<?php

namespace App\Http\Controllers\Api;

use App\Models\Configuration;
use App\Models\TeacherClass;
use App\Models\User;
use App\Models\Teacher;
use App\Models\Student;
use App\Models\ClassSection;
use App\Models\StudentClass;
use App\Models\StudentMedicalCondition;
use App\Models\StudentAllergy;
use App\Models\StaffAttendance;
use App\Services\EmailService;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Log;
use Symfony\Component\HttpFoundation\Response;

class TeacherController extends BaseApiController
{
    protected User $user;
    protected TeacherClass $teacherClass;
    protected Configuration $config;
    protected Teacher $teacher;
    protected Student $student;
    protected ClassSection $classSection;
    protected StudentClass $studentClass;
    protected StudentMedicalCondition $medical;
    protected StudentAllergy $allergy;
    protected StaffAttendance $staffAttendance;
    protected EmailService $emailService;
    protected string $semester;
    protected string $schoolYear;

    public function __construct()
    {
        parent::__construct();
        $this->user           = model(User::class);
        $this->teacherClass   = model(TeacherClass::class);
        $this->config         = model(Configuration::class);
        $this->teacher        = model(Teacher::class);
        $this->student        = model(Student::class);
        $this->classSection   = model(ClassSection::class);
        $this->studentClass   = model(StudentClass::class);
        $this->medical        = model(StudentMedicalCondition::class);
        $this->allergy        = model(StudentAllergy::class);
        $this->staffAttendance = model(StaffAttendance::class);
        $this->emailService        = app(EmailService::class);
        $this->semester            = (string) ($this->config->getConfig('semester') ?? '');
        $this->schoolYear          = (string) ($this->config->getConfig('school_year') ?? '');
    }

    public function index()
    {
        $page    = max(1, (int) ($this->request->getGet('page') ?? 1));
        $perPage = min(100, max(1, (int) ($this->request->getGet('per_page') ?? 20)));

        $query = $this->user->newQuery()
            ->select('users.*')
            ->join('user_roles', 'user_roles.user_id', '=', 'users.id')
            ->join('roles', 'roles.id', '=', 'user_roles.role_id')
            ->whereIn('LOWER(roles.name)', ['teacher', 'teacher_assistant'])
            ->groupBy('users.id')
            ->orderBy('users.lastname', 'ASC');

        $result = $this->paginate($query, $page, $perPage);

        foreach ($result['data'] as &$teacher) {
            unset($teacher['password'], $teacher['token']);

            $assignments = $this->teacherClass->newQuery()
                ->where('teacher_id', $teacher['id'])
                ->where('school_year', $this->schoolYear)
                ->where('semester', $this->semester)
                ->get()
                ->toArray();

            $teacher['class_assignments'] = $assignments;
        }

        return $this->success($result, 'Teachers retrieved successfully');
    }

    public function show($id = null)
    {
        $teacher = $this->user->newQuery()
            ->select('users.*')
            ->join('user_roles', 'user_roles.user_id', '=', 'users.id')
            ->join('roles', 'roles.id', '=', 'user_roles.role_id')
            ->whereIn('LOWER(roles.name)', ['teacher', 'teacher_assistant'])
            ->where('users.id', $id)
            ->first();

        if (!$teacher) {
            return $this->respondError('Teacher not found', Response::HTTP_NOT_FOUND);
        }

        $teacherArray = $teacher->toArray();
        unset($teacherArray['password'], $teacherArray['token']);

        $assignments = $this->teacherClass->newQuery()
            ->where('teacher_id', $id)
            ->where('school_year', $this->schoolYear)
            ->where('semester', $this->semester)
            ->get()
            ->toArray();

