feat: v2 rewrite — hexagonal arch, ActivityPub federation, NATS, deployment-ready (#1)

crates/domain/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "domain"
+version = "0.1.0"
+edition = "2021"
+
+[features]
+test-helpers = ["dep:sha2", "dep:hex"]
+
+[dependencies]
+async-trait = { workspace = true }
+thiserror   = { workspace = true }
+uuid        = { workspace = true }
+chrono      = { workspace = true }
+serde       = { workspace = true }
+futures     = { workspace = true }
+url         = { workspace = true }
+sha2        = { version = "0.10", optional = true }
+hex         = { version = "0.4", optional = true }
+
+[dev-dependencies]
+tokio = { workspace = true, features = ["full"] }
+sha2  = "0.10"
+hex   = "0.4"

crates/domain/src/errors.rs

@@ -0,0 +1,21 @@
+use thiserror::Error;
+
+#[derive(Debug, Error, Clone)]
+pub enum DomainError {
+    #[error("not found")]
+    NotFound,
+    #[error("unauthorized")]
+    Unauthorized,
+    #[error("forbidden")]
+    Forbidden,
+    #[error("conflict: {0}")]
+    Conflict(String),
+    #[error("unique violation on field: {field}")]
+    UniqueViolation { field: &'static str },
+    #[error("invalid input: {0}")]
+    InvalidInput(String),
+    #[error("external service error: {0}")]
+    ExternalService(String),
+    #[error("internal error: {0}")]
+    Internal(String),
+}

crates/domain/src/events.rs

@@ -0,0 +1,86 @@
+use crate::value_objects::{BoostId, LikeId, ThoughtId, UserId};
+
+#[derive(Debug, Clone)]
+pub enum DomainEvent {
+    ThoughtCreated {
+        thought_id: ThoughtId,
+        user_id: UserId,
+        in_reply_to_id: Option<ThoughtId>,
+    },
+    ThoughtDeleted {
+        thought_id: ThoughtId,
+        user_id: UserId,
+    },
+    ThoughtUpdated {
+        thought_id: ThoughtId,
+        user_id: UserId,
+    },
+    LikeAdded {
+        like_id: LikeId,
+        user_id: UserId,
+        thought_id: ThoughtId,
+    },
+    LikeRemoved {
+        user_id: UserId,
+        thought_id: ThoughtId,
+    },
+    BoostAdded {
+        boost_id: BoostId,
+        user_id: UserId,
+        thought_id: ThoughtId,
+    },
+    BoostRemoved {
+        user_id: UserId,
+        thought_id: ThoughtId,
+    },
+    FollowRequested {
+        follower_id: UserId,
+        following_id: UserId,
+    },
+    FollowAccepted {
+        follower_id: UserId,
+        following_id: UserId,
+    },
+    FollowRejected {
+        follower_id: UserId,
+        following_id: UserId,
+    },
+    Unfollowed {
+        follower_id: UserId,
+        following_id: UserId,
+    },
+    UserBlocked {
+        blocker_id: UserId,
+        blocked_id: UserId,
+    },
+    UserUnblocked {
+        blocker_id: UserId,
+        blocked_id: UserId,
+    },
+    UserRegistered {
+        user_id: UserId,
+    },
+    ProfileUpdated {
+        user_id: UserId,
+    },
+    MentionReceived {
+        thought_id: ThoughtId,
+        mentioned_user_id: UserId,
+        author_user_id: UserId,
+    },
+}
+
+pub struct EventEnvelope {
+    pub event: DomainEvent,
+    pub delivery_count: u64,
+    pub ack: Box<dyn Fn() + Send + Sync>,
+    pub nack: Box<dyn Fn() + Send + Sync>,
+}
+impl std::fmt::Debug for EventEnvelope {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("EventEnvelope")
+            .field("event", &self.event)
+            .field("delivery_count", &self.delivery_count)
+            .finish()
+    }
+}

crates/domain/src/hashtag.rs

@@ -0,0 +1,139 @@
+use std::collections::HashSet;
+
+/// A hashtag extracted from content.
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct Hashtag {
+    /// Original casing, e.g. "Rust"
+    pub raw: String,
+    /// Lowercased, e.g. "rust" — used for DB lookups
+    pub normalized: String,
+    /// "tags/rust" — callers prepend base_url
+    pub url_slug: String,
+    /// "#rust" — used directly in AP tag array
+    pub ap_name: String,
+}
+
+/// Extract hashtags from content using a char-by-char scan.
+///
+/// Rules:
+/// - Tag starts after a bare `#` followed immediately by an alphanumeric char.
+/// - Tag chars: `[A-Za-z0-9_]`.
+/// - Deduplicated case-insensitively; first occurrence wins.
+/// - Returned in order of first appearance.
+pub fn extract(content: &str) -> Vec<Hashtag> {
+    let mut seen: HashSet<String> = HashSet::new();
+    let mut tags: Vec<Hashtag> = Vec::new();
+    let mut chars = content.char_indices().peekable();
+
+    while let Some((_, c)) = chars.next() {
+        if c == '#'
+            && chars
+                .peek()
+                .map(|(_, nc)| nc.is_alphanumeric())
+                .unwrap_or(false)
+        {
+            let raw: String = chars
+                .by_ref()
+                .take_while(|(_, nc)| nc.is_alphanumeric() || *nc == '_')
+                .map(|(_, nc)| nc)
+                .collect();
+
+            if raw.is_empty() {
+                continue;
+            }
+
+            let normalized = raw.to_lowercase();
+            if seen.insert(normalized.clone()) {
+                tags.push(Hashtag {
+                    url_slug: format!("tags/{}", normalized),
+                    ap_name: format!("#{}", normalized),
+                    raw,
+                    normalized,
+                });
+            }
+        }
+    }
+
+    tags
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn names(tags: &[Hashtag]) -> Vec<&str> {
+        tags.iter().map(|h| h.normalized.as_str()).collect()
+    }
+
+    #[test]
+    fn basic() {
+        let tags = extract("Hello #world and #Rust!");
+        assert_eq!(names(&tags), ["world", "rust"]);
+    }
+
+    #[test]
+    fn fields() {
+        let tags = extract("#Rust");
+        assert_eq!(tags.len(), 1);
+        let h = &tags[0];
+        assert_eq!(h.raw, "Rust");
+        assert_eq!(h.normalized, "rust");
+        assert_eq!(h.url_slug, "tags/rust");
+        assert_eq!(h.ap_name, "#rust");
+    }
+
+    #[test]
+    fn dedup_case_insensitive() {
+        let tags = extract("#rust #Rust #RUST");
+        assert_eq!(names(&tags), ["rust"]);
+        assert_eq!(tags[0].raw, "rust"); // first occurrence wins
+    }
+
+    #[test]
+    fn deduplicates_non_adjacent() {
+        // The old algorithm used Vec::dedup() which only removes adjacent duplicates.
+        // Using HashSet silently fixed this bug. This test documents the fix.
+        let tags = extract("#a #b #a");
+        assert_eq!(tags.len(), 2);
+        assert_eq!(tags[0].normalized, "a");
+        assert_eq!(tags[1].normalized, "b");
+    }
+
+    #[test]
+    fn mid_word_extracted() {
+        // `text#tag` — `#` not preceded by whitespace is still matched by the
+        // char-by-char scan (the old algorithm didn't require whitespace before `#`).
+        // This test documents the authoritative behaviour: mid-word tags ARE extracted.
+        let tags = extract("text#tag");
+        assert_eq!(names(&tags), ["tag"]);
+    }
+
+    #[test]
+    fn hash_only_ignored() {
+        assert!(extract("# lone hash").is_empty());
+    }
+
+    #[test]
+    fn trailing_punctuation_excluded() {
+        // punctuation after tag terminates the tag, not included
+        let tags = extract("#rust.");
+        assert_eq!(names(&tags), ["rust"]);
+    }
+
+    #[test]
+    fn underscore_allowed() {
+        let tags = extract("#hello_world");
+        assert_eq!(names(&tags), ["hello_world"]);
+    }
+
+    #[test]
+    fn empty_content() {
+        assert!(extract("").is_empty());
+    }
+
+    #[test]
+    fn order_of_appearance() {
+        let tags = extract("#b #a #c");
+        assert_eq!(names(&tags), ["b", "a", "c"]);
+    }
+}

