', $student->id)->orWhereHas('students', fn ($sq) => $sq->whereKey($student->id)))
             ->first();
     }
@@ -108,18 +108,18 @@ public function existingSubmission(): ?AssignmentSubmission
     {
         $student = $this->student;
 
-        if ($this->record->type === AssignmentType::Group) {
+        if ($this->record?->type === AssignmentType::Group) {
             $group = $this->currentGroup;
             if (! $group) {
                 return null;
             }
 
-            return AssignmentSubmission::where('assignment_id', $this->record->id)
+            return AssignmentSubmission::where('assignment_id', $this->record?->id)
                 ->where('study_group_id', $group->id)
                 ->first();
         }
 
-        return AssignmentSubmission::where('assignment_id', $this->record->id)
+        return AssignmentSubmission::where('assignment_id', $this->record?->id)
             ->where('student_id', $student->id)
             ->first();
     }
@@ -133,19 +133,19 @@ public function isResubmit(): bool
     #[Computed]
     public function isOverdue(): bool
     {
-        return now()->isAfter($this->record->due_date);
+        return now()->isAfter($this->record?->due_date);
     }
 
     #[Computed]
     public function canSubmit(): bool
     {
-        if ($this->record->type === AssignmentType::Individual) {
+        if ($this->record?->type === AssignmentType::Individual) {
             return true;
         }
 
         $group = $this->currentGroup;
 
-        return $group && $group->leader_id === $this->student->id;
+        return $group && $group->leader_id === $this->student?->id;
     }
 
     #[Computed]
@@ -251,7 +251,7 @@ public function submit(): void
         }
 
         $existingSubmission = $this->existingSubmission;
-        $state = $this->form->getState();
+        $state = $this->form?->getState();
 
         if (! $existingSubmission && empty($state['file'])) {
             SystemNotification::send('submission_file_missing', type: 'warning')
@@ -300,7 +300,7 @@ public function submit(): void
                 ->send();
         }
 
-        $this->form->fill([
+        $this->form?->fill([
             'is_resubmit' => $this->isResubmit,
         ]);
         unset($this->existingSubmission, $this->isResubmit);
diff --git a/app/Filament/Resources/Learning/Attendances/Pages/ManageAttendances.php b/app/Filament/Resources/Learning/Attendances/Pages/ManageAttendances.php
index 872a342..1b0fa7e 100644
--- a/app/Filament/Resources/Learning/Attendances/Pages/ManageAttendances.php
+++ b/app/Filament/Resources/Learning/Attendances/Pages/ManageAttendances.php
@@ -95,7 +95,7 @@ public function scheduleCards()
     {
         return $this->getSchedules()
             ->map(function ($schedule) {
-                $attendance = $schedule->attendances->first();
+                $attendance = $schedule->attendances?->first();
                 $isAttended = $attendance !== null;
 
                 $now = now();
@@ -118,15 +118,15 @@ public function scheduleCards()
 
                 return (object) [
                     'id' => $schedule->id,
-                    'course_name' => $schedule->course->name,
-                    'lecturer_name' => $schedule->course->lecturer ?? 'Belum Ditentukan',
-                    'time_range' => $schedule->start_time->format('H:i').' - '.$schedule->end_time->format('H:i'),
+                    'course_name' => $schedule->course?->name,
+                    'lecturer_name' => $schedule->course?->lecturer ?? 'Belum Ditentukan',
+                    'time_range' => $schedule->start_time?->format('H:i').' - '.$schedule->end_time?->format('H:i'),
                     'is_attended' => $isAttended,
                     'can_attend' => $canAttend && ! $isAttended,
                     'status_label' => $statusLabel,
                     'status_color' => $statusColor,
                     'status_icon' => $statusIcon,
-                    'attended_at' => $isAttended ? $attendance->attended_at->format('H:i') : null,
+                    'attended_at' => $isAttended ? $attendance?->attended_at?->format('H:i') : null,
                     // Pre-calculated classes
                     'card_classes' => Arr::toCssClasses([
                         'fi-card flex flex-col justify-between rounded-xl border transition duration-200 group relative',
@@ -204,14 +204,14 @@ public function attend(int $sessionId): void
 
