feat(sync) : add slot selection controllers, custom field sync, and position fallbacks

- Add selectedPieceId support to ComposantPieceSlotController
- Create ComposantProductSlotController and ComposantSubcomponentSlotController
- Add updateCustomFields() to SkeletonStructureService for managing CustomField entities
- Fix position/orderIndex fallback to array index in all 3 sync strategies
- Fix type comparison in ProductSyncStrategy for dual format support
- Update CLAUDE.md with new entities, controllers, and fixtures documentation
- Update frontend submodule with interactive slot selectors

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CLAUDE.md

@@ -64,6 +64,14 @@ npm run build                 # Build production
 npm run lint:fix              # ESLint fix
 npx nuxi typecheck            # TypeScript check (0 errors attendu)
 
+# Database / Fixtures
+make db-reset                 # Reset database (drop + recreate schema)
+make fixtures-dump            # Dump la DB vers fixtures/data.sql
+make fixtures-load            # Charger les fixtures SQL (désactive FK)
+make fixtures-reset           # Reset DB + recharger fixtures
+make import-data              # Importer les dumps SQL normalisés
+make cache-clear              # Clear cache Symfony
+
 # Release
 ./scripts/release.sh patch    # Bump patch version (ou minor/major)
 ```
@@ -101,6 +109,11 @@ Le frontend est un submodule git. Lors d'un commit frontend :
 ### Entités Principales
 `Machine`, `Piece`, `Composant`, `Product`, `Constructeur`, `Site`, `ModelType`, `CustomField`, `CustomFieldValue`, `Document`, `AuditLog`, `Comment`, `Profile`, `MachineComponentLink`, `MachinePieceLink`, `MachineProductLink`
 
+#### Entités de normalisation (slots & skeleton requirements)
+Remplacent les anciennes colonnes JSON `structure` et `productIds` par des tables relationnelles :
+- **Slots** (données réelles d'un composant) : `ComposantPieceSlot`, `ComposantSubcomponentSlot`, `ComposantProductSlot`
+- **Skeleton Requirements** (définitions du ModelType) : `SkeletonPieceRequirement`, `SkeletonProductRequirement`, `SkeletonSubcomponentRequirement`
+
 ### Patterns
 - **IDs** : CUID-like strings (`'cl' + bin2hex(random_bytes(12))`), pas d'auto-increment
 - **ORM** : Attributs PHP 8 (`#[ORM\Column(...)]`, `#[Groups([...])]`)
@@ -110,15 +123,32 @@ Le frontend est un submodule git. Lors d'un commit frontend :
 - **Migrations** : Raw SQL PostgreSQL avec `IF NOT EXISTS`/`IF EXISTS` pour idempotence
 
 ### Custom Controllers (pas API Platform)
-- `MachineStructureController` — `/api/machines/{id}/structure` (GET/PATCH) : hiérarchie complète machine avec normalisation JSON manuelle (pas Symfony Serializer). Source principale de données pour la page détail machine.
+- `MachineStructureController` — `/api/machines/{id}/structure` (GET/PATCH), `/api/machines/{id}/clone` (POST) : hiérarchie complète machine avec normalisation JSON manuelle. Source principale de données pour la page détail machine.
 - `MachineCustomFieldsController` — `/api/machines/{id}/add-custom-fields` (POST) : initialise les CustomFieldValue manquants pour une machine.
 - `CustomFieldValueController` — `/api/custom-fields/values/*` : CRUD + upsert pour les valeurs de champs perso.
+- `ComposantPieceSlotController` — `/api/composant-piece-slots/{id}` (PATCH) : mise à jour des slots pièce d'un composant.
+- `SessionProfileController` — `/api/session/profile` (GET/POST/DELETE) : auth session (login/logout/current user).
+- `SessionProfilesController` — `/api/session/profiles` (GET) : liste des profils disponibles pour la session.
+- `AdminProfileController` — `/api/admin/profiles` : CRUD profils, gestion rôles et mots de passe (ROLE_ADMIN).
+- `CommentController` — `/api/comments` : création, résolution, compteur non-résolus.
+- `ActivityLogController` — `/api/activity-logs` (GET) : journal d'activité global.
+- `EntityHistoryController` — `/api/{entity}/{id}/history` (GET) : historique audit par entité (machines, pièces, composants, produits).
+- `DocumentQueryController` — `/api/documents/{entity}/{id}` (GET) : documents par site/machine/composant/pièce/produit.
+- `DocumentServeController` — `/api/documents/{id}/file|download` (GET) : servir/télécharger fichiers.
+- `ModelTypeConversionController` — `/api/model_types/{id}/conversion-check|convert` : vérification et conversion de ModelType.
+- `HealthCheckController` — `/api/health` (GET) : health check.
 
 ### Custom Fields — Architecture
-- **Composants/Pièces/Produits** : définitions dans le JSON `structure` du ModelType
+- **Composants/Pièces/Produits** : définitions dans les entités `SkeletonPieceRequirement`, `SkeletonProductRequirement`, `SkeletonSubcomponentRequirement` du ModelType (anciennement JSON `structure`, normalisé en tables relationnelles). Les custom fields de ces entités sont définis dans `customFields` JSON sur chaque Skeleton*Requirement.
 - **Machines** : définitions = entités `CustomField` liées directement via `machineId` FK (pas de ModelType)
 - Les deux partagent la même entité `CustomFieldValue` pour stocker les valeurs
 
+### Normalisation JSON → Tables (architecture slots)
+Les anciennes colonnes JSON `structure` et `productIds` des Composants ont été remplacées par des tables relationnelles :
+- **ModelType** définit le squelette via `SkeletonPieceRequirement`, `SkeletonProductRequirement`, `SkeletonSubcomponentRequirement`
+- **Composant** stocke les données réelles via `ComposantPieceSlot`, `ComposantProductSlot`, `ComposantSubcomponentSlot`
+- Chaque slot référence son skeleton requirement (`skeletonRequirement` FK) + l'entité sélectionnée + position
+
 ### Rôles (hiérarchie)
 ```
 ROLE_ADMIN → ROLE_GESTIONNAIRE → ROLE_VIEWER → ROLE_USER
@@ -193,8 +223,8 @@ make test-setup               # Créer/mettre à jour le schéma test
 ### Pattern de test
 - Hériter de `AbstractApiTestCase` (helpers auth + factories)
 - Ne PAS faire de TRUNCATE/cleanup dans tearDown — DAMA s'en occupe par rollback
-- Factories : `createProfile()`, `createMachine()`, `createSite()`, `createComposant()`, `createPiece()`, `createProduct()`, `createCustomField()`, `createCustomFieldValue()`, `createModelType()`, `createMachineComponentLink()`, `createMachinePieceLink()`, `createMachineProductLink()`
-- Auth : `createViewerClient()`, `createGestionnaireClient()`, `createAdminClient()`
+- Factories : `createProfile()`, `createMachine()`, `createSite()`, `createComposant()`, `createPiece()`, `createProduct()`, `createConstructeur()`, `createCustomField()`, `createCustomFieldValue()`, `createModelType()`, `createMachineComponentLink()`, `createMachinePieceLink()`, `createMachineProductLink()`, `createComposantPieceSlot()`, `createComposantSubcomponentSlot()`, `createComposantProductSlot()`
+- Auth : `createViewerClient()`, `createGestionnaireClient()`, `createAdminClient()`, `createUnauthenticatedClient()`
 
 ## URLs Locales
 - API Symfony : `http://localhost:8081/api`

config/reference.php

@@ -1626,6 +1626,19 @@ use Symfony\Component\Config\Loader\ParamConfigurator as Param;
  *     nelmio_cors?: NelmioCorsConfig,
  *     api_platform?: ApiPlatformConfig,
  *     lexik_jwt_authentication?: LexikJwtAuthenticationConfig,
+ *     "when@dev"?: array{
+ *         imports?: ImportsConfig,
+ *         parameters?: ParametersConfig,
+ *         services?: ServicesConfig,
+ *         framework?: FrameworkConfig,
+ *         twig?: TwigConfig,
+ *         security?: SecurityConfig,
+ *         doctrine?: DoctrineConfig,
+ *         doctrine_migrations?: DoctrineMigrationsConfig,
+ *         nelmio_cors?: NelmioCorsConfig,
+ *         api_platform?: ApiPlatformConfig,
+ *         lexik_jwt_authentication?: LexikJwtAuthenticationConfig,
+ *     },
  *     "when@prod"?: array{
  *         imports?: ImportsConfig,
  *         parameters?: ParametersConfig,
@@ -1732,6 +1745,7 @@ namespace Symfony\Component\Routing\Loader\Configurator;
  *     deprecated?: array{package:string, version:string, message?:string},
  * }
  * @psalm-type RoutesConfig = array{
+ *     "when@dev"?: array<string, RouteConfig|ImportConfig|AliasConfig>,
  *     "when@prod"?: array<string, RouteConfig|ImportConfig|AliasConfig>,
  *     "when@test"?: array<string, RouteConfig|ImportConfig|AliasConfig>,
  *     ...<string, RouteConfig|ImportConfig|AliasConfig>

config/services.yaml

@@ -38,3 +38,25 @@ services:
         decorates: 'api_platform.openapi.factory'
         arguments:
             $decorated: '@.inner'
+
+when@test:
+    services:
+        App\Service\Sync\ProductSyncStrategy:
+            autowire: true
+            autoconfigure: true
+            public: true
+
+        App\Service\Sync\ComposantSyncStrategy:
+            autowire: true
+            autoconfigure: true
+            public: true
+
+        App\Service\Sync\PieceSyncStrategy:
+            autowire: true
+            autoconfigure: true
+            public: true
+
+        App\Service\ModelTypeSyncService:
+            autowire: true
+            autoconfigure: true
+            public: true