crates/domain/src/lib.rs

@@ -0,0 +1,9 @@
+pub mod errors;
+pub mod events;
+pub mod hashtag;
+pub mod models;
+pub mod ports;
+pub mod value_objects;
+
+#[cfg(any(test, feature = "test-helpers"))]
+pub mod testing;

crates/domain/src/models/actor_connection_summary.rs

@@ -0,0 +1,7 @@
+#[derive(Debug, Clone)]
+pub struct ActorConnectionSummary {
+    pub url: String,
+    pub handle: String,
+    pub display_name: Option<String>,
+    pub avatar_url: Option<String>,
+}

crates/domain/src/models/api_key.rs

@@ -0,0 +1,11 @@
+use crate::value_objects::{ApiKeyId, UserId};
+use chrono::{DateTime, Utc};
+
+#[derive(Debug, Clone)]
+pub struct ApiKey {
+    pub id: ApiKeyId,
+    pub user_id: UserId,
+    pub key_hash: String,
+    pub name: String,
+    pub created_at: DateTime<Utc>,
+}

crates/domain/src/models/connection_type.rs

@@ -0,0 +1,14 @@
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum ConnectionType {
+    Followers,
+    Following,
+}
+
+impl ConnectionType {
+    pub fn as_str(&self) -> &'static str {
+        match self {
+            Self::Followers => "followers",
+            Self::Following => "following",
+        }
+    }
+}

crates/domain/src/models/feed.rs

@@ -0,0 +1,60 @@
+use crate::models::{thought::Thought, user::User};
+use crate::value_objects::UserId;
+
+#[derive(Debug, Clone)]
+pub struct EngagementStats {
+    pub like_count: i64,
+    pub boost_count: i64,
+    pub reply_count: i64,
+}
+
+/// Present only when an authenticated viewer made the request.
+/// `liked`/`boosted` are the viewer's interaction state with this thought.
+/// `None` means anonymous request or viewer context unavailable.
+#[derive(Debug, Clone)]
+pub struct ViewerContext {
+    pub liked: bool,
+    pub boosted: bool,
+}
+
+#[derive(Debug, Clone)]
+pub struct FeedEntry {
+    pub thought: Thought,
+    pub author: User,
+    pub stats: EngagementStats,
+    pub viewer: Option<ViewerContext>,
+}
+
+#[derive(Debug, Clone)]
+pub struct UserSummary {
+    pub id: UserId,
+    pub username: String,
+    pub display_name: Option<String>,
+    pub avatar_url: Option<String>,
+    pub bio: Option<String>,
+    pub thought_count: i64,
+    pub follower_count: i64,
+    pub following_count: i64,
+}
+
+#[derive(Debug, Clone)]
+pub struct PageParams {
+    pub page: u64,
+    pub per_page: u64,
+}
+impl PageParams {
+    pub fn offset(&self) -> i64 {
+        ((self.page.saturating_sub(1)) * self.per_page) as i64
+    }
+    pub fn limit(&self) -> i64 {
+        self.per_page as i64
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct Paginated<T> {
+    pub items: Vec<T>,
+    pub total: i64,
+    pub page: u64,
+    pub per_page: u64,
+}

crates/domain/src/models/mod.rs

@@ -0,0 +1,12 @@
+pub mod actor_connection_summary;
+pub mod api_key;
+pub mod connection_type;
+pub mod feed;
+pub mod notification;
+pub mod remote_actor;
+pub mod remote_note;
+pub mod social;
+pub mod tag;
+pub mod thought;
+pub mod top_friend;
+pub mod user;

