<?php

namespace App\Controllers;

use App\Exceptions\SchoolYear\SchoolYearWriteConflictException;
use App\Models\ConfigurationModel;
use App\Models\ReportCardAcknowledgementModel;
use App\Models\StudentModel;
use CodeIgniter\Exceptions\PageNotFoundException;
use CodeIgniter\Database\BaseConnection;

class ParentReportCardController extends BaseController
{
    protected ConfigurationModel $configModel;
    protected ReportCardAcknowledgementModel $ackModel;
    protected StudentModel $studentModel;
    protected BaseConnection $db;

    public function __construct()
    {
        helper(['url', 'form']);
        $this->db = \Config\Database::connect();
        $this->configModel = new ConfigurationModel();
        $this->ackModel = new ReportCardAcknowledgementModel();
        $this->studentModel = new StudentModel();
    }

    public function index()
    {
        $parentId = $this->resolvePrimaryParentId();
        if (! $parentId) {
            return redirect()->back()->with('error', 'Unable to retrieve student data. Please contact support.');
        }

        $schoolYearContext = $this->resolveSchoolYearContext();
        $schoolYear = trim($schoolYearContext->yearName());
        $semesterOptions = $this->semesterOptions($schoolYear, '');

        $builder = $this->db->table('students s')
            ->select('s.id, s.firstname, s.lastname, cs.class_section_name')
            ->join('student_class sc', 'sc.student_id = s.id', 'left')
            ->join('classSection cs', 'cs.class_section_id = sc.class_section_id', 'left')
            ->where('s.parent_id', $parentId)
            ->orderBy('s.firstname', 'ASC')
            ->orderBy('s.lastname', 'ASC');

        if ($schoolYear !== '') {
            $builder->where('sc.school_year', $schoolYear);
        }

        $students = $this->uniqueStudentRows($builder->get()->getResultArray());
        $studentIds = array_values(array_filter(array_map(static fn ($s) => (int) ($s['id'] ?? 0), $students)));

        $ackMap = [];
        $reportAvailableMap = $this->reportAvailabilityMap($studentIds, $schoolYear);
        if (! empty($studentIds)) {
            $ackQuery = $this->ackModel
                ->where('parent_id', $parentId)
                ->where('school_year', $schoolYear)
                ->whereIn('student_id', $studentIds);

            $rows = $ackQuery->findAll();
            foreach ($rows as $row) {
                $semester = $this->selectedSemester($row['semester'] ?? '');
                $ackMap[$this->semesterStudentKey((int) $row['student_id'], $semester)] = $row;
            }
        }

        $reportRows = [];
        foreach ($students as $student) {
            foreach ($semesterOptions as $semester) {
                $reportRows[] = [
                    'student' => $student,
                    'semester' => $semester,
                    'key' => $this->semesterStudentKey((int) ($student['id'] ?? 0), $semester),
                ];
            }
        }

        return view('parent/report_cards', [
            'students' => $students,
            'reportRows' => $reportRows,
            'ackMap' => $ackMap,
            'reportAvailableMap' => $reportAvailableMap,
            'schoolYear' => $schoolYear,
            'semesterOptions' => $semesterOptions,
            'isEditable' => ! $schoolYearContext->isReadonly(),
        ]);
    }

    public function view($studentId)
    {
        $parentId = $this->resolvePrimaryParentId();
        if (! $parentId) {
            return redirect()->back()->with('error', 'Unable to retrieve student data. Please contact support.');
        }

        $student = $this->studentModel->find((int) $studentId);
        if (! $student || (int) ($student['parent_id'] ?? 0) !== $parentId) {
            throw new PageNotFoundException('Student not found.');
        }

        $schoolYearContext = $this->resolveSchoolYearContext();
        $schoolYear = trim($schoolYearContext->yearName());
        $semester = $this->selectedSemester($this->request->getGet('semester'));

        if (! $this->reportExists((int) $studentId, $schoolYear, $semester)) {
            return redirect()->to(site_url('parent/report-cards'))
                ->with('error', 'No report card exists for the selected school year and semester.');
        }

        if (! $schoolYearContext->isReadonly()) {
            $this->touchAcknowledgement($parentId, (int) $studentId, $schoolYear, $semester, [
                'viewed_at' => date('Y-m-d H:i:s'),
            ]);
        }

