function fetch_stock_data() {
    $output = shell_exec('python3 fetch_stocks.py');
    if ($output === null) {
        error_log("Python script did not execute properly.");
        return false;
    }
    $data = json_decode($output, true);
    if (json_last_error() !== JSON_ERROR_NONE) {
        error_log("JSON decode error: " . json_last_error_msg());
        error_log("Python script output: " . $output);
        return false;
    }
    return $data;
}

function display_stock_screener() {
    $stocks = fetch_stock_data();

    if (!$stocks) {
        return "Error fetching stock data. Check the error log for details.";
    }

    // Build HTML output
    $output = "<h1>Top 15 Most Active Stocks Under $11 with Largest Gap</h1>";
    $output .= "<table border='1'>";
    $output .= "<tr><th>Symbol</th><th>Price</th><th>Volume</th><th>Gap</th></tr>";
    foreach ($stocks as $stock) {
        $output .= "<tr>";
        $output .= "<td>{$stock['symbol']}</td>";
        $output .= "<td>{$stock['price']}</td>";
        $output .= "<td>{$stock['volume']}</td>";
        $output .= "<td>{$stock['gap']}</td>";
        $output .= "</tr>";
    }
    $output .= "</table>";

    return $output;
}
XML-RPC server accepts POST requests only.