feat: implement pagination for user retrieval and update feed fetching logic

thoughts-backend/api/src/routers/feed.rs

@@ -1,7 +1,7 @@
 use axum::{extract::State, response::IntoResponse, routing::get, Json, Router};
 
 use app::{
-    persistence::{follow::get_following_ids, thought::get_feed_for_user},
+    persistence::{follow::get_following_ids, thought::get_feed_for_users_and_self},
     state::AppState,
 };
 use models::schemas::thought::{ThoughtListSchema, ThoughtSchema};
@@ -24,12 +24,8 @@ async fn feed_get(
     auth_user: AuthUser,
 ) -> Result<impl IntoResponse, ApiError> {
     let following_ids = get_following_ids(&state.conn, auth_user.id).await?;
-    let mut thoughts_with_authors =
-        get_feed_for_user(&state.conn, following_ids, Some(auth_user.id)).await?;
-
-    let own_thoughts =
-        get_feed_for_user(&state.conn, vec![auth_user.id], Some(auth_user.id)).await?;
-    thoughts_with_authors.extend(own_thoughts);
+    let thoughts_with_authors =
+        get_feed_for_users_and_self(&state.conn, auth_user.id, following_ids).await?;
 
     let thoughts_schema: Vec<ThoughtSchema> = thoughts_with_authors
         .into_iter()

thoughts-backend/api/src/routers/user.rs

@@ -17,8 +17,14 @@ use app::persistence::{
 };
 use app::state::AppState;
 use app::{error::UserError, persistence::user::get_user_by_username};
-use models::schemas::user::{MeSchema, UserListSchema, UserSchema};
-use models::{params::user::UpdateUserParams, schemas::thought::ThoughtListSchema};
+use models::{
+    params::user::UpdateUserParams,
+    schemas::{pagination::PaginatedResponse, thought::ThoughtListSchema},
+};
+use models::{
+    queries::pagination::PaginationQuery,
+    schemas::user::{MeSchema, UserListSchema, UserSchema},
+};
 use models::{queries::user::UserQuery, schemas::thought::ThoughtSchema};
 
 use crate::{error::ApiError, extractor::AuthUser};
@@ -418,16 +424,31 @@ async fn get_user_followers(
 #[utoipa::path(
     get,
     path = "/all",
+    params(PaginationQuery),
     responses(
-        (status = 200, description = "A public list of all users", body = UserListSchema)
+        (status = 200, description = "A public, paginated list of all users", body = PaginatedResponse<UserSchema>)
     ),
     tag = "user"
 )]
 async fn get_all_users_public(
     State(state): State<AppState>,
+    Query(pagination): Query<PaginationQuery>,
 ) -> Result<impl IntoResponse, ApiError> {
-    let users = get_all_users(&state.conn).await?;
-    Ok(Json(UserListSchema::from(users)))
+    let (users, total_items) = get_all_users(&state.conn, &pagination).await?;
+
+    let page = pagination.page();
+    let page_size = pagination.page_size();
+    let total_pages = (total_items as f64 / page_size as f64).ceil() as u64;
+
+    let response = PaginatedResponse {
+        items: users.into_iter().map(UserSchema::from).collect(),
+        page,
+        page_size,
+        total_pages,
+        total_items,
+    };
+
+    Ok(Json(response))
 }
 
 pub fn create_user_router() -> Router<AppState> {

thoughts-backend/app/src/persistence/thought.rs

@@ -156,6 +156,37 @@ pub async fn get_feed_for_user(
         .map_err(|e| UserError::Internal(e.to_string()))
 }
 
+pub async fn get_feed_for_users_and_self(
+    db: &DbConn,
+    user_id: Uuid,
+    following_ids: Vec<Uuid>,
+) -> Result<Vec<ThoughtWithAuthor>, DbErr> {
+    let mut authors_to_include = following_ids;
+    authors_to_include.push(user_id);
+
+    thought::Entity::find()
+        .select_only()
+        .column(thought::Column::Id)
+        .column(thought::Column::Content)
+        .column(thought::Column::ReplyToId)
+        .column(thought::Column::CreatedAt)
+        .column(thought::Column::Visibility)
+        .column(thought::Column::AuthorId)
+        .column_as(user::Column::Username, "author_username")
+        .column_as(user::Column::DisplayName, "author_display_name")
+        .join(JoinType::InnerJoin, thought::Relation::User.def())
+        .filter(thought::Column::AuthorId.is_in(authors_to_include))
+        .filter(
+            Condition::any()
+                .add(thought::Column::Visibility.eq(thought::Visibility::Public))
+                .add(thought::Column::Visibility.eq(thought::Visibility::FriendsOnly)),
+        )
+        .order_by_desc(thought::Column::CreatedAt)
+        .into_model::<ThoughtWithAuthor>()
+        .all(db)
+        .await
+}
+
 pub async fn get_thoughts_by_tag_name(
     db: &DbConn,
     tag_name: &str,

