feat: add reply functionality to thoughts, including database migration and tests

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

@@ -24,6 +24,7 @@ pub async fn create_thought(
     let new_thought = thought::ActiveModel {
         author_id: Set(author_id),
         content: Set(params.content.clone()),
+        reply_to_id: Set(params.reply_to_id),
         ..Default::default()
     }
     .insert(&txn)
@@ -56,6 +57,7 @@ pub async fn get_thoughts_by_user(
         .select_only()
         .column(thought::Column::Id)
         .column(thought::Column::Content)
+        .column(thought::Column::ReplyToId)
         .column(thought::Column::CreatedAt)
         .column(thought::Column::AuthorId)
         .column_as(user::Column::Username, "author_username")
@@ -79,6 +81,7 @@ pub async fn get_feed_for_user(
         .select_only()
         .column(thought::Column::Id)
         .column(thought::Column::Content)
+        .column(thought::Column::ReplyToId)
         .column(thought::Column::CreatedAt)
         .column(thought::Column::AuthorId)
         .column_as(user::Column::Username, "author_username")
@@ -99,6 +102,7 @@ pub async fn get_thoughts_by_tag_name(
         .select_only()
         .column(thought::Column::Id)
         .column(thought::Column::Content)
+        .column(thought::Column::ReplyToId)
         .column(thought::Column::CreatedAt)
         .column(thought::Column::AuthorId)
         .column_as(user::Column::Username, "author_username")

thoughts-backend/migration/src/lib.rs

@@ -5,6 +5,8 @@ mod m20250905_000001_init;
 mod m20250906_100000_add_profile_fields;
 mod m20250906_130237_add_tags;
 mod m20250906_134056_add_api_keys;
+mod m20250906_145148_add_reply_to_thoughts;
+mod m20250906_145755_add_visibility_to_thoughts;
 
 pub struct Migrator;
 
@@ -17,6 +19,8 @@ impl MigratorTrait for Migrator {
             Box::new(m20250906_100000_add_profile_fields::Migration),
             Box::new(m20250906_130237_add_tags::Migration),
             Box::new(m20250906_134056_add_api_keys::Migration),
+            Box::new(m20250906_145148_add_reply_to_thoughts::Migration),
+            Box::new(m20250906_145755_add_visibility_to_thoughts::Migration),
         ]
     }
 }

thoughts-backend/migration/src/m20250906_145148_add_reply_to_thoughts.rs

@@ -0,0 +1,46 @@
+use sea_orm_migration::{prelude::*, schema::*};
+
+use crate::m20250905_000001_init::Thought;
+
+#[derive(DeriveMigrationName)]
+pub struct Migration;
+
+#[async_trait::async_trait]
+impl MigrationTrait for Migration {
+    async fn up(&self, manager: &SchemaManager) -> Result<(), DbErr> {
+        manager
+            .alter_table(
+                Table::alter()
+                    .table(Thought::Table)
+                    .add_column(uuid_null(ThoughtExtension::ReplyToId))
+                    .add_foreign_key(
+                        TableForeignKey::new()
+                            .name("fk_thought_reply_to_id")
+                            .from_tbl(Thought::Table)
+                            .from_col(ThoughtExtension::ReplyToId)
+                            .to_tbl(Thought::Table)
+                            .to_col(Thought::Id)
+                            .on_delete(ForeignKeyAction::SetNull),
+                    )
+                    .to_owned(),
+            )
+            .await
+    }
+
+    async fn down(&self, manager: &SchemaManager) -> Result<(), DbErr> {
+        manager
+            .alter_table(
+                Table::alter()
+                    .table(Thought::Table)
+                    .drop_foreign_key(Alias::new("fk_thought_reply_to_id"))
+                    .drop_column(ThoughtExtension::ReplyToId)
+                    .to_owned(),
+            )
+            .await
+    }
+}
+
+#[derive(DeriveIden)]
+enum ThoughtExtension {
+    ReplyToId,
+}

thoughts-backend/models/src/domains/thought.rs

@@ -7,6 +7,7 @@ pub struct Model {
     pub id: Uuid,
     pub author_id: Uuid,
     pub content: String,
+    pub reply_to_id: Option<Uuid>,
     pub created_at: DateTimeWithTimeZone,
 }
 

thoughts-backend/models/src/params/thought.rs

@@ -1,5 +1,6 @@
 use serde::Deserialize;
 use utoipa::ToSchema;
+use uuid::Uuid;
 use validator::Validate;
 