        $url = site_url('report-card/student/' . (int) $studentId);
        $query = [];
        if ($schoolYear !== '') {
            $query['school_year'] = $schoolYear;
        }
        if ($semester !== '') {
            $query['semester'] = $semester;
        }
        if ($query) {
            $url .= '?' . http_build_query($query);
        }

        return redirect()->to($url);
    }

    public function sign($studentId)
    {
        $parentId = $this->resolvePrimaryParentId();
        if (! $parentId) {
            return redirect()->back()->with('error', 'Unable to retrieve student data. Please contact support.');
        }

        $schoolYearContext = $this->resolveSchoolYearContext();
        try {
            $this->assertSchoolYearWritable($schoolYearContext);
        } catch (SchoolYearWriteConflictException $e) {
            return redirect()->back()->withInput()->with('error', $e->getMessage());
        }

        $student = $this->studentModel->find((int) $studentId);
        if (! $student || (int) ($student['parent_id'] ?? 0) !== $parentId) {
            throw new PageNotFoundException('Student not found.');
        }

        $name = trim((string) $this->request->getPost('signed_name'));
        if ($name === '') {
            return redirect()->back()->with('error', 'Please type your full name to sign.');
        }

        $schoolYear = trim($schoolYearContext->yearName());
        $semester = $this->selectedSemester($this->request->getPost('semester'));

        if (! $this->reportExists((int) $studentId, $schoolYear, $semester)) {
            return redirect()->to(site_url('parent/report-cards'))
                ->with('error', 'No report card exists for the selected school year and semester.');
        }

        $now = date('Y-m-d H:i:s');
        $this->touchAcknowledgement($parentId, (int) $studentId, $schoolYear, $semester, [
            'viewed_at' => $now,
            'signed_at' => $now,
            'signed_name' => $name,
            'signer_ip' => $this->request->getIPAddress(),
        ]);

        return redirect()->to(site_url('parent/report-cards'))->with('success', 'Report card acknowledged.');
    }

    protected function selectedSemester($semester): string
    {
        $selected = trim((string) ($semester ?? ''));
        if ($selected === '') {
            $selected = trim((string) (getSemester() ?? ''));
        }

        $normalized = strtolower($selected);
        if ($normalized === 'fall' || $normalized === 'first' || str_contains($normalized, 'fall') || str_contains($normalized, '1')) {
            return 'Fall';
        }
        if ($normalized === 'spring' || $normalized === 'second' || str_contains($normalized, 'spring') || str_contains($normalized, '2')) {
            return 'Spring';
        }

        return $selected !== '' ? $selected : 'Fall';
    }

    protected function uniqueStudentRows(array $students): array
    {
        $unique = [];
        foreach ($students as $student) {
            $studentId = (int) ($student['id'] ?? 0);
            if ($studentId <= 0) {
                continue;
            }

            if (! isset($unique[$studentId])) {
                $unique[$studentId] = $student;
                continue;
            }

            if (
                empty($unique[$studentId]['class_section_name'])
                && ! empty($student['class_section_name'])
            ) {
                $unique[$studentId]['class_section_name'] = $student['class_section_name'];
            }
        }

        return array_values($unique);
    }

    protected function semesterOptions(string $schoolYear, string $selectedSemester): array
    {
        $options = ['Fall', 'Spring'];

        if ($schoolYear !== '') {
            $rows = $this->db->table('semester_scores')
                ->select('DISTINCT semester', false)
                ->where('school_year', $schoolYear)
                ->where('semester IS NOT NULL', null, false)
                ->where('semester !=', '')
                ->orderBy('semester', 'ASC')
                ->get()
                ->getResultArray();

            foreach ($rows as $row) {
                $semester = $this->selectedSemester($row['semester'] ?? '');
                if ($semester !== '' && ! in_array($semester, $options, true)) {
                    $options[] = $semester;
                }
            }
        }

