Rejestr obecności

{
  "attendance": [
    {
      "id": 1,
      "date": "2026-02-10",
      "student": "Jan Kowalski",
      "student_id": "1A01",
      "status": "present",
      "notes": "",
      "recorded_by": "Nauczyciel",
      "created_at": "2026-02-10 08:15:00"
    },
    {
      "id": 2,
      "date": "2026-02-10",
      "student": "Anna Nowak",
      "student_id": "1A02",
      "status": "late",
      "notes": "Spóźnienie 10 min",
      "recorded_by": "Nauczyciel",
      "created_at": "2026-02-10 08:20:00"
    },
    {
      "id": 3,
      "date": "2026-02-10",
      "student": "Piotr Wiśniewski",
      "student_id": "1A03",
      "status": "absent",
      "notes": "Choroba - zwolnienie lekarskie",
      "recorded_by": "Nauczyciel",
      "created_at": "2026-02-10 08:00:00"
    }
  ]
}

$date = $_POST['date'] ?? '';
$student = trim($_POST['student'] ?? '');
$status = $_POST['status'] ?? '';

$validStatuses = ['present', 'absent', 'late', 'excused'];

if (empty($date)) {
    $errors[] = "Data jest wymagana";
}

if (empty($student)) {
    $errors[] = "Wybierz ucznia";
}

if (!in_array($status, $validStatuses)) {
    $errors[] = "Nieprawidłowy status obecności";
}

// Walidacja formatu daty
if (!preg_match('/^\d{4}-\d{2}-\d{2}$/', $date)) {
    $errors[] = "Nieprawidłowy format daty (YYYY-MM-DD)";
}

// Data nie może być z przyszłości
if ($date > date('Y-m-d')) {
    $errors[] = "Data nie może być z przyszłości";
}

function getStatuses(): array {
    return [
        'present' => ['label' => 'Obecny', 'icon' => '✅', 'color' => '#27ae60'],
        'absent' => ['label' => 'Nieobecny', 'icon' => '❌', 'color' => '#e74c3c'],
        'late' => ['label' => 'Spóźniony', 'icon' => '⏰', 'color' => '#f39c12'],
        'excused' => ['label' => 'Usprawiedliwiony', 'icon' => '📋', 'color' => '#3498db'],
    ];
}

function getStatusLabel(string $status): string {
    $statuses = getStatuses();
    return $statuses[$status]['label'] ?? 'Nieznany';
}

function getStatusColor(string $status): string {
    $statuses = getStatuses();
    return $statuses[$status]['color'] ?? '#95a5a6';
}

function addAttendance(array &$attendance, array $data): int {
    $newId = empty($attendance) ? 1 : max(array_column($attendance, 'id')) + 1;

    $newEntry = [
        'id' => $newId,
        'date' => $data['date'],
        'student' => $data['student'],
        'student_id' => $data['student_id'] ?? '',
        'status' => $data['status'],
        'notes' => $data['notes'] ?? '',
        'recorded_by' => $data['recorded_by'] ?? 'System',
        'created_at' => date('Y-m-d H:i:s'),
    ];

    $attendance[] = $newEntry;
    return $newId;
}

function getStudentSummary(array $attendance, string $student): array {
    $studentRecords = array_filter($attendance, fn($a) => $a['student'] === $student);

    $counts = [
        'present' => 0,
        'absent' => 0,
        'late' => 0,
        'excused' => 0,
    ];

    foreach ($studentRecords as $record) {
        $status = $record['status'];
        if (isset($counts[$status])) {
            $counts[$status]++;
        }
    }

    $total = count($studentRecords);
    $attended = $counts['present'] + $counts['late'];
    $frequency = $total > 0 ? round(($attended / $total) * 100, 1) : 0;

    return [
        'student' => $student,
        'total' => $total,
        'counts' => $counts,
        'frequency' => $frequency,
    ];
}

function getDaySummary(array $attendance, string $date): array {
    $dayRecords = array_filter($attendance, fn($a) => $a['date'] === $date);

    $statusCounts = array_count_values(array_column($dayRecords, 'status'));

    $total = count($dayRecords);
    $present = ($statusCounts['present'] ?? 0) + ($statusCounts['late'] ?? 0);
    $frequency = $total > 0 ? round(($present / $total) * 100, 1) : 0;

    return [
        'date' => $date,
        'total' => $total,
        'present' => $statusCounts['present'] ?? 0,
        'absent' => $statusCounts['absent'] ?? 0,
        'late' => $statusCounts['late'] ?? 0,
        'excused' => $statusCounts['excused'] ?? 0,
        'frequency' => $frequency,
    ];
}

function filterByDate(array $attendance, string $date): array {
    return array_filter($attendance, fn($a) => $a['date'] === $date);
}

function filterByStudent(array $attendance, string $student): array {
    return array_filter($attendance, fn($a) => $a['student'] === $student);
}

function filterByStatus(array $attendance, string $status): array {
    return array_filter($attendance, fn($a) => $a['status'] === $status);
}

function sortByDate(array $attendance, string $order = 'desc'): array {
    usort($attendance, function($a, $b) use ($order) {
        $result = strcmp($a['date'], $b['date']);
        return $order === 'desc' ? -$result : $result;
    });

    return $attendance;
}

function generateReport(array $attendance, string $dateFrom, string $dateTo): string {
    $filtered = array_filter($attendance, function($a) use ($dateFrom, $dateTo) {
        return $a['date'] >= $dateFrom && $a['date'] <= $dateTo;
    });

    $students = array_unique(array_column($filtered, 'student'));
    sort($students);

    $html = '<!DOCTYPE html><html><head><meta charset="UTF-8">';
    $html .= '<title>Raport obecności ' . $dateFrom . ' - ' . $dateTo . '</title>';
    $html .= '<style>table { border-collapse: collapse; width: 100%; }';
    $html .= 'th, td { border: 1px solid #ddd; padding: 8px; text-align: left; }';
    $html .= 'th { background: #333; color: white; }</style></head><body>';
    $html .= '<h1>Raport obecności</h1>';
    $html .= '<p>Okres: ' . $dateFrom . ' - ' . $dateTo . '</p>';
    $html .= '<table><tr><th>Uczeń</th><th>Obecny</th><th>Nieobecny</th><th>Spóźniony</th><th>Frekwencja</th></tr>';

    foreach ($students as $student) {
        $summary = getStudentSummary($filtered, $student);
        $html .= '<tr>';
        $html .= '<td>' . htmlspecialchars($student) . '</td>';
        $html .= '<td>' . $summary['counts']['present'] . '</td>';
        $html .= '<td>' . $summary['counts']['absent'] . '</td>';
        $html .= '<td>' . $summary['counts']['late'] . '</td>';
        $html .= '<td>' . $summary['frequency'] . '%</td>';
        $html .= '</tr>';
    }

    $html .= '</table></body></html>';
    return $html;
}