<?php

namespace App\Http\Controllers\Api;

use App\Models\AttendanceData;
use App\Models\AttendanceDay;
use App\Models\Calendar;
use App\Models\ClassSection;
use App\Models\Configuration;
use App\Models\StaffAttendance;
use App\Models\StudentClass;
use App\Models\Student;
use App\Models\TeacherClass;
use App\Models\User;
use Illuminate\Http\JsonResponse;
use Illuminate\Support\Facades\DB;
use Symfony\Component\HttpFoundation\Response;

class AttendanceController extends BaseApiController
{
    protected AttendanceData $attendance;
    protected StudentClass $studentClass;
    protected ClassSection $classSection;
    protected Configuration $config;
    protected TeacherClass $teacherClass;
    protected StaffAttendance $staffAttendance;
    protected AttendanceDay $attendanceDay;
    protected Student $student;
    protected Calendar $calendar;
    protected User $user;
    protected string $schoolYear;
    protected string $semester;
    protected int $enableAttendance;

    public function __construct()
    {
        $this->attendance        = model(AttendanceData::class);
        $this->studentClass      = model(StudentClass::class);
        $this->classSection      = model(ClassSection::class);
        $this->config            = model(Configuration::class);
        $this->teacherClass      = model(TeacherClass::class);
        $this->staffAttendance   = model(StaffAttendance::class);
        $this->attendanceDay     = model(AttendanceDay::class);
        $this->student           = model(Student::class);
        $this->calendar          = model(Calendar::class);
        $this->user              = model(User::class);
        $this->schoolYear             = (string) ($this->config->getConfig('school_year') ?? '');
        $this->semester               = (string) ($this->config->getConfig('semester') ?? '');
        $this->enableAttendance       = (int) ($this->config->getConfig('enable_attendance') ?? 0);
    }

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

        $builder = $this->attendance;

        if ($studentId) {
            $builder = $builder->where('student_id', $studentId);
        }

        if ($date) {
            $builder = $builder->where('date', $date);
        }

        $data  = $builder->paginate($perPage, 'default', $page);
        $pager = $builder->pager;

        return $this->respondSuccess([
            'data' => $data,
            'pagination' => [
                'current_page' => $pager->getCurrentPage(),
                'per_page'     => $pager->getPerPage(),
                'total'        => $pager->getTotal(),
                'total_pages'  => $pager->getPageCount(),
            ],
        ], 'Attendance records retrieved successfully');
    }

    public function show($id = null)
    {
        $record = $this->attendance->find($id);

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

        return $this->respondSuccess($record, 'Attendance record retrieved successfully');
    }

    public function store()
    {
        $data = $this->request->getJSON(true);

        $rules = [
            'student_id' => 'required|integer',
            'date'       => 'required|valid_date[Y-m-d]',
            'status'     => 'required|in_list[present,absent,late]',
            'notes'      => 'permit_empty|string',
        ];

        if (!$this->validate($rules)) {
            return $this->respondValidationError($this->validator->getErrors());
        }

        $existing = $this->attendance
            ->where('student_id', $data['student_id'])
            ->where('date', $data['date'])
            ->first();

        if ($existing) {
            return $this->respondError('Attendance already recorded for this student and date', 409);
        }

        $this->attendance->insert($data);
        $id = $this->attendance->getInsertID();

        return $this->respondCreated([
            'id' => $id,
            'data' => $data,
        ], 'Attendance record created successfully');
    }

    public function update($id = null)
    {
        $record = $this->attendance->find($id);

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

        $data = $this->request->getJSON(true);

        $rules = [
            'status' => 'permit_empty|in_list[present,absent,late]',
            'notes'  => 'permit_empty|string',
        ];

        if (!$this->validate($rules)) {
            return $this->respondValidationError($this->validator->getErrors());
        }

        $this->attendance->update($id, $data);

        return $this->respondSuccess($this->attendance->find($id), 'Attendance record updated successfully');
    }

    public function delete($id = null)
    {
        $record = $this->attendance->find($id);

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

        $this->attendance->delete($id);
        return $this->respondDeleted(null, 'Attendance record deleted successfully');
    }

    public function student($id = null)
    {
        $records = $this->attendance
            ->where('student_id', $id)
            ->orderBy('date', 'DESC')
            ->findAll();

        return $this->respondSuccess($records, 'Student attendance retrieved successfully');
    }

    public function classRoster($classSectionId)
    {
        $date = $this->request->getGet('date') ?: date('Y-m-d');
        $db = $this->getDatabaseConnection();