crates/domain/src/models/notification.rs

@@ -0,0 +1,66 @@
+use crate::value_objects::{NotificationId, ThoughtId, UserId};
+use chrono::{DateTime, Utc};
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum NotificationKind {
+    Like {
+        thought_id: ThoughtId,
+        from_user_id: UserId,
+    },
+    Boost {
+        thought_id: ThoughtId,
+        from_user_id: UserId,
+    },
+    Reply {
+        thought_id: ThoughtId,
+        from_user_id: UserId,
+    },
+    Mention {
+        thought_id: ThoughtId,
+        from_user_id: UserId,
+    },
+    Follow {
+        from_user_id: UserId,
+    },
+}
+
+impl NotificationKind {
+    pub fn from_user_id(&self) -> &UserId {
+        match self {
+            Self::Like { from_user_id, .. } => from_user_id,
+            Self::Boost { from_user_id, .. } => from_user_id,
+            Self::Reply { from_user_id, .. } => from_user_id,
+            Self::Mention { from_user_id, .. } => from_user_id,
+            Self::Follow { from_user_id } => from_user_id,
+        }
+    }
+
+    pub fn thought_id(&self) -> Option<&ThoughtId> {
+        match self {
+            Self::Like { thought_id, .. } => Some(thought_id),
+            Self::Boost { thought_id, .. } => Some(thought_id),
+            Self::Reply { thought_id, .. } => Some(thought_id),
+            Self::Mention { thought_id, .. } => Some(thought_id),
+            Self::Follow { .. } => None,
+        }
+    }
+
+    pub fn kind_str(&self) -> &'static str {
+        match self {
+            Self::Like { .. } => "like",
+            Self::Boost { .. } => "boost",
+            Self::Reply { .. } => "reply",
+            Self::Mention { .. } => "mention",
+            Self::Follow { .. } => "follow",
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct Notification {
+    pub id: NotificationId,
+    pub user_id: UserId,
+    pub kind: NotificationKind,
+    pub read: bool,
+    pub created_at: DateTime<Utc>,
+}

crates/domain/src/models/remote_actor.rs

@@ -0,0 +1,17 @@
+use chrono::{DateTime, Utc};
+
+#[derive(Debug, Clone)]
+pub struct RemoteActor {
+    pub url: String,
+    pub handle: String,
+    pub display_name: Option<String>,
+    pub avatar_url: Option<String>,
+    pub bio: Option<String>,
+    pub banner_url: Option<String>,
+    pub also_known_as: Option<String>,
+    pub outbox_url: Option<String>,
+    pub followers_url: Option<String>,
+    pub following_url: Option<String>,
+    pub attachment: Vec<(String, String)>,
+    pub last_fetched_at: DateTime<Utc>,
+}

crates/domain/src/models/remote_note.rs

@@ -0,0 +1,10 @@
+use chrono::{DateTime, Utc};
+
+#[derive(Debug, Clone)]
+pub struct RemoteNote {
+    pub ap_id: String,
+    pub content: String,
+    pub published: DateTime<Utc>,
+    pub sensitive: bool,
+    pub content_warning: Option<String>,
+}

crates/domain/src/models/social.rs

@@ -0,0 +1,64 @@
+use crate::value_objects::{BoostId, LikeId, ThoughtId, UserId};
+use chrono::{DateTime, Utc};
+
+#[derive(Debug, Clone)]
+pub struct Like {
+    pub id: LikeId,
+    pub user_id: UserId,
+    pub thought_id: ThoughtId,
+    pub ap_id: Option<String>,
+    pub created_at: DateTime<Utc>,
+}
+
+#[derive(Debug, Clone)]
+pub struct Boost {
+    pub id: BoostId,
+    pub user_id: UserId,
+    pub thought_id: ThoughtId,
+    pub ap_id: Option<String>,
+    pub created_at: DateTime<Utc>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum FollowState {
+    Pending,
+    Accepted,
+    Rejected,
+}
+
+impl FollowState {
+    pub fn as_str(&self) -> &'static str {
+        match self {
+            Self::Pending => "pending",
+            Self::Accepted => "accepted",
+            Self::Rejected => "rejected",
+        }
+    }
+
+    pub fn from_db_str(s: &str) -> Result<Self, crate::errors::DomainError> {
+        match s {
+            "pending" => Ok(Self::Pending),
+            "accepted" => Ok(Self::Accepted),
+            "rejected" => Ok(Self::Rejected),
+            other => Err(crate::errors::DomainError::Internal(format!(
+                "unknown follow_state: '{other}'"
+            ))),
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct Follow {
+    pub follower_id: UserId,
+    pub following_id: UserId,
+    pub state: FollowState,
+    pub ap_id: Option<String>,
+    pub created_at: DateTime<Utc>,
+}
+
+#[derive(Debug, Clone)]
+pub struct Block {
+    pub blocker_id: UserId,
+    pub blocked_id: UserId,
+    pub created_at: DateTime<Utc>,
+}

crates/domain/src/models/tag.rs

@@ -0,0 +1,5 @@
+#[derive(Debug, Clone)]
+pub struct Tag {
+    pub id: i32,
+    pub name: String,
+}

crates/domain/src/models/thought.rs

@@ -0,0 +1,72 @@
+use crate::value_objects::{Content, ThoughtId, UserId};
+use chrono::{DateTime, Utc};
+
+#[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
+pub enum Visibility {
+    Public,
+    Followers,
+    Unlisted,
+    Direct,
+}
+
+#[derive(Debug, Clone)]
+pub struct Thought {
+    pub id: ThoughtId,
+    pub user_id: UserId,
+    pub content: Content,
+    pub in_reply_to_id: Option<ThoughtId>,
+    pub visibility: Visibility,
+    pub content_warning: Option<String>,
+    pub sensitive: bool,
+    pub local: bool,
+    pub created_at: DateTime<Utc>,
+    pub updated_at: Option<DateTime<Utc>>,
+}
+
+impl Visibility {
+    pub fn as_str(&self) -> &'static str {
+        match self {
+            Visibility::Public => "public",
+            Visibility::Followers => "followers",
+            Visibility::Unlisted => "unlisted",
+            Visibility::Direct => "direct",
+        }
+    }
+
+    pub fn from_db_str(s: &str) -> Result<Self, crate::errors::DomainError> {
+        match s {
+            "public" => Ok(Self::Public),
+            "followers" => Ok(Self::Followers),
+            "unlisted" => Ok(Self::Unlisted),
+            "direct" => Ok(Self::Direct),
+            other => Err(crate::errors::DomainError::Internal(format!(
+                "unknown visibility: '{other}'"
+            ))),
+        }
+    }
+}
+
+impl Thought {
+    pub fn new_local(
+        id: ThoughtId,
+        user_id: UserId,
+        content: Content,
+        in_reply_to_id: Option<ThoughtId>,
+        visibility: Visibility,
+        content_warning: Option<String>,
+        sensitive: bool,
+    ) -> Self {
+        Self {
+            id,
+            user_id,
+            content,
+            in_reply_to_id,
+            visibility,
+            content_warning,
+            sensitive,
+            local: true,
+            created_at: Utc::now(),
+            updated_at: None,
+        }
+    }
+}