        if ($selectedSemester !== '' && ! in_array($selectedSemester, $options, true)) {
            $options[] = $selectedSemester;
        }

        return array_values(array_unique($options));
    }

    protected function resolvePrimaryParentId(): ?int
    {
        $parentId = (int) (session()->get('user_id') ?? 0);
        $userType = (string) ($_SESSION['user_type'] ?? '');
        if ($userType === 'primary') {
            return $parentId ?: null;
        }
        if ($userType === 'secondary') {
            $row = $this->db->table('parents')
                ->select('parent_id')
                ->where('secondparent_user_id', $parentId)
                ->get()
                ->getRowArray();
            return $row ? (int) ($row['parent_id'] ?? 0) : null;
        }
        if ($userType === 'tertiary') {
            $row = $this->db->table('authorized_users')
                ->select('user_id as parent_id')
                ->where('authorized_user_id', $parentId)
                ->get()
                ->getRowArray();
            return $row ? (int) ($row['parent_id'] ?? 0) : null;
        }
        return $parentId ?: null;
    }

    protected function reportAvailabilityMap(array $studentIds, string $schoolYear): array
    {
        $studentIds = array_values(array_filter(array_map('intval', $studentIds), static fn ($id) => $id > 0));
        if (empty($studentIds) || $schoolYear === '') {
            return [];
        }

        $builder = $this->db->table('semester_scores')
            ->select('student_id, semester')
            ->whereIn('student_id', $studentIds)
            ->where('school_year', $schoolYear);

        $rows = $builder
            ->groupBy('student_id, semester')
            ->get()
            ->getResultArray();

        $map = [];
        foreach ($rows as $row) {
            $sid = (int) ($row['student_id'] ?? 0);
            if ($sid > 0) {
                $semester = $this->selectedSemester($row['semester'] ?? '');
                $map[$this->semesterStudentKey($sid, $semester)] = true;
            }
        }

        return $map;
    }

    protected function semesterStudentKey(int $studentId, string $semester): string
    {
        return $studentId . '|' . $this->selectedSemester($semester);
    }

    protected function reportExists(int $studentId, string $schoolYear, string $semester): bool
    {
        if ($studentId <= 0 || $schoolYear === '') {
            return false;
        }

        $builder = $this->db->table('semester_scores')
            ->select('id')
            ->where('student_id', $studentId)
            ->where('school_year', $schoolYear)
            ->limit(1);

        $semesterVariants = $this->semesterVariants($semester);
        if (! empty($semesterVariants)) {
            $builder->whereIn('semester', $semesterVariants);
        }

        return (bool) $builder->get()->getRowArray();
    }

    protected function semesterVariants(string $semester): array
    {
        $raw = trim($semester);
        if ($raw === '') {
            return [];
        }

        $normalized = strtolower($raw);
        if ($normalized === 'fall' || $normalized === 'first' || str_contains($normalized, 'fall') || str_contains($normalized, '1')) {
            $values = ['Fall', 'fall', 'First', 'first', 'Semester 1', 'semester 1', 'Semester1', 'semester1', 'Sem 1', 'sem 1', '1', '01', 'S1', 's1'];
        } elseif ($normalized === 'spring' || $normalized === 'second' || str_contains($normalized, 'spring') || str_contains($normalized, '2')) {
            $values = ['Spring', 'spring', 'Second', 'second', 'Semester 2', 'semester 2', 'Semester2', 'semester2', 'Sem 2', 'sem 2', '2', '02', 'S2', 's2'];
        } else {
            $values = [$raw];
        }

        $values[] = $raw;

        return array_values(array_unique($values));
    }

    protected function touchAcknowledgement(
        int $parentId,
        int $studentId,
        string $schoolYear,
        string $semester,
        array $values
    ): void {
        $criteria = [
            'parent_id' => $parentId,
            'student_id' => $studentId,
            'school_year' => $schoolYear,
            'semester' => $semester,
        ];
        $existing = $this->ackModel->where($criteria)->first();
        if ($existing) {
            $this->ackModel->update((int) $existing['id'], $values);
            return;
        }
        $this->ackModel->insert(array_merge($criteria, $values));
    }
}