        $teacherArray['class_assignments'] = $assignments;

        return $this->success($teacherArray, 'Teacher retrieved successfully');
    }

    public function getClasses($id = null)
    {
        $assignments = $this->teacherClass->newQuery()
            ->select([
                'tc.*',
                'cs.class_section_name',
                'c.name as class_name',
            ])
            ->from('teacher_class as tc')
            ->leftJoin('class_sections as cs', 'cs.class_section_id', '=', 'tc.class_section_id')
            ->leftJoin('classes as c', 'c.id', '=', 'cs.class_id')
            ->where('tc.teacher_id', $id)
            ->where('tc.school_year', $this->schoolYear)
            ->where('tc.semester', $this->semester)
            ->orderBy('cs.class_section_name', 'ASC')
            ->get()
            ->toArray();

        return $this->success($assignments, 'Teacher classes retrieved successfully');
    }

    /**
     * GET /api/v1/teachers/class-view
     * Get class view data for the logged-in teacher
     */
    public function getClassView()
    {
        try {
            $userId = $this->getCurrentUserId();
            if (!$userId) {
                return $this->respondError('User not logged in', Response::HTTP_UNAUTHORIZED);
            }

            // Fetch all assignments (as main or TA)
            $classes = $this->teacherClass->getClassAssignmentsByUserId($userId, $this->schoolYear);

            if (empty($classes)) {
                return $this->success([
                    'has_classes' => false,
                    'message' => 'You do not have an assigned class yet. Please contact the administration.',
                ], 'No classes found');
            }

            // Identify user and their role
            $user = $this->user->find($userId);
            if (!$user) {
                return $this->respondError('User not found', Response::HTTP_NOT_FOUND);
            }

            $roles = DB::table('user_roles ur')
                ->select('r.name')
                ->join('roles r', 'r.id', '=', 'ur.role_id')
                ->where('ur.user_id', $userId)
                ->get()
                ->map(fn($r) => strtolower($r->name))
                ->toArray();

            $roleName = 'teacher';
            if (in_array('teacher', $roles)) {
                $roleName = 'teacher';
            } elseif (in_array('teacher_assistant', $roles)) {
                $roleName = 'teacher_assistant';
            } else {
                return $this->respondError('Access denied', Response::HTTP_FORBIDDEN);
            }

            // Collect class section IDs
            $classSectionIds = array_column($classes, 'class_section_id');
            $studentsData = [];

            if (!empty($classSectionIds)) {
                // Fetch all students for the selected class sections
                $students = $this->studentClass->getStudentsByClassSectionIds($classSectionIds);

                if (!empty($students)) {
                    // Collect unique student IDs
                    $studentIds = array_values(array_unique(array_map(
                        static fn(array $row) => (int) ($row['student_id'] ?? 0),
                        $students
                    )));
                    $studentIds = array_values(array_filter($studentIds));

                    // Bulk fetch medical conditions & allergies grouped by student_id
                    $conditionsByStudent = !empty($studentIds)
                        ? $this->medical->getMedicalByStudentIds($studentIds)
                        : [];

                    $allergiesByStudent = !empty($studentIds)
                        ? $this->allergy->getAllergiesByStudentIds($studentIds)
                        : [];

                    // Attach medical/allergy data to each student
                    foreach ($students as $student) {
                        $sid = (int) ($student['student_id'] ?? 0);
                        $cid = (int) ($student['class_section_id'] ?? 0);

                        $medList = array_column($conditionsByStudent[$sid] ?? [], 'condition_name');
                        $algList = array_column($allergiesByStudent[$sid] ?? [], 'allergy');

                        $student['medical_conditions'] = $medList;
                        $student['allergies'] = $algList;
                        $student['medical_conditions_text'] = implode(', ', $medList);
                        $student['allergies_text'] = implode(', ', $algList);

                        $studentsData[$cid][] = $student;
                    }
                }
            }

