function action_woocommerce_email_before_order_table( $order, $sent_to_admin, $plain_text, $email ) {
if ( $email->id == 'customer_completed_order' ) {
$cat_one = false;
$cat_two = false;
$cat_three = false;
$cat_four = false;
$output = '';
foreach ( $order->get_items() as $item ) {
$product_id = $item->get_variation_id() > 0 ? $item->get_variation_id() : $item->get_product_id();
if ( has_term( 'cat-one', 'product_cat', $product_id ) ) {
$cat_one = true;
}
if ( has_term( 'cat-two', 'product_cat', $product_id ) ) {
$cat_two = true;
}
if ( has_term( 'cat-three', 'product_cat', $product_id ) ) {
$cat_three = true;
}
if ( has_term( 'cat-four', 'product_cat', $product_id ) ) {
$cat_four = true;
}
}
if ( $cat_one ) {
$output = "SOME TEXT";
if ( $cat_two || $cat_three || $cat_four ) {
$output = "SOME OTHER TEXT";
}
} else {
if ( $cat_two && $cat_three && $cat_four ) {
$output = "ANOTHER TEXT";
}
}
echo $output;
}
}
add_action( 'woocommerce_email_before_order_table', 'action_woocommerce_email_before_order_table', 10, 4 );