thoughts-backend/app/src/persistence/user.rs

@@ -1,7 +1,8 @@
+use models::queries::pagination::PaginationQuery;
 use sea_orm::prelude::Uuid;
 use sea_orm::{
-    ActiveModelTrait, ColumnTrait, DbConn, DbErr, EntityTrait, JoinType, QueryFilter, QueryOrder,
-    QuerySelect, RelationTrait, Set, TransactionTrait,
+    ActiveModelTrait, ColumnTrait, DbConn, DbErr, EntityTrait, JoinType, PaginatorTrait,
+    QueryFilter, QueryOrder, QuerySelect, RelationTrait, Set, TransactionTrait,
 };
 
 use models::domains::{top_friends, user};
@@ -166,9 +167,16 @@ pub async fn get_followers(db: &DbConn, user_id: Uuid) -> Result<Vec<user::Model
     get_users_by_ids(db, follower_ids).await
 }
 
-pub async fn get_all_users(db: &DbConn) -> Result<Vec<user::Model>, DbErr> {
-    user::Entity::find()
+pub async fn get_all_users(
+    db: &DbConn,
+    pagination: &PaginationQuery,
+) -> Result<(Vec<user::Model>, u64), DbErr> {
+    let paginator = user::Entity::find()
         .order_by_desc(user::Column::CreatedAt)
-        .all(db)
-        .await
+        .paginate(db, pagination.page_size());
+
+    let total_items = paginator.num_items().await?;
+    let users = paginator.fetch_page(pagination.page() - 1).await?;
+
+    Ok((users, total_items))
 }

thoughts-backend/models/src/queries/mod.rs

@@ -1 +1,2 @@
+pub mod pagination;
 pub mod user;

thoughts-backend/models/src/queries/pagination.rs

@@ -0,0 +1,27 @@
+use serde::Deserialize;
+use utoipa::IntoParams;
+
+const DEFAULT_PAGE: u64 = 1;
+const DEFAULT_PAGE_SIZE: u64 = 20;
+
+#[derive(Deserialize, IntoParams)]
+pub struct PaginationQuery {
+    #[param(nullable = true, example = 1)]
+    page: Option<u64>,
+    #[param(nullable = true, example = 20)]
+    page_size: Option<u64>,
+}
+
+impl PaginationQuery {
+    pub fn page(&self) -> u64 {
+        self.page.unwrap_or(DEFAULT_PAGE).max(1)
+    }
+
+    pub fn page_size(&self) -> u64 {
+        self.page_size.unwrap_or(DEFAULT_PAGE_SIZE).max(1)
+    }
+
+    pub fn offset(&self) -> u64 {
+        (self.page() - 1) * self.page_size()
+    }
+}

thoughts-backend/models/src/schemas/mod.rs

@@ -1,4 +1,5 @@
 pub mod api_key;
+pub mod pagination;
 pub mod search;
 pub mod thought;
 pub mod user;

thoughts-backend/models/src/schemas/pagination.rs

@@ -0,0 +1,12 @@
+use serde::Serialize;
+use utoipa::ToSchema;
+
+#[derive(Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct PaginatedResponse<T> {
+    pub items: Vec<T>,
+    pub page: u64,
+    pub page_size: u64,
+    pub total_pages: u64,
+    pub total_items: u64,
+}

thoughts-backend/tests/api/feed.rs

@@ -1,7 +1,10 @@
+use std::time::Duration;
+
 use super::main::{create_user_with_password, setup};
 use axum::http::StatusCode;
 use http_body_util::BodyExt;
 use serde_json::json;
+use tokio::time::sleep;
 use utils::testing::make_jwt_request;
 