         // Find schedule for compatibility
         $schedule = CourseSchedule::where('course_id', $session->course_id)
-            ->where('day_of_week', $session->date->dayOfWeekIso)
+            ->where('day_of_week', $session->date?->dayOfWeekIso)
             ->first();
 
         Attendance::create([
             'student_id' => $student->id,
             'class_session_id' => $sessionId,
             'course_schedule_id' => $schedule?->id,
-            'date' => $session->date->toDateString(),
+            'date' => $session->date?->toDateString(),
             'attended_at' => now(),
         ]);
 
@@ -232,7 +232,7 @@ public function table(Table $table): Table
                     ->label('Tanggal')
                     ->date('l, d F Y')
                     ->sortable()
-                    ->description(fn (Attendance $record): string => $record->attended_at->format('H:i').' ')
+                    ->description(fn (Attendance $record): string => $record->attended_at?->format('H:i').' ')
                     ->color('gray'),
 
                 TextColumn::make('courseSchedule.course.name')
@@ -240,7 +240,7 @@ public function table(Table $table): Table
                     ->searchable()
                     ->sortable()
                     ->wrap()
-                    ->description(fn (Attendance $record): string => $record->courseSchedule->course->lecturer ?? 'Belum Ditentukan'),
+                    ->description(fn (Attendance $record): string => $record->courseSchedule?->course?->lecturer ?? 'Belum Ditentukan'),
             ])
             ->defaultSort('date', 'desc')
             ->filters([
diff --git a/app/Filament/Resources/Learning/ClassSessions/Actions/CopyAttendanceLinkAction.php b/app/Filament/Resources/Learning/ClassSessions/Actions/CopyAttendanceLinkAction.php
index 2a451e1..fb8d42f 100644
--- a/app/Filament/Resources/Learning/ClassSessions/Actions/CopyAttendanceLinkAction.php
+++ b/app/Filament/Resources/Learning/ClassSessions/Actions/CopyAttendanceLinkAction.php
@@ -24,7 +24,7 @@ protected function setUp(): void
             ->action(function (array $arguments, $livewire) {
                 $course = $livewire->course;
                 $session = ClassSession::find($arguments['session'] ?? null);
-                $date = $session ? $session->date->toDateString() : null;
+                $date = $session ? $session->date?->toDateString() : null;
 
                 $url = URL::temporarySignedRoute('share.attendance', now()->addHour(), ['course' => $course->id, 'date' => $date]);
 
diff --git a/app/Filament/Resources/Learning/ClassSessions/Actions/GenerateSessionsAction.php b/app/Filament/Resources/Learning/ClassSessions/Actions/GenerateSessionsAction.php
index 3506a66..bccef6e 100644
--- a/app/Filament/Resources/Learning/ClassSessions/Actions/GenerateSessionsAction.php
+++ b/app/Filament/Resources/Learning/ClassSessions/Actions/GenerateSessionsAction.php
@@ -28,7 +28,7 @@ protected function setUp(): void
             ->modalHeading('Generate Sesi Pembelajaran')
             ->modalDescription('Sistem akan men-generate atau memperbarui sesi secara otomatis berdasarkan jadwal mata kuliah ini.')
             ->schema(function ($livewire) {
-                $lastSession = $livewire->course->classSessions()->latest('session_number')->first();
+                $lastSession = $livewire->course?->classSessions()->latest('session_number')->first();
                 $lastNumber = $lastSession?->session_number ?? 0;
                 $nextNumber = $lastNumber + 1;
                 $lastDate = $lastSession?->date ? Carbon::parse($lastSession->date) : now();
diff --git a/app/Filament/Resources/Learning/ClassSessions/Actions/ShareAttendanceAction.php b/app/Filament/Resources/Learning/ClassSessions/Actions/ShareAttendanceAction.php
index 5073598..314939b 100644
--- a/app/Filament/Resources/Learning/ClassSessions/Actions/ShareAttendanceAction.php
+++ b/app/Filament/Resources/Learning/ClassSessions/Actions/ShareAttendanceAction.php
@@ -34,11 +34,11 @@ protected function setUp(): void
             ->action(function (array $arguments, $livewire) {
                 $course = $livewire->course;
                 $session = ClassSession::find($arguments['session'] ?? null);
-                $date = $session ? $session->date->toDateString() : null;
+                $date = $session ? $session->date?->toDateString() : null;
 