migrations/Version20260313124029.php

@@ -0,0 +1,118 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+/**
+ * Create piece_product_slots table (mirroring composant_product_slots)
+ * and add version columns to composants, pieces, products.
+ */
+final class Version20260313124029 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Create piece_product_slots table, add version columns to composants/pieces/products, migrate piece_products data';
+    }
+
+    public function up(Schema $schema): void
+    {
+        // ── Create piece_product_slots table (idempotent) ─────────────────────
+
+        $this->addSql(<<<'SQL'
+                CREATE TABLE IF NOT EXISTS piece_product_slots (
+                    id VARCHAR(36) NOT NULL,
+                    "pieceid" VARCHAR(36) NOT NULL,
+                    "typeproductid" VARCHAR(36) DEFAULT NULL,
+                    "selectedproductid" VARCHAR(36) DEFAULT NULL,
+                    "familycode" VARCHAR(255) DEFAULT NULL,
+                    position INT NOT NULL DEFAULT 0,
+                    "createdat" TIMESTAMP(0) WITHOUT TIME ZONE NOT NULL,
+                    "updatedat" TIMESTAMP(0) WITHOUT TIME ZONE NOT NULL,
+                    PRIMARY KEY (id)
+                )
+            SQL);
+
+        // ── Indexes (idempotent) ──────────────────────────────────────────────
+
+        $this->addSql('CREATE INDEX IF NOT EXISTS idx_piece_prod_slot_piece ON piece_product_slots ("pieceid")');
+        $this->addSql('CREATE INDEX IF NOT EXISTS idx_piece_prod_slot_type ON piece_product_slots ("typeproductid")');
+        $this->addSql('CREATE INDEX IF NOT EXISTS idx_piece_prod_slot_selected ON piece_product_slots ("selectedproductid")');
+        $this->addSql('CREATE INDEX IF NOT EXISTS idx_piece_product_slots_piece_pos ON piece_product_slots ("pieceid", position)');
+
+        // ── Foreign keys (idempotent via DO $$ block) ─────────────────────────
+
+        $this->addSql(<<<'SQL'
+                DO $$ BEGIN
+                    IF NOT EXISTS (SELECT 1 FROM pg_constraint WHERE conname = 'fk_piece_prod_slot_piece') THEN
+                        ALTER TABLE piece_product_slots
+                            ADD CONSTRAINT fk_piece_prod_slot_piece
+                            FOREIGN KEY ("pieceid") REFERENCES pieces (id) ON DELETE CASCADE;
+                    END IF;
+                END $$
+            SQL);
+
+        $this->addSql(<<<'SQL'
+                DO $$ BEGIN
+                    IF NOT EXISTS (SELECT 1 FROM pg_constraint WHERE conname = 'fk_piece_prod_slot_type') THEN
+                        ALTER TABLE piece_product_slots
+                            ADD CONSTRAINT fk_piece_prod_slot_type
+                            FOREIGN KEY ("typeproductid") REFERENCES model_types (id) ON DELETE SET NULL;
+                    END IF;
+                END $$
+            SQL);
+
+        $this->addSql(<<<'SQL'
+                DO $$ BEGIN
+                    IF NOT EXISTS (SELECT 1 FROM pg_constraint WHERE conname = 'fk_piece_prod_slot_selected') THEN
+                        ALTER TABLE piece_product_slots
+                            ADD CONSTRAINT fk_piece_prod_slot_selected
+                            FOREIGN KEY ("selectedproductid") REFERENCES products (id) ON DELETE SET NULL;
+                    END IF;
+                END $$
+            SQL);
+
+        // ── Add version columns (idempotent) ─────────────────────────────────
+
+        $this->addSql('ALTER TABLE composants ADD COLUMN IF NOT EXISTS version INT NOT NULL DEFAULT 1');
+        $this->addSql('ALTER TABLE pieces ADD COLUMN IF NOT EXISTS version INT NOT NULL DEFAULT 1');
+        $this->addSql('ALTER TABLE products ADD COLUMN IF NOT EXISTS version INT NOT NULL DEFAULT 1');
+
+        // ── Data migration: piece_products → piece_product_slots ─────────────
+
+        $this->addSql(<<<'SQL'
+                DO $$
+                BEGIN
+                    IF EXISTS (SELECT 1 FROM information_schema.tables WHERE table_name = 'piece_products') THEN
+                        INSERT INTO piece_product_slots (id, "pieceid", "typeproductid", "selectedproductid", "familycode", position, "createdat", "updatedat")
+                        SELECT
+                            'cl' || encode(gen_random_bytes(12), 'hex'),
+                            pp.piece_id,
+                            p.typeproductid,
+                            pp.product_id,
+                            NULL,
+                            ROW_NUMBER() OVER (PARTITION BY pp.piece_id ORDER BY pp.product_id) - 1,
+                            NOW(),
+                            NOW()
+                        FROM piece_products pp
+                        JOIN products p ON p.id = pp.product_id
+                        WHERE NOT EXISTS (
+                            SELECT 1 FROM piece_product_slots pps
+                            WHERE pps."pieceid" = pp.piece_id AND pps."selectedproductid" = pp.product_id
+                        );
+                    END IF;
+                END $$
+            SQL);
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('DROP TABLE IF EXISTS piece_product_slots');
+        $this->addSql('ALTER TABLE composants DROP COLUMN IF EXISTS version');
+        $this->addSql('ALTER TABLE pieces DROP COLUMN IF EXISTS version');
+        $this->addSql('ALTER TABLE products DROP COLUMN IF EXISTS version');
+    }
+}

src/Controller/ComposantPieceSlotController.php

@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace App\Controller;
 
 use App\Entity\ComposantPieceSlot;
+use App\Entity\Piece;
 use Doctrine\ORM\EntityManagerInterface;
 use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
 use Symfony\Component\HttpFoundation\JsonResponse;
@@ -37,12 +38,22 @@ class ComposantPieceSlotController extends AbstractController
             $slot->setQuantity(max(1, (int) $payload['quantity']));
         }
 
+        if (array_key_exists('selectedPieceId', $payload)) {
+            if (null === $payload['selectedPieceId']) {
+                $slot->setSelectedPiece(null);
+            } else {
+                $piece = $this->entityManager->find(Piece::class, $payload['selectedPieceId']);
+                $slot->setSelectedPiece($piece);
+            }
+        }
+
         $this->entityManager->flush();
 
         return $this->json([
-            'success'  => true,
-            'id'       => $slot->getId(),
-            'quantity' => $slot->getQuantity(),
+            'success'         => true,
+            'id'              => $slot->getId(),
+            'quantity'        => $slot->getQuantity(),
+            'selectedPieceId' => $slot->getSelectedPiece()?->getId(),
         ]);
     }
 }

src/Controller/ComposantProductSlotController.php

@@ -0,0 +1,54 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Controller;
+
+use App\Entity\ComposantProductSlot;
+use App\Entity\Product;
+use Doctrine\ORM\EntityManagerInterface;
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\JsonResponse;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\Routing\Attribute\Route;
+
+#[Route('/api/composant-product-slots')]
+class ComposantProductSlotController extends AbstractController
+{
+    public function __construct(
+        private readonly EntityManagerInterface $entityManager,
+    ) {}
+
+    #[Route('/{id}', name: 'composant_product_slot_patch', methods: ['PATCH'])]
+    public function patch(string $id, Request $request): JsonResponse
+    {
+        $this->denyAccessUnlessGranted('ROLE_GESTIONNAIRE');
+
+        $slot = $this->entityManager->find(ComposantProductSlot::class, $id);
+        if (!$slot) {
+            return $this->json(['success' => false, 'error' => 'Slot not found.'], 404);
+        }
+
+        $payload = json_decode($request->getContent(), true);
+        if (!is_array($payload)) {
+            return $this->json(['success' => false, 'error' => 'Invalid JSON payload.'], 400);
+        }
+
+        if (array_key_exists('selectedProductId', $payload)) {
+            if (null === $payload['selectedProductId']) {
+                $slot->setSelectedProduct(null);
+            } else {
+                $product = $this->entityManager->find(Product::class, $payload['selectedProductId']);
+                $slot->setSelectedProduct($product);
+            }
+        }
+
+        $this->entityManager->flush();
+
+        return $this->json([
+            'success'           => true,
+            'id'                => $slot->getId(),
+            'selectedProductId' => $slot->getSelectedProduct()?->getId(),
+        ]);
+    }
+}

src/Controller/ComposantSubcomponentSlotController.php

@@ -0,0 +1,54 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Controller;
+
+use App\Entity\Composant;
+use App\Entity\ComposantSubcomponentSlot;
+use Doctrine\ORM\EntityManagerInterface;
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\JsonResponse;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\Routing\Attribute\Route;
+
+#[Route('/api/composant-subcomponent-slots')]
+class ComposantSubcomponentSlotController extends AbstractController
+{
+    public function __construct(
+        private readonly EntityManagerInterface $entityManager,
+    ) {}
+
+    #[Route('/{id}', name: 'composant_subcomponent_slot_patch', methods: ['PATCH'])]
+    public function patch(string $id, Request $request): JsonResponse
+    {
+        $this->denyAccessUnlessGranted('ROLE_GESTIONNAIRE');
+
+        $slot = $this->entityManager->find(ComposantSubcomponentSlot::class, $id);
+        if (!$slot) {
+            return $this->json(['success' => false, 'error' => 'Slot not found.'], 404);
+        }
+
+        $payload = json_decode($request->getContent(), true);
+        if (!is_array($payload)) {
+            return $this->json(['success' => false, 'error' => 'Invalid JSON payload.'], 400);
+        }
+
+        if (array_key_exists('selectedComposantId', $payload)) {
+            if (null === $payload['selectedComposantId']) {
+                $slot->setSelectedComposant(null);
+            } else {
+                $composant = $this->entityManager->find(Composant::class, $payload['selectedComposantId']);
+                $slot->setSelectedComposant($composant);
+            }
+        }
+
+        $this->entityManager->flush();
+
+        return $this->json([
+            'success'             => true,
+            'id'                  => $slot->getId(),
+            'selectedComposantId' => $slot->getSelectedComposant()?->getId(),
+        ]);
+    }
+}

src/Controller/ModelTypeSyncController.php

@@ -0,0 +1,74 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Controller;
+
+use App\DTO\SyncConfirmation;
+use App\Repository\ModelTypeRepository;
+use App\Service\ModelTypeSyncService;
+use Doctrine\ORM\EntityManagerInterface;
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\JsonResponse;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\Routing\Attribute\Route;
+
+#[Route('/api/model_types/{id}')]
+final class ModelTypeSyncController extends AbstractController
+{
+    public function __construct(
+        private readonly ModelTypeRepository $modelTypes,
+        private readonly ModelTypeSyncService $syncService,
+        private readonly EntityManagerInterface $em,
+    ) {}
+
+    #[Route('/sync-preview', name: 'api_model_type_sync_preview', methods: ['POST'])]
+    public function preview(string $id, Request $request): JsonResponse
+    {
+        $this->denyAccessUnlessGranted('ROLE_GESTIONNAIRE');
+
+        $modelType = $this->modelTypes->find($id);
+
+        if (!$modelType) {
+            return new JsonResponse(
+                ['message' => 'Catégorie introuvable.'],
+                Response::HTTP_NOT_FOUND,
+            );
+        }
+
+        $body      = json_decode($request->getContent(), true);
+        $structure = $body['structure'] ?? [];
+
+        $result = $this->syncService->preview($modelType, $structure);
+
+        return new JsonResponse($result);
+    }
+
+    #[Route('/sync', name: 'api_model_type_sync', methods: ['POST'])]
+    public function sync(string $id, Request $request): JsonResponse
+    {
+        $this->denyAccessUnlessGranted('ROLE_GESTIONNAIRE');
+
+        $modelType = $this->modelTypes->find($id);
+
+        if (!$modelType) {
+            return new JsonResponse(
+                ['message' => 'Catégorie introuvable.'],
+                Response::HTTP_NOT_FOUND,
+            );
+        }
+
+        $body         = json_decode($request->getContent(), true);
+        $confirmation = new SyncConfirmation(
+            confirmDeletions: $body['confirmDeletions'] ?? false,
+            confirmTypeChanges: $body['confirmTypeChanges'] ?? false,
+        );
+
+        $result = $this->em->wrapInTransaction(function () use ($modelType, $confirmation) {
+            return $this->syncService->execute($modelType, $confirmation);
+        });
+
+        return new JsonResponse($result);
+    }
+}

src/DTO/SyncConfirmation.php

@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\DTO;
+
+class SyncConfirmation
+{
+    public function __construct(
+        public readonly bool $confirmDeletions = false,
+        public readonly bool $confirmTypeChanges = false,
+    ) {}
+}

src/DTO/SyncExecutionResult.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\DTO;
+
+use JsonSerializable;
+
+class SyncExecutionResult implements JsonSerializable
+{
+    public function __construct(
+        public readonly int $itemsUpdated,
+        public readonly array $additions = [],
+        public readonly array $deletions = [],
+        public readonly array $modifications = [],
+    ) {}
+
+    public function jsonSerialize(): array
+    {
+        return [
+            'itemsUpdated'  => $this->itemsUpdated,
+            'additions'     => $this->additions,
+            'deletions'     => $this->deletions,
+            'modifications' => $this->modifications,
+        ];
+    }
+}

src/DTO/SyncPreviewResult.php

@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\DTO;
+
+use JsonSerializable;
+
+class SyncPreviewResult implements JsonSerializable
+{
+    public function __construct(
+        public readonly string $modelTypeId,
+        public readonly string $category,
+        public readonly int $itemCount,
+        public readonly array $additions = [],
+        public readonly array $deletions = [],
+        public readonly array $modifications = [],
+    ) {}
+
+    public function hasImpact(): bool
+    {
+        return array_sum($this->additions) > 0
+            || array_sum($this->deletions) > 0
+            || array_sum($this->modifications) > 0;
+    }
+
+    public function jsonSerialize(): array
+    {
+        return [
+            'modelTypeId'   => $this->modelTypeId,
+            'category'      => $this->category,
+            'itemCount'     => $this->itemCount,
+            'additions'     => $this->additions,
+            'deletions'     => $this->deletions,
+            'modifications' => $this->modifications,
+        ];
+    }
+}

src/Entity/Composant.php

@@ -130,6 +130,10 @@ class Composant
     #[ORM\OrderBy(['position' => 'ASC'])]
     private Collection $productSlots;
 
