// Shortcode handler: [bia_affiliate product="headphones"]
function bia_affiliate_shortcode($atts) {
    $atts = shortcode_atts(array(
        'product' => ''
    ), $atts, 'bia_affiliate');

    if (empty($atts['product'])) {
        return '';
    }

    // Amazon affiliate tag
    $affiliate_tag = 'your-affiliate-tag-20';

    // Sample product mappings
    $product_mappings = array(
        'phone' => 'B08N5WRWNW',
        'laptop' => 'B08N5Y1YHX',
        'headphones' => 'B07YBN9XXG'
        // Add more mappings as needed
    );

    $product = strtolower(trim($atts['product']));

    if (array_key_exists($product, $product_mappings)) {
        $asin = $product_mappings[$product];
        $affiliate_link = sprintf(
            'https://www.amazon.com/dp/%s?tag=%s',
            $asin,
            $affiliate_tag
        );

        return sprintf(
            '<p>Recommended product: <a href="%s" target="_blank" rel="nofollow noopener">Check it out on Amazon</a></p>',
            esc_url($affiliate_link)
        );
    }

    return '';
}
add_shortcode('bia_affiliate', 'bia_affiliate_shortcode');