                 $url = URL::temporarySignedRoute('share.attendance', now()->addHour(), ['course' => $course->id, 'date' => $date]);
 
-                $text = "*Info Kelas {$course->name}*\nSesi ke-".($session->session_number ?? '-').' ('.($session->date->translatedFormat('d M Y') ?? '').")\n\nSilakan cek detail/rekap kehadiran melalui tautan ini:\n\n{$url}";
+                $text = "*Info Kelas {$course->name}*\nSesi ke-".($session->session_number ?? '-').' ('.($session->date?->translatedFormat('d M Y') ?? '').")\n\nSilakan cek detail/rekap kehadiran melalui tautan ini:\n\n{$url}";
 
                 $escapedText = json_encode($text);
 
diff --git a/app/Filament/Resources/Learning/ClassSessions/Actions/ViewAssignmentsAction.php b/app/Filament/Resources/Learning/ClassSessions/Actions/ViewAssignmentsAction.php
index 302622c..1010353 100644
--- a/app/Filament/Resources/Learning/ClassSessions/Actions/ViewAssignmentsAction.php
+++ b/app/Filament/Resources/Learning/ClassSessions/Actions/ViewAssignmentsAction.php
@@ -37,7 +37,7 @@ protected function setUp(): void
                     return ['assignment' => null];
                 }
 
-                $assignment = $session->assignments->first();
+                $assignment = $session->assignments?->first();
 
                 if (! $assignment) {
                     return ['assignment' => null];
@@ -48,7 +48,7 @@ protected function setUp(): void
                     ->orderBy('full_name')
                     ->get();
 
-                $submissionMap = $assignment->assignmentSubmissions->keyBy('student_id');
+                $submissionMap = $assignment->assignmentSubmissions?->keyBy('student_id');
 
                 $data = (object) [
                     'id' => $assignment->id,
diff --git a/app/Filament/Resources/Learning/ClassSessions/Actions/ViewAttendanceAction.php b/app/Filament/Resources/Learning/ClassSessions/Actions/ViewAttendanceAction.php
index 6a33013..da593d5 100644
--- a/app/Filament/Resources/Learning/ClassSessions/Actions/ViewAttendanceAction.php
+++ b/app/Filament/Resources/Learning/ClassSessions/Actions/ViewAttendanceAction.php
@@ -40,7 +40,7 @@ protected function setUp(): void
                     ->orderBy('full_name')
                     ->get();
 
-                $attendanceMap = $session->attendances->keyBy('student_id');
+                $attendanceMap = $session->attendances?->keyBy('student_id');
 
                 $students = $activeStudents->map(fn ($student) => (object) [
                     'student' => $student,
diff --git a/app/Filament/Resources/Learning/ClassSessions/Pages/ListCourseSessions.php b/app/Filament/Resources/Learning/ClassSessions/Pages/ListCourseSessions.php
index 3fcc534..4ad186d 100644
--- a/app/Filament/Resources/Learning/ClassSessions/Pages/ListCourseSessions.php
+++ b/app/Filament/Resources/Learning/ClassSessions/Pages/ListCourseSessions.php
@@ -46,15 +46,15 @@ public function sessions(): Collection
             ->whereHas('user', fn ($q) => $q->active())
             ->count();
 