crates/domain/src/models/top_friend.rs

@@ -0,0 +1,8 @@
+use crate::value_objects::UserId;
+
+#[derive(Debug, Clone)]
+pub struct TopFriend {
+    pub user_id: UserId,
+    pub friend_id: UserId,
+    pub position: i16,
+}

crates/domain/src/models/user.rs

@@ -0,0 +1,43 @@
+use crate::value_objects::{Email, PasswordHash, UserId, Username};
+use chrono::{DateTime, Utc};
+
+#[derive(Debug, Clone)]
+pub struct User {
+    pub id: UserId,
+    pub username: Username,
+    pub email: Email,
+    pub password_hash: PasswordHash,
+    pub display_name: Option<String>,
+    pub bio: Option<String>,
+    pub avatar_url: Option<String>,
+    pub header_url: Option<String>,
+    pub custom_css: Option<String>,
+    pub local: bool,
+    pub created_at: DateTime<Utc>,
+    pub updated_at: DateTime<Utc>,
+}
+
+impl User {
+    pub fn new_local(
+        id: UserId,
+        username: Username,
+        email: Email,
+        password_hash: PasswordHash,
+    ) -> Self {
+        let now = Utc::now();
+        Self {
+            id,
+            username,
+            email,
+            password_hash,
+            display_name: None,
+            bio: None,
+            avatar_url: None,
+            header_url: None,
+            custom_css: None,
+            local: true,
+            created_at: now,
+            updated_at: now,
+        }
+    }
+}