        $rows = $db->table('student_class sc')
            ->select('s.id AS student_id, s.firstname, s.lastname')
            ->join('students s', 's.id = sc.student_id', 'inner')
            ->where('sc.class_section_id', (int)$classSectionId)
            ->where('sc.school_year', $this->schoolYear)
            ->orderBy('s.lastname', 'ASC')->orderBy('s.firstname', 'ASC')
            ->get()->getResultArray();

        $list = [];
        foreach ($rows as $r) {
            $att = $this->attendance->getAttendance((int)$r['student_id'], (int)$classSectionId, $date);
            $list[] = [
                'student_id' => (int)$r['student_id'],
                'firstname'  => $r['firstname'],
                'lastname'   => $r['lastname'],
                'status'     => $att['status'] ?? null,
                'reason'     => $att['reason'] ?? null,
            ];
        }

        return $this->success([
            'class_section_id' => (int)$classSectionId,
            'date'             => $date,
            'students'         => $list,
        ], 'Class roster attendance retrieved');
    }

    public function recordClass($classSectionId)
    {
        $payload = $this->request->getJSON(true) ?? [];
        $date    = isset($payload['date']) ? trim((string)$payload['date']) : '';
        $records = isset($payload['records']) && is_array($payload['records']) ? $payload['records'] : [];

        if ($date === '' || empty($records)) {
            return $this->respondError('Invalid payload: date and records are required.', Response::HTTP_BAD_REQUEST);
        }

        $allowedStatuses = ['present', 'absent', 'late'];
        $now = utc_now();

        DB::beginTransaction();
        try {
            foreach ($records as $record) {
                $studentId = (int) ($record['student_id'] ?? 0);
                $status    = strtolower(trim((string) ($record['status'] ?? '')));
                $reason    = isset($record['reason']) ? trim((string) $record['reason']) : null;

                if ($studentId <= 0 || !in_array($status, $allowedStatuses, true)) {
                    DB::rollBack();
                    return $this->respondError('Invalid record provided.', Response::HTTP_UNPROCESSABLE_ENTITY);
                }

                $existing = $this->attendance
                    ->where('student_id', $studentId)
                    ->where('class_section_id', (int)$classSectionId)
                    ->where('date', $date)
                    ->first();

                $payload = [
                    'class_section_id' => (int) $classSectionId,
                    'student_id'       => $studentId,
                    'status'           => $status,
                    'reason'           => $reason ?: null,
                    'semester'         => $this->semester,
                    'school_year'      => $this->schoolYear,
                    'date'             => $date,
                    'updated_at'       => $now,
                ];

                if ($existing) {
                    $payload['modified_by'] = $this->getCurrentUserId();
                    $this->attendance->update($existing['id'], $payload);
                } else {
                    $payload['created_at']  = $now;
                    $payload['modified_by'] = $this->getCurrentUserId();
                    $this->attendance->insert($payload);
                }
            }

            DB::commit();
        } catch (\Throwable $e) {
            DB::rollBack();
            return $this->respondError('Failed to record attendance.', Response::HTTP_INTERNAL_SERVER_ERROR);
        }

        return $this->success(null, 'Class attendance recorded successfully');
    }

    public function teacherSectionGrid(): JsonResponse
    {
        $semester   = (string) ($this->request->get('semester') ?? $this->semester);
        $schoolYear = (string) ($this->request->get('school_year') ?? $this->schoolYear);
        $date       = (string) ($this->request->get('date') ?? local_date(utc_now(), 'Y-m-d'));
        $sectionCode = (int) ($this->request->get('class_section_id') ?? 0);

        $assignedBySection = (array) ($this->teacherClass->assignedBySectionForTerm($semester, $schoolYear) ?? []);
        $sectionCodes = array_keys($assignedBySection);
        $labels = [];

        if (!empty($sectionCodes)) {
            $labelRows = $this->classSection
                ->select('class_section_id, class_section_name')
                ->whereIn('class_section_id', $sectionCodes)
                ->orderBy('class_section_id', 'ASC')
                ->findAll();

            foreach ($labelRows as $row) {
                $code = (int) ($row['class_section_id'] ?? 0);
                if ($code <= 0) continue;
                $name = trim((string) ($row['class_section_name'] ?? ''));
                $labels[$code] = $name !== '' ? $name : ('Section #' . $code);
            }

            foreach ($sectionCodes as $code) {
                if (!isset($labels[$code])) {
                    $labels[$code] = 'Section #' . $code;
                }
            }
        }

