<?php
// export_attendance_advanced.php

include('session_validator.php');
include('includes/db_pdo.php');

// Get export parameters
$academic_year = $_POST['academic_year'] ?? '';
$class_id = $_POST['class_id'] ?? '';
$section_ids = $_POST['section_ids'] ?? [];
$nepali_months = $_POST['nepali_months'] ?? [];
$min_attendance = isset($_POST['min_attendance']) && $_POST['min_attendance'] !== '' ? floatval($_POST['min_attendance']) : null;
$max_attendance = isset($_POST['max_attendance']) && $_POST['max_attendance'] !== '' ? floatval($_POST['max_attendance']) : null;
$view_type = $_POST['view_type'] ?? 'monthly';
$data_display = $_POST['data_display'] ?? 'percentage';
$export_type = $_POST['export_type'] ?? 'excel';

// Fetch data using the same logic as get_attendance_report_data_advanced.php
// ... (same query logic as above)

// Generate export based on type
if ($export_type == 'excel') {
    header('Content-Type: application/vnd.ms-excel');
    header('Content-Disposition: attachment; filename="attendance_report_' . date('Y-m-d') . '.xls"');
    
    // Output HTML table for Excel
    echo '<table border="1">';
    // ... table generation code
    echo '</table>';
    
} elseif ($export_type == 'csv') {
    header('Content-Type: text/csv');
    header('Content-Disposition: attachment; filename="attendance_report_' . date('Y-m-d') . '.csv"');
    
    $output = fopen('php://output', 'w');
    // ... CSV generation code
    fclose($output);
    
} elseif ($export_type == 'pdf') {
    // You might want to use a PDF library like TCPDF or Dompdf
    // For simplicity, we'll redirect to a PDF generation script
    header('Location: generate_attendance_pdf.php?' . http_build_query($_POST));
}
?>