chore: refactor direct database call from service to model

internal/models/waitlist_user.go

@@ -2,6 +2,7 @@ package models
 
 import (
 	"errors"
+	"net/http"
 	"time"
 
 	"github.com/hngprojects/hng_boilerplate_golang_web/pkg/repository/storage/postgresql"
@@ -33,3 +34,16 @@ func (w *WaitlistUser) CreateWaitlistUser(db *gorm.DB) error {
 
 	return err
 }
+
+func (w *WaitlistUser) GetWaitlistUserByEmail(db *gorm.DB) (int, error) {
+	err, nerr := postgresql.SelectOneFromDb(db, &w, "email = ?", w.Email)
+	if nerr != nil {
+		return http.StatusBadRequest, nerr 
+	}
+
+	if err != nil {
+		return http.StatusInternalServerError, err
+	}
+
+	return http.StatusOK, nil
+}

services/waitlist/waitlist.go

@@ -6,7 +6,6 @@ import (
 	"strings"
 
 	"github.com/hngprojects/hng_boilerplate_golang_web/internal/models"
-	"github.com/hngprojects/hng_boilerplate_golang_web/pkg/repository/storage/postgresql"
 	"github.com/hngprojects/hng_boilerplate_golang_web/utility"
 	"gorm.io/gorm"
 )
@@ -20,11 +19,11 @@ func SignupWaitlistUserService(db *gorm.DB, req models.CreateWaitlistUserRequest
 
 	if req.Email != "" {
 		req.Email = strings.ToLower(req.Email)
-		
-		existingUser := models.WaitlistUser{}
-		_, err := postgresql.SelectOneFromDb(db, &existingUser, "email = ?", req.Email)
+
+		existingUser := &models.WaitlistUser{Email: req.Email}
+		code, err := existingUser.GetWaitlistUserByEmail(db)
 		if err != nil {
-			return nil, http.StatusBadRequest, models.ErrWaitlistUserExist
+			return nil, code, models.ErrWaitlistUserExist
 		}
 	}