        $grid   = [];
        $locked = false;

        if ($sectionCode > 0) {
            $assigned = (array) ($this->teacherClass->assignedForSectionTerm($sectionCode, $semester, $schoolYear) ?? []);
            $teacherIds = array_map(static fn($row) => (int) ($row['teacher_id'] ?? 0), $assigned);
            $teacherIds = array_values(array_filter($teacherIds));

            $statusMap = [];
            if (!empty($teacherIds)) {
                $rows = DB::table('staff_attendance as sa')
                    ->select('sa.user_id', 'sa.status', 'sa.reason')
                    ->where('sa.semester', $semester)
                    ->where('sa.school_year', $schoolYear)
                    ->where('sa.date', $date)
                    ->whereIn('sa.user_id', $teacherIds)
                    ->get();

                foreach ($rows as $row) {
                    $statusMap[(int) $row->user_id] = [
                        'status' => $row->status ?? null,
                        'reason' => $row->reason ?? null,
                    ];
                }
            }

            foreach ($assigned as $teacherRow) {
                $tid  = (int) ($teacherRow['teacher_id'] ?? 0);
                $name = trim(($teacherRow['firstname'] ?? '') . ' ' . ($teacherRow['lastname'] ?? ''));
                $name = $name !== '' ? $name : 'User #' . $tid;
                $posRaw = strtolower((string) ($teacherRow['position'] ?? 'main'));
                $pos    = in_array($posRaw, ['main', 'ta'], true) ? $posRaw : 'main';
                $cell   = $statusMap[$tid] ?? ['status' => null, 'reason' => null];

                $grid[] = [
                    'teacher_id' => $tid,
                    'name'       => $name,
                    'position'   => $pos,
                    'status'     => $cell['status'],
                    'reason'     => $cell['reason'],
                ];
            }

            try {
                $locked = (bool) $this->attendanceDay->isFinalized($sectionCode, $date, $semester, $schoolYear);
            } catch (\Throwable $e) {
                $locked = false;
            }
        }

        return $this->success([
            'semester'         => $semester,
            'school_year'      => $schoolYear,
            'date'             => $date,
            'class_section_id' => $sectionCode,
            'sections'         => $labels,
            'grid'             => $grid,
            'locked'           => $locked,
        ], 'Teacher attendance grid retrieved');
    }

    public function teacherUpdateData(): JsonResponse
    {
        $teacherId = (int) ($this->request->get('teacher_id') ?? $this->getCurrentUserId() ?? 0);
        if ($teacherId <= 0) {
            return $this->respondError('Teacher not found or unauthorized.', Response::HTTP_UNAUTHORIZED);
        }

        $classSectionParam = (int) ($this->request->get('class_section_id') ?? 0);
        if ($classSectionParam <= 0) {
            $classSection = $this->teacherClass->getClassSectionIdByUserId($teacherId);
            if (empty($classSection)) {
                return $this->respondError('No class assigned to this teacher.', Response::HTTP_BAD_REQUEST);
            }
            $classSectionId = (int) ($classSection['class_section_id'] ?? 0);
        } else {
            $classSectionId = $classSectionParam;
        }

        if ($classSectionId <= 0) {
            return $this->respondError('Invalid class section.', Response::HTTP_BAD_REQUEST);
        }

        $semester   = (string) ($this->request->get('semester') ?? $this->semester);
        $schoolYear = (string) ($this->request->get('school_year') ?? $this->schoolYear);
        $today      = local_date(utc_now(), 'Y-m-d');

        $recentDatesRows = $this->attendance
            ->select('date')
            ->distinct()
            ->orderBy('date', 'DESC')
            ->limit(3)
            ->findAll();

        $recentDates = array_map(static fn($row) => (string) ($row['date'] ?? ''), $recentDatesRows);
        $recentDates = array_values(array_filter($recentDates, static fn($d) => $d !== ''));
        $allDates = array_values(array_unique(array_merge([$today], $recentDates)));

        $dateSlots = [
            'day_before_before_yesterday' => $allDates[3] ?? null,
            'day_before_yesterday'        => $allDates[2] ?? null,
            'yesterday'                   => $allDates[1] ?? null,
            'today'                       => $allDates[0] ?? $today,
        ];

