[hw-1] implement cart service

cart/internal/app/server/add_item_handler.go

@@ -0,0 +1,96 @@
+package server
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"strconv"
+
+	"route256/cart/internal/domain/entity"
+	"route256/cart/internal/domain/model"
+
+	"github.com/rs/zerolog/log"
+)
+
+type CreateReviewRequest struct {
+	Count uint32 `json:"count" validate:"required,gt=0"`
+}
+
+func (s *Server) AddItemHandler(w http.ResponseWriter, r *http.Request) {
+	var request CreateReviewRequest
+	if err := json.NewDecoder(r.Body).Decode(&request); err != nil {
+		makeErrorResponse(w, err, http.StatusBadRequest)
+
+		log.Trace().Err(err).Msg("failed decoding request")
+
+		return
+	}
+	defer r.Body.Close()
+
+	if request.Count <= 0 {
+		err := fmt.Errorf("count must be greater than 0")
+
+		makeErrorResponse(w, err, http.StatusBadRequest)
+
+		log.Trace().Err(err).Msg("body validation failed")
+
+		return
+	}
+
+	strUserID := r.PathValue("user_id")
+	userID, err := strconv.ParseInt(strUserID, 10, 64)
+	if err != nil || userID <= 0 {
+		if err == nil {
+			err = fmt.Errorf("user_id must be greater than 0")
+		}
+
+		makeErrorResponse(w, err, http.StatusBadRequest)
+
+		log.Trace().Err(err).Msgf("user_id=`%s`", strUserID)
+
+		return
+	}
+
+	strSku := r.PathValue("sku_id")
+	sku, err := strconv.ParseInt(strSku, 10, 64)
+	if err != nil || sku <= 0 {
+		if err == nil {
+			err = fmt.Errorf("sku_id must be greater than 0")
+		}
+
+		makeErrorResponse(w, err, http.StatusBadRequest)
+
+		log.Trace().Err(err).Msgf("sku_id=`%s`", strUserID)
+
+		return
+	}
+
+	item := &model.Item{
+		Product: &model.Product{
+			Name:  "",
+			Price: 0,
+			Sku:   entity.Sku(sku),
+		},
+		Count: request.Count,
+	}
+
+	uid := entity.UID(userID)
+
+	if err := s.cartService.AddItem(r.Context(), uid, item); err != nil {
+		switch {
+		case errors.Is(err, model.ErrProductNotFound):
+			makeErrorResponse(w, err, http.StatusPreconditionFailed)
+
+			log.Trace().Err(err).Msgf("product does not exist")
+		default:
+			makeErrorResponse(w, err, http.StatusInternalServerError)
+
+			log.Trace().Err(err).Msgf("unknown error")
+		}
+
+		return
+	}
+
+	w.WriteHeader(http.StatusOK)
+}