+    #[ORM\Column(type: Types::INTEGER, options: ['default' => 1])]
+    #[Groups(['composant:read'])]
+    private int $version = 1;
+
     #[ORM\Column(type: Types::DATETIME_IMMUTABLE, name: 'createdAt')]
     #[Groups(['composant:read'])]
     private DateTimeImmutable $createdAt;
@@ -406,4 +410,16 @@ class Composant
 
         return $this;
     }
+
+    public function getVersion(): int
+    {
+        return $this->version;
+    }
+
+    public function incrementVersion(): static
+    {
+        ++$this->version;
+
+        return $this;
+    }
 }

src/Entity/CustomField.php

@@ -184,4 +184,40 @@ class CustomField
 
         return $this;
     }
+
+    public function getTypeComposant(): ?ModelType
+    {
+        return $this->typeComposant;
+    }
+
+    public function setTypeComposant(?ModelType $typeComposant): static
+    {
+        $this->typeComposant = $typeComposant;
+
+        return $this;
+    }
+
+    public function getTypePiece(): ?ModelType
+    {
+        return $this->typePiece;
+    }
+
+    public function setTypePiece(?ModelType $typePiece): static
+    {
+        $this->typePiece = $typePiece;
+
+        return $this;
+    }
+
+    public function getTypeProduct(): ?ModelType
+    {
+        return $this->typeProduct;
+    }
+
+    public function setTypeProduct(?ModelType $typeProduct): static
+    {
+        $this->typeProduct = $typeProduct;
+
+        return $this;
+    }
 }

src/Entity/Piece.php

@@ -114,12 +114,23 @@ class Piece
     #[ORM\InverseJoinColumn(name: 'product_id', referencedColumnName: 'id', onDelete: 'CASCADE')]
     private Collection $products;
 
+    /**
+     * @var Collection<int, PieceProductSlot>
+     */
+    #[ORM\OneToMany(targetEntity: PieceProductSlot::class, mappedBy: 'piece', cascade: ['persist', 'remove'], orphanRemoval: true)]
+    #[ORM\OrderBy(['position' => 'ASC'])]
+    private Collection $productSlots;
+
     /**
      * @var Collection<int, MachinePieceLink>
      */
     #[ORM\OneToMany(mappedBy: 'piece', targetEntity: MachinePieceLink::class)]
     private Collection $machineLinks;
 
+    #[ORM\Column(type: Types::INTEGER, options: ['default' => 1])]
+    #[Groups(['piece:read'])]
+    private int $version = 1;
+
     #[ORM\Column(type: Types::DATETIME_IMMUTABLE, name: 'createdAt')]
     #[Groups(['piece:read'])]
     private DateTimeImmutable $createdAt;
@@ -136,6 +147,7 @@ class Piece
         $this->documents         = new ArrayCollection();
         $this->customFieldValues = new ArrayCollection();
         $this->products          = new ArrayCollection();
+        $this->productSlots      = new ArrayCollection();
         $this->machineLinks      = new ArrayCollection();
     }
 
@@ -287,4 +299,41 @@ class Piece
 
         return $this;
     }
+
+    /**
+     * @return Collection<int, PieceProductSlot>
+     */
+    public function getProductSlots(): Collection
+    {
+        return $this->productSlots;
+    }
+
+    public function addProductSlot(PieceProductSlot $slot): static
+    {
+        if (!$this->productSlots->contains($slot)) {
+            $this->productSlots->add($slot);
+            $slot->setPiece($this);
+        }
+
+        return $this;
+    }
+
+    public function removeProductSlot(PieceProductSlot $slot): static
+    {
+        $this->productSlots->removeElement($slot);
+
+        return $this;
+    }
+
+    public function getVersion(): int
+    {
+        return $this->version;
+    }
+
+    public function incrementVersion(): static
+    {
+        ++$this->version;
+
+        return $this;
+    }
 }

src/Entity/PieceProductSlot.php

@@ -0,0 +1,112 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Entity;
+
+use App\Entity\Trait\CuidEntityTrait;
+use DateTimeImmutable;
+use Doctrine\DBAL\Types\Types;
+use Doctrine\ORM\Mapping as ORM;
+
+#[ORM\Entity]
+#[ORM\Table(name: 'piece_product_slots')]
+#[ORM\HasLifecycleCallbacks]
+class PieceProductSlot
+{
+    use CuidEntityTrait;
+
+    #[ORM\Id]
+    #[ORM\Column(type: Types::STRING, length: 36)]
+    private ?string $id = null;
+
+    #[ORM\ManyToOne(targetEntity: Piece::class, inversedBy: 'productSlots')]
+    #[ORM\JoinColumn(name: 'pieceId', referencedColumnName: 'id', nullable: false, onDelete: 'CASCADE')]
+    private Piece $piece;
+
+    #[ORM\ManyToOne(targetEntity: ModelType::class)]
+    #[ORM\JoinColumn(name: 'typeProductId', referencedColumnName: 'id', nullable: true, onDelete: 'SET NULL')]
+    private ?ModelType $typeProduct = null;
+
+    #[ORM\ManyToOne(targetEntity: Product::class)]
+    #[ORM\JoinColumn(name: 'selectedProductId', referencedColumnName: 'id', nullable: true, onDelete: 'SET NULL')]
+    private ?Product $selectedProduct = null;
+
+    #[ORM\Column(type: Types::STRING, length: 255, nullable: true, name: 'familyCode')]
+    private ?string $familyCode = null;
+
+    #[ORM\Column(type: Types::INTEGER, options: ['default' => 0])]
+    private int $position = 0;
+
+    #[ORM\Column(type: Types::DATETIME_IMMUTABLE, name: 'createdAt')]
+    private DateTimeImmutable $createdAt;
+
+    #[ORM\Column(type: Types::DATETIME_IMMUTABLE, name: 'updatedAt')]
+    private DateTimeImmutable $updatedAt;
+
+    public function __construct()
+    {
+        $this->createdAt = new DateTimeImmutable();
+        $this->updatedAt = new DateTimeImmutable();
+    }
+
+    public function getPiece(): Piece
+    {
+        return $this->piece;
+    }
+
+    public function setPiece(Piece $piece): static
+    {
+        $this->piece = $piece;
+
+        return $this;
+    }
+
+    public function getTypeProduct(): ?ModelType
+    {
+        return $this->typeProduct;
+    }
+
+    public function setTypeProduct(?ModelType $typeProduct): static
+    {
+        $this->typeProduct = $typeProduct;
+
+        return $this;
+    }
+
+    public function getSelectedProduct(): ?Product
+    {
+        return $this->selectedProduct;
+    }
+
+    public function setSelectedProduct(?Product $selectedProduct): static
+    {
+        $this->selectedProduct = $selectedProduct;
+
+        return $this;
+    }
+
+    public function getFamilyCode(): ?string
+    {
+        return $this->familyCode;
+    }
+
+    public function setFamilyCode(?string $familyCode): static
+    {
+        $this->familyCode = $familyCode;
+
+        return $this;
+    }
+
+    public function getPosition(): int
+    {
+        return $this->position;
+    }
+
+    public function setPosition(int $position): static
+    {
+        $this->position = $position;
+
+        return $this;
+    }
+}

src/Entity/Product.php

@@ -118,6 +118,10 @@ class Product
     #[ORM\OneToMany(mappedBy: 'product', targetEntity: MachineProductLink::class)]
     private Collection $machineLinks;
 
+    #[ORM\Column(type: Types::INTEGER, options: ['default' => 1])]
+    #[Groups(['product:read'])]
+    private int $version = 1;
+
     #[ORM\Column(type: Types::DATETIME_IMMUTABLE, name: 'createdAt')]
     #[Groups(['product:read'])]
     private DateTimeImmutable $createdAt;
@@ -234,4 +238,16 @@ class Product
     {
         return $this->linkedPieces;
     }
+
+    public function getVersion(): int
+    {
+        return $this->version;
+    }
+
+    public function incrementVersion(): static
+    {
+        ++$this->version;
+
+        return $this;
+    }
 }

src/Service/ModelTypeSyncService.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service;
+
+use App\DTO\SyncConfirmation;
+use App\DTO\SyncExecutionResult;
+use App\DTO\SyncPreviewResult;
+use App\Entity\ModelType;
+use App\Service\Sync\SyncStrategyInterface;
+use LogicException;
+use Symfony\Component\DependencyInjection\Attribute\AutowireIterator;
+
+class ModelTypeSyncService
+{
+    /** @param iterable<SyncStrategyInterface> $strategies */
+    public function __construct(
+        #[AutowireIterator('app.sync_strategy')]
+        private readonly iterable $strategies,
+    ) {}
+
+    public function preview(ModelType $modelType, array $newStructure): SyncPreviewResult
+    {
+        foreach ($this->strategies as $strategy) {
+            if ($strategy->supports($modelType)) {
+                return $strategy->preview($modelType, $newStructure);
+            }
+        }
+
+        throw new LogicException('No sync strategy found for category: '.$modelType->getCategory()->value);
+    }
+
+    public function execute(ModelType $modelType, SyncConfirmation $confirmation): SyncExecutionResult
+    {
+        foreach ($this->strategies as $strategy) {
+            if ($strategy->supports($modelType)) {
+                return $strategy->execute($modelType, $confirmation);
+            }
+        }
+
+        throw new LogicException('No sync strategy found for category: '.$modelType->getCategory()->value);
+    }
+}

src/Service/SkeletonStructureService.php

@@ -4,10 +4,12 @@ declare(strict_types=1);
 
 namespace App\Service;
 
+use App\Entity\CustomField;
 use App\Entity\ModelType;
 use App\Entity\SkeletonPieceRequirement;
 use App\Entity\SkeletonProductRequirement;
 use App\Entity\SkeletonSubcomponentRequirement;
+use App\Enum\ModelCategory;
 use Doctrine\ORM\EntityManagerInterface;
 