        $teacher = $this->user->find($teacherId);
        $teacherName = $teacher ? trim(($teacher['firstname'] ?? '') . ' ' . ($teacher['lastname'] ?? '')) : 'Teacher';

        $students = (array) ($this->student->getByClassAndYear($classSectionId, $schoolYear) ?? []);
        $studentIds = array_map(static fn($row) => (int) ($row['id'] ?? 0), $students);
        $studentIds = array_values(array_filter($studentIds));

        $studentAttendance = [];
        if (!empty($studentIds) && !empty($allDates)) {
            $rows = $this->attendance
                ->newQuery()
                ->whereIn('student_id', $studentIds)
                ->whereIn('date', $allDates)
                ->get()
                ->map(fn($row) => (array) $row)
                ->toArray();

            foreach ($rows as $row) {
                $studentAttendance[(int) $row['student_id']][$row['date']] = $row['status'] ?? null;
            }
        }

        $studentsPayload = [];
        foreach ($students as $student) {
            $sid = (int) ($student['id'] ?? 0);
            $slots = [];
            foreach ($dateSlots as $key => $date) {
                $slots[$key] = $date ? ($studentAttendance[$sid][$date] ?? 'N/A') : 'N/A';
            }

            $studentsPayload[] = [
                'id'        => $sid,
                'firstname' => $student['firstname'] ?? '',
                'lastname'  => $student['lastname'] ?? '',
                'school_id' => $student['school_id'] ?? '',
                'statuses'  => $slots,
            ];
        }

        $assignedTeachers = (array) ($this->teacherClass->assignedForSectionTerm($classSectionId, $semester, $schoolYear) ?? []);
        $teacherIds = array_map(static fn($row) => (int) ($row['teacher_id'] ?? 0), $assignedTeachers);
        $teacherIds = array_values(array_filter($teacherIds));

        $teacherStatusMap = [];
        if (!empty($teacherIds) && !empty($allDates)) {
            $rows = DB::table('staff_attendance')
                ->select('user_id', 'date', 'status')
                ->where('semester', $semester)
                ->where('school_year', $schoolYear)
                ->whereIn('user_id', $teacherIds)
                ->whereIn('date', $allDates)
                ->get();

            foreach ($rows as $row) {
                $teacherStatusMap[(int) $row->user_id][$row->date] = $row->status ?? null;
            }
        }

        $teacherRows = [];
        foreach ($assignedTeachers as $row) {
            $tid = (int) ($row['teacher_id'] ?? 0);
            $posRaw = strtolower((string) ($row['position'] ?? 'main'));
            $position = in_array($posRaw, ['main', 'ta'], true) ? $posRaw : 'main';
            $name = trim(($row['firstname'] ?? '') . ' ' . ($row['lastname'] ?? ''));
            if ($name === '') {
                $name = 'User #' . $tid;
            }

            $slots = [];
            foreach ($dateSlots as $key => $date) {
                $slots[$key] = $date ? ($teacherStatusMap[$tid][$date] ?? 'N/A') : 'N/A';
            }

            $teacherRows[] = [
                'teacher_id' => $tid,
                'name'       => $name,
                'position'   => $position,
                'statuses'   => $slots,
            ];
        }

        $wantedDates = array_values(array_filter(array_unique(array_filter($dateSlots))));
        $noSchool = [];
        if (!empty($wantedDates)) {
            $events = $this->calendar
                ->where('no_school', 1)
                ->whereIn('date', $wantedDates)
                ->where('semester', $semester)
                ->where('school_year', $schoolYear)
                ->findAll();

            foreach ($events as $event) {
                $d = (string) ($event['date'] ?? '');
                if ($d === '') continue;
                $noSchool[$d] = [
                    'title'       => $event['title'] ?? 'No School',
                    'description' => $event['description'] ?? '',
                ];
            }
        }

        return $this->success([
            'teacher' => [
                'id'   => $teacherId,
                'name' => $teacherName,
            ],
            'class_section_id' => $classSectionId,
            'semester'         => $semester,
            'school_year'      => $schoolYear,
            'dates'            => $dateSlots,
            'students'         => $studentsPayload,
            'teachers'         => $teacherRows,
            'no_school_days'   => $noSchool,
            'enable_attendance'=> $this->enableAttendance,
        ], 'Teacher attendance update data retrieved');
    }
}