feat(application): all use cases

crates/application/src/use_cases/feed.rs

@@ -0,0 +1,43 @@
+use domain::{
+    errors::DomainError,
+    models::{
+        feed::{FeedEntry, PageParams, Paginated, UserSummary},
+        thought::Thought,
+        user::User,
+    },
+    ports::{FeedRepository, FollowRepository, TagRepository, ThoughtRepository, UserRepository},
+    value_objects::UserId,
+};
+
+pub async fn get_home_feed(feed: &dyn FeedRepository, follows: &dyn FollowRepository, user_id: &UserId, page: PageParams) -> Result<Paginated<FeedEntry>, DomainError> {
+    let following_ids = follows.get_accepted_following_ids(user_id).await?;
+    feed.home_feed(&following_ids, &page, Some(user_id)).await
+}
+
+pub async fn get_public_feed(feed: &dyn FeedRepository, viewer_id: Option<&UserId>, page: PageParams) -> Result<Paginated<FeedEntry>, DomainError> {
+    feed.public_feed(&page, viewer_id).await
+}
+
+pub async fn get_user_feed(thoughts: &dyn ThoughtRepository, user_id: &UserId, page: PageParams) -> Result<Paginated<FeedEntry>, DomainError> {
+    thoughts.list_by_user(user_id, &page).await
+}
+
+pub async fn get_followers(follows: &dyn FollowRepository, user_id: &UserId, page: PageParams) -> Result<Paginated<User>, DomainError> {
+    follows.list_followers(user_id, &page).await
+}
+
+pub async fn get_following(follows: &dyn FollowRepository, user_id: &UserId, page: PageParams) -> Result<Paginated<User>, DomainError> {
+    follows.list_following(user_id, &page).await
+}
+
+pub async fn get_by_tag(tags: &dyn TagRepository, tag_name: &str, page: PageParams) -> Result<Paginated<Thought>, DomainError> {
+    tags.list_thoughts_by_tag(tag_name, &page).await
+}
+
+pub async fn search(feed: &dyn FeedRepository, query: &str, page: PageParams, viewer_id: Option<&UserId>) -> Result<Paginated<FeedEntry>, DomainError> {
+    feed.search(query, &page, viewer_id).await
+}
+
+pub async fn list_users(users: &dyn UserRepository) -> Result<Vec<UserSummary>, DomainError> {
+    users.list_with_stats().await
+}