            // Build assigned staff lists (all Main teachers and all TAs) per class section
            $assignedNames = [];
            if (!empty($classSectionIds)) {
                $rows = DB::table('teacher_class tc')
                    ->select('tc.class_section_id', 'tc.position', 'u.firstname', 'u.lastname')
                    ->join('users u', 'u.id', '=', 'tc.teacher_id')
                    ->whereIn('tc.class_section_id', $classSectionIds)
                    ->where('tc.school_year', $this->schoolYear)
                    ->where('tc.semester', $this->semester)
                    ->orderBy('tc.class_section_id', 'ASC')
                    ->orderByRaw("FIELD(tc.position,'main','ta')")
                    ->orderBy('u.firstname', 'ASC')
                    ->get();

                foreach ($rows as $r) {
                    $sid = (int) ($r->class_section_id ?? 0);
                    $pos = strtolower((string) ($r->position ?? ''));
                    $name = trim(($r->firstname ?? '') . ' ' . ($r->lastname ?? ''));

                    if ($sid === 0 || $name === '') continue;

                    if (in_array($pos, ['main', 'teacher'], true)) {
                        $assignedNames[$sid]['mains'][] = $name;
                    } elseif (in_array($pos, ['ta', 'assistant', 'teacher_assistant'], true)) {
                        $assignedNames[$sid]['tas'][] = $name;
                    } else {
                        $assignedNames[$sid]['others'][] = $name;
                    }
                }
            }

            $classSectionId = $classSectionIds[0] ?? null;

            return $this->success([
                'teacher_name' => trim(($user['firstname'] ?? '') . ' ' . ($user['lastname'] ?? '')),
                'role_name' => $roleName,
                'classes' => $classes,
                'students' => $studentsData[$classSectionId] ?? [],
                'studentsData' => $studentsData,
                'class_section_id' => $classSectionId,
                'assignedNames' => $assignedNames,
            ], 'Class view data retrieved successfully');
        } catch (\Exception $e) {
            Log::error('Error in TeacherController::getClassView(): ' . $e->getMessage());
            return $this->respondError('An error occurred. Please try again later.', Response::HTTP_INTERNAL_SERVER_ERROR);
        }
    }

    /**
     * GET /api/v1/teachers/class-assignments
     * Get teacher class assignment data for administration
     */
    public function getTeacherClassAssignments()
    {
        $forYear = trim((string) ($this->request->getGet('schoolYear') ?? $this->request->getGet('school_year') ?? ''));
        $payload = $this->buildTeacherClassAssignmentPayload($forYear !== '' ? $forYear : null);
        $payload['ok'] = true;
        return $this->success($payload, 'Teacher class assignments retrieved successfully');
    }

    /**
     * POST /api/v1/teachers/class-assignments/assign
     * Assign a teacher to a class
     */
    public function assignClassTeacher()
    {
        $data = $this->payloadData();
        $result = $this->handleAssignClassTeacher($data);
        $statusCode = $result['ok'] ? Response::HTTP_OK : Response::HTTP_UNPROCESSABLE_ENTITY;
        return response()->json($result, $statusCode);
    }

    /**
     * DELETE /api/v1/teachers/class-assignments
     * Delete a teacher class assignment
     */
    public function deleteAssignment()
    {
        $data = $this->payloadData();
        $result = $this->handleDeleteAssignment($data);
        $statusCode = $result['ok'] ? Response::HTTP_OK : Response::HTTP_UNPROCESSABLE_ENTITY;
        return response()->json($result, $statusCode);
    }

    /**
     * GET /api/v1/teachers/absence-form
     * Get absence form data for the logged-in teacher
     */
    public function getAbsenceForm()
    {
        $userId = $this->getCurrentUserId();
        if (!$userId) {
            return $this->respondError('Please log in first.', Response::HTTP_UNAUTHORIZED);
        }

        $teacher = $this->user->find($userId);
        $displayName = $teacher ? trim(($teacher['firstname'] ?? '') . ' ' . ($teacher['lastname'] ?? '')) : 'Unknown';

        // Fetch existing self-reported staff attendance rows for this user (current term)
        $existing = $this->staffAttendance
            ->where('user_id', $userId)
            ->where('semester', $this->semester)
            ->where('school_year', $this->schoolYear)
            ->orderBy('date', 'DESC')
            ->findAll();

        return $this->success([
            'teacher_name' => $displayName,
            'semester' => $this->semester,
            'schoolYear' => $this->schoolYear,
            'existing' => $existing,
            'availableDates' => $this->allowedAbsenceDates(),
        ], 'Absence form data retrieved successfully');
    }