 #[tokio::test]
@@ -84,3 +87,80 @@ async fn test_feed_and_user_thoughts() {
     assert_eq!(v["thoughts"][1]["authorUsername"], "user1");
     assert_eq!(v["thoughts"][1]["content"], "A thought from user1");
 }
+
+#[tokio::test]
+async fn test_feed_strict_chronological_order() {
+    let app = setup().await;
+    create_user_with_password(&app.db, "user1", "password123", "u1@e.com").await;
+    create_user_with_password(&app.db, "user2", "password123", "u2@e.com").await;
+    create_user_with_password(&app.db, "user3", "password123", "u3@e.com").await;
+
+    let token1 = super::main::login_user(app.router.clone(), "user1", "password123").await;
+    let token2 = super::main::login_user(app.router.clone(), "user2", "password123").await;
+    let token3 = super::main::login_user(app.router.clone(), "user3", "password123").await;
+
+    make_jwt_request(
+        app.router.clone(),
+        "/users/user2/follow",
+        "POST",
+        None,
+        &token1,
+    )
+    .await;
+    make_jwt_request(
+        app.router.clone(),
+        "/users/user3/follow",
+        "POST",
+        None,
+        &token1,
+    )
+    .await;
+
+    let body_t1 = json!({ "content": "Thought 1 from user2" }).to_string();
+    make_jwt_request(
+        app.router.clone(),
+        "/thoughts",
+        "POST",
+        Some(body_t1),
+        &token2,
+    )
+    .await;
+    sleep(Duration::from_millis(10)).await;
+
+    let body_t2 = json!({ "content": "Thought 2 from user3" }).to_string();
+    make_jwt_request(
+        app.router.clone(),
+        "/thoughts",
+        "POST",
+        Some(body_t2),
+        &token3,
+    )
+    .await;
+    sleep(Duration::from_millis(10)).await;
+
+    let body_t3 = json!({ "content": "Thought 3 from user2" }).to_string();
+    make_jwt_request(
+        app.router.clone(),
+        "/thoughts",
+        "POST",
+        Some(body_t3),
+        &token2,
+    )
+    .await;
+
+    let response = make_jwt_request(app.router.clone(), "/feed", "GET", None, &token1).await;
+    assert_eq!(response.status(), StatusCode::OK);
+
+    let body = response.into_body().collect().await.unwrap().to_bytes();
+    let v: serde_json::Value = serde_json::from_slice(&body).unwrap();
+    let thoughts = v["thoughts"].as_array().unwrap();
+
+    assert_eq!(
+        thoughts.len(),
+        3,
+        "Feed should contain 3 thoughts from followed users"
+    );
+    assert_eq!(thoughts[0]["content"], "Thought 3 from user2");
+    assert_eq!(thoughts[1]["content"], "Thought 2 from user3");
+    assert_eq!(thoughts[2]["content"], "Thought 1 from user2");
+}

thoughts-backend/tests/api/user.rs

@@ -247,23 +247,44 @@ async fn test_update_me_css_and_images() {
 }
 
 #[tokio::test]
-async fn test_get_all_users_public() {
+async fn test_get_all_users_paginated() {
     let app = setup().await;
 
-    create_user_with_password(&app.db, "userA", "password123", "a@example.com").await;
-    create_user_with_password(&app.db, "userB", "password123", "b@example.com").await;
-    create_user_with_password(&app.db, "userC", "password123", "c@example.com").await;
+    for i in 0..25 {
+        create_user_with_password(
+            &app.db,
+            &format!("user{}", i),
+            "password123",
+            &format!("u{}@e.com", i),
+        )
+        .await;
+    }
 
-    let response = make_get_request(app.router.clone(), "/users/all", None).await;
-    assert_eq!(response.status(), StatusCode::OK);
-
-    let body = response.into_body().collect().await.unwrap().to_bytes();
-    let v: Value = serde_json::from_slice(&body).unwrap();
-    let users_list = v["users"].as_array().unwrap();
+    let response_p1 = make_get_request(app.router.clone(), "/users/all", None).await;
+    assert_eq!(response_p1.status(), StatusCode::OK);
+    let body_p1 = response_p1.into_body().collect().await.unwrap().to_bytes();
+    let v_p1: Value = serde_json::from_slice(&body_p1).unwrap();
 
     assert_eq!(
-        users_list.len(),
-        3,
-        "Should return a list of all 3 registered users"
+        v_p1["items"].as_array().unwrap().len(),
+        20,
+        "First page should have 20 items"
     );
+    assert_eq!(v_p1["page"], 1);
+    assert_eq!(v_p1["pageSize"], 20);
+    assert_eq!(v_p1["totalPages"], 2);
+    assert_eq!(v_p1["totalItems"], 25);
+
+    let response_p2 = make_get_request(app.router.clone(), "/users/all?page=2", None).await;
+    assert_eq!(response_p2.status(), StatusCode::OK);
+    let body_p2 = response_p2.into_body().collect().await.unwrap().to_bytes();
+    let v_p2: Value = serde_json::from_slice(&body_p2).unwrap();
+
+    assert_eq!(
+        v_p2["items"].as_array().unwrap().len(),
+        5,
+        "Second page should have 5 items"
+    );
+    assert_eq!(v_p2["page"], 2);
+    assert_eq!(v_p2["totalPages"], 2);
 }