 class SkeletonStructureService
@@ -60,5 +62,118 @@ class SkeletonStructureService
             $req->setPosition($i);
             $modelType->addSkeletonSubcomponentRequirement($req);
         }
+
+        // Update custom field definitions
+        $this->updateCustomFields($modelType, $structure['customFields'] ?? []);
+    }
+
+    /**
+     * Sync CustomField entities for this ModelType.
+     * Handles two frontend formats:
+     *   - COMPONENT: {key, value: {type, required, options?, defaultValue?}, id?, customFieldId?}
+     *   - PIECE/PRODUCT: {name, type, required, options?, orderIndex?, defaultValue?}.
+     */
+    private function updateCustomFields(ModelType $modelType, array $proposedFields): void
+    {
+        // Determine which FK to use based on category
+        $category = $modelType->getCategory();
+        $fkField  = match ($category) {
+            ModelCategory::COMPONENT => 'typeComposant',
+            ModelCategory::PIECE     => 'typePiece',
+            ModelCategory::PRODUCT   => 'typeProduct',
+        };
+
+        // Load existing custom fields
+        $existingFields = $this->em->getRepository(CustomField::class)->findBy(
+            [$fkField => $modelType],
+            ['orderIndex' => 'ASC']
+        );
+
+        // Index existing by ID for matching
+        $existingById = [];
+        foreach ($existingFields as $cf) {
+            $existingById[$cf->getId()] = $cf;
+        }
+
+        $processedIds = [];
+
+        foreach ($proposedFields as $i => $fieldData) {
+            // Normalize both formats to a common shape
+            $normalized = $this->normalizeCustomFieldData($fieldData, $i);
+
+            // Try to match an existing field by ID
+            $existingField = null;
+            $fieldId       = $fieldData['customFieldId'] ?? $fieldData['id'] ?? null;
+            if ($fieldId && isset($existingById[$fieldId])) {
+                $existingField = $existingById[$fieldId];
+            }
+
+            if ($existingField) {
+                // Update existing field
+                $existingField->setName($normalized['name']);
+                $existingField->setType($normalized['type']);
+                $existingField->setRequired($normalized['required']);
+                $existingField->setOptions($normalized['options']);
+                $existingField->setDefaultValue($normalized['defaultValue']);
+                $existingField->setOrderIndex($normalized['orderIndex']);
+                $processedIds[$existingField->getId()] = true;
+            } else {
+                // Create new field
+                $cf = new CustomField();
+                $cf->setName($normalized['name']);
+                $cf->setType($normalized['type']);
+                $cf->setRequired($normalized['required']);
+                $cf->setOptions($normalized['options']);
+                $cf->setDefaultValue($normalized['defaultValue']);
+                $cf->setOrderIndex($normalized['orderIndex']);
+
+                match ($category) {
+                    ModelCategory::COMPONENT => $cf->setTypeComposant($modelType),
+                    ModelCategory::PIECE     => $cf->setTypePiece($modelType),
+                    ModelCategory::PRODUCT   => $cf->setTypeProduct($modelType),
+                };
+
+                $this->em->persist($cf);
+            }
+        }
+
+        // Remove orphaned fields (exist in DB but not in proposed)
+        foreach ($existingFields as $cf) {
+            if (!isset($processedIds[$cf->getId()])) {
+                $this->em->remove($cf);
+            }
+        }
+    }
+
+    /**
+     * Normalize frontend custom field data to a common shape.
+     *
+     * @return array{name: string, type: string, required: bool, options: ?array, defaultValue: ?string, orderIndex: int}
+     */
+    private function normalizeCustomFieldData(array $fieldData, int $index): array
+    {
+        // COMPONENT format: {key: "name", value: {type, required, options?, defaultValue?}}
+        if (isset($fieldData['key'], $fieldData['value'])) {
+            $value = $fieldData['value'];
+
+            return [
+                'name'         => $fieldData['key'],
+                'type'         => $value['type'] ?? 'text',
+                'required'     => (bool) ($value['required'] ?? false),
+                'options'      => $value['options'] ?? null,
+                'defaultValue' => $value['defaultValue'] ?? null,
+                'orderIndex'   => $index,
+            ];
+        }
+
+        // PIECE/PRODUCT format: {name, type, required, options?, orderIndex?, defaultValue?}
+        return [
+            'name'         => $fieldData['name'] ?? '',
+            'type'         => $fieldData['type'] ?? 'text',
+            'required'     => (bool) ($fieldData['required'] ?? false),
+            'options'      => $fieldData['options'] ?? null,
+            'defaultValue' => $fieldData['defaultValue'] ?? null,
+            'orderIndex'   => $fieldData['orderIndex'] ?? $index,
+        ];
     }
 }

src/Service/Sync/ComposantSyncStrategy.php

@@ -0,0 +1,392 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service\Sync;
+
+use App\DTO\SyncConfirmation;
+use App\DTO\SyncExecutionResult;
+use App\DTO\SyncPreviewResult;
+use App\Entity\Composant;
+use App\Entity\ComposantPieceSlot;
+use App\Entity\ComposantProductSlot;
+use App\Entity\ComposantSubcomponentSlot;
+use App\Entity\CustomField;
+use App\Entity\CustomFieldValue;
+use App\Entity\ModelType;
+use App\Entity\SkeletonPieceRequirement;
+use App\Entity\SkeletonProductRequirement;
+use App\Entity\SkeletonSubcomponentRequirement;
+use App\Enum\ModelCategory;
+use Doctrine\ORM\EntityManagerInterface;
+use Symfony\Component\DependencyInjection\Attribute\AutoconfigureTag;
+
+#[AutoconfigureTag('app.sync_strategy')]
+class ComposantSyncStrategy implements SyncStrategyInterface
+{
+    public function __construct(
+        private readonly EntityManagerInterface $em,
+    ) {}
+
+    public function supports(ModelType $modelType): bool
+    {
+        return ModelCategory::COMPONENT === $modelType->getCategory();
+    }
+
+    public function preview(ModelType $modelType, array $newStructure): SyncPreviewResult
+    {
+        $composants = $this->em->getRepository(Composant::class)->findBy(['typeComposant' => $modelType]);
+
+        $proposedPieces        = $newStructure['pieces'] ?? [];
+        $proposedProducts      = $newStructure['products'] ?? [];
+        $proposedSubcomponents = $newStructure['subcomponents'] ?? [];
+        $proposedCustomFields  = $newStructure['customFields'] ?? [];
+
+        $addedPieceSlots     = 0;
+        $deletedPieceSlots   = 0;
+        $addedProductSlots   = 0;
+        $deletedProductSlots = 0;
+        $addedSubSlots       = 0;
+        $deletedSubSlots     = 0;
+        $addedCfValues       = 0;
+        $deletedCfValues     = 0;
+
+        // Map proposed by (typeId, position) keys — position defaults to array index
+        $proposedPieceKeys = [];
+        foreach ($proposedPieces as $i => $pp) {
+            $pos                                            = $pp['position'] ?? $i;
+            $proposedPieceKeys[$pp['typePieceId'].'|'.$pos] = true;
+        }
+
+        $proposedProductKeys = [];
+        foreach ($proposedProducts as $i => $pp) {
+            $pos                                                = $pp['position'] ?? $i;
+            $proposedProductKeys[$pp['typeProductId'].'|'.$pos] = true;
+        }
+
+        $proposedSubKeys = [];
+        foreach ($proposedSubcomponents as $i => $ps) {
+            $pos                                              = $ps['position'] ?? $i;
+            $proposedSubKeys[$ps['typeComposantId'].'|'.$pos] = true;
+        }
+
+        // Map proposed custom fields by orderIndex (falls back to array index)
+        $proposedCfByOrder = [];
+        foreach ($proposedCustomFields as $i => $pcf) {
+            $order                     = $pcf['orderIndex'] ?? $i;
+            $proposedCfByOrder[$order] = $pcf;
+        }
+
+        // Get existing custom fields for this model type
+        $existingFields = $this->em->getRepository(CustomField::class)->findBy(
+            ['typeComposant' => $modelType],
+            ['orderIndex' => 'ASC']
+        );
+        $existingCfByOrder = [];
+        foreach ($existingFields as $field) {
+            $existingCfByOrder[$field->getOrderIndex()] = $field;
+        }
+
+        // Count custom field additions/deletions (definition-level, affects all composants)
+        $cfAdded   = 0;
+        $cfDeleted = 0;
+        foreach ($proposedCfByOrder as $orderIndex => $pcf) {
+            if (!isset($existingCfByOrder[$orderIndex])) {
+                ++$cfAdded;
+            }
+        }
+        foreach ($existingCfByOrder as $orderIndex => $ef) {
+            if (!isset($proposedCfByOrder[$orderIndex])) {
+                ++$cfDeleted;
+            }
+        }
+
+        foreach ($composants as $composant) {
+            // Piece slots — query from repository to avoid stale collection
+            $pieceSlots        = $this->em->getRepository(ComposantPieceSlot::class)->findBy(['composant' => $composant]);
+            $existingPieceKeys = [];
+            foreach ($pieceSlots as $slot) {
+                $key                     = ($slot->getTypePiece()?->getId() ?? '').'|'.$slot->getPosition();
+                $existingPieceKeys[$key] = true;
+            }
+            foreach ($proposedPieceKeys as $key => $_) {
+                if (!isset($existingPieceKeys[$key])) {
+                    ++$addedPieceSlots;
+                }
+            }
+            foreach ($existingPieceKeys as $key => $_) {
+                if (!isset($proposedPieceKeys[$key])) {
+                    ++$deletedPieceSlots;
+                }
+            }
+
+            // Product slots
+            $productSlots        = $this->em->getRepository(ComposantProductSlot::class)->findBy(['composant' => $composant]);
+            $existingProductKeys = [];
+            foreach ($productSlots as $slot) {
+                $key                       = ($slot->getTypeProduct()?->getId() ?? '').'|'.$slot->getPosition();
+                $existingProductKeys[$key] = true;
+            }
+            foreach ($proposedProductKeys as $key => $_) {
+                if (!isset($existingProductKeys[$key])) {
+                    ++$addedProductSlots;
+                }
+            }
+            foreach ($existingProductKeys as $key => $_) {
+                if (!isset($proposedProductKeys[$key])) {
+                    ++$deletedProductSlots;
+                }
+            }
+
+            // Subcomponent slots
+            $subSlots        = $this->em->getRepository(ComposantSubcomponentSlot::class)->findBy(['composant' => $composant]);
+            $existingSubKeys = [];
+            foreach ($subSlots as $slot) {
+                $key                   = ($slot->getTypeComposant()?->getId() ?? '').'|'.$slot->getPosition();
+                $existingSubKeys[$key] = true;
+            }
+            foreach ($proposedSubKeys as $key => $_) {
+                if (!isset($existingSubKeys[$key])) {
+                    ++$addedSubSlots;
+                }
+            }
+            foreach ($existingSubKeys as $key => $_) {
+                if (!isset($proposedSubKeys[$key])) {
+                    ++$deletedSubSlots;
+                }
+            }
+
+            // Custom field values
+            $addedCfValues += $cfAdded;
+            $deletedCfValues += $cfDeleted;
+        }
+
+        $itemCount = count($composants);
+
+        return new SyncPreviewResult(
+            modelTypeId: $modelType->getId(),
+            category: 'component',
+            itemCount: $itemCount,
+            additions: [
+                'pieceSlots'        => $addedPieceSlots,
+                'productSlots'      => $addedProductSlots,
+                'subcomponentSlots' => $addedSubSlots,
+                'customFieldValues' => $addedCfValues,
+            ],
+            deletions: [
+                'pieceSlots'        => $deletedPieceSlots,
+                'productSlots'      => $deletedProductSlots,
+                'subcomponentSlots' => $deletedSubSlots,
+                'customFieldValues' => $deletedCfValues,
+            ],
+        );
+    }
+
+    public function execute(ModelType $modelType, SyncConfirmation $confirmation): SyncExecutionResult
+    {
+        $composants = $this->em->getRepository(Composant::class)->findBy(['typeComposant' => $modelType]);
+
+        // Load skeleton requirements
+        $pieceReqs    = $this->em->getRepository(SkeletonPieceRequirement::class)->findBy(['modelType' => $modelType]);
+        $productReqs  = $this->em->getRepository(SkeletonProductRequirement::class)->findBy(['modelType' => $modelType]);
+        $subReqs      = $this->em->getRepository(SkeletonSubcomponentRequirement::class)->findBy(['modelType' => $modelType]);
+        $customFields = $this->em->getRepository(CustomField::class)->findBy(
+            ['typeComposant' => $modelType],
+            ['orderIndex' => 'ASC']
+        );
+
+        // Map requirements by (typeId, position)
+        $pieceReqKeys = [];
+        foreach ($pieceReqs as $req) {
+            $pieceReqKeys[$req->getTypePiece()->getId().'|'.$req->getPosition()] = $req;
+        }
+
+        $productReqKeys = [];
+        foreach ($productReqs as $req) {
+            $productReqKeys[$req->getTypeProduct()->getId().'|'.$req->getPosition()] = $req;
+        }
+
+        $subReqKeys = [];
+        foreach ($subReqs as $req) {
+            $key              = ($req->getTypeComposant()?->getId() ?? '').'|'.$req->getPosition();
+            $subReqKeys[$key] = $req;
+        }
+
+        $addedPieceSlots     = 0;
+        $deletedPieceSlots   = 0;
+        $addedProductSlots   = 0;
+        $deletedProductSlots = 0;
+        $addedSubSlots       = 0;
+        $deletedSubSlots     = 0;
+        $addedCfValues       = 0;
+        $deletedCfValues     = 0;
+        $itemsUpdated        = 0;
+
+        foreach ($composants as $composant) {
+            $changed = false;
+
+            // --- Piece slots — query from repository to avoid stale collection ---
+            $pieceSlotEntities  = $this->em->getRepository(ComposantPieceSlot::class)->findBy(['composant' => $composant]);
+            $existingPieceSlots = [];
+            foreach ($pieceSlotEntities as $slot) {
+                $key                      = ($slot->getTypePiece()?->getId() ?? '').'|'.$slot->getPosition();
+                $existingPieceSlots[$key] = $slot;
+            }
+
+            // Add missing piece slots
+            foreach ($pieceReqKeys as $key => $req) {
+                if (!isset($existingPieceSlots[$key])) {
+                    $slot = new ComposantPieceSlot();
+                    $slot->setComposant($composant);
+                    $slot->setTypePiece($req->getTypePiece());
+                    $slot->setPosition($req->getPosition());
+                    // Default quantity = 1, selectedPiece = null (already defaults)
+                    $this->em->persist($slot);
+                    ++$addedPieceSlots;
+                    $changed = true;
+                }
+            }
+
+            // Delete orphaned piece slots
+            if ($confirmation->confirmDeletions) {
+                foreach ($existingPieceSlots as $key => $slot) {
+                    if (!isset($pieceReqKeys[$key])) {
+                        $composant->removePieceSlot($slot);
+                        $this->em->remove($slot);
+                        ++$deletedPieceSlots;
+                        $changed = true;
+                    }
+                }
+            }
+
+            // --- Product slots ---
+            $productSlotEntities  = $this->em->getRepository(ComposantProductSlot::class)->findBy(['composant' => $composant]);
+            $existingProductSlots = [];
+            foreach ($productSlotEntities as $slot) {
+                $key                        = ($slot->getTypeProduct()?->getId() ?? '').'|'.$slot->getPosition();
+                $existingProductSlots[$key] = $slot;
+            }
+
+            // Add missing product slots
+            foreach ($productReqKeys as $key => $req) {
+                if (!isset($existingProductSlots[$key])) {
+                    $slot = new ComposantProductSlot();
+                    $slot->setComposant($composant);
+                    $slot->setTypeProduct($req->getTypeProduct());
+                    $slot->setPosition($req->getPosition());
+                    if (null !== $req->getFamilyCode()) {
+                        $slot->setFamilyCode($req->getFamilyCode());
+                    }
+                    $this->em->persist($slot);
+                    ++$addedProductSlots;
+                    $changed = true;
+                }
+            }
+
+            // Delete orphaned product slots
+            if ($confirmation->confirmDeletions) {
+                foreach ($existingProductSlots as $key => $slot) {
+                    if (!isset($productReqKeys[$key])) {
+                        $composant->removeProductSlot($slot);
+                        $this->em->remove($slot);
+                        ++$deletedProductSlots;
+                        $changed = true;
+                    }
+                }
+            }
+
+            // --- Subcomponent slots ---
+            $subSlotEntities  = $this->em->getRepository(ComposantSubcomponentSlot::class)->findBy(['composant' => $composant]);
+            $existingSubSlots = [];
+            foreach ($subSlotEntities as $slot) {
+                $key                    = ($slot->getTypeComposant()?->getId() ?? '').'|'.$slot->getPosition();
+                $existingSubSlots[$key] = $slot;
+            }
+
+            // Add missing subcomponent slots
+            foreach ($subReqKeys as $key => $req) {
+                if (!isset($existingSubSlots[$key])) {
+                    $slot = new ComposantSubcomponentSlot();
+                    $slot->setComposant($composant);
+                    $slot->setTypeComposant($req->getTypeComposant());
+                    $slot->setPosition($req->getPosition());
+                    $slot->setAlias($req->getAlias());
+                    $slot->setFamilyCode($req->getFamilyCode());
+                    $this->em->persist($slot);
+                    ++$addedSubSlots;
+                    $changed = true;
+                }
+            }
+
+            // Delete orphaned subcomponent slots
+            if ($confirmation->confirmDeletions) {
+                foreach ($existingSubSlots as $key => $slot) {
+                    if (!isset($subReqKeys[$key])) {
+                        $composant->removeSubcomponentSlot($slot);
+                        $this->em->remove($slot);
+                        ++$deletedSubSlots;
+                        $changed = true;
+                    }
+                }
+            }
+
+            // --- Custom field values ---
+            $existingValues = $this->em->getRepository(CustomFieldValue::class)->findBy([
+                'composant' => $composant,
+            ]);
+
+            $existingByFieldId = [];
+            foreach ($existingValues as $cfv) {
+                $existingByFieldId[$cfv->getCustomField()->getId()] = $cfv;
+            }
+
+            // Add missing custom field values
+            foreach ($customFields as $cf) {
+                if (!isset($existingByFieldId[$cf->getId()])) {
+                    $cfv = new CustomFieldValue();
+                    $cfv->setCustomField($cf);
+                    $cfv->setComposant($composant);
+                    $cfv->setValue('');
+                    $this->em->persist($cfv);
+                    ++$addedCfValues;
+                    $changed = true;
+                }
+            }
+
+            // Delete orphaned custom field values
+            if ($confirmation->confirmDeletions) {
+                $fieldIds = array_map(fn (CustomField $cf) => $cf->getId(), $customFields);
+                foreach ($existingValues as $cfv) {
+                    if (!in_array($cfv->getCustomField()->getId(), $fieldIds, true)) {
+                        $this->em->remove($cfv);
+                        ++$deletedCfValues;
+                        $changed = true;
+                    }
+                }
+            }
+
+            if ($changed) {
+                $composant->incrementVersion();
+                ++$itemsUpdated;
+            }
+        }
+
+        $this->em->flush();
+
+        return new SyncExecutionResult(
+            itemsUpdated: $itemsUpdated,
+            additions: [
+                'pieceSlots'        => $addedPieceSlots,
+                'productSlots'      => $addedProductSlots,
+                'subcomponentSlots' => $addedSubSlots,
+                'customFieldValues' => $addedCfValues,
+            ],
+            deletions: [
+                'pieceSlots'        => $deletedPieceSlots,
+                'productSlots'      => $deletedProductSlots,
+                'subcomponentSlots' => $deletedSubSlots,
+                'customFieldValues' => $deletedCfValues,
+            ],
+        );
+    }
+}

