abstract class Notification {
/**
* Map of notification type identifiers to their corresponding subclass.
*
* @var array<string, class-string<Notification>>
*/
const NOTIFICATION_CLASSES = array(
'store_order' => NewOrderNotification::class,
'store_review' => NewReviewNotification::class,
'store_stock' => StockNotification::class,
);
/**
* The ID of the resource this notification is about (e.g. order ID, comment
* ID).
*
* @var int
*/
private int $resource_id;
/**
* Creates a new Notification instance.
*
* @param int $resource_id The resource ID.
*
* @throws InvalidArgumentException If the resource ID is invalid.
*
* @since 10.7.0
*/
public function __construct( int $resource_id ) {
if ( $resource_id <= 0 ) {
throw new InvalidArgumentException( 'Notification resource_id must be positive.' );
}
$this->resource_id = $resource_id;
}
/**
* Returns the notification type identifier, this should match the subtype
* or type (if there isn't a subtype) values attributed to notes in
* WordPress.com.
*
* @return string
*
* @since 10.7.0
*/
abstract public function get_type(): string;
/**
* Returns the WPCOM-ready payload for this notification.
*
* Returns null if the underlying resource no longer exists.
*
* @return array|null
*
* @since 10.7.0
*/
abstract public function to_payload(): ?array;
/**
* Checks whether a meta key exists for this notification's resource.
*
* @param string $key The meta key.
* @return bool
*
* @since 10.7.0
*/
abstract public function has_meta( string $key ): bool;
/**
* Writes a meta key with a timestamp to this notification's resource.
*
* @param string $key The meta key.
* @return void
*
* @since 10.7.0
*/
abstract public function write_meta( string $key ): void;
/**
* Deletes a meta key from this notification's resource.
*
* @param string $key The meta key.
* @return void
*
* @since 10.8.0
*/
abstract public function delete_meta( string $key ): void;
/**
* Returns the notification data as an array.
*
* @return array{type: string, resource_id: int}
*
* @since 10.7.0
*/
public function to_array(): array {
return array(
'type' => $this->get_type(),
'resource_id' => $this->resource_id,
);
}
/**
* Reconstructs a Notification subclass from a serialized array.
*
* @param array{type: string, resource_id: int} $data The notification data.
* @return self
*
* @throws InvalidArgumentException If the type is unknown.
*
* @since 10.7.0
*/
public static function from_array( array $data ): self {
$type = $data['type'] ?? '';
$resource_id = (int) ( $data['resource_id'] ?? 0 );
$class = self::NOTIFICATION_CLASSES[ $type ] ?? null;
if ( ! $class ) {
// phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped
throw new InvalidArgumentException( sprintf( 'Unknown notification type: %s', $type ) );
}
$instance = new $class( $resource_id );
if ( method_exists( $instance, 'hydrate' ) ) {
$instance->hydrate( $data );
}
return $instance;
}
/**
* Returns a unique identifier for this notification, used for
* deduplication.
*
* @return string
*
* @since 10.7.0
*/
public function get_identifier(): string {
return sprintf( '%s_%s_%s', get_current_blog_id(), $this->get_type(), $this->resource_id );
}
/**
* Gets the resource ID.
*
* @return int
*
* @since 10.7.0
*/
public function get_resource_id(): int {
return $this->resource_id;
}
/**
* Canonical positional ActionScheduler arguments for the safety-net job.
*
* Single source of truth shared by the scheduler (and its dedupe guard) and
* the cancel path so the serialized args always match. Action Scheduler
* matches the stored args by exact equality, so any divergence between the
* schedule-side and cancel-side shapes silently breaks cancellation.
*
* The args are keyed on the notification's *identity* — the minimal data
* needed to uniquely identify and reconstruct the notification — mirroring
* {@see self::get_identifier()}. Volatile payload fields (e.g. a stock
* snapshot captured at trigger time) must not be included: they are not part
* of the identity and may differ between schedule and cancel.
*
* @return array<int, mixed>
*
* @since 10.9.0
*/
public function get_safety_net_args(): array {
return array( $this->get_type(), $this->get_resource_id() );
}
/**
* Decide whether this notification should be delivered to a user given
* their stored preference value for {@see static::get_type()}.
*
* `$pref_value` is whatever the user has stored under this notification
* type's preference key, or `null` if they have nothing stored. The
* {@see NotificationPreferencesService} stores each preference as an
* object so future sub-fields (thresholds, sub-toggles) can be added
* without bumping the schema version — today's shape is
* `['enabled' => bool]`, future shapes might add e.g.
* `['enabled' => true, 'min_value' => 500]` for an order threshold.
*
* Default: read the universal `enabled` sub-field, defaulting to `true`
* when the value is missing or has no `enabled` key (so newly-added
* notification types are opt-in by default). Subclasses override to
* read richer sub-fields and to consult their own resource (e.g.
* compare an order total to the user's `min_value`).
*
* Subclasses must keep this side-effect-free — the {@see NotificationProcessor}
* may call it once per recipient user per notification.
*
* @param mixed $pref_value The user's stored preference value, or null.
* @return bool True if this notification should be sent to that user.
*
* @since 10.9.0
*/
public function should_send_to_user( $pref_value ): bool {
if ( null === $pref_value ) {
return true;
}
if ( is_array( $pref_value ) ) {
return (bool) ( $pref_value['enabled'] ?? true );
}
// Defensive fallback for unexpected scalar values; the service
// always normalises stored prefs to the array shape above.
return (bool) $pref_value;
}
}