    /**
     * POST /api/v1/teachers/absence
     * Submit absence/vacation request
     */
    public function submitAbsence()
    {
        $userId = $this->getCurrentUserId();
        if (!$userId) {
            return $this->respondError('Please log in first.', Response::HTTP_UNAUTHORIZED);
        }

        if ($this->semester === '' || $this->schoolYear === '') {
            return $this->respondError('Semester or school year not configured.', Response::HTTP_BAD_REQUEST);
        }

        $data = $this->payloadData();
        $dates = (array) ($data['dates'] ?? []);
        $reasonType = trim((string) ($data['reason_type'] ?? ''));
        $reasonText = trim((string) ($data['reason'] ?? ''));

        if ($reasonText === '') {
            return $this->respondValidationError(['reason' => ['Reason is required.']]);
        }

        // Build reason string
        $reasonBase = ($reasonType !== '') ? strtolower($reasonType) : '';
        $reason = $reasonBase !== '' ? ($reasonBase . ': ' . $reasonText) : $reasonText;

        // Enforce allowed Sundays list
        $allowedDates = $this->allowedAbsenceDates();
        $allowedSet = array_fill_keys($allowedDates, true);

        $roleName = $this->user->getUserRole($userId) ?: null;

        // Validate dates and save
        $saved = 0;
        $invalid = [];
        $savedDates = [];

        $dates = array_values(array_unique(array_map('strval', $dates)));

        foreach ($dates as $d) {
            $d = trim((string) $d);
            if ($d === '') continue;

            $dt = \DateTimeImmutable::createFromFormat('Y-m-d', $d);
            if (!$dt || $dt->format('Y-m-d') !== $d || empty($allowedSet[$d])) {
                $invalid[] = $d;
                continue;
            }

            $ok = $this->staffAttendance->upsertOne(
                userId: $userId,
                roleName: $roleName,
                date: $d,
                semester: $this->semester,
                schoolYear: $this->schoolYear,
                status: StaffAttendance::STATUS_ABSENT,
                reason: $reason,
                editorId: $userId
            );

            if ($ok) {
                $saved++;
                $savedDates[] = $d;
            }
        }

        if (!empty($invalid)) {
            return $this->respondError('Invalid dates: ' . implode(', ', $invalid), Response::HTTP_BAD_REQUEST);
        }

        // Send notification email to principal
        try {
            $user = $this->user->find($userId) ?: [];
            $fullName = trim(($user['firstname'] ?? '') . ' ' . ($user['lastname'] ?? '')) ?: 'Unknown';
            $userEmail = $user['email'] ?? '';
            $role = $roleName ?: 'staff';
            $dateList = !empty($savedDates) ? implode(', ', $savedDates) : implode(', ', $dates);

            // If teacher/TA, include assigned class(es) for current term
            $assignedText = '-';
            if (in_array(strtolower((string) $roleName), ['teacher', 'teacher_assistant'], true)) {
                try {
                    $assignments = $this->teacherClass->getClassAssignmentsByUserId($userId, $this->schoolYear, $this->semester);
                    if (!empty($assignments)) {
                        $parts = [];
                        foreach ($assignments as $as) {
                            $name = (string) ($as['class_section_name'] ?? '');
                            $r = (string) ($as['teacher_role'] ?? '');
                            if ($name !== '') {
                                $parts[] = $r ? ($name . ' (' . $r . ')') : $name;
                            }
                        }
                        if (!empty($parts)) {
                            $assignedText = implode(', ', $parts);
                        } else {
                            $assignedText = 'No assigned class';
                        }
                    } else {
                        $assignedText = 'No assigned class';
                    }
                } catch (\Throwable $e) {
                    $assignedText = 'N/A';
                }
            }

