Ajout des notification + page employé (#6)

| Numéro du ticket | Titre du ticket |
|------------------|-----------------|
|                  |                 |

## Description de la PR

## Modification du .env

## Check list

- [ ] Pas de régression
- [ ] TU/TI/TF rédigée
- [ ] TU/TI/TF OK
- [ ] CHANGELOG modifié

Reviewed-on: #6
Co-authored-by: tristan <tristan@yuno.malio.fr>
Co-committed-by: tristan <tristan@yuno.malio.fr>

src/Service/Contracts/EmployeeContractPeriodValidator.php

@@ -0,0 +1,63 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service\Contracts;
+
+use App\Entity\EmployeeContractPeriod;
+use App\Enum\ContractNature;
+use DateTimeImmutable;
+use Symfony\Component\HttpKernel\Exception\UnprocessableEntityHttpException;
+
+final class EmployeeContractPeriodValidator
+{
+    public function assertPeriodDates(
+        DateTimeImmutable $startDate,
+        ?DateTimeImmutable $endDate,
+        ContractNature $nature,
+        bool $allowCdiEndDate = false
+    ): void {
+        if (null !== $endDate && $endDate < $startDate) {
+            throw new UnprocessableEntityHttpException('contractEndDate cannot be before contractStartDate.');
+        }
+
+        if ($nature->requiresEndDate() && null === $endDate) {
+            throw new UnprocessableEntityHttpException('contractEndDate is required for CDD and INTERIM.');
+        }
+
+        if (!$allowCdiEndDate && ContractNature::CDI === $nature && null !== $endDate) {
+            throw new UnprocessableEntityHttpException('contractEndDate must be empty for CDI.');
+        }
+    }
+
+    public function assertCloseEndDateCanBeApplied(
+        DateTimeImmutable $startDate,
+        ?DateTimeImmutable $currentEndDate,
+        DateTimeImmutable $requestedEndDate,
+        ContractNature $nature
+    ): void {
+        $this->assertPeriodDates($startDate, $requestedEndDate, $nature, true);
+
+        if (null !== $currentEndDate && $requestedEndDate > $currentEndDate) {
+            throw new UnprocessableEntityHttpException('contractEndDate cannot be increased on current contract.');
+        }
+    }
+
+    public function assertNextStartDateCompatible(
+        DateTimeImmutable $startDate,
+        EmployeeContractPeriod $currentPeriod
+    ): void {
+        $currentEndDate = $currentPeriod->getEndDate();
+        if (null === $currentEndDate) {
+            if ($startDate <= $currentPeriod->getStartDate()) {
+                throw new UnprocessableEntityHttpException('contractStartDate must be after current contract start date.');
+            }
+
+            return;
+        }
+
+        if ($startDate <= $currentEndDate) {
+            throw new UnprocessableEntityHttpException('contractStartDate must be after current contract end date.');
+        }
+    }
+}