crates/domain/src/ports.rs

@@ -0,0 +1,411 @@
+use std::collections::HashMap;
+
+use crate::{
+    errors::DomainError,
+    events::{DomainEvent, EventEnvelope},
+    models::{
+        api_key::ApiKey,
+        feed::{EngagementStats, FeedEntry, PageParams, Paginated, UserSummary, ViewerContext},
+        notification::Notification,
+        remote_actor::RemoteActor,
+        social::{Block, Boost, Follow, FollowState, Like},
+        tag::Tag,
+        thought::Thought,
+        top_friend::TopFriend,
+        user::User,
+    },
+    value_objects::{
+        ApiKeyId, Content, Email, NotificationId, PasswordHash, ThoughtId, UserId, Username,
+    },
+};
+use async_trait::async_trait;
+
+pub struct GeneratedToken {
+    pub token: String,
+    pub user_id: UserId,
+}
+
+#[async_trait]
+pub trait AuthService: Send + Sync {
+    fn generate_token(&self, user_id: &UserId) -> Result<GeneratedToken, DomainError>;
+    fn validate_token(&self, token: &str) -> Result<UserId, DomainError>;
+}
+
+#[async_trait]
+pub trait PasswordHasher: Send + Sync {
+    async fn hash(&self, plain: &str) -> Result<PasswordHash, DomainError>;
+    async fn verify(&self, plain: &str, hash: &PasswordHash) -> Result<bool, DomainError>;
+}
+
+#[async_trait]
+pub trait EventPublisher: Send + Sync {
+    async fn publish(&self, event: &DomainEvent) -> Result<(), DomainError>;
+}
+
+pub trait EventConsumer: Send + Sync {
+    fn consume(&self) -> futures::stream::BoxStream<'_, Result<EventEnvelope, DomainError>>;
+}
+
+#[async_trait]
+pub trait OutboxWriter: Send + Sync {
+    async fn append(&self, event: &DomainEvent) -> Result<(), DomainError>;
+}
+
+#[async_trait]
+pub trait UserReader: Send + Sync {
+    async fn find_by_id(&self, id: &UserId) -> Result<Option<User>, DomainError>;
+    async fn find_by_username(&self, username: &Username) -> Result<Option<User>, DomainError>;
+    async fn find_by_email(&self, email: &Email) -> Result<Option<User>, DomainError>;
+    async fn list_with_stats(&self) -> Result<Vec<UserSummary>, DomainError>;
+    async fn count(&self) -> Result<i64, DomainError>;
+    async fn list_paginated(&self, page: PageParams) -> Result<Paginated<UserSummary>, DomainError>;
+    async fn find_by_ids(&self, ids: &[UserId]) -> Result<HashMap<UserId, User>, DomainError>;
+}
+
+#[async_trait]
+pub trait UserWriter: Send + Sync {
+    async fn save(&self, user: &User) -> Result<(), DomainError>;
+    async fn update_profile(
+        &self,
+        user_id: &UserId,
+        display_name: Option<String>,
+        bio: Option<String>,
+        avatar_url: Option<String>,
+        header_url: Option<String>,
+        custom_css: Option<String>,
+    ) -> Result<(), DomainError>;
+}
+
+/// Combined supertrait — `AppState.users` stays `Arc<dyn UserRepository>`.
+/// Blanket impl: any type implementing both sub-traits gets `UserRepository` for free.
+pub trait UserRepository: UserReader + UserWriter {}
+impl<T: UserReader + UserWriter> UserRepository for T {}
+
+#[async_trait]
+pub trait ThoughtRepository: Send + Sync {
+    async fn save(&self, thought: &Thought) -> Result<(), DomainError>;
+    async fn find_by_id(&self, id: &ThoughtId) -> Result<Option<Thought>, DomainError>;
+    async fn delete(&self, id: &ThoughtId, user_id: &UserId) -> Result<(), DomainError>;
+    async fn update_content(&self, id: &ThoughtId, content: &Content) -> Result<(), DomainError>;
+    async fn get_thread(&self, id: &ThoughtId) -> Result<Vec<Thought>, DomainError>;
+    async fn list_by_user(
+        &self,
+        user_id: &UserId,
+        page: &PageParams,
+    ) -> Result<Paginated<Thought>, DomainError>;
+}
+
+#[async_trait]
+pub trait LikeRepository: Send + Sync {
+    async fn save(&self, like: &Like) -> Result<(), DomainError>;
+    async fn delete(&self, user_id: &UserId, thought_id: &ThoughtId) -> Result<(), DomainError>;
+    async fn find(
+        &self,
+        user_id: &UserId,
+        thought_id: &ThoughtId,
+    ) -> Result<Option<Like>, DomainError>;
+    async fn count_for_thought(&self, thought_id: &ThoughtId) -> Result<i64, DomainError>;
+}
+
+#[async_trait]
+pub trait BoostRepository: Send + Sync {
+    async fn save(&self, boost: &Boost) -> Result<(), DomainError>;
+    async fn delete(&self, user_id: &UserId, thought_id: &ThoughtId) -> Result<(), DomainError>;
+    async fn find(
+        &self,
+        user_id: &UserId,
+        thought_id: &ThoughtId,
+    ) -> Result<Option<Boost>, DomainError>;
+    async fn count_for_thought(&self, thought_id: &ThoughtId) -> Result<i64, DomainError>;
+}
+
+#[async_trait]
+pub trait EngagementRepository: Send + Sync {
+    async fn get_for_thoughts(
+        &self,
+        thought_ids: &[ThoughtId],
+        viewer_id: Option<&UserId>,
+    ) -> Result<HashMap<ThoughtId, (EngagementStats, Option<ViewerContext>)>, DomainError>;
+}
+
+#[async_trait]
+pub trait FollowRepository: Send + Sync {
+    async fn save(&self, follow: &Follow) -> Result<(), DomainError>;
+    async fn delete(&self, follower_id: &UserId, following_id: &UserId) -> Result<(), DomainError>;
+    async fn find(
+        &self,
+        follower_id: &UserId,
+        following_id: &UserId,
+    ) -> Result<Option<Follow>, DomainError>;
+    async fn update_state(
+        &self,
+        follower_id: &UserId,
+        following_id: &UserId,
+        state: &FollowState,
+    ) -> Result<(), DomainError>;
+    async fn list_followers(
+        &self,
+        user_id: &UserId,
+        page: &PageParams,
+    ) -> Result<Paginated<User>, DomainError>;
+    async fn list_following(
+        &self,
+        user_id: &UserId,
+        page: &PageParams,
+    ) -> Result<Paginated<User>, DomainError>;
+    async fn get_accepted_following_ids(
+        &self,
+        user_id: &UserId,
+    ) -> Result<Vec<UserId>, DomainError>;
+}
+
+#[async_trait]
+pub trait BlockRepository: Send + Sync {
+    async fn save(&self, block: &Block) -> Result<(), DomainError>;
+    async fn delete(&self, blocker_id: &UserId, blocked_id: &UserId) -> Result<(), DomainError>;
+    async fn exists(&self, blocker_id: &UserId, blocked_id: &UserId) -> Result<bool, DomainError>;
+}
+
+#[async_trait]
+pub trait TagRepository: Send + Sync {
+    async fn find_or_create(&self, name: &str) -> Result<Tag, DomainError>;
+    async fn attach_to_thought(
+        &self,
+        thought_id: &ThoughtId,
+        tag_id: i32,
+    ) -> Result<(), DomainError>;
+    async fn detach_from_thought(&self, thought_id: &ThoughtId) -> Result<(), DomainError>;
+    async fn list_for_thought(&self, thought_id: &ThoughtId) -> Result<Vec<Tag>, DomainError>;
+    async fn list_thoughts_by_tag(
+        &self,
+        tag_name: &str,
+        page: &PageParams,
+    ) -> Result<Paginated<Thought>, DomainError>;
+    /// Returns (tag_name, thought_count) pairs ordered by usage, most popular first.
+    async fn popular_tags(&self, limit: usize) -> Result<Vec<(String, i64)>, DomainError>;
+}
+
+#[async_trait]
+pub trait ApiKeyRepository: Send + Sync {
+    async fn save(&self, key: &ApiKey) -> Result<(), DomainError>;
+    async fn find_by_hash(&self, key_hash: &str) -> Result<Option<ApiKey>, DomainError>;