            $subject = sprintf('TimeOff Request: %s (%s) — %s', $fullName, ucfirst((string) $role), $dateList ?: 'No dates');
            $submittedAt = utc_now();

            $body = '<div style="font-family:Arial,Helvetica,sans-serif;font-size:14px;line-height:1.5;">'
                  . '<h3 style="margin:0 0 8px;">New TimeOff Request</h3>'
                  . '<p style="margin:0 0 12px;">A staff time-off request was submitted from the teacher portal.</p>'
                  . '<table cellpadding="6" cellspacing="0" style="border-collapse:collapse;">'
                  . '<tr><td><strong>Name</strong></td><td>' . esc($fullName) . '</td></tr>'
                  . '<tr><td><strong>Email</strong></td><td>' . esc($userEmail) . '</td></tr>'
                  . '<tr><td><strong>Role</strong></td><td>' . esc((string) $role) . '</td></tr>'
                  . '<tr><td><strong>Semester</strong></td><td>' . esc($this->semester) . '</td></tr>'
                  . '<tr><td><strong>School Year</strong></td><td>' . esc($this->schoolYear) . '</td></tr>'
                  . '<tr><td><strong>Reason Type</strong></td><td>' . esc($reasonType ?: '-') . '</td></tr>'
                  . '<tr><td><strong>Reason</strong></td><td>' . esc($reasonText) . '</td></tr>'
                  . '<tr><td><strong>Dates</strong></td><td>' . esc($dateList ?: '-') . '</td></tr>'
                  . (in_array(strtolower((string) $roleName), ['teacher', 'teacher_assistant'], true)
                        ? '<tr><td><strong>Assigned Class(es)</strong></td><td>' . esc($assignedText) . '</td></tr>'
                        : '')
                  . '<tr><td><strong>Submitted At</strong></td><td>' . esc($submittedAt) . '</td></tr>'
                  . '</table>'
                  . '</div>';

            // Note: StaffTimeOffLinkService not found, skipping link generation
            $principalEmail = env('PRINCIPAL_EMAIL') ?: 'principal@alrahmaisgl.org';
            $this->emailService->send($principalEmail, $subject, $body);
        } catch (\Throwable $e) {
            Log::error('Failed to send TimeOff email: ' . $e->getMessage());
        }

        return $this->success([
            'saved' => $saved,
            'savedDates' => $savedDates,
        ], $saved . ' day(s) saved as absent.');
    }

    /**
     * Build teacher class assignment payload
     */
    private function buildTeacherClassAssignmentPayload(?string $forYear = null): array
    {
        $schoolYear = $forYear ?: $this->schoolYear;

        $teachers = $this->teacher->getTeachersAndTAs();

        // Prefer class sections for the selected year, fallback to all if none
        $classSections = $this->classSection
            ->where('school_year', $schoolYear)
            ->orderBy('class_section_name', 'ASC')
            ->findAll();

        if (empty($classSections)) {
            $classSections = $this->classSection->orderBy('class_section_name', 'ASC')->findAll();
        }

        $classNames = [];
        foreach ($classSections as $section) {
            $sectionId = (int) ($section['class_section_id'] ?? $section['id'] ?? 0);
            if ($sectionId <= 0) continue;
            $classNames[$sectionId] = $section['class_section_name'] ?? ($section['name'] ?? 'N/A');
        }

        $assignments = $this->teacherClass
            ->where('school_year', $schoolYear)
            ->findAll();

        $assignmentMap = [];
        foreach ($assignments as $assign) {
            $teacherId = (int) ($assign['teacher_id'] ?? 0);
            $sectionId = (int) ($assign['class_section_id'] ?? 0);
            if ($teacherId <= 0 || $sectionId <= 0) continue;

            $role = strtolower((string) ($assign['position'] ?? ''));
            if (!in_array($role, ['main', 'ta'], true)) continue;

            if (!isset($assignmentMap[$teacherId])) {
                $assignmentMap[$teacherId] = ['main' => [], 'ta' => []];
            }

