refac: better error handling & moved IsOnline logic to cleaner place

internal/domain/article/articleDomain.go

@@ -2,9 +2,15 @@ package article
 
 import (
 	domain "RenewCMS/internal/domain/image"
+	"errors"
 	"time"
 )
 
+var (
+	ErrArticleNotFound = errors.New("article not found")
+	ErrArticleOffline  = errors.New("article is offline")
+)
+
 type Article struct {
 	ID        uint32          `json:"id"`
 	Title     string          `json:"title"`

internal/domain/article/articleRepositoryInterface.go

@@ -1,6 +1,11 @@
 package article
 
+type Filters struct {
+	IsOnline *bool
+}
+
 type Repository interface {
+	FindByFilters(filters Filters) ([]Article, error)
 	Get(id uint32) (Article, error)
 	GetByName(name string) (Article, error)
 	GetAll() []Article