refactor(handler): extract product and inventory handlers

- Extract 7 handlers to product_handler.go (216 lines)
  - CreateProduct, ListProducts, GetProduct, UpdateProduct, DeleteProduct
  - ListInventory, AdjustInventory
- handler.go reduced from 1025 to 806 lines
- Total refactoring: ~60% of original (1471 -> 806)

All tests passing

backend/internal/http/handler/handler.go

@@ -3,9 +3,7 @@ package handler
 import (
 	"errors"
 	"net/http"
-	"strconv"
 	"strings"
-	"time"
 
 	jsoniter "github.com/json-iterator/go"
 
@@ -113,223 +111,6 @@ func (h *Handler) Login(w http.ResponseWriter, r *http.Request) {
 	writeJSON(w, http.StatusOK, authResponse{Token: token, ExpiresAt: exp})
 }
 
-// CreateProduct godoc
-// @Summary Cadastro de produto com rastreabilidade de lote
-// @Tags Produtos
-// @Accept json
-// @Produce json
-// @Param product body registerProductRequest true "Produto"
-// @Success 201 {object} domain.Product
-// @Router /api/v1/products [post]
-func (h *Handler) CreateProduct(w http.ResponseWriter, r *http.Request) {
-	var req registerProductRequest
-	if err := decodeJSON(r.Context(), r, &req); err != nil {
-		writeError(w, http.StatusBadRequest, err)
-		return
-	}
-
-	product := &domain.Product{
-		SellerID:    req.SellerID,
-		Name:        req.Name,
-		Description: req.Description,
-		Batch:       req.Batch,
-		ExpiresAt:   req.ExpiresAt,
-		PriceCents:  req.PriceCents,
-		Stock:       req.Stock,
-	}
-
-	if err := h.svc.RegisterProduct(r.Context(), product); err != nil {
-		writeError(w, http.StatusInternalServerError, err)
-		return
-	}
-
-	writeJSON(w, http.StatusCreated, product)
-}
-
-// ListProducts godoc
-// @Summary Lista catálogo com lote e validade
-// @Tags Produtos
-// @Produce json
-// @Success 200 {array} domain.Product
-// @Router /api/v1/products [get]
-func (h *Handler) ListProducts(w http.ResponseWriter, r *http.Request) {
-	products, err := h.svc.ListProducts(r.Context())
-	if err != nil {
-		writeError(w, http.StatusInternalServerError, err)
-		return
-	}
-	writeJSON(w, http.StatusOK, products)
-}
-
-// GetProduct godoc
-// @Summary Obter produto
-// @Tags Produtos
-// @Produce json
-// @Param id path string true "Product ID"
-// @Success 200 {object} domain.Product
-// @Failure 404 {object} map[string]string
-// @Router /api/v1/products/{id} [get]
-func (h *Handler) GetProduct(w http.ResponseWriter, r *http.Request) {
-	id, err := parseUUIDFromPath(r.URL.Path)
-	if err != nil {
-		writeError(w, http.StatusBadRequest, err)
-		return
-	}
-
-	product, err := h.svc.GetProduct(r.Context(), id)
-	if err != nil {
-		writeError(w, http.StatusNotFound, err)
-		return
-	}
-
-	writeJSON(w, http.StatusOK, product)
-}
-
-// UpdateProduct godoc
-// @Summary Atualizar produto
-// @Tags Produtos
-// @Accept json
-// @Produce json
-// @Param id path string true "Product ID"
-// @Param payload body updateProductRequest true "Campos para atualização"
-// @Success 200 {object} domain.Product
-// @Failure 400 {object} map[string]string
-// @Failure 404 {object} map[string]string
-// @Router /api/v1/products/{id} [patch]
-func (h *Handler) UpdateProduct(w http.ResponseWriter, r *http.Request) {
-	id, err := parseUUIDFromPath(r.URL.Path)
-	if err != nil {
-		writeError(w, http.StatusBadRequest, err)
-		return
-	}
-
-	var req updateProductRequest
-	if err := decodeJSON(r.Context(), r, &req); err != nil {
-		writeError(w, http.StatusBadRequest, err)
