# Filters and hooks - Preorderline 1.x documentation

> React to pre-orders being placed and released, or extend Preorderline with modes, settings and payment handling from code.

Preorderline's hooks are WordPress actions and filters. Put the examples in a small custom plugin or your child theme's `functions.php`. Preorderline Pro is built on the same hooks.

## Data

| Where | Key | Value |
|---|---|---|
| Product or variation meta | `_preorderline_mode` | `launch`, `off` (a variation only), an add-on's mode, or empty |
| | `_preorderline_date` | Local date and time, `Y-m-d\TH:i`, or empty |
| | `_preorderline_message` | The product's own availability text |
| Order item meta | `_preorderline_date` | Release timestamp (0 without a date). Marks the line as a pre-order |
| | `_preorderline_released` | When the line was released |
| Order meta | `_preorderline_charge` | `upfront` (Preorderline Pro also uses `release` and `deposit`) |
| | `_preorderline_released` | When the order was released |
| Order status | `wc-pre-ordered` | |

`Extendiment\Preorderline\Preorder` and `Extendiment\Preorderline\Orders` read them for you, for example `Preorder::is_active( $product )`, `Preorder::date( $product )` and `Orders::waiting_items( $order )`.

## Actions

### preorderline_order_preordered

An order entered the Pre-ordered status. Gets the order and its previous status.

```php
add_action( 'preorderline_order_preordered', function ( $order, $from ) {
	// e.g. tag the customer in your mailing list.
}, 10, 2 );
```

### preorderline_order_released

An order's pre-orders were released and it moved on. Gets the order, the ID of the Preorderline email that's sent (`preorderline_customer_released` for a paid order, empty when Preorderline has none for it) and details for the email.

```php
add_action( 'preorderline_order_released', function ( $order, $email, $data ) {
	error_log( 'Pre-order released: #' . $order->get_order_number() );
}, 10, 3 );
```

### preorderline_product_released

A product's (or a variation's) pre-orders were released. Gets its ID and the number of orders that moved on.

### preorderline_loaded

Fires once Preorderline has loaded (on `plugins_loaded`, only when WooCommerce is active). Hook an add-on's setup to it. `PREORDERLINE_VERSION` is defined from then on.

## Filters for add-ons

| Filter | Use it to |
|---|---|
| `preorderline_modes` | Add a pre-order mode (key => label). Stored as `_preorderline_mode`. |
| `preorderline_is_active` | Say whether a product in your mode takes pre-orders right now (`$active, $product, $mode`). |
| `preorderline_settings` | Add WooCommerce settings fields to **Settings → Products → Pre-orders**, before the texts. |
| `preorderline_product_fields` (action) | Print fields in the Pre-order tab, after the release date (`$product`). |
| `preorderline_variation_fields` (action) | Print fields in a variation's Pre-order fields (`$loop, $variation, $parent`). |
| `preorderline_save_product` (action) | Save your fields (`$product, $row`; `$row` is null for a product). `ProductTab::posted( $field, $row )` reads a posted value. |
| `preorderline_cart_item_rows` | Add rows under a pre-ordered cart item (`$rows, $cart_item, $product`; each row a `key` and `value`). |
| `preorderline_order_item_rows` | Add rows under a waiting order line (`$rows, $item, $order`). |
| `preorderline_payment_text` | What customers are told about paying, in their order notice and the Pre-order received email (`$text, $order`). |
| `preorderline_customer_notice` | The notice above the order details (`$message, $order`; HTML). |
| `preorderline_payment_label` | The payment part of a Packboard card, e.g. "Paid" (`$label, $order`). |
| `preorderline_list_columns` / `preorderline_list_column` | Add columns to WooCommerce → Pre-orders, and fill or change cells (`$html, $column, $product`). |
| `preorderline_handles_payment` | Return true when your add-on takes the payment of orders paid on release or with a deposit (`$handled, $order, $kind`). |
| `preorderline_release_order` | Take over how a released order moves on, once per order (`$result, $order`; return `handled` true when you moved it on and emailed the customer, or add `data` for the email). |

### Example: a different button text for one category

```php
add_filter( 'woocommerce_product_single_add_to_cart_text', function ( $text, $product ) {
	$id = $product->get_parent_id() ?: $product->get_id();
	if ( Extendiment\Preorderline\Preorder::is_active( $product ) && has_term( 'books', 'product_cat', $id ) ) {
		return 'Reserve your copy';
	}
	return $text;
}, 30, 2 );
```

Run it after priority 20, where Preorderline sets its own button text.

Source: https://extendiment.com/plugins/preorderline/docs/1.x/filters-and-hooks