Implement the SKUs and the Inventory Movement Manager, to apply variability and functions for sales, restock co.

apps/workspace-api/src/main/java/com/voyage/workspace/inventory/InventoryController.java

@@ -0,0 +1,37 @@
+package com.voyage.workspace.inventory;
+
+import com.voyage.workspace.products.SkuRepository;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@RequestMapping("/api/inventory")
+public class InventoryController {
+
+    private final InventoryMovementRepository movementRepo;
+    private final SkuRepository skuRepo;
+
+    public InventoryController(InventoryMovementRepository movementRepo, SkuRepository skuRepo) {
+        this.movementRepo = movementRepo;
+        this.skuRepo = skuRepo;
+    }
+
+    @PostMapping("/movements")
+    public ResponseEntity<?> createMovement(@RequestBody InventoryMovementCreateRequest req) {
+        var skuOpt = skuRepo.findById(req.skuId());
+        if (skuOpt.isEmpty()) return ResponseEntity.badRequest().body("Unknown skuId: " + req.skuId());
+
+        InventoryMovement m = new InventoryMovement();
+        m.setSku(skuOpt.get());
+        m.setDelta(req.delta());
+        m.setReason(req.reason());
+        m.setReference(req.reference());
+
+        return ResponseEntity.ok(movementRepo.save(m));
+    }
+
+    @GetMapping("/stock/{skuId}")
+    public int getCurrentStock(@PathVariable Long skuId) {
+        return movementRepo.currentStock(skuId);
+    }
+}

apps/workspace-api/src/main/java/com/voyage/workspace/inventory/InventoryMovement.java

@@ -0,0 +1,44 @@
+package com.voyage.workspace.inventory;
+
+import com.voyage.workspace.products.Sku;
+import jakarta.persistence.*;
+
+import java.time.Instant;
+
+@Entity
+@Table(name = "inventory_movements")
+public class InventoryMovement {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @ManyToOne(optional = false, fetch = FetchType.LAZY)
+    @JoinColumn(name = "sku_id", nullable = false)
+    private Sku sku;
+
+    @Column(nullable = false)
+    private int delta;
+
+    @Column(nullable = false)
+    private String reason; // PRODUCTION, SALE, RETURN, ADJUSTMENT
+
+    private String reference;
+
+    @Column(nullable=false, updatable=false)
+    private Instant createdAt = Instant.now();
+
+    public InventoryMovement() {}
+
+    public Long getId() { return id; }
+    public Sku getSku() { return sku; }
+    public int getDelta() { return delta; }
+    public String getReason() { return reason; }
+    public String getReference() { return reference; }
+    public Instant getCreatedAt() { return createdAt; }
+
+    public void setSku(Sku sku) { this.sku = sku; }
+    public void setDelta(int delta) { this.delta = delta; }
+    public void setReason(String reason) { this.reason = reason; }
+    public void setReference(String reference) { this.reference = reference; }
+}

apps/workspace-api/src/main/java/com/voyage/workspace/inventory/InventoryMovementCreateRequest.java

@@ -0,0 +1,8 @@
+package com.voyage.workspace.inventory;
+
+public record InventoryMovementCreateRequest(
+        Long skuId,
+        int delta,
+        String reason,
+        String reference
+) {}

apps/workspace-api/src/main/java/com/voyage/workspace/inventory/InventoryMovementRepository.java

@@ -0,0 +1,11 @@
+package com.voyage.workspace.inventory;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
+
+public interface InventoryMovementRepository extends JpaRepository<InventoryMovement, Long> {
+
+    @Query("select coalesce(sum(m.delta), 0) from InventoryMovement m where m.sku.id = :skuId")
+    int currentStock(@Param("skuId") Long skuId);
+}

apps/workspace-api/src/main/java/com/voyage/workspace/products/Sku.java

@@ -0,0 +1,46 @@
+package com.voyage.workspace.products;
+
+import jakarta.persistence.*;
+import java.math.BigDecimal;
+
+@Entity
+@Table(name = "skus")
+public class Sku {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @ManyToOne(optional = false, fetch = FetchType.LAZY)
+    @JoinColumn(name = "product_id", nullable = false)
+    private Product product;
+
+    @Column(nullable = false, unique = true)
+    private String skuCode;
+
+    private String size;
+    private String color;
+
+    @Column(nullable = false)
+    private BigDecimal price;
+
+    @Column(nullable = false)
+    private boolean active = true;
+
+    public Sku() {}
+
+    public Long getId() { return id; }
+    public Product getProduct() { return product; }
+    public String getSkuCode() { return skuCode; }
+    public String getSize() { return size; }
+    public String getColor() { return color; }
+    public BigDecimal getPrice() { return price; }
+    public boolean isActive() { return active; }
+
+    public void setProduct(Product product) { this.product = product; }
+    public void setSkuCode(String skuCode) { this.skuCode = skuCode; }
+    public void setSize(String size) { this.size = size; }
+    public void setColor(String color) { this.color = color; }
+    public void setPrice(BigDecimal price) { this.price = price; }
+    public void setActive(boolean active) { this.active = active; }
+}

apps/workspace-api/src/main/java/com/voyage/workspace/products/SkuController.java

@@ -0,0 +1,42 @@
+package com.voyage.workspace.products;
+
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+
+@RestController
+@RequestMapping("/api/skus")
+public class SkuController {
+
+    private final SkuRepository skuRepo;
+    private final ProductRepository productRepo;
+
+    public SkuController(SkuRepository skuRepo, ProductRepository productRepo) {
+        this.skuRepo = skuRepo;
+        this.productRepo = productRepo;
+    }
+
+    @GetMapping
+    public List<Sku> list(@RequestParam(required = false) Long productId) {
+        if (productId != null) return skuRepo.findByProductId(productId);
+        return skuRepo.findAll();
+    }
+
+    @PostMapping
+    public ResponseEntity<?> create(@RequestBody SkuCreateRequest req) {
+        var productOpt = productRepo.findById(req.productId());
+        if (productOpt.isEmpty()) {
+            return ResponseEntity.badRequest().body("Unknown productId: " + req.productId());
+        }
+
+        Sku sku = new Sku();
+        sku.setProduct(productOpt.get());
+        sku.setSkuCode(req.skuCode());
+        sku.setSize(req.size());
+        sku.setColor(req.color());
+        sku.setPrice(req.price());
+
+        return ResponseEntity.ok(skuRepo.save(sku));
+    }
+}

apps/workspace-api/src/main/java/com/voyage/workspace/products/SkuCreateRequest.java

@@ -0,0 +1,11 @@
+package com.voyage.workspace.products;
+
+import java.math.BigDecimal;
+
+public record SkuCreateRequest(
+        Long productId,
+        String skuCode,
+        String size,
+        String color,
+        BigDecimal price
+) {}

apps/workspace-api/src/main/java/com/voyage/workspace/products/SkuRepository.java

@@ -0,0 +1,11 @@
+package com.voyage.workspace.products;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+
+import java.util.List;
+import java.util.Optional;
+
+public interface SkuRepository extends JpaRepository<Sku, Long> {
+    List<Sku> findByProductId(Long productId);
+    Optional<Sku> findBySkuCode(String skuCode);
+}