-		return
-	}
-
-	product, err := h.svc.GetProduct(r.Context(), id)
-	if err != nil {
-		writeError(w, http.StatusNotFound, err)
-		return
-	}
-
-	if req.SellerID != nil {
-		product.SellerID = *req.SellerID
-	}
-	if req.Name != nil {
-		product.Name = *req.Name
-	}
-	if req.Description != nil {
-		product.Description = *req.Description
-	}
-	if req.Batch != nil {
-		product.Batch = *req.Batch
-	}
-	if req.ExpiresAt != nil {
-		product.ExpiresAt = *req.ExpiresAt
-	}
-	if req.PriceCents != nil {
-		product.PriceCents = *req.PriceCents
-	}
-	if req.Stock != nil {
-		product.Stock = *req.Stock
-	}
-
-	if err := h.svc.UpdateProduct(r.Context(), product); err != nil {
-		writeError(w, http.StatusInternalServerError, err)
-		return
-	}
-
-	writeJSON(w, http.StatusOK, product)
-}
-
-// DeleteProduct godoc
-// @Summary Remover produto
-// @Tags Produtos
-// @Param id path string true "Product ID"
-// @Success 204 ""
-// @Failure 400 {object} map[string]string
-// @Failure 404 {object} map[string]string
-// @Router /api/v1/products/{id} [delete]
-func (h *Handler) DeleteProduct(w http.ResponseWriter, r *http.Request) {
-	id, err := parseUUIDFromPath(r.URL.Path)
-	if err != nil {
-		writeError(w, http.StatusBadRequest, err)
-		return
-	}
-
-	if err := h.svc.DeleteProduct(r.Context(), id); err != nil {
-		writeError(w, http.StatusBadRequest, err)
-		return
-	}
-
-	w.WriteHeader(http.StatusNoContent)
-}
-
-// ListInventory godoc
-// @Summary Listar estoque
-// @Tags Estoque
-// @Security BearerAuth
-// @Produce json
-// @Param expires_in_days query int false "Dias para expiração"
-// @Success 200 {array} domain.InventoryItem
-// @Router /api/v1/inventory [get]
-// ListInventory exposes stock with expiring batch filters.
-func (h *Handler) ListInventory(w http.ResponseWriter, r *http.Request) {
-	var filter domain.InventoryFilter
-	if days := r.URL.Query().Get("expires_in_days"); days != "" {
-		n, err := strconv.Atoi(days)
-		if err != nil || n < 0 {
-			writeError(w, http.StatusBadRequest, errors.New("invalid expires_in_days"))
-			return
-		}
-		expires := time.Now().Add(time.Duration(n) * 24 * time.Hour)
-		filter.ExpiringBefore = &expires
-	}
-
-	inventory, err := h.svc.ListInventory(r.Context(), filter)
-	if err != nil {
-		writeError(w, http.StatusInternalServerError, err)
-		return
-	}
-
-	writeJSON(w, http.StatusOK, inventory)
-}
-
-// AdjustInventory godoc
-// @Summary Ajustar estoque
-// @Tags Estoque
-// @Security BearerAuth
-// @Accept json
-// @Produce json
-// @Param payload body inventoryAdjustRequest true "Ajuste de estoque"
-// @Success 200 {object} domain.InventoryItem
-// @Failure 400 {object} map[string]string
-// @Router /api/v1/inventory/adjust [post]
-// AdjustInventory handles manual stock corrections.
-func (h *Handler) AdjustInventory(w http.ResponseWriter, r *http.Request) {
-	var req inventoryAdjustRequest
-	if err := decodeJSON(r.Context(), r, &req); err != nil {
-		writeError(w, http.StatusBadRequest, err)
-		return
-	}
-
-	if req.Delta == 0 {
-		writeError(w, http.StatusBadRequest, errors.New("delta must be non-zero"))
-		return
-	}
-
-	item, err := h.svc.AdjustInventory(r.Context(), req.ProductID, req.Delta, req.Reason)
-	if err != nil {
-		writeError(w, http.StatusBadRequest, err)
-		return
-	}
-
-	writeJSON(w, http.StatusOK, item)
-}
-
 // CreateOrder godoc
 // @Summary Criação de pedido com split
 // @Tags Pedidos