            $assignmentMap[$teacherId][$role][] = [
                'section_id' => $sectionId,
                'class_section_name' => $classNames[$sectionId] ?? 'N/A',
                'role' => $role,
                'semester' => (string) ($assign['semester'] ?? $this->semester ?? ''),
                'school_year' => (string) ($assign['school_year'] ?? $schoolYear),
            ];
        }

        $teacherData = [];
        foreach ($teachers as $teacher) {
            $tid = (int) ($teacher['id'] ?? 0);
            if ($tid <= 0) continue;

            $assigned = $assignmentMap[$tid] ?? ['main' => [], 'ta' => []];
            $firstName = $teacher['firstname'] ?? '';
            $lastName = $teacher['lastname'] ?? '';
            $name = trim($firstName . ' ' . $lastName);
            if ($name === '') {
                $name = 'User#' . $tid;
            }

            $teacherData[] = [
                'teacher_id' => $tid,
                'firstname' => $firstName,
                'lastname' => $lastName,
                'name' => $name,
                'email' => $teacher['email'] ?? '',
                'cellphone' => $teacher['cellphone'] ?? '',
                'role' => $teacher['role'] ?? '',
                'school_year' => $this->schoolYear,
                'main_assignments' => $assigned['main'],
                'ta_assignments' => $assigned['ta'],
            ];
        }

        $classesPayload = [];
        foreach ($classSections as $section) {
            $sectionId = (int) ($section['class_section_id'] ?? $section['id'] ?? 0);
            if ($sectionId <= 0) continue;

            $classesPayload[] = [
                'class_section_id' => $sectionId,
                'class_section_name' => $section['class_section_name'] ?? ($section['name'] ?? 'N/A'),
            ];
        }

        return [
            'school_year' => $schoolYear,
            'teachers' => $teacherData,
            'classes' => $classesPayload,
        ];
    }

    /**
     * Handle assign class teacher logic
     */
    private function handleAssignClassTeacher(array $input): array
    {
        $teacherId = (int) ($input['teacher_id'] ?? 0);
        $classSectionId = (int) ($input['class_section_id'] ?? 0);
        $teacherRole = $input['teacher_role'] ?? null;
        $loggedInUserId = $this->getCurrentUserId() ?? 0;
        $currentDateTime = utc_now();

        if ($teacherId <= 0 || $classSectionId <= 0) {
            return ['ok' => false, 'status' => 'error', 'message' => 'Missing required parameters for assignment.'];
        }

        if (empty($this->semester) || empty($this->schoolYear)) {
            return ['ok' => false, 'status' => 'error', 'message' => 'Semester or school year not configured.'];
        }

        if ($teacherRole === null || $teacherRole === '') {
            $teacherRole = $this->user->getUserRole($teacherId);
        }

        $isAssistant = strtolower((string) $teacherRole) === 'teacher_assistant';
        $position = $isAssistant ? 'ta' : 'main';

        $alreadyAssigned = $this->teacherClass->where([
            'teacher_id' => $teacherId,
            'class_section_id' => $classSectionId,
            'position' => $position,
            'semester' => $this->semester,
            'school_year' => $this->schoolYear,
        ])->first();

        if ($alreadyAssigned) {
            return ['ok' => false, 'status' => 'info', 'message' => 'This teacher is already assigned to this class with the same role.'];
        }

        $insertData = [
            'teacher_id' => $teacherId,
            'class_section_id' => $classSectionId,
            'position' => $position,
            'semester' => $this->semester,
            'school_year' => $this->schoolYear,
            'created_at' => $currentDateTime,
            'updated_at' => $currentDateTime,
            'updated_by' => $loggedInUserId,
        ];

        try {
            $this->teacherClass->insert($insertData);
        } catch (\Throwable $e) {
            Log::error('assignClassTeacher failed: ' . $e->getMessage());
            return ['ok' => false, 'status' => 'error', 'message' => 'Unable to assign class. Please try again.'];
        }

        return [
            'ok' => true,
            'status' => 'success',
            'message' => 'Class assigned to ' . ($isAssistant ? 'Teacher Assistant' : 'Main Teacher') . ' successfully.',
            'position' => $position,
        ];
    }

