DX: [budget calculator] restore previous budget's element type to Charge/Resource kind

+ improve typing

src/Bundle/ChillBudgetBundle/Calculator/CalculatorInterface.php

@@ -11,7 +11,6 @@ declare(strict_types=1);
 
 namespace Chill\BudgetBundle\Calculator;
 
-use Chill\BudgetBundle\Entity\AbstractElement;
 use Chill\BudgetBundle\Entity\Charge;
 use Chill\BudgetBundle\Entity\Resource;
 

src/Bundle/ChillBudgetBundle/Calculator/CalculatorManager.php

@@ -12,6 +12,8 @@ declare(strict_types=1);
 namespace Chill\BudgetBundle\Calculator;
 
 use Chill\BudgetBundle\Entity\AbstractElement;
+use Chill\BudgetBundle\Entity\Charge;
+use Chill\BudgetBundle\Entity\Resource;
 use OutOfBoundsException;
 
 use function array_key_exists;
@@ -21,11 +23,14 @@ use function implode;
 class CalculatorManager
 {
     /**
-     * @var CalculatorInterface[]
+     * @var array<string, CalculatorInterface>
      */
-    protected $calculators = [];
+    private array $calculators = [];
 
-    protected $defaultCalculator = [];
+    /**
+     * @var string[]
+     */
+    private array $defaultCalculator = [];
 
     public function addCalculator(CalculatorInterface $calculator, bool $default)
     {
@@ -37,7 +42,7 @@ class CalculatorManager
     }
 
     /**
-     * @param AbstractElement[] $elements
+     * @param array<Resource|Charge> $elements
      *
      * @return CalculatorResult[]
      */
@@ -46,23 +51,17 @@ class CalculatorManager
         $results = [];
 
         foreach ($this->defaultCalculator as $alias) {
-            $calculator = $this->calculators[$alias];
-            $result = $calculator->calculate($elements);
+            $result = $this->getCalculator($alias)->calculate($elements);
 
             if (null !== $result) {
-                $results[$calculator->getAlias()] = $result;
+                $results[$alias] = $result;
             }
         }
 
         return $results;
     }
 
-    /**
-     * @param string $alias
-     *
-     * @return CalculatorInterface
-     */
-    public function getCalculator($alias)
+    public function getCalculator(string $alias): CalculatorInterface
     {
         if (false === array_key_exists($alias, $this->calculators)) {
             throw new OutOfBoundsException("The calculator with alias '{$alias}' does "