backend/internal/http/handler/product_handler.go

@@ -0,0 +1,227 @@
+package handler
+
+import (
+	"errors"
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/saveinmed/backend-go/internal/domain"
+)
+
+// CreateProduct godoc
+// @Summary Cadastro de produto com rastreabilidade de lote
+// @Tags Produtos
+// @Accept json
+// @Produce json
+// @Param product body registerProductRequest true "Produto"
+// @Success 201 {object} domain.Product
+// @Router /api/v1/products [post]
+func (h *Handler) CreateProduct(w http.ResponseWriter, r *http.Request) {
+	var req registerProductRequest
+	if err := decodeJSON(r.Context(), r, &req); err != nil {
+		writeError(w, http.StatusBadRequest, err)
+		return
+	}
+
+	product := &domain.Product{
+		SellerID:    req.SellerID,
+		Name:        req.Name,
+		Description: req.Description,
+		Batch:       req.Batch,
+		ExpiresAt:   req.ExpiresAt,
+		PriceCents:  req.PriceCents,
+		Stock:       req.Stock,
+	}
+
+	if err := h.svc.RegisterProduct(r.Context(), product); err != nil {
+		writeError(w, http.StatusInternalServerError, err)
+		return
+	}
+
+	writeJSON(w, http.StatusCreated, product)
+}
+
+// ListProducts godoc
+// @Summary Lista catálogo com lote e validade
+// @Tags Produtos
+// @Produce json
+// @Success 200 {array} domain.Product
+// @Router /api/v1/products [get]
+func (h *Handler) ListProducts(w http.ResponseWriter, r *http.Request) {
+	products, err := h.svc.ListProducts(r.Context())
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, err)
+		return
+	}
+	writeJSON(w, http.StatusOK, products)
+}
+
+// GetProduct godoc
+// @Summary Obter produto
+// @Tags Produtos
+// @Produce json
+// @Param id path string true "Product ID"
+// @Success 200 {object} domain.Product
+// @Failure 404 {object} map[string]string
+// @Router /api/v1/products/{id} [get]
+func (h *Handler) GetProduct(w http.ResponseWriter, r *http.Request) {
+	id, err := parseUUIDFromPath(r.URL.Path)
+	if err != nil {
+		writeError(w, http.StatusBadRequest, err)
+		return
+	}
+
+	product, err := h.svc.GetProduct(r.Context(), id)
+	if err != nil {
+		writeError(w, http.StatusNotFound, err)
+		return
+	}
+
+	writeJSON(w, http.StatusOK, product)
+}
+
+// UpdateProduct godoc
+// @Summary Atualizar produto
+// @Tags Produtos
+// @Accept json
+// @Produce json
+// @Param id path string true "Product ID"
+// @Param payload body updateProductRequest true "Campos para atualização"
+// @Success 200 {object} domain.Product
+// @Failure 400 {object} map[string]string
+// @Failure 404 {object} map[string]string
+// @Router /api/v1/products/{id} [patch]
+func (h *Handler) UpdateProduct(w http.ResponseWriter, r *http.Request) {
+	id, err := parseUUIDFromPath(r.URL.Path)
+	if err != nil {
+		writeError(w, http.StatusBadRequest, err)
+		return
+	}
+
+	var req updateProductRequest
+	if err := decodeJSON(r.Context(), r, &req); err != nil {
+		writeError(w, http.StatusBadRequest, err)
+		return
+	}
+
+	product, err := h.svc.GetProduct(r.Context(), id)
+	if err != nil {
+		writeError(w, http.StatusNotFound, err)
+		return
+	}
+
+	if req.SellerID != nil {
