add tag & favorite usecases

domain/user.go

@@ -12,6 +12,7 @@ type User struct {
 	Bio       *string
 	ImageLink *string
 	FollowIDs []string
+	Favorites []Article
 }
 
 func UpdateUser(initial *User, opts ...func(fields *User)) {
@@ -101,3 +102,19 @@ func (user *User) UpdateFollowees(followeeName string, follow bool) {
 		user.FollowIDs = nil
 	}
 }
+
+func (user *User) UpdateFavorites(favorite Article, fav bool) {
+	if fav {
+		user.Favorites = append(user.Favorites, favorite)
+		return
+	}
+
+	for i := 0; i < len(user.Favorites); i++ {
+		if user.Favorites[i].Slug == favorite.Slug {
+			user.Favorites = append(user.Favorites[:i], user.Favorites[i+1:]...) // memory leak ? https://github.com/golang/go/wiki/SliceTricks
+		}
+	}
+	if len(user.Favorites) == 0 {
+		user.Favorites = nil
+	}
+}

uc/INTERACTOR.go

@@ -15,6 +15,7 @@ type interactor struct {
 	authHandler      AuthHandler
 	slugger          Slugger
 	commentRW        CommentRW
+	tagsRW           TagsRW
 }
 
 // Logger : only used to log stuff
@@ -49,6 +50,10 @@ type CommentRW interface {
 	Delete(id int) error
 }
 
+type TagsRW interface {
+	GetAll() ([]string, error)
+}
+
 type Slugger interface {
 	NewSlug(string) string
 }

uc/favorite.go

@@ -2,6 +2,21 @@ package uc
 
 import "github.com/err0r500/go-realworld-clean/domain"
 
-func (i interactor) FavoritesUpdate(username, slug string, favortie bool) (*domain.Article, error) {
-	return nil, nil
+func (i interactor) FavoritesUpdate(username, slug string, favorite bool) (*domain.Article, error) {
+	article, err := i.articleRW.GetBySlug(slug)
+	if err != nil {
+		return nil, err
+	}
+
+	user, err := i.userRW.GetByName(username)
+	if err != nil {
+		return nil, err
+	}
+
+	user.UpdateFavorites(*article, favorite)
+	if err := i.userRW.Save(*user); err != nil {
+		return nil, err
+	}
+
+	return article, nil
 }

uc/tags.go

@@ -1,5 +1,5 @@
 package uc
 
 func (i interactor) Tags() ([]string, error) {
-	return nil, nil
+	return i.tagsRW.GetAll()
 }