src/Service/Sync/PieceSyncStrategy.php

@@ -0,0 +1,240 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service\Sync;
+
+use App\DTO\SyncConfirmation;
+use App\DTO\SyncExecutionResult;
+use App\DTO\SyncPreviewResult;
+use App\Entity\CustomField;
+use App\Entity\CustomFieldValue;
+use App\Entity\ModelType;
+use App\Entity\Piece;
+use App\Entity\PieceProductSlot;
+use App\Entity\SkeletonProductRequirement;
+use App\Enum\ModelCategory;
+use Doctrine\ORM\EntityManagerInterface;
+use Symfony\Component\DependencyInjection\Attribute\AutoconfigureTag;
+
+#[AutoconfigureTag('app.sync_strategy')]
+class PieceSyncStrategy implements SyncStrategyInterface
+{
+    public function __construct(
+        private readonly EntityManagerInterface $em,
+    ) {}
+
+    public function supports(ModelType $modelType): bool
+    {
+        return ModelCategory::PIECE === $modelType->getCategory();
+    }
+
+    public function preview(ModelType $modelType, array $newStructure): SyncPreviewResult
+    {
+        $pieces = $this->em->getRepository(Piece::class)->findBy(['typePiece' => $modelType]);
+
+        $proposedProducts     = $newStructure['products'] ?? [];
+        $proposedCustomFields = $newStructure['customFields'] ?? [];
+
+        $addedProductSlots   = 0;
+        $deletedProductSlots = 0;
+        $addedCfValues       = 0;
+        $deletedCfValues     = 0;
+
+        // Map proposed products by (typeProductId, position) keys — position defaults to array index
+        $proposedProductKeys = [];
+        foreach ($proposedProducts as $i => $pp) {
+            $pos                                                = $pp['position'] ?? $i;
+            $proposedProductKeys[$pp['typeProductId'].'|'.$pos] = true;
+        }
+
+        // Map proposed custom fields by orderIndex (falls back to array index)
+        $proposedCfByOrder = [];
+        foreach ($proposedCustomFields as $i => $pcf) {
+            $order                     = $pcf['orderIndex'] ?? $i;
+            $proposedCfByOrder[$order] = $pcf;
+        }
+
+        // Get existing custom fields for this model type
+        $existingFields = $this->em->getRepository(CustomField::class)->findBy(
+            ['typePiece' => $modelType],
+            ['orderIndex' => 'ASC']
+        );
+        $existingCfByOrder = [];
+        foreach ($existingFields as $field) {
+            $existingCfByOrder[$field->getOrderIndex()] = $field;
+        }
+
+        // Count custom field additions/deletions (definition-level, affects all pieces)
+        $cfAdded   = 0;
+        $cfDeleted = 0;
+        foreach ($proposedCfByOrder as $orderIndex => $pcf) {
+            if (!isset($existingCfByOrder[$orderIndex])) {
+                ++$cfAdded;
+            }
+        }
+        foreach ($existingCfByOrder as $orderIndex => $ef) {
+            if (!isset($proposedCfByOrder[$orderIndex])) {
+                ++$cfDeleted;
+            }
+        }
+
+        foreach ($pieces as $piece) {
+            // Product slots
+            $productSlots        = $this->em->getRepository(PieceProductSlot::class)->findBy(['piece' => $piece]);
+            $existingProductKeys = [];
+            foreach ($productSlots as $slot) {
+                $key                       = ($slot->getTypeProduct()?->getId() ?? '').'|'.$slot->getPosition();
+                $existingProductKeys[$key] = true;
+            }
+            foreach ($proposedProductKeys as $key => $_) {
+                if (!isset($existingProductKeys[$key])) {
+                    ++$addedProductSlots;
+                }
+            }
+            foreach ($existingProductKeys as $key => $_) {
+                if (!isset($proposedProductKeys[$key])) {
+                    ++$deletedProductSlots;
+                }
+            }
+
+            // Custom field values
+            $addedCfValues += $cfAdded;
+            $deletedCfValues += $cfDeleted;
+        }
+
+        $itemCount = count($pieces);
+
+        return new SyncPreviewResult(
+            modelTypeId: $modelType->getId(),
+            category: 'piece',
+            itemCount: $itemCount,
+            additions: [
+                'productSlots'      => $addedProductSlots,
+                'customFieldValues' => $addedCfValues,
+            ],
+            deletions: [
+                'productSlots'      => $deletedProductSlots,
+                'customFieldValues' => $deletedCfValues,
+            ],
+        );
+    }
+
+    public function execute(ModelType $modelType, SyncConfirmation $confirmation): SyncExecutionResult
+    {
+        $pieces = $this->em->getRepository(Piece::class)->findBy(['typePiece' => $modelType]);
+
+        // Load skeleton requirements
+        $productReqs  = $this->em->getRepository(SkeletonProductRequirement::class)->findBy(['modelType' => $modelType]);
+        $customFields = $this->em->getRepository(CustomField::class)->findBy(
+            ['typePiece' => $modelType],
+            ['orderIndex' => 'ASC']
+        );
+
+        // Map requirements by (typeProductId, position)
+        $productReqKeys = [];
+        foreach ($productReqs as $req) {
+            $productReqKeys[$req->getTypeProduct()->getId().'|'.$req->getPosition()] = $req;
+        }
+
+        $addedProductSlots   = 0;
+        $deletedProductSlots = 0;
+        $addedCfValues       = 0;
+        $deletedCfValues     = 0;
+        $itemsUpdated        = 0;
+
+        foreach ($pieces as $piece) {
+            $changed = false;
+
+            // --- Product slots ---
+            $productSlotEntities  = $this->em->getRepository(PieceProductSlot::class)->findBy(['piece' => $piece]);
+            $existingProductSlots = [];
+            foreach ($productSlotEntities as $slot) {
+                $key                        = ($slot->getTypeProduct()?->getId() ?? '').'|'.$slot->getPosition();
+                $existingProductSlots[$key] = $slot;
+            }
+
+            // Add missing product slots
+            foreach ($productReqKeys as $key => $req) {
+                if (!isset($existingProductSlots[$key])) {
+                    $slot = new PieceProductSlot();
+                    $slot->setPiece($piece);
+                    $slot->setTypeProduct($req->getTypeProduct());
+                    $slot->setPosition($req->getPosition());
+                    if (null !== $req->getFamilyCode()) {
+                        $slot->setFamilyCode($req->getFamilyCode());
+                    }
+                    $this->em->persist($slot);
+                    ++$addedProductSlots;
+                    $changed = true;
+                }
+            }
+
+            // Delete orphaned product slots
+            if ($confirmation->confirmDeletions) {
+                foreach ($existingProductSlots as $key => $slot) {
+                    if (!isset($productReqKeys[$key])) {
+                        $piece->removeProductSlot($slot);
+                        $this->em->remove($slot);
+                        ++$deletedProductSlots;
+                        $changed = true;
+                    }
+                }
+            }
+
+            // --- Custom field values ---
+            $existingValues = $this->em->getRepository(CustomFieldValue::class)->findBy([
+                'piece' => $piece,
+            ]);
+
+            $existingByFieldId = [];
+            foreach ($existingValues as $cfv) {
+                $existingByFieldId[$cfv->getCustomField()->getId()] = $cfv;
+            }
+
+            // Add missing custom field values
+            foreach ($customFields as $cf) {
+                if (!isset($existingByFieldId[$cf->getId()])) {
+                    $cfv = new CustomFieldValue();
+                    $cfv->setCustomField($cf);
+                    $cfv->setPiece($piece);
+                    $cfv->setValue('');
+                    $this->em->persist($cfv);
+                    ++$addedCfValues;
+                    $changed = true;
+                }
+            }
+
+            // Delete orphaned custom field values
+            if ($confirmation->confirmDeletions) {
+                $fieldIds = array_map(fn (CustomField $cf) => $cf->getId(), $customFields);
+                foreach ($existingValues as $cfv) {
+                    if (!in_array($cfv->getCustomField()->getId(), $fieldIds, true)) {
+                        $this->em->remove($cfv);
+                        ++$deletedCfValues;
+                        $changed = true;
+                    }
+                }
+            }
+
+            if ($changed) {
+                $piece->incrementVersion();
+                ++$itemsUpdated;
+            }
+        }
+
+        $this->em->flush();
+
+        return new SyncExecutionResult(
+            itemsUpdated: $itemsUpdated,
+            additions: [
+                'productSlots'      => $addedProductSlots,
+                'customFieldValues' => $addedCfValues,
+            ],
+            deletions: [
+                'productSlots'      => $deletedProductSlots,
+                'customFieldValues' => $deletedCfValues,
+            ],
+        );
+    }
+}