-        return $this->course->classSessions()
+        return $this->course?->classSessions()
             ->withCount(['attendances', 'materials', 'assignments'])
             ->orderByDesc('session_number')
             ->get()
             ->map(fn ($session) => (object) [
                 'id' => $session->id,
                 'session_number' => $session->session_number,
-                'date_formatted' => $session->date->translatedFormat('l, d F Y'),
-                'time_range' => $session->start_time->format('H:i').' - '.$session->end_time->format('H:i'),
+                'date_formatted' => $session->date?->translatedFormat('l, d F Y'),
+                'time_range' => $session->start_time?->format('H:i').' - '.$session->end_time?->format('H:i'),
                 'attendances_count' => $session->attendances_count,
                 'total_students' => $totalActiveStudents,
                 'attendance_percentage' => $totalActiveStudents > 0 ? round(($session->attendances_count / $totalActiveStudents) * 100) : 0,
@@ -71,12 +71,12 @@ public function form(Schema $schema): Schema
     #[Computed]
     public function description(): string
     {
-        return 'Data sesi pembelajaran untuk mata kuliah '.$this->course->name;
+        return 'Data sesi pembelajaran untuk mata kuliah '.$this->course?->name;
     }
 
     public function getTitle(): string
     {
-        return 'Sesi Kelas - '.$this->course->name;
+        return 'Sesi Kelas - '.$this->course?->name;
     }
 
     protected function getHeaderActions(): array
diff --git a/app/Filament/Resources/Learning/ClassSessions/Pages/ManageClassSessions.php b/app/Filament/Resources/Learning/ClassSessions/Pages/ManageClassSessions.php
index bcef960..d4b2b45 100644
--- a/app/Filament/Resources/Learning/ClassSessions/Pages/ManageClassSessions.php
+++ b/app/Filament/Resources/Learning/ClassSessions/Pages/ManageClassSessions.php
@@ -32,7 +32,7 @@ class ManageClassSessions extends Page implements HasActions, HasForms
 
     public function mount(): void
     {
-        $this->form->fill();
+        $this->form?->fill();
     }
 
     #[Computed]
@@ -76,10 +76,10 @@ public function todaySessions(): Collection
                     'id' => $session->id,
                     'is_pending' => false,
                     'session_number' => $session->session_number,
-                    'course_name' => $session->course->name,
-                    'course_code' => $session->course->code,
-                    'lecturer' => $session->course->lecturer ?? '-',
-                    'time_range' => $session->start_time->format('H:i').' - '.$session->end_time->format('H:i'),
+                    'course_name' => $session->course?->name,
+                    'course_code' => $session->course?->code,
+                    'lecturer' => $session->course?->lecturer ?? '-',
+                    'time_range' => $session->start_time?->format('H:i').' - '.$session->end_time?->format('H:i'),
                     'attendances_count' => $session->attendances_count,
                     'total_students' => $totalActiveStudents,
                     'attendance_percentage' => $percentage,
@@ -124,7 +124,7 @@ public function courses(): Collection
                     'name' => $course->name,
                     'code' => $course->code,
                     'lecturer' => $course->lecturer ?? 'Dosen Belum Ditentukan',
-                    'sessions_count' => $course->classSessions->count(),
+                    'sessions_count' => $course->classSessions?->count(),
                     'total_students' => $totalActiveStudents,
                     'url' => ClassSessionResource::getUrl('course', ['course' => $course]),
                 ];
diff --git a/app/Filament/Resources/Learning/Materials/Tables/MaterialTable.php b/app/Filament/Resources/Learning/Materials/Tables/MaterialTable.php
index b8642fe..0a40baa 100644
--- a/app/Filament/Resources/Learning/Materials/Tables/MaterialTable.php
+++ b/app/Filament/Resources/Learning/Materials/Tables/MaterialTable.php
@@ -36,7 +36,7 @@ public static function configure(Table $table): Table
                     ->label('Mata Kuliah')
                     ->searchable()
                     ->sortable()
-                    ->description(fn (Material $record) => $record->classSession?->session_number ? "Sesi Ke-{$record->classSession->session_number}" : ''),
+                    ->description(fn (Material $record) => $record->classSession?->session_number ? "Sesi Ke-{$record->classSession?->session_number}" : ''),
 