+    async fn list_for_user(&self, user_id: &UserId) -> Result<Vec<ApiKey>, DomainError>;
+    async fn delete(&self, id: &ApiKeyId, user_id: &UserId) -> Result<(), DomainError>;
+}
+
+#[async_trait]
+pub trait ApiKeyService: Send + Sync {
+    async fn validate_key(&self, raw_key: &str) -> Result<Option<UserId>, DomainError>;
+}
+
+#[async_trait]
+pub trait TopFriendRepository: Send + Sync {
+    async fn set_top_friends(
+        &self,
+        user_id: &UserId,
+        friends: Vec<(UserId, i16)>,
+    ) -> Result<(), DomainError>;
+    async fn list_for_user(&self, user_id: &UserId) -> Result<Vec<(TopFriend, User)>, DomainError>;
+}
+
+#[async_trait]
+pub trait NotificationRepository: Send + Sync {
+    async fn save(&self, n: &Notification) -> Result<(), DomainError>;
+    async fn list_for_user(
+        &self,
+        user_id: &UserId,
+        page: &PageParams,
+    ) -> Result<Paginated<Notification>, DomainError>;
+    async fn count_unread(&self, user_id: &UserId) -> Result<u64, DomainError>;
+    async fn mark_read(&self, id: &NotificationId, user_id: &UserId) -> Result<(), DomainError>;
+    async fn mark_all_read(&self, user_id: &UserId) -> Result<(), DomainError>;
+}
+
+#[async_trait]
+pub trait RemoteActorRepository: Send + Sync {
+    async fn upsert(&self, actor: &RemoteActor) -> Result<(), DomainError>;
+    async fn find_by_url(&self, url: &str) -> Result<Option<RemoteActor>, DomainError>;
+}
+
+#[async_trait]
+pub trait RemoteActorConnectionRepository: Send + Sync {
+    async fn upsert_connections(
+        &self,
+        actor_url: &str,
+        connection_type: &str,
+        page: u32,
+        actors: &[crate::models::actor_connection_summary::ActorConnectionSummary],
+    ) -> Result<(), DomainError>;
+
+    async fn list_connections(
+        &self,
+        actor_url: &str,
+        connection_type: &str,
+        page: u32,
+    ) -> Result<Vec<crate::models::actor_connection_summary::ActorConnectionSummary>, DomainError>;
+
+    async fn connection_page_age(
+        &self,
+        actor_url: &str,
+        connection_type: &str,
+        page: u32,
+    ) -> Result<Option<chrono::DateTime<chrono::Utc>>, DomainError>;
+}
+
+#[async_trait]
+pub trait FederationLookupPort: Send + Sync {
+    async fn lookup_actor(&self, handle: &str) -> Result<RemoteActor, DomainError>;
+    async fn actor_json(&self, user_id: &UserId) -> Result<String, DomainError>;
+    async fn followers_collection_json(
+        &self,
+        user_id: &UserId,
+        page: Option<u32>,
+    ) -> Result<String, DomainError>;
+    async fn following_collection_json(
+        &self,
+        user_id: &UserId,
+        page: Option<u32>,
+    ) -> Result<String, DomainError>;
+}
+
+#[async_trait]
+pub trait FederationFollowPort: Send + Sync {
+    async fn follow_remote(&self, local_user_id: &UserId, handle: &str) -> Result<(), DomainError>;
+    async fn unfollow_remote(
+        &self,
+        local_user_id: &UserId,
+        handle: &str,
+    ) -> Result<(), DomainError>;
+    async fn get_remote_following(&self, user_id: &UserId)
+        -> Result<Vec<RemoteActor>, DomainError>;
+}
+
+#[async_trait]
+pub trait FederationFollowRequestPort: Send + Sync {
+    async fn get_pending_followers(
+        &self,
+        user_id: &UserId,
+    ) -> Result<Vec<RemoteActor>, DomainError>;
+    async fn accept_follow_request(
+        &self,
+        user_id: &UserId,
+        actor_url: &str,
+    ) -> Result<(), DomainError>;
+    async fn reject_follow_request(
+        &self,
+        user_id: &UserId,
+        actor_url: &str,
+    ) -> Result<(), DomainError>;
+    async fn get_remote_followers(&self, user_id: &UserId)
+        -> Result<Vec<RemoteActor>, DomainError>;
+    async fn remove_remote_follower(
+        &self,
+        user_id: &UserId,
+        actor_url: &str,
+    ) -> Result<(), DomainError>;
+}
+
+#[async_trait]
+pub trait FederationFetchPort: Send + Sync {
+    async fn fetch_outbox_page(
+        &self,
+        outbox_url: &str,
+        page: u32,
+    ) -> Result<Vec<crate::models::remote_note::RemoteNote>, DomainError>;
+    async fn fetch_actor_urls_from_collection(
+        &self,
+        collection_url: &str,
+    ) -> Result<Vec<String>, DomainError>;
+    async fn resolve_actor_profiles(
+        &self,
+        urls: Vec<String>,
+    ) -> Vec<crate::models::actor_connection_summary::ActorConnectionSummary>;
+}
+
+pub trait FederationActionPort:
+    FederationLookupPort + FederationFollowPort + FederationFollowRequestPort + FederationFetchPort
+{
+}
+impl<
+        T: FederationLookupPort
+            + FederationFollowPort
+            + FederationFollowRequestPort
+            + FederationFetchPort,
+    > FederationActionPort for T
+{
+}
+
+#[derive(Debug, Clone)]
+pub enum FeedScope {
+    Home { following_ids: Vec<UserId> },
+    Public,
+    Tag { tag_name: String },
+    User { user_id: UserId },
+    Search { query: String },
+}
+
+#[derive(Debug, Clone)]
+pub struct FeedQuery {
+    pub scope: FeedScope,
+    pub page: PageParams,
+    pub viewer_id: Option<UserId>,
+}
+
+impl FeedQuery {
+    pub fn home(viewer_id: UserId, following_ids: Vec<UserId>, page: PageParams) -> Self {
+        Self { scope: FeedScope::Home { following_ids }, page, viewer_id: Some(viewer_id) }
+    }
+    pub fn public(page: PageParams, viewer_id: Option<UserId>) -> Self {
+        Self { scope: FeedScope::Public, page, viewer_id }
+    }
+    pub fn tag(tag_name: impl Into<String>, page: PageParams, viewer_id: Option<UserId>) -> Self {
+        Self { scope: FeedScope::Tag { tag_name: tag_name.into() }, page, viewer_id }
+    }
+    pub fn user(user_id: UserId, page: PageParams, viewer_id: Option<UserId>) -> Self {
+        Self { scope: FeedScope::User { user_id }, page, viewer_id }
+    }
+    pub fn search(query: impl Into<String>, page: PageParams, viewer_id: Option<UserId>) -> Self {
+        Self { scope: FeedScope::Search { query: query.into() }, page, viewer_id }
+    }
+}
+
+#[async_trait]
+pub trait FeedRepository: Send + Sync {
+    async fn query(&self, q: &FeedQuery) -> Result<Paginated<FeedEntry>, DomainError>;
+}
+
+#[async_trait]
+pub trait SearchPort: Send + Sync {
+    /// Full-text search over public thoughts, ranked by trigram similarity.
+    async fn search_thoughts(
+        &self,
+        query: &str,
+        page: &PageParams,
+        viewer_id: Option<&UserId>,
+    ) -> Result<Paginated<FeedEntry>, DomainError>;
+
+    /// Search users by username or display_name, ranked by trigram similarity.
+    async fn search_users(
+        &self,
+        query: &str,
+        page: &PageParams,
+    ) -> Result<Paginated<User>, DomainError>;
+}
+
+
+#[async_trait]
+pub trait FederationSchedulerPort: Send + Sync {
+    async fn schedule_actor_posts_fetch(
+        &self,
+        actor_ap_url: &str,
+        outbox_url: &str,
+    ) -> Result<(), DomainError>;
+
+    async fn schedule_connections_fetch(
+        &self,
+        actor_ap_url: &str,
+        collection_url: &str,
+        connection_type: &str,
+        page: u32,
+    ) -> Result<(), DomainError>;
+}