src/Service/Sync/ProductSyncStrategy.php

@@ -0,0 +1,153 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service\Sync;
+
+use App\DTO\SyncConfirmation;
+use App\DTO\SyncExecutionResult;
+use App\DTO\SyncPreviewResult;
+use App\Entity\CustomField;
+use App\Entity\CustomFieldValue;
+use App\Entity\ModelType;
+use App\Entity\Product;
+use App\Enum\ModelCategory;
+use Doctrine\ORM\EntityManagerInterface;
+use Symfony\Component\DependencyInjection\Attribute\AutoconfigureTag;
+
+#[AutoconfigureTag('app.sync_strategy')]
+class ProductSyncStrategy implements SyncStrategyInterface
+{
+    public function __construct(
+        private readonly EntityManagerInterface $em,
+    ) {}
+
+    public function supports(ModelType $modelType): bool
+    {
+        return ModelCategory::PRODUCT === $modelType->getCategory();
+    }
+
+    public function preview(ModelType $modelType, array $newStructure): SyncPreviewResult
+    {
+        $products       = $this->em->getRepository(Product::class)->findBy(['typeProduct' => $modelType]);
+        $existingFields = $this->em->getRepository(CustomField::class)->findBy(
+            ['typeProduct' => $modelType],
+            ['orderIndex' => 'ASC']
+        );
+
+        $proposedFields = $newStructure['customFields'] ?? [];
+
+        // Map existing fields by orderIndex
+        $existingByOrder = [];
+        foreach ($existingFields as $field) {
+            $existingByOrder[$field->getOrderIndex()] = $field;
+        }
+
+        // Map proposed fields by orderIndex (falls back to array index)
+        $proposedByOrder = [];
+        foreach ($proposedFields as $i => $pf) {
+            $order                   = $pf['orderIndex'] ?? $i;
+            $proposedByOrder[$order] = $pf;
+        }
+
+        $addedFields    = 0;
+        $deletedFields  = 0;
+        $modifiedFields = 0;
+
+        // New fields (in proposed but not in existing)
+        foreach ($proposedByOrder as $orderIndex => $pf) {
+            if (!isset($existingByOrder[$orderIndex])) {
+                ++$addedFields;
+            } elseif ($existingByOrder[$orderIndex]->getType() !== ($pf['type'] ?? $pf['value']['type'] ?? null)) {
+                ++$modifiedFields;
+            }
+        }
+
+        // Deleted fields (in existing but not in proposed)
+        foreach ($existingByOrder as $orderIndex => $ef) {
+            if (!isset($proposedByOrder[$orderIndex])) {
+                ++$deletedFields;
+            }
+        }
+
+        $itemCount = count($products);
+
+        return new SyncPreviewResult(
+            modelTypeId: $modelType->getId(),
+            category: 'product',
+            itemCount: $itemCount,
+            additions: ['customFieldValues' => $addedFields * $itemCount],
+            deletions: ['customFieldValues' => $deletedFields * $itemCount],
+            modifications: ['customFieldValues' => $modifiedFields * $itemCount],
+        );
+    }
+
+    public function execute(ModelType $modelType, SyncConfirmation $confirmation): SyncExecutionResult
+    {
+        $products     = $this->em->getRepository(Product::class)->findBy(['typeProduct' => $modelType]);
+        $customFields = $this->em->getRepository(CustomField::class)->findBy(
+            ['typeProduct' => $modelType],
+            ['orderIndex' => 'ASC']
+        );
+
+        $addedValues    = 0;
+        $deletedValues  = 0;
+        $modifiedValues = 0;
+        $itemsUpdated   = 0;
+
+        foreach ($products as $product) {
+            $changed = false;
+
+            // Get existing custom field values for this product
+            $existingValues = $this->em->getRepository(CustomFieldValue::class)->findBy([
+                'product' => $product,
+            ]);
+
+            // Map existing values by custom field ID
+            $existingByFieldId = [];
+            foreach ($existingValues as $cfv) {
+                $existingByFieldId[$cfv->getCustomField()->getId()] = $cfv;
+            }
+
+            // For each custom field defined on the model type, ensure a value exists
+            foreach ($customFields as $cf) {
+                if (!isset($existingByFieldId[$cf->getId()])) {
+                    // Create missing custom field value
+                    $cfv = new CustomFieldValue();
+                    $cfv->setCustomField($cf);
+                    $cfv->setProduct($product);
+                    $cfv->setValue('');
+                    $this->em->persist($cfv);
+                    ++$addedValues;
+                    $changed = true;
+                }
+            }
+
+            // Delete orphaned values if confirmDeletions
+            if ($confirmation->confirmDeletions) {
+                $fieldIds = array_map(fn (CustomField $cf) => $cf->getId(), $customFields);
+                foreach ($existingValues as $cfv) {
+                    if (!in_array($cfv->getCustomField()->getId(), $fieldIds, true)) {
+                        $this->em->remove($cfv);
+                        ++$deletedValues;
+                        $changed = true;
+                    }
+                }
+            }
+
+            if ($changed) {
+                $product->incrementVersion();
+                ++$itemsUpdated;
+            }
+        }
+
+        $this->em->flush();
+
+        return new SyncExecutionResult(
+            itemsUpdated: $itemsUpdated,
+            additions: ['customFieldValues' => $addedValues],
+            deletions: ['customFieldValues' => $deletedValues],
+            modifications: ['customFieldValues' => $modifiedValues],
+        );
+    }
+}

src/Service/Sync/SyncStrategyInterface.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service\Sync;
+
+use App\DTO\SyncConfirmation;
+use App\DTO\SyncExecutionResult;
+use App\DTO\SyncPreviewResult;
+use App\Entity\ModelType;
+
+interface SyncStrategyInterface
+{
+    public function supports(ModelType $modelType): bool;
+
+    /**
+     * Compute diff between proposed structure and current items' slots.
+     * Does NOT persist anything.
+     */
+    public function preview(ModelType $modelType, array $newStructure): SyncPreviewResult;
+
+    /**
+     * Apply sync: compare current skeleton requirements (already persisted)
+     * with items' slots and add/remove as needed.
+     */
+    public function execute(ModelType $modelType, SyncConfirmation $confirmation): SyncExecutionResult;
+}

tests/AbstractApiTestCase.php

@@ -19,6 +19,7 @@ use App\Entity\MachinePieceLink;
 use App\Entity\MachineProductLink;
 use App\Entity\ModelType;
 use App\Entity\Piece;
+use App\Entity\PieceProductSlot;
 use App\Entity\Product;
 use App\Entity\Profile;
 use App\Entity\Site;
@@ -236,13 +237,27 @@ abstract class AbstractApiTestCase extends ApiTestCase
         string $name = 'Custom Field',
         string $type = 'text',
         ?Machine $machine = null,
+        ?ModelType $typeComposant = null,
+        ?ModelType $typePiece = null,
+        ?ModelType $typeProduct = null,
+        int $orderIndex = 0,
     ): CustomField {
         $cf = new CustomField();
         $cf->setName($name);
         $cf->setType($type);
+        $cf->setOrderIndex($orderIndex);
         if (null !== $machine) {
             $cf->setMachine($machine);
         }
+        if (null !== $typeComposant) {
+            $cf->setTypeComposant($typeComposant);
+        }
+        if (null !== $typePiece) {
+            $cf->setTypePiece($typePiece);
+        }
+        if (null !== $typeProduct) {
+            $cf->setTypeProduct($typeProduct);
+        }
 
         $em = $this->getEntityManager();
         $em->persist($cf);
@@ -394,6 +409,31 @@ abstract class AbstractApiTestCase extends ApiTestCase
         return $slot;
     }
 
+    protected function createPieceProductSlot(
+        Piece $piece,
+        ?ModelType $typeProduct = null,
+        ?Product $selectedProduct = null,
+        ?string $familyCode = null,
+        int $position = 0,
+    ): PieceProductSlot {
+        $slot = new PieceProductSlot();
+        $slot->setPiece($piece);
+        $slot->setFamilyCode($familyCode);
+        $slot->setPosition($position);
+        if (null !== $typeProduct) {
+            $slot->setTypeProduct($typeProduct);
+        }
+        if (null !== $selectedProduct) {
+            $slot->setSelectedProduct($selectedProduct);
+        }
+
+        $em = $this->getEntityManager();
+        $em->persist($slot);
+        $em->flush();
+
+        return $slot;
+    }
+
     // ── Assertion helpers ───────────────────────────────────────────
 