                 TextColumn::make('title')
                     ->label('Judul')
diff --git a/app/Http/Controllers/ShareAttendanceController.php b/app/Http/Controllers/ShareAttendanceController.php
index 6ef37f3..4c9b7d9 100644
--- a/app/Http/Controllers/ShareAttendanceController.php
+++ b/app/Http/Controllers/ShareAttendanceController.php
@@ -23,7 +23,7 @@ public function show(Request $request, Course $course): View
             ->latest('date')
             ->first();
 
-        $defaultDate = $latestAttendance ? $latestAttendance->date->toDateString() : now()->toDateString();
+        $defaultDate = $latestAttendance ? $latestAttendance->date?->toDateString() : now()->toDateString();
         $date = $request->query('date', $defaultDate);
 
         $attendances = Attendance::with('student')
diff --git a/app/Http/Middleware/DynamicFilamentTheme.php b/app/Http/Middleware/DynamicFilamentTheme.php
index 24db0fb..311de39 100644
--- a/app/Http/Middleware/DynamicFilamentTheme.php
+++ b/app/Http/Middleware/DynamicFilamentTheme.php
@@ -28,7 +28,7 @@ public function handle(Request $request, Closure $next): Response
         if ($user && $user->settings) {
             // Register Colors
             FilamentColor::register([
-                'primary' => match ($user->settings->primary_color) {
+                'primary' => match ($user->settings?->primary_color) {
                     'blue' => Color::Blue,
                     'sky' => Color::Sky,
                     'cyan' => Color::Cyan,
@@ -48,12 +48,12 @@ public function handle(Request $request, Closure $next): Response
             // Register Top Navigation
             $panel = Filament::getCurrentOrDefaultPanel();
             if ($panel && method_exists($panel, 'topNavigation')) {
-                $panel->topNavigation((bool) $user->settings->top_navigation);
+                $panel->topNavigation((bool) $user->settings?->top_navigation);
             }
 
             // Register Font & UI Styles
-            $font = $user->settings->font ?? 'Inter';
-            $radius = match ($user->settings->border_radius ?? 'md') {
+            $font = $user->settings?->font ?? 'Inter';
+            $radius = match ($user->settings?->border_radius ?? 'md') {
                 'none' => '0px',
                 'md' => '0.375rem',
                 'lg' => '0.5rem',
@@ -61,7 +61,7 @@ public function handle(Request $request, Closure $next): Response
                 '2xl' => '1rem',
                 default => '0.5rem',
             };
-            $maxWidth = match ($user->settings->content_width ?? 'full') {
+            $maxWidth = match ($user->settings?->content_width ?? 'full') {
                 'centered' => '80rem',
                 default => 'none',
             };
diff --git a/app/Models/Assignment.php b/app/Models/Assignment.php
index 586e9cc..f70cd79 100644
--- a/app/Models/Assignment.php
+++ b/app/Models/Assignment.php
@@ -42,7 +42,7 @@ protected function formattedDueDate(): Attribute
 
     protected function formattedCreatedAt(): Attribute
     {
-        return Attribute::get(fn () => $this->created_at->translatedFormat('l, d M Y H:i'));
+        return Attribute::get(fn () => $this->created_at?->translatedFormat('l, d M Y H:i'));
     }
 
     protected function formattedUpdatedAt(): Attribute
diff --git a/app/Models/AssignmentPin.php b/app/Models/AssignmentPin.php
index 248fd6a..19c710f 100644
--- a/app/Models/AssignmentPin.php
+++ b/app/Models/AssignmentPin.php
@@ -16,7 +16,7 @@ class AssignmentPin extends Model
 
     protected function formattedCreatedAt(): Attribute
     {
-        return Attribute::get(fn () => $this->created_at->translatedFormat('l, d M Y H:i'));
+        return Attribute::get(fn () => $this->created_at?->translatedFormat('l, d M Y H:i'));
     }
 
     protected function formattedUpdatedAt(): Attribute
diff --git a/app/Models/AssignmentSubmission.php b/app/Models/AssignmentSubmission.php
index 4183b03..2f1e56a 100644
--- a/app/Models/AssignmentSubmission.php
+++ b/app/Models/AssignmentSubmission.php
@@ -37,7 +37,7 @@ protected function formattedSubmittedAt(): Attribute
 