 #[derive(Deserialize, Validate, ToSchema)]
@@ -10,4 +11,6 @@ pub struct CreateThoughtParams {
         message = "Content must be between 1 and 128 characters"
     ))]
     pub content: String,
+
+    pub reply_to_id: Option<Uuid>,
 }

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

@@ -12,6 +12,7 @@ pub struct ThoughtSchema {
     pub author_username: String,
     #[schema(example = "This is my first thought! #welcome")]
     pub content: String,
+    pub reply_to_id: Option<Uuid>,
     pub created_at: DateTimeWithTimeZoneWrapper,
 }
 
@@ -21,6 +22,7 @@ impl ThoughtSchema {
             id: thought.id,
             author_username: author.username.clone(),
             content: thought.content.clone(),
+            reply_to_id: thought.reply_to_id,
             created_at: thought.created_at.into(),
         }
     }
@@ -44,6 +46,7 @@ pub struct ThoughtWithAuthor {
     pub created_at: sea_orm::prelude::DateTimeWithTimeZone,
     pub author_id: Uuid,
     pub author_username: String,
+    pub reply_to_id: Option<Uuid>,
 }
 
 impl From<ThoughtWithAuthor> for ThoughtSchema {
@@ -53,6 +56,7 @@ impl From<ThoughtWithAuthor> for ThoughtSchema {
             author_username: model.author_username,
             content: model.content,
             created_at: model.created_at.into(),
+            reply_to_id: model.reply_to_id,
         }
     }
 }

thoughts-backend/tests/api/thought.rs

@@ -4,7 +4,7 @@ use super::main::setup;
 use axum::http::StatusCode;
 use http_body_util::BodyExt;
 use sea_orm::prelude::Uuid;
-use serde_json::json;
+use serde_json::{json, Value};
 use utils::testing::{make_delete_request, make_post_request};
 
 #[tokio::test]
@@ -48,3 +48,36 @@ async fn test_thought_endpoints() {
     .await;
     assert_eq!(response.status(), StatusCode::NO_CONTENT);
 }
+
+#[tokio::test]
+async fn test_thought_replies() {
+    let app = setup().await;
+    let user1 =
+        create_user_with_password(&app.db, "user1", "password123", "user1@example.com").await;
+    let user2 =
+        create_user_with_password(&app.db, "user2", "password123", "user2@example.com").await;
+
+    // 1. User 1 posts an original thought
+    let body = json!({ "content": "This is the original post!" }).to_string();
+    let response = make_post_request(app.router.clone(), "/thoughts", body, Some(user1.id)).await;
+    assert_eq!(response.status(), StatusCode::CREATED);
+    let body = response.into_body().collect().await.unwrap().to_bytes();
+    let original_thought: Value = serde_json::from_slice(&body).unwrap();
+    let original_thought_id = original_thought["id"].as_str().unwrap();
+
+    // 2. User 2 replies to the original thought
+    let reply_body = json!({
+        "content": "This is a reply.",
+        "reply_to_id": original_thought_id
+    })
+    .to_string();
+    let response =
+        make_post_request(app.router.clone(), "/thoughts", reply_body, Some(user2.id)).await;
+    assert_eq!(response.status(), StatusCode::CREATED);
+    let body = response.into_body().collect().await.unwrap().to_bytes();
+    let reply_thought: Value = serde_json::from_slice(&body).unwrap();
+
+    // 3. Verify the reply is linked correctly
+    assert_eq!(reply_thought["reply_to_id"], original_thought_id);
+    assert_eq!(reply_thought["author_username"], "user2");
+}