     protected function assertJsonContainsHydraCollection(): void

tests/Api/Controller/ModelTypeSyncControllerTest.php

@@ -0,0 +1,267 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Api\Controller;
+
+use App\Entity\SkeletonPieceRequirement;
+use App\Entity\SkeletonProductRequirement;
+use App\Enum\ModelCategory;
+use App\Tests\AbstractApiTestCase;
+
+/**
+ * @internal
+ */
+class ModelTypeSyncControllerTest extends AbstractApiTestCase
+{
+    // ── sync-preview ────────────────────────────────────────────────
+
+    public function testPreviewReturnsNoImpactWhenNoItems(): void
+    {
+        $mt = $this->createModelType('Comp Cat', 'CC-001', ModelCategory::COMPONENT);
+
+        $client = $this->createGestionnaireClient();
+        $client->request('POST', '/api/model_types/'.$mt->getId().'/sync-preview', [
+            'json' => [
+                'structure' => [
+                    'pieces'        => [],
+                    'products'      => [],
+                    'subcomponents' => [],
+                    'customFields'  => [],
+                ],
+            ],
+        ]);
+
+        $this->assertResponseIsSuccessful();
+        $data = json_decode($client->getResponse()->getContent(), true);
+        $this->assertSame(0, $data['itemCount']);
+        $this->assertSame($mt->getId(), $data['modelTypeId']);
+    }
+
+    public function testPreviewDetectsNewSlots(): void
+    {
+        $mt        = $this->createModelType('Comp Cat', 'CC-001', ModelCategory::COMPONENT);
+        $pieceType = $this->createModelType('Piece Type', 'PT-001', ModelCategory::PIECE);
+        $this->createComposant('C1', $mt);
+
+        $client = $this->createGestionnaireClient();
+        $client->request('POST', '/api/model_types/'.$mt->getId().'/sync-preview', [
+            'json' => [
+                'structure' => [
+                    'pieces'        => [['typePieceId' => $pieceType->getId(), 'position' => 0]],
+                    'products'      => [],
+                    'subcomponents' => [],
+                    'customFields'  => [],
+                ],
+            ],
+        ]);
+
+        $this->assertResponseIsSuccessful();
+        $data = json_decode($client->getResponse()->getContent(), true);
+        $this->assertSame(1, $data['itemCount']);
+        $this->assertSame(1, $data['additions']['pieceSlots']);
+    }
+
+    public function testPreview403ForViewer(): void
+    {
+        $mt = $this->createModelType('Comp Cat', 'CC-001', ModelCategory::COMPONENT);
+
+        $client = $this->createViewerClient();
+        $client->request('POST', '/api/model_types/'.$mt->getId().'/sync-preview', [
+            'json' => ['structure' => []],
+        ]);
+
+        $this->assertResponseStatusCodeSame(403);
+    }
+
+    public function testPreview401ForUnauthenticated(): void
+    {
+        $mt = $this->createModelType('Comp Cat', 'CC-001', ModelCategory::COMPONENT);
+
+        $client = $this->createUnauthenticatedClient();
+        $client->request('POST', '/api/model_types/'.$mt->getId().'/sync-preview', [
+            'json' => ['structure' => []],
+        ]);
+
+        $this->assertResponseStatusCodeSame(401);
+    }
+
+    public function testPreview404ForUnknownModelType(): void
+    {
+        $client = $this->createGestionnaireClient();
+        $client->request('POST', '/api/model_types/nonexistent-id/sync-preview', [
+            'json' => ['structure' => []],
+        ]);
+
+        $this->assertResponseStatusCodeSame(404);
+    }
+
+    // ── sync ────────────────────────────────────────────────────────
+
+    public function testSyncAddsSlots(): void
+    {
+        $mt        = $this->createModelType('Comp Cat', 'CC-001', ModelCategory::COMPONENT);
+        $pieceType = $this->createModelType('Piece Type', 'PT-001', ModelCategory::PIECE);
+        $this->createComposant('C1', $mt);
+
+        // Add a skeleton requirement (simulates a PATCH that already happened)
+        $em  = $this->getEntityManager();
+        $req = new SkeletonPieceRequirement();
+        $req->setModelType($mt);
+        $req->setTypePiece($pieceType);
+        $req->setPosition(0);
+        $em->persist($req);
+        $em->flush();
+
+        $client = $this->createGestionnaireClient();
+        $client->request('POST', '/api/model_types/'.$mt->getId().'/sync', [
+            'json' => [
+                'confirmDeletions'   => false,
+                'confirmTypeChanges' => false,
+            ],
+        ]);
+
+        $this->assertResponseIsSuccessful();
+        $data = json_decode($client->getResponse()->getContent(), true);
+        $this->assertSame(1, $data['itemsUpdated']);
+        $this->assertSame(1, $data['additions']['pieceSlots']);
+    }
+
+    public function testSyncDeletesSlotsWithConfirmation(): void
+    {
+        $mt        = $this->createModelType('Comp Cat', 'CC-001', ModelCategory::COMPONENT);
+        $pieceType = $this->createModelType('Piece Type', 'PT-001', ModelCategory::PIECE);
+        $composant = $this->createComposant('C1', $mt);
+        $this->createComposantPieceSlot($composant, $pieceType, null, 1, 0);
+
+        // No skeleton requirements → slot is orphaned
+        $client = $this->createGestionnaireClient();
+        $client->request('POST', '/api/model_types/'.$mt->getId().'/sync', [
+            'json' => [
+                'confirmDeletions'   => true,
+                'confirmTypeChanges' => false,
+            ],
+        ]);
+
+        $this->assertResponseIsSuccessful();
+        $data = json_decode($client->getResponse()->getContent(), true);
+        $this->assertSame(1, $data['deletions']['pieceSlots']);
+    }
+
+    public function testSyncSkipsDeletionsWithoutConfirmation(): void
+    {
+        $mt        = $this->createModelType('Comp Cat', 'CC-001', ModelCategory::COMPONENT);
+        $pieceType = $this->createModelType('Piece Type', 'PT-001', ModelCategory::PIECE);
+        $composant = $this->createComposant('C1', $mt);
+        $this->createComposantPieceSlot($composant, $pieceType, null, 1, 0);
+
+        $client = $this->createGestionnaireClient();
+        $client->request('POST', '/api/model_types/'.$mt->getId().'/sync', [
+            'json' => [
+                'confirmDeletions'   => false,
+                'confirmTypeChanges' => false,
+            ],
+        ]);
+
+        $this->assertResponseIsSuccessful();
+        $data = json_decode($client->getResponse()->getContent(), true);
+        $this->assertSame(0, $data['deletions']['pieceSlots']);
+    }
+
+    public function testSync403ForViewer(): void
+    {
+        $mt = $this->createModelType('Comp Cat', 'CC-001', ModelCategory::COMPONENT);
+
+        $client = $this->createViewerClient();
+        $client->request('POST', '/api/model_types/'.$mt->getId().'/sync', [
+            'json' => ['confirmDeletions' => false, 'confirmTypeChanges' => false],
+        ]);
+
+        $this->assertResponseStatusCodeSame(403);
+    }
+
+    public function testSync404ForUnknownModelType(): void
+    {
+        $client = $this->createGestionnaireClient();
+        $client->request('POST', '/api/model_types/nonexistent-id/sync', [
+            'json' => ['confirmDeletions' => false, 'confirmTypeChanges' => false],
+        ]);
+
+        $this->assertResponseStatusCodeSame(404);
+    }
+
+    public function testSyncIsIdempotent(): void
+    {
+        $mt        = $this->createModelType('Comp Cat', 'CC-001', ModelCategory::COMPONENT);
+        $pieceType = $this->createModelType('Piece Type', 'PT-001', ModelCategory::PIECE);
+        $this->createComposant('C1', $mt);
+
+        $em  = $this->getEntityManager();
+        $req = new SkeletonPieceRequirement();
+        $req->setModelType($mt);
+        $req->setTypePiece($pieceType);
+        $req->setPosition(0);
+        $em->persist($req);
+        $em->flush();
+
+        $client = $this->createGestionnaireClient();
+
+        // First sync
+        $client->request('POST', '/api/model_types/'.$mt->getId().'/sync', [
+            'json' => ['confirmDeletions' => false, 'confirmTypeChanges' => false],
+        ]);
+        $this->assertResponseIsSuccessful();
+        $data1 = json_decode($client->getResponse()->getContent(), true);
+        $this->assertSame(1, $data1['itemsUpdated']);
+
+        // Second sync — idempotent, no changes
+        $client->request('POST', '/api/model_types/'.$mt->getId().'/sync', [
+            'json' => ['confirmDeletions' => false, 'confirmTypeChanges' => false],
+        ]);
+        $this->assertResponseIsSuccessful();
+        $data2 = json_decode($client->getResponse()->getContent(), true);
+        $this->assertSame(0, $data2['itemsUpdated']);
+    }
+
+    public function testSyncWorksForPieceCategory(): void
+    {
+        $mt          = $this->createModelType('Piece Cat', 'PC-001', ModelCategory::PIECE);
+        $productType = $this->createModelType('Prod Type', 'PD-001', ModelCategory::PRODUCT);
+        $this->createPiece('P1', 'P1-REF', $mt);
+
+        $em  = $this->getEntityManager();
+        $req = new SkeletonProductRequirement();
+        $req->setModelType($mt);
+        $req->setTypeProduct($productType);
+        $req->setPosition(0);
+        $em->persist($req);
+        $em->flush();
+
+        $client = $this->createGestionnaireClient();
+        $client->request('POST', '/api/model_types/'.$mt->getId().'/sync', [
+            'json' => ['confirmDeletions' => false, 'confirmTypeChanges' => false],
+        ]);
+
+        $this->assertResponseIsSuccessful();
+        $data = json_decode($client->getResponse()->getContent(), true);
+        $this->assertSame(1, $data['itemsUpdated']);
+        $this->assertSame(1, $data['additions']['productSlots']);
+    }
+
+    public function testSyncWorksForProductCategory(): void
+    {
+        $mt = $this->createModelType('Prod Cat', 'PD-001', ModelCategory::PRODUCT);
+        $this->createProduct('PR1', 'PR1-REF', $mt);
+        $this->createCustomField('CF1', 'text', typeProduct: $mt, orderIndex: 0);
+
+        $client = $this->createGestionnaireClient();
+        $client->request('POST', '/api/model_types/'.$mt->getId().'/sync', [
+            'json' => ['confirmDeletions' => false, 'confirmTypeChanges' => false],
+        ]);
+
+        $this->assertResponseIsSuccessful();
+        $data = json_decode($client->getResponse()->getContent(), true);
+        $this->assertSame(1, $data['itemsUpdated']);
+        $this->assertSame(1, $data['additions']['customFieldValues']);
+    }
+}