     protected function formattedCreatedAt(): Attribute
     {
-        return Attribute::get(fn () => $this->created_at->translatedFormat('l, d M Y H:i'));
+        return Attribute::get(fn () => $this->created_at?->translatedFormat('l, d M Y H:i'));
     }
 
     protected function formattedUpdatedAt(): Attribute
diff --git a/app/Models/AssignmentTarget.php b/app/Models/AssignmentTarget.php
index 4d9d21d..b49192a 100644
--- a/app/Models/AssignmentTarget.php
+++ b/app/Models/AssignmentTarget.php
@@ -21,7 +21,7 @@ class AssignmentTarget extends Model
 
     protected function formattedCreatedAt(): Attribute
     {
-        return Attribute::get(fn () => $this->created_at->translatedFormat('l, d M Y H:i'));
+        return Attribute::get(fn () => $this->created_at?->translatedFormat('l, d M Y H:i'));
     }
 
     protected function formattedUpdatedAt(): Attribute
diff --git a/app/Models/Attendance.php b/app/Models/Attendance.php
index 282dc67..ce7b42d 100644
--- a/app/Models/Attendance.php
+++ b/app/Models/Attendance.php
@@ -41,7 +41,7 @@ protected function formattedAttendedAt(): Attribute
 
     protected function formattedCreatedAt(): Attribute
     {
-        return Attribute::get(fn () => $this->created_at->translatedFormat('l, d M Y H:i'));
+        return Attribute::get(fn () => $this->created_at?->translatedFormat('l, d M Y H:i'));
     }
 
     protected function formattedUpdatedAt(): Attribute
diff --git a/app/Models/Changelog.php b/app/Models/Changelog.php
index 63d56a7..abe60d6 100644
--- a/app/Models/Changelog.php
+++ b/app/Models/Changelog.php
@@ -42,12 +42,12 @@ protected function formattedVersion(): Attribute
 
     protected function formattedReleaseDate(): Attribute
     {
-        return Attribute::get(fn () => $this->release_date->translatedFormat('l, d M Y'));
+        return Attribute::get(fn () => $this->release_date?->translatedFormat('l, d M Y'));
     }
 
     protected function formattedCreatedAt(): Attribute
     {
-        return Attribute::get(fn () => $this->created_at->translatedFormat('l, d M Y H:i'));
+        return Attribute::get(fn () => $this->created_at?->translatedFormat('l, d M Y H:i'));
     }
 
     protected function formattedUpdatedAt(): Attribute
diff --git a/app/Models/ClassSession.php b/app/Models/ClassSession.php
index 88af5fe..6750f15 100644
--- a/app/Models/ClassSession.php
+++ b/app/Models/ClassSession.php
@@ -50,7 +50,7 @@ protected function formattedEndTime(): Attribute
 
     protected function formattedCreatedAt(): Attribute
     {
-        return Attribute::get(fn () => $this->created_at->translatedFormat('l, d M Y H:i'));
+        return Attribute::get(fn () => $this->created_at?->translatedFormat('l, d M Y H:i'));
     }
 
     protected function formattedUpdatedAt(): Attribute
diff --git a/app/Models/Course.php b/app/Models/Course.php
index 08c1186..35a83d4 100644
--- a/app/Models/Course.php
+++ b/app/Models/Course.php
@@ -23,7 +23,7 @@ class Course extends Model
 
     protected function formattedCreatedAt(): Attribute
     {
-        return Attribute::get(fn () => $this->created_at->translatedFormat('l, d M Y H:i'));
+        return Attribute::get(fn () => $this->created_at?->translatedFormat('l, d M Y H:i'));
     }
 
     protected function formattedUpdatedAt(): Attribute
diff --git a/app/Models/CourseSchedule.php b/app/Models/CourseSchedule.php
index 182b275..ba4fdc8 100644
--- a/app/Models/CourseSchedule.php
+++ b/app/Models/CourseSchedule.php
@@ -43,7 +43,7 @@ protected function formattedEndTime(): Attribute
 