crates/domain/src/testing.rs

@@ -0,0 +1,964 @@
+use crate::{
+    errors::DomainError,
+    events::DomainEvent,
+    models::{
+        api_key::ApiKey,
+        feed::{FeedEntry, PageParams, Paginated, UserSummary},
+        notification::Notification,
+        remote_actor::RemoteActor,
+        social::{Block, Boost, Follow, FollowState, Like},
+        tag::Tag,
+        thought::Thought,
+        top_friend::TopFriend,
+        user::User,
+    },
+    ports::*,
+    value_objects::{
+        ApiKeyId, Content, Email, NotificationId, PasswordHash, ThoughtId, UserId, Username,
+    },
+};
+use async_trait::async_trait;
+use chrono::Utc;
+use std::collections::HashMap;
+use std::sync::{Arc, Mutex};
+
+#[derive(Default, Clone)]
+pub struct TestStore {
+    pub users: Arc<Mutex<Vec<User>>>,
+    pub thoughts: Arc<Mutex<Vec<Thought>>>,
+    pub likes: Arc<Mutex<Vec<Like>>>,
+    pub boosts: Arc<Mutex<Vec<Boost>>>,
+    pub follows: Arc<Mutex<Vec<Follow>>>,
+    pub blocks: Arc<Mutex<Vec<Block>>>,
+    pub tags: Arc<Mutex<Vec<Tag>>>,
+    pub api_keys: Arc<Mutex<Vec<ApiKey>>>,
+    pub top_friends: Arc<Mutex<Vec<TopFriend>>>,
+    pub notifications: Arc<Mutex<Vec<Notification>>>,
+    pub events: Arc<Mutex<Vec<DomainEvent>>>,
+    /// AP URL → UserId for remote actors (used by find_remote_actor_id / intern_remote_actor)
+    pub actor_ap_ids: Arc<Mutex<HashMap<String, UserId>>>,
+    /// ThoughtId → AP object URL (used by get_thought_ap_id)
+    pub thought_ap_ids: Arc<Mutex<HashMap<ThoughtId, String>>>,
+}
+
+#[async_trait]
+impl UserReader for TestStore {
+    async fn find_by_id(&self, id: &UserId) -> Result<Option<User>, DomainError> {
+        Ok(self
+            .users
+            .lock()
+            .unwrap()
+            .iter()
+            .find(|u| &u.id == id)
+            .cloned())
+    }
+    async fn find_by_username(&self, username: &Username) -> Result<Option<User>, DomainError> {
+        Ok(self
+            .users
+            .lock()
+            .unwrap()
+            .iter()
+            .find(|u| u.username.as_str() == username.as_str())
+            .cloned())
+    }
+    async fn find_by_email(&self, email: &Email) -> Result<Option<User>, DomainError> {
+        Ok(self
+            .users
+            .lock()
+            .unwrap()
+            .iter()
+            .find(|u| u.email.as_str() == email.as_str())
+            .cloned())
+    }
+    async fn list_with_stats(&self) -> Result<Vec<UserSummary>, DomainError> {
+        Ok(vec![])
+    }
+    async fn count(&self) -> Result<i64, DomainError> {
+        Ok(self
+            .users
+            .lock()
+            .unwrap()
+            .iter()
+            .filter(|u| u.local)
+            .count() as i64)
+    }
+
+    async fn list_paginated(&self, page: PageParams) -> Result<Paginated<UserSummary>, DomainError> {
+        let all = self.list_with_stats().await?;
+        let total = all.len() as i64;
+        let start = page.offset() as usize;
+        let items: Vec<UserSummary> = all.into_iter().skip(start).take(page.limit() as usize).collect();
+        Ok(Paginated { items, total, page: page.page, per_page: page.per_page })
+    }
+
+    async fn find_by_ids(&self, ids: &[UserId]) -> Result<HashMap<UserId, User>, DomainError> {
+        let g = self.users.lock().unwrap();
+        let map = g.iter()
+            .filter(|u| ids.contains(&u.id))
+            .map(|u| (u.id.clone(), u.clone()))
+            .collect();
+        Ok(map)
+    }
+}
+
+#[async_trait]
+impl UserWriter for TestStore {
+    async fn save(&self, user: &User) -> Result<(), DomainError> {
+        let mut g = self.users.lock().unwrap();
+        g.retain(|u| u.id != user.id);
+        g.push(user.clone());
+        Ok(())
+    }
+    async fn update_profile(
+        &self,
+        user_id: &UserId,
+        display_name: Option<String>,
+        bio: Option<String>,
+        avatar_url: Option<String>,
+        header_url: Option<String>,
+        custom_css: Option<String>,
+    ) -> Result<(), DomainError> {
+        if let Some(u) = self
+            .users
+            .lock()
+            .unwrap()
+            .iter_mut()
+            .find(|u| &u.id == user_id)
+        {
+            u.display_name = display_name;
+            u.bio = bio;
+            u.avatar_url = avatar_url;
+            u.header_url = header_url;
+            u.custom_css = custom_css;
+        }
+        Ok(())
+    }
+}
+
+#[async_trait]
+impl ThoughtRepository for TestStore {
+    async fn save(&self, t: &Thought) -> Result<(), DomainError> {
+        let mut g = self.thoughts.lock().unwrap();
+        g.retain(|x| x.id != t.id);
+        g.push(t.clone());
+        Ok(())
+    }
+    async fn find_by_id(&self, id: &ThoughtId) -> Result<Option<Thought>, DomainError> {
+        Ok(self
+            .thoughts
+            .lock()
+            .unwrap()
+            .iter()
+            .find(|t| &t.id == id)
+            .cloned())
+    }
+    async fn delete(&self, id: &ThoughtId, user_id: &UserId) -> Result<(), DomainError> {
+        let mut g = self.thoughts.lock().unwrap();
+        let before = g.len();
+        g.retain(|t| !(&t.id == id && &t.user_id == user_id));
+        if g.len() == before {
+            return Err(DomainError::NotFound);
+        }
+        Ok(())
+    }
+    async fn update_content(&self, id: &ThoughtId, content: &Content) -> Result<(), DomainError> {
+        if let Some(t) = self
+            .thoughts
+            .lock()
+            .unwrap()
+            .iter_mut()
+            .find(|t| &t.id == id)
+        {
+            t.content = content.clone();
+            t.updated_at = Some(Utc::now());
+        }
+        Ok(())
+    }
+    async fn get_thread(&self, id: &ThoughtId) -> Result<Vec<Thought>, DomainError> {
