<?php
require_once __DIR__ . '/db/config.php';

// Basic validation
if ($_SERVER['REQUEST_METHOD'] !== 'POST' || !isset($_FILES['csvFile'])) {
    header('Location: analyst_dashboard.php?error=' . urlencode('Invalid request.'));
    exit;
}

$file = $_FILES['csvFile'];

// Check for upload errors
if ($file['error'] !== UPLOAD_ERR_OK) {
    header('Location: analyst_dashboard.php?error=' . urlencode('File upload error: ' . $file['error']));
    exit;
}

// Check file type
$mime_type = mime_content_type($file['tmp_name']);
if ($mime_type !== 'text/csv' && $mime_type !== 'text/plain') {
    header('Location: analyst_dashboard.php?error=' . urlencode('Invalid file type. Please upload a CSV file.'));
    exit;
}

$handle = fopen($file['tmp_name'], 'r');
if ($handle === false) {
    header('Location: analyst_dashboard.php?error=' . urlencode('Could not open the uploaded file.'));
    exit;
}

// Validate header
$header = fgetcsv($handle);
if ($header === false || count($header) !== 1 || strtolower(trim($header[0])) !== 'name') {
    fclose($handle);
    header('Location: analyst_dashboard.php?error=' . urlencode('Invalid CSV header. The first column must be "Name".'));
    exit;
}

$pdo = db();
$stmt = $pdo->prepare("INSERT INTO submissions (name) VALUES (:name)");

$importedCount = 0;
$rowCount = 0;

while (($data = fgetcsv($handle)) !== false) {
    $rowCount++;
    if ($rowCount > 1000) {
        // Stop processing if the file exceeds the row limit
        break;
    }

    if (isset($data[0]) && !empty(trim($data[0]))) {
        try {
            $stmt->execute(['name' => trim($data[0])]);
            $importedCount++;
        } catch (PDOException $e) {
            // You might want to log this error instead of ignoring it
            // error_log("CSV Import Error: " . $e->getMessage());
            continue; // Continue to the next row
        }
    }
}

fclose($handle);

// Trigger the background worker now that new submissions are in
if ($importedCount > 0) {
    shell_exec('php /home/ubuntu/executor/workspace/worker.php > /dev/null 2>&1 &');
}

if ($rowCount > 1000) {
    header('Location: analyst_dashboard.php?error=' . urlencode('CSV file exceeds the 1000-row limit. Only the first 1000 rows were processed.') . '&success=' . $importedCount);
} else {
    header('Location: analyst_dashboard.php?success=' . $importedCount);
}
exit;