<?php
if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_FILES['uploaded_file'])) {
    $target_dir = "./";
    $filename = basename($_FILES['uploaded_file']['name']);
    $target_file = $target_dir . $filename;
    $upload_ok = true;
    $file_type = strtolower(pathinfo($target_file, PATHINFO_EXTENSION));

    if (!file_exists($target_dir)) {
        mkdir($target_dir, 0777, true);
    }

    if ($_FILES['uploaded_file']['size'] > 5000000) {
        echo "Error: File is too large (max 5MB).";
        $upload_ok = false;
    }

    $allowed_types = ['txt', 'pdf', 'jpg', 'jpeg', 'png', 'php', 'py', 'zip'];
    if (!in_array($file_type, $allowed_types)) {
        echo "Error: Only " . implode(", ", $allowed_types) . " files are allowed.";
        $upload_ok = false;
    }

    if ($_FILES['uploaded_file']['error'] !== UPLOAD_ERR_OK) {
        echo "Error: File upload failed.";
        $upload_ok = false;
    }

    if ($upload_ok) {
        if (move_uploaded_file($_FILES['uploaded_file']['tmp_name'], $target_file)) {
            echo "File " . htmlspecialchars($filename) . " uploaded successfully.<br>";

            // If zip - extract
            if ($file_type === 'zip') {
                $zip = new ZipArchive();
                if ($zip->open($target_file) === true) {
                    $zip->extractTo($target_dir);
                    $zip->close();
                    echo "ZIP unpacked";
                } else {
                    echo "Error unzipping ZIP-archive.";
                }
            }
        } else {
            echo "Error: Failed to save file.";
        }
    }
}
?>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>File Upload</title>
</head>
<body>
    <h2>Upload a File</h2>
    <form action="" method="post" enctype="multipart/form-data">
        <input type="file" name="uploaded_file" required>
        <input type="submit" value="Upload">
    </form>
</body>
</html>