     protected function formattedCreatedAt(): Attribute
     {
-        return Attribute::get(fn () => $this->created_at->translatedFormat('l, d M Y H:i'));
+        return Attribute::get(fn () => $this->created_at?->translatedFormat('l, d M Y H:i'));
     }
 
     protected function formattedUpdatedAt(): Attribute
diff --git a/app/Models/Material.php b/app/Models/Material.php
index 63d2d44..fdd64b3 100644
--- a/app/Models/Material.php
+++ b/app/Models/Material.php
@@ -24,7 +24,7 @@ class Material extends Model implements HasMedia
 
     protected function formattedCreatedAt(): Attribute
     {
-        return Attribute::get(fn () => $this->created_at->translatedFormat('l, d M Y H:i'));
+        return Attribute::get(fn () => $this->created_at?->translatedFormat('l, d M Y H:i'));
     }
 
     protected function formattedUpdatedAt(): Attribute
diff --git a/app/Models/Student.php b/app/Models/Student.php
index 94e816e..f581f45 100644
--- a/app/Models/Student.php
+++ b/app/Models/Student.php
@@ -56,7 +56,7 @@ protected function formattedDateOfBirth(): Attribute
 
     protected function formattedCreatedAt(): Attribute
     {
-        return Attribute::get(fn () => $this->created_at->translatedFormat('l, d M Y H:i'));
+        return Attribute::get(fn () => $this->created_at?->translatedFormat('l, d M Y H:i'));
     }
 
     protected function formattedUpdatedAt(): Attribute
diff --git a/app/Models/StudyGroup.php b/app/Models/StudyGroup.php
index d0632e5..0735ddb 100644
--- a/app/Models/StudyGroup.php
+++ b/app/Models/StudyGroup.php
@@ -24,7 +24,7 @@ class StudyGroup extends Model
 
     protected function formattedCreatedAt(): Attribute
     {
-        return Attribute::get(fn () => $this->created_at->translatedFormat('l, d M Y H:i'));
+        return Attribute::get(fn () => $this->created_at?->translatedFormat('l, d M Y H:i'));
     }
 
     protected function formattedUpdatedAt(): Attribute
diff --git a/app/Models/StudyGroupMember.php b/app/Models/StudyGroupMember.php
index 47d655f..6cbc38f 100644
--- a/app/Models/StudyGroupMember.php
+++ b/app/Models/StudyGroupMember.php
@@ -21,7 +21,7 @@ class StudyGroupMember extends Model
 
     protected function formattedCreatedAt(): Attribute
     {
-        return Attribute::get(fn () => $this->created_at->translatedFormat('l, d M Y H:i'));
+        return Attribute::get(fn () => $this->created_at?->translatedFormat('l, d M Y H:i'));
     }
 
     protected function formattedUpdatedAt(): Attribute
diff --git a/app/Models/User.php b/app/Models/User.php
index bceb993..2394af9 100644
--- a/app/Models/User.php
+++ b/app/Models/User.php
@@ -68,7 +68,7 @@ protected function name(): Attribute
 
     protected function formattedCreatedAt(): Attribute
     {
-        return Attribute::get(fn () => $this->created_at->translatedFormat('l, d M Y H:i'));
+        return Attribute::get(fn () => $this->created_at?->translatedFormat('l, d M Y H:i'));
     }
 
     protected function formattedUpdatedAt(): Attribute
diff --git a/app/Models/UserSetting.php b/app/Models/UserSetting.php
index afe19b6..b426de9 100644
--- a/app/Models/UserSetting.php
+++ b/app/Models/UserSetting.php
@@ -27,7 +27,7 @@ protected function casts(): array
 
     protected function formattedCreatedAt(): Attribute
     {
-        return Attribute::get(fn () => $this->created_at->translatedFormat('l, d M Y H:i'));
+        return Attribute::get(fn () => $this->created_at?->translatedFormat('l, d M Y H:i'));
     }
 
     protected function formattedUpdatedAt(): Attribute