tests/Api/Service/ComposantSyncStrategyTest.php

@@ -0,0 +1,178 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Api\Service;
+
+use App\DTO\SyncConfirmation;
+use App\Entity\SkeletonPieceRequirement;
+use App\Enum\ModelCategory;
+use App\Service\Sync\ComposantSyncStrategy;
+use App\Tests\AbstractApiTestCase;
+
+/**
+ * @internal
+ */
+class ComposantSyncStrategyTest extends AbstractApiTestCase
+{
+    private ComposantSyncStrategy $strategy;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $this->strategy = static::getContainer()->get(ComposantSyncStrategy::class);
+    }
+
+    public function testSupportsComponentCategory(): void
+    {
+        $mt = $this->createModelType('Comp Cat', 'CC-001', ModelCategory::COMPONENT);
+        $this->assertTrue($this->strategy->supports($mt));
+    }
+
+    public function testPreviewNoImpactWhenNoComposants(): void
+    {
+        $mt     = $this->createModelType('Comp Cat', 'CC-001', ModelCategory::COMPONENT);
+        $result = $this->strategy->preview($mt, ['pieces' => [], 'products' => [], 'subcomponents' => [], 'customFields' => []]);
+        $this->assertSame(0, $result->itemCount);
+        $this->assertFalse($result->hasImpact());
+    }
+
+    public function testPreviewDetectsNewPieceSlot(): void
+    {
+        $mt        = $this->createModelType('Comp Cat', 'CC-001', ModelCategory::COMPONENT);
+        $pieceType = $this->createModelType('Piece Type', 'PT-001', ModelCategory::PIECE);
+        $this->createComposant('C1', $mt);
+
+        $result = $this->strategy->preview($mt, [
+            'pieces'        => [['typePieceId' => $pieceType->getId(), 'position' => 0]],
+            'products'      => [],
+            'subcomponents' => [],
+            'customFields'  => [],
+        ]);
+
+        $this->assertSame(1, $result->itemCount);
+        $this->assertSame(1, $result->additions['pieceSlots']);
+    }
+
+    public function testPreviewDetectsSlotDeletion(): void
+    {
+        $mt        = $this->createModelType('Comp Cat', 'CC-001', ModelCategory::COMPONENT);
+        $pieceType = $this->createModelType('Piece Type', 'PT-001', ModelCategory::PIECE);
+        $composant = $this->createComposant('C1', $mt);
+        $this->createComposantPieceSlot($composant, $pieceType, null, 1, 0);
+
+        $result = $this->strategy->preview($mt, [
+            'pieces'        => [],
+            'products'      => [],
+            'subcomponents' => [],
+            'customFields'  => [],
+        ]);
+
+        $this->assertSame(1, $result->deletions['pieceSlots']);
+    }
+
+    public function testPreviewNoImpactWhenSlotsMatch(): void
+    {
+        $mt        = $this->createModelType('Comp Cat', 'CC-001', ModelCategory::COMPONENT);
+        $pieceType = $this->createModelType('Piece Type', 'PT-001', ModelCategory::PIECE);
+        $composant = $this->createComposant('C1', $mt);
+        $this->createComposantPieceSlot($composant, $pieceType, null, 1, 0);
+
+        $result = $this->strategy->preview($mt, [
+            'pieces'        => [['typePieceId' => $pieceType->getId(), 'position' => 0]],
+            'products'      => [],
+            'subcomponents' => [],
+            'customFields'  => [],
+        ]);
+
+        $this->assertFalse($result->hasImpact());
+    }
+
+    public function testExecuteAddsMissingSlots(): void
+    {
+        $mt        = $this->createModelType('Comp Cat', 'CC-001', ModelCategory::COMPONENT);
+        $pieceType = $this->createModelType('Piece Type', 'PT-001', ModelCategory::PIECE);
+        $composant = $this->createComposant('C1', $mt);
+
+        $em  = $this->getEntityManager();
+        $req = new SkeletonPieceRequirement();
+        $req->setModelType($mt);
+        $req->setTypePiece($pieceType);
+        $req->setPosition(0);
+        $em->persist($req);
+        $em->flush();
+
+        $result = $this->strategy->execute($mt, new SyncConfirmation());
+
+        $this->assertSame(1, $result->itemsUpdated);
+        $this->assertSame(1, $result->additions['pieceSlots']);
+
+        $em->refresh($composant);
+        $this->assertSame(2, $composant->getVersion());
+    }
+
+    public function testExecutePreservesExistingSelections(): void
+    {
+        $mt        = $this->createModelType('Comp Cat', 'CC-001', ModelCategory::COMPONENT);
+        $pieceType = $this->createModelType('Piece Type', 'PT-001', ModelCategory::PIECE);
+        $composant = $this->createComposant('C1', $mt);
+        $piece     = $this->createPiece('P1', 'P1-REF', $pieceType);
+        $slot      = $this->createComposantPieceSlot($composant, $pieceType, $piece, 5, 0);
+
+        $em  = $this->getEntityManager();
+        $req = new SkeletonPieceRequirement();
+        $req->setModelType($mt);
+        $req->setTypePiece($pieceType);
+        $req->setPosition(0);
+        $em->persist($req);
+        $em->flush();
+
+        $result = $this->strategy->execute($mt, new SyncConfirmation());
+
+        // No changes — slot already matches
+        $this->assertSame(0, $result->itemsUpdated);
+
+        // Selection and quantity preserved
+        $em->refresh($slot);
+        $this->assertSame($piece->getId(), $slot->getSelectedPiece()->getId());
+        $this->assertSame(5, $slot->getQuantity());
+    }
+
+    public function testExecuteDeletesSlotsOnlyWithConfirmation(): void
+    {
+        $mt        = $this->createModelType('Comp Cat', 'CC-001', ModelCategory::COMPONENT);
+        $pieceType = $this->createModelType('Piece Type', 'PT-001', ModelCategory::PIECE);
+        $composant = $this->createComposant('C1', $mt);
+        $this->createComposantPieceSlot($composant, $pieceType, null, 1, 0);
+
+        // No skeleton requirements -> slot should be deleted
+        $result = $this->strategy->execute($mt, new SyncConfirmation(confirmDeletions: false));
+        $this->assertSame(0, $result->deletions['pieceSlots']);
+
+        // With confirmation
+        $result = $this->strategy->execute($mt, new SyncConfirmation(confirmDeletions: true));
+        $this->assertSame(1, $result->deletions['pieceSlots']);
+    }
+
+    public function testExecuteIsIdempotent(): void
+    {
+        $mt        = $this->createModelType('Comp Cat', 'CC-001', ModelCategory::COMPONENT);
+        $pieceType = $this->createModelType('Piece Type', 'PT-001', ModelCategory::PIECE);
+        $composant = $this->createComposant('C1', $mt);
+
+        $em  = $this->getEntityManager();
+        $req = new SkeletonPieceRequirement();
+        $req->setModelType($mt);
+        $req->setTypePiece($pieceType);
+        $req->setPosition(0);
+        $em->persist($req);
+        $em->flush();
+
+        $result1 = $this->strategy->execute($mt, new SyncConfirmation());
+        $this->assertSame(1, $result1->additions['pieceSlots']);
+
+        $em->refresh($composant);
+        $result2 = $this->strategy->execute($mt, new SyncConfirmation());
+        $this->assertSame(0, $result2->itemsUpdated);
+    }
+}

tests/Api/Service/PieceSyncStrategyTest.php

@@ -0,0 +1,103 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Api\Service;
+
+use App\DTO\SyncConfirmation;
+use App\Entity\SkeletonProductRequirement;
+use App\Enum\ModelCategory;
+use App\Service\Sync\PieceSyncStrategy;
+use App\Tests\AbstractApiTestCase;
+
+/**
+ * @internal
+ */
+class PieceSyncStrategyTest extends AbstractApiTestCase
+{
+    private PieceSyncStrategy $strategy;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $this->strategy = static::getContainer()->get(PieceSyncStrategy::class);
+    }
+
+    public function testSupportsPieceCategory(): void
+    {
+        $mt = $this->createModelType('Piece Cat', 'PC-001', ModelCategory::PIECE);
+        $this->assertTrue($this->strategy->supports($mt));
+    }
+
+    public function testPreviewDetectsNewProductSlot(): void
+    {
+        $mt          = $this->createModelType('Piece Cat', 'PC-001', ModelCategory::PIECE);
+        $productType = $this->createModelType('Product Type', 'PT-001', ModelCategory::PRODUCT);
+        $this->createPiece('P1', 'P1-REF', $mt);
+
+        $result = $this->strategy->preview($mt, [
+            'products'     => [['typeProductId' => $productType->getId(), 'position' => 0]],
+            'customFields' => [],
+        ]);
+
+        $this->assertSame(1, $result->itemCount);
+        $this->assertSame(1, $result->additions['productSlots']);
+    }
+
+    public function testExecuteAddsProductSlots(): void
+    {
+        $mt          = $this->createModelType('Piece Cat', 'PC-001', ModelCategory::PIECE);
+        $productType = $this->createModelType('Product Type', 'PT-001', ModelCategory::PRODUCT);
+        $piece       = $this->createPiece('P1', 'P1-REF', $mt);
+
+        $em  = $this->getEntityManager();
+        $req = new SkeletonProductRequirement();
+        $req->setModelType($mt);
+        $req->setTypeProduct($productType);
+        $req->setPosition(0);
+        $em->persist($req);
+        $em->flush();
+
+        $result = $this->strategy->execute($mt, new SyncConfirmation());
+
+        $this->assertSame(1, $result->itemsUpdated);
+        $this->assertSame(1, $result->additions['productSlots']);
+
+        $em->refresh($piece);
+        $this->assertSame(2, $piece->getVersion());
+        $this->assertCount(1, $piece->getProductSlots());
+    }
+
+    public function testExecuteDeletesWithConfirmation(): void
+    {
+        $mt          = $this->createModelType('Piece Cat', 'PC-001', ModelCategory::PIECE);
+        $productType = $this->createModelType('Product Type', 'PT-001', ModelCategory::PRODUCT);
+        $piece       = $this->createPiece('P1', 'P1-REF', $mt);
+        $this->createPieceProductSlot($piece, $productType, null, null, 0);
+
+        $result = $this->strategy->execute($mt, new SyncConfirmation(confirmDeletions: true));
+        $this->assertSame(1, $result->deletions['productSlots']);
+    }
+
+    public function testExecuteIsIdempotent(): void
+    {
+        $mt          = $this->createModelType('Piece Cat', 'PC-001', ModelCategory::PIECE);
+        $productType = $this->createModelType('Product Type', 'PT-001', ModelCategory::PRODUCT);
+        $piece       = $this->createPiece('P1', 'P1-REF', $mt);
+
+        $em  = $this->getEntityManager();
+        $req = new SkeletonProductRequirement();
+        $req->setModelType($mt);
+        $req->setTypeProduct($productType);
+        $req->setPosition(0);
+        $em->persist($req);
+        $em->flush();
+
+        $result1 = $this->strategy->execute($mt, new SyncConfirmation());
+        $this->assertSame(1, $result1->additions['productSlots']);
+
+        $em->refresh($piece);
+        $result2 = $this->strategy->execute($mt, new SyncConfirmation());
+        $this->assertSame(0, $result2->itemsUpdated);
+    }
+}

tests/Api/Service/ProductSyncStrategyTest.php

@@ -0,0 +1,92 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Api\Service;
+
+use App\DTO\SyncConfirmation;
+use App\Enum\ModelCategory;
+use App\Service\Sync\ProductSyncStrategy;
+use App\Tests\AbstractApiTestCase;
+
+/**
+ * @internal
+ */
+class ProductSyncStrategyTest extends AbstractApiTestCase
+{
+    private ProductSyncStrategy $strategy;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $this->strategy = static::getContainer()->get(ProductSyncStrategy::class);
+    }
+
+    public function testSupportsProductCategory(): void
+    {
+        $mt = $this->createModelType('Product Cat', 'PC-001', ModelCategory::PRODUCT);
+        $this->assertTrue($this->strategy->supports($mt));
+    }
+
+    public function testDoesNotSupportComponentCategory(): void
+    {
+        $mt = $this->createModelType('Comp Cat', 'CC-001', ModelCategory::COMPONENT);
+        $this->assertFalse($this->strategy->supports($mt));
+    }
+
+    public function testPreviewNoImpactWhenNoProducts(): void
+    {
+        $mt     = $this->createModelType('Product Cat', 'PC-001', ModelCategory::PRODUCT);
+        $result = $this->strategy->preview($mt, ['customFields' => []]);
+        $this->assertSame(0, $result->itemCount);
+        $this->assertFalse($result->hasImpact());
+    }
+
+    public function testPreviewDetectsNewCustomField(): void
+    {
+        $mt = $this->createModelType('Product Cat', 'PC-001', ModelCategory::PRODUCT);
+        $this->createProduct('P1', 'P1-REF', $mt);
+
+        $result = $this->strategy->preview($mt, [
+            'customFields' => [
+                ['name' => 'Weight', 'type' => 'text', 'orderIndex' => 0],
+            ],
+        ]);
+
+        $this->assertSame(1, $result->itemCount);
+        $this->assertSame(1, $result->additions['customFieldValues']);
+    }
+
+    public function testExecuteCreatesCustomFieldValues(): void
+    {
+        $mt      = $this->createModelType('Product Cat', 'PC-001', ModelCategory::PRODUCT);
+        $product = $this->createProduct('P1', 'P1-REF', $mt);
+
+        // Create a custom field on the model type
+        $this->createCustomField('Weight', 'text', null, null, null, $mt, 0);
+
+        $result = $this->strategy->execute($mt, new SyncConfirmation());
+
+        $this->assertSame(1, $result->itemsUpdated);
+        $this->assertSame(1, $result->additions['customFieldValues']);
+
+        // Verify version incremented
+        $this->getEntityManager()->refresh($product);
+        $this->assertSame(2, $product->getVersion());
+    }
+
+    public function testExecuteIsIdempotent(): void
+    {
+        $mt      = $this->createModelType('Product Cat', 'PC-001', ModelCategory::PRODUCT);
+        $product = $this->createProduct('P1', 'P1-REF', $mt);
+        $cf      = $this->createCustomField('Weight', 'text', null, null, null, $mt, 0);
+
+        // First execute
+        $result1 = $this->strategy->execute($mt, new SyncConfirmation());
+        $this->assertSame(1, $result1->additions['customFieldValues']);
+
+        // Second execute — no-op
+        $result2 = $this->strategy->execute($mt, new SyncConfirmation());
+        $this->assertSame(0, $result2->itemsUpdated);
+    }
+}