allow to remove some units from date interval

Form/Type/DateIntervalType.php

@@ -23,9 +23,38 @@ use Symfony\Component\Form\Extension\Core\Type\IntegerType;
 use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
 use Chill\MainBundle\Form\Type\DataTransformer\DateIntervalTransformer;
 use Symfony\Component\Validator\Constraints\GreaterThan;
+use Symfony\Component\OptionsResolver\OptionsResolver;
+use Symfony\Component\OptionsResolver\Exception\InvalidOptionsException;
+
 
 /**
+ * Show a dateInterval type
  * 
+ * Options:
+ * 
+ * - `unit_choices`: an array of available units choices. 
+ * 
+ * The oiriginal `unit_choices` are : 
+ * ```
+ * [
+ *      'Days' => 'D',
+ *      'Weeks' => 'W',
+ *      'Months' => 'M',
+ *      'Years' => 'Y'
+ * ]
+ * ```
+ * 
+ * You can remove one or more entries:
+ * 
+ * ```
+ * $builder        
+ *      ->add('duration', DateIntervalType::class, array(
+ *          'unit_choices' => [
+ *              'Years' => 'Y',
+ *              'Months' => 'M',
+ *      ]
+ * ));
+ * ```
  *
  */
 class DateIntervalType extends AbstractType
@@ -42,16 +71,39 @@ class DateIntervalType extends AbstractType
                 ]
             ])
             ->add('unit', ChoiceType::class, [
-                'choices' => [
-                    'Days' => 'D',
-                    'Weeks' => 'W',
-                    'Months' => 'M',
-                    'Years' => 'Y'
-                ],
+                'choices' => $options['unit_choices'],
                 'choices_as_values' => true
             ])
             ;
         
         $builder->addModelTransformer(new DateIntervalTransformer());
     }
+    
+    public function configureOptions(OptionsResolver $resolver)
+    {
+        $resolver
+            ->setDefined('unit_choices')
+            ->setDefault('unit_choices', [
+                'Days' => 'D',
+                'Weeks' => 'W',
+                'Months' => 'M',
+                'Years' => 'Y'
+            ])
+            ->setAllowedValues('unit_choices', function($values) {
+                if (FALSE === is_array($values)) {
+                    throw new InvalidOptionsException("The value `unit_choice` should be an array");
+                }
+                
+                $diff = \array_diff(\array_values($values), ['D', 'W', 'M', 'Y']);
+                if (count($diff) == 0) {
+                    return true;
+                } else {
+                    throw new InvalidOptionsException(sprintf("The values of the "
+                        . "units should be 'D', 'W', 'M', 'Y', those are invalid: %s",
+                        \implode(', ', $diff)));
+                }
+            })
+            ;
+    }
+
 }