    /**
     * Handle delete assignment logic
     */
    private function handleDeleteAssignment(array $input): array
    {
        $teacherId = (int) ($input['teacher_id'] ?? 0);
        $classSectionId = (int) ($input['class_section_id'] ?? 0);
        $position = strtolower((string) ($input['position'] ?? ''));

        if ($teacherId <= 0 || $classSectionId <= 0 || !in_array($position, ['main', 'ta'], true)) {
            return ['ok' => false, 'status' => 'error', 'message' => 'Missing or invalid data for deletion.'];
        }

        if (empty($this->semester) || empty($this->schoolYear)) {
            return ['ok' => false, 'status' => 'error', 'message' => 'Semester or school year not configured.'];
        }

        $requestedSemester = trim((string) ($input['semester'] ?? ''));
        $requestedSchoolYear = trim((string) ($input['school_year'] ?? ''));

        $semester = $requestedSemester !== '' ? $requestedSemester : $this->semester;
        $schoolYear = $requestedSchoolYear !== '' ? $requestedSchoolYear : $this->schoolYear;

        if ($semester === '' || $schoolYear === '') {
            return ['ok' => false, 'status' => 'error', 'message' => 'Semester or school year not configured.'];
        }

        $assignment = $this->teacherClass
            ->where('teacher_id', $teacherId)
            ->where('class_section_id', $classSectionId)
            ->where('semester', $semester)
            ->where('school_year', $schoolYear)
            ->where('position', $position)
            ->first();

        if (!$assignment) {
            return ['ok' => false, 'status' => 'error', 'message' => 'Assignment not found.'];
        }

        try {
            $this->teacherClass->delete($assignment['id']);
        } catch (\Throwable $e) {
            Log::error('deleteAssignment failed: ' . $e->getMessage());
            return ['ok' => false, 'status' => 'error', 'message' => 'Unable to remove assignment. Please try again.'];
        }

        return [
            'ok' => true,
            'status' => 'success',
            'message' => ucfirst($position) . ' assignment removed successfully.',
        ];
    }

    /**
     * Compute all allowed absence dates (Sundays) for the configured school year
     */
    private function allowedAbsenceDates(): array
    {
        $todayStr = local_date(utc_now(), 'Y-m-d');
        try {
            $today = new \DateTimeImmutable($todayStr);
        } catch (\Throwable $e) {
            $today = new \DateTimeImmutable();
        }

        $sy = $this->schoolYear;
        $startYear = null;
        $endYear = null;

        if (preg_match('/^(\d{4})\D+(\d{4})$/', $sy, $m)) {
            $startYear = (int) $m[1];
            $endYear = (int) $m[2];
        } else {
            // Fallback based on current date
            $cy = (int) date('Y');
            $cm = (int) date('n');
            if ($cm >= 9) { // Sep-Dec
                $startYear = $cy;
                $endYear = $cy + 1;
            } else { // Jan-Aug
                $startYear = $cy - 1;
                $endYear = $cy;
            }
        }

        try {
            $start = new \DateTimeImmutable(sprintf('%04d-09-01', $startYear));
            $end = new \DateTimeImmutable(sprintf('%04d-05-31', $endYear));
        } catch (\Throwable $e) {
            return [];
        }

        // Clamp start to today if in range
        if ($start < $today) {
            $start = $today;
        }

        // Iterate and collect Sundays in range [start..end]
        $dates = [];
        for ($cursor = $start; $cursor <= $end; $cursor = $cursor->modify('+1 day')) {
            if ((int) $cursor->format('w') === 0) { // Sunday
                $dates[] = $cursor->format('Y-m-d');
            }
        }

        return $dates;
    }
}