[COMPONENT][Notification] Make logic more generic and robust

Fixed various bugs

Some important concepts to bear in mind:

* Notification: Associated with activities, won't be reconstructed
together with objects, can be thought of as transient

* Attention: Associated with objects, will be reconstructed with them, can
be thought as persistent

* Notifications and Attentions have no direct implications.

* Mentions are a specific form of attentions in notes, leads to the creation of Attentions.

Finally,

Potential PHP issue detected and reported: https://github.com/php/php-src/issues/8199
`static::method()` from a non static context (such as a class method) calls `__call`, rather than
the expected `__callStatic`. Can be fixed by using `(static fn() => static::method())()`, but the
usage of the magic method is strictly unnecessary in this case.

src/Core/Entity.php

@@ -24,12 +24,15 @@ declare(strict_types = 1);
 namespace App\Core;
 
 use App\Core\DB\DB;
+use App\Entity\Actor;
 use App\Util\Exception\NotFoundException;
 use App\Util\Formatting;
 use BadMethodCallException;
+use Component\Notification\Entity\Attention;
 use DateTime;
 use DateTimeInterface;
 use Exception;
+use Functional as F;
 use InvalidArgumentException;
 
 /**
@@ -37,6 +40,14 @@ use InvalidArgumentException;
  */
 abstract class Entity
 {
+    /**
+     * @return string Returns the name of this entity's DB table
+     */
+    public static function schemaName(): string
+    {
+        return static::schemaDef()['name'];
+    }
+
     public function __call(string $name, array $arguments): mixed
     {
         if (Formatting::startsWith($name, 'has')) {
@@ -46,7 +57,7 @@ abstract class Entity
             $private_property_accessor = $private_property_accessor->bindTo($this, static::class);
             return $private_property_accessor($prop);
         }
-        throw new BadMethodCallException('Non existent method ' . static::class . "::{$name} called with arguments: " . print_r($arguments, true));
+        throw new BadMethodCallException('Non existent non-static method ' . static::class . "->{$name} called with arguments: " . var_export($arguments, true));
     }
 
     abstract public static function schemaDef(): array;
@@ -55,10 +66,8 @@ abstract class Entity
      * Create an instance of the called class or fill in the
      * properties of $obj with the associative array $args. Doesn't
      * persist the result
-     *
-     * @param null|mixed $obj
      */
-    public static function create(array $args, $obj = null)
+    public static function create(array $args, mixed $obj = null)
     {
         $class = static::class;
 
@@ -126,7 +135,7 @@ abstract class Entity
      *     Entity::getByPK([42, 'foo']);
      *     Entity::getByPK(['key1' => 42, 'key2' => 'foo'])
      *
-     * @return null|static
+     * @throws \App\Util\Exception\DuplicateFoundException
      */
     public static function getByPK(mixed $values): ?self
     {
@@ -175,27 +184,28 @@ abstract class Entity
     }
 
     /**
-     * Who should be notified about this object?
+     * Ids of the Actors that should be informed about this object.
+     * BEWARE: If you call this, your object must have a serial integer id!
      *
-     * @return array of ids of Actors
+     * @return array int[] of Actor's id
      */
-    public function getNotificationTargetIds(array $ids_already_known = [], ?int $sender_id = null, bool $include_additional = true): array
+    public function getAttentionTargetIds(): array
     {
-        // Additional actors that should know about this
-        if (\array_key_exists('additional', $ids_already_known)) {
-            return $ids_already_known['additional'];
-        }
-        return [];
+        $attention = DB::findBy(Attention::class, [
+            'object_type' => static::schemaName(),
+            'object_id'   => $this->getId(),
+        ]);
+        return F\map($attention, fn ($cc) => $cc->getTargetId());
     }
 
     /**
-     * Who should be notified about this object?
+     * To whom should this be brought attention to?
      *
-     * @return array of Actors
+     * @return array Actor[]
      */
-    public function getNotificationTargets(array $ids_already_known = [], ?int $sender_id = null, bool $include_additional = true): array
+    public function getAttentionTargets(): array
     {
-        $target_ids = $this->getNotificationTargetIds($ids_already_known, $sender_id, $include_additional);
-        return $target_ids === [] ? [] : DB::findBy('actor', ['id' => $target_ids]);
+        $target_ids = $this->getAttentionTargetIds();
+        return DB::findBy(Actor::class, ['id' => $target_ids]);
     }
 }