+		product.SellerID = *req.SellerID
+	}
+	if req.Name != nil {
+		product.Name = *req.Name
+	}
+	if req.Description != nil {
+		product.Description = *req.Description
+	}
+	if req.Batch != nil {
+		product.Batch = *req.Batch
+	}
+	if req.ExpiresAt != nil {
+		product.ExpiresAt = *req.ExpiresAt
+	}
+	if req.PriceCents != nil {
+		product.PriceCents = *req.PriceCents
+	}
+	if req.Stock != nil {
+		product.Stock = *req.Stock
+	}
+
+	if err := h.svc.UpdateProduct(r.Context(), product); err != nil {
+		writeError(w, http.StatusInternalServerError, err)
+		return
+	}
+
+	writeJSON(w, http.StatusOK, product)
+}
+
+// DeleteProduct godoc
+// @Summary Remover produto
+// @Tags Produtos
+// @Param id path string true "Product ID"
+// @Success 204 ""
+// @Failure 400 {object} map[string]string
+// @Failure 404 {object} map[string]string
+// @Router /api/v1/products/{id} [delete]
+func (h *Handler) DeleteProduct(w http.ResponseWriter, r *http.Request) {
+	id, err := parseUUIDFromPath(r.URL.Path)
+	if err != nil {
+		writeError(w, http.StatusBadRequest, err)
+		return
+	}
+
+	if err := h.svc.DeleteProduct(r.Context(), id); err != nil {
+		writeError(w, http.StatusBadRequest, err)
+		return
+	}
+
+	w.WriteHeader(http.StatusNoContent)
+}
+
+// ListInventory godoc
+// @Summary Listar estoque
+// @Tags Estoque
+// @Security BearerAuth
+// @Produce json
+// @Param expires_in_days query int false "Dias para expiração"
+// @Success 200 {array} domain.InventoryItem
+// @Router /api/v1/inventory [get]
+// ListInventory exposes stock with expiring batch filters.
+func (h *Handler) ListInventory(w http.ResponseWriter, r *http.Request) {
+	var filter domain.InventoryFilter
+	if days := r.URL.Query().Get("expires_in_days"); days != "" {
+		n, err := strconv.Atoi(days)
+		if err != nil || n < 0 {
+			writeError(w, http.StatusBadRequest, errors.New("invalid expires_in_days"))
+			return
+		}
+		expires := time.Now().Add(time.Duration(n) * 24 * time.Hour)
+		filter.ExpiringBefore = &expires
+	}
+
+	inventory, err := h.svc.ListInventory(r.Context(), filter)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, err)
+		return
+	}
+
+	writeJSON(w, http.StatusOK, inventory)
+}
+
+// AdjustInventory godoc
+// @Summary Ajustar estoque
+// @Tags Estoque
+// @Security BearerAuth
+// @Accept json
+// @Produce json
+// @Param payload body inventoryAdjustRequest true "Ajuste de estoque"
+// @Success 200 {object} domain.InventoryItem
+// @Failure 400 {object} map[string]string
+// @Router /api/v1/inventory/adjust [post]
+// AdjustInventory handles manual stock corrections.
+func (h *Handler) AdjustInventory(w http.ResponseWriter, r *http.Request) {
+	var req inventoryAdjustRequest
+	if err := decodeJSON(r.Context(), r, &req); err != nil {
+		writeError(w, http.StatusBadRequest, err)
+		return
+	}
+
+	if req.Delta == 0 {
+		writeError(w, http.StatusBadRequest, errors.New("delta must be non-zero"))
+		return
+	}
+
+	item, err := h.svc.AdjustInventory(r.Context(), req.ProductID, req.Delta, req.Reason)
+	if err != nil {
+		writeError(w, http.StatusBadRequest, err)
+		return
+	}
+
+	writeJSON(w, http.StatusOK, item)
+}