+        Ok(self
+            .thoughts
+            .lock()
+            .unwrap()
+            .iter()
+            .filter(|t| t.in_reply_to_id.as_ref() == Some(id) || &t.id == id)
+            .cloned()
+            .collect())
+    }
+    async fn list_by_user(
+        &self,
+        _user_id: &UserId,
+        _page: &PageParams,
+    ) -> Result<Paginated<Thought>, DomainError> {
+        Ok(Paginated {
+            items: vec![],
+            total: 0,
+            page: 1,
+            per_page: 20,
+        })
+    }
+}
+
+#[async_trait]
+impl LikeRepository for TestStore {
+    async fn save(&self, like: &Like) -> Result<(), DomainError> {
+        let mut g = self.likes.lock().unwrap();
+        if g.iter()
+            .any(|l| l.user_id == like.user_id && l.thought_id == like.thought_id)
+        {
+            return Err(DomainError::Conflict("already liked".into()));
+        }
+        g.push(like.clone());
+        Ok(())
+    }
+    async fn delete(&self, user_id: &UserId, thought_id: &ThoughtId) -> Result<(), DomainError> {
+        let mut g = self.likes.lock().unwrap();
+        let before = g.len();
+        g.retain(|l| !(&l.user_id == user_id && &l.thought_id == thought_id));
+        if g.len() == before {
+            return Err(DomainError::NotFound);
+        }
+        Ok(())
+    }
+    async fn find(
+        &self,
+        user_id: &UserId,
+        thought_id: &ThoughtId,
+    ) -> Result<Option<Like>, DomainError> {
+        Ok(self
+            .likes
+            .lock()
+            .unwrap()
+            .iter()
+            .find(|l| &l.user_id == user_id && &l.thought_id == thought_id)
+            .cloned())
+    }
+    async fn count_for_thought(&self, thought_id: &ThoughtId) -> Result<i64, DomainError> {
+        Ok(self
+            .likes
+            .lock()
+            .unwrap()
+            .iter()
+            .filter(|l| &l.thought_id == thought_id)
+            .count() as i64)
+    }
+}
+
+#[async_trait]
+impl BoostRepository for TestStore {
+    async fn save(&self, boost: &Boost) -> Result<(), DomainError> {
+        let mut g = self.boosts.lock().unwrap();
+        if g.iter()
+            .any(|b| b.user_id == boost.user_id && b.thought_id == boost.thought_id)
+        {
+            return Err(DomainError::Conflict("already boosted".into()));
+        }
+        g.push(boost.clone());
+        Ok(())
+    }
+    async fn delete(&self, user_id: &UserId, thought_id: &ThoughtId) -> Result<(), DomainError> {
+        let mut g = self.boosts.lock().unwrap();
+        let before = g.len();
+        g.retain(|b| !(&b.user_id == user_id && &b.thought_id == thought_id));
+        if g.len() == before {
+            return Err(DomainError::NotFound);
+        }
+        Ok(())
+    }
+    async fn find(
+        &self,
+        user_id: &UserId,
+        thought_id: &ThoughtId,
+    ) -> Result<Option<Boost>, DomainError> {
+        Ok(self
+            .boosts
+            .lock()
+            .unwrap()
+            .iter()
+            .find(|b| &b.user_id == user_id && &b.thought_id == thought_id)
+            .cloned())
+    }
+    async fn count_for_thought(&self, thought_id: &ThoughtId) -> Result<i64, DomainError> {
+        Ok(self
+            .boosts
+            .lock()
+            .unwrap()
+            .iter()
+            .filter(|b| &b.thought_id == thought_id)
+            .count() as i64)
+    }
+}
+
+#[async_trait]
+impl EngagementRepository for TestStore {
+    async fn get_for_thoughts(
+        &self,
+        thought_ids: &[ThoughtId],
+        viewer_id: Option<&UserId>,
+    ) -> Result<HashMap<ThoughtId, (crate::models::feed::EngagementStats, Option<crate::models::feed::ViewerContext>)>, DomainError> {
+        use crate::models::feed::{EngagementStats, ViewerContext};
+        let likes = self.likes.lock().unwrap();
+        let boosts = self.boosts.lock().unwrap();
+        let thoughts = self.thoughts.lock().unwrap();
+
+        let mut result = HashMap::new();
+        for tid in thought_ids {
+            let like_count = likes.iter().filter(|l| &l.thought_id == tid).count() as i64;
+            let boost_count = boosts.iter().filter(|b| &b.thought_id == tid).count() as i64;
+            let reply_count = thoughts.iter().filter(|t| t.in_reply_to_id.as_ref() == Some(tid)).count() as i64;
+            let viewer = viewer_id.map(|vid| ViewerContext {
+                liked: likes.iter().any(|l| &l.thought_id == tid && &l.user_id == vid),
+                boosted: boosts.iter().any(|b| &b.thought_id == tid && &b.user_id == vid),
+            });
+            result.insert(tid.clone(), (EngagementStats { like_count, boost_count, reply_count }, viewer));
+        }
+        Ok(result)
+    }
+}
+
+#[async_trait]
+impl FollowRepository for TestStore {
+    async fn save(&self, follow: &Follow) -> Result<(), DomainError> {
+        let mut g = self.follows.lock().unwrap();
+        g.retain(|f| {
+            !(f.follower_id == follow.follower_id && f.following_id == follow.following_id)
+        });
+        g.push(follow.clone());
+        Ok(())
+    }
+    async fn delete(&self, follower_id: &UserId, following_id: &UserId) -> Result<(), DomainError> {
+        let mut g = self.follows.lock().unwrap();
+        let before = g.len();
+        g.retain(|f| !(&f.follower_id == follower_id && &f.following_id == following_id));
+        if g.len() == before {
+            return Err(DomainError::NotFound);
+        }
+        Ok(())
+    }
+    async fn find(
+        &self,
+        follower_id: &UserId,
+        following_id: &UserId,
+    ) -> Result<Option<Follow>, DomainError> {
+        Ok(self
+            .follows
+            .lock()
+            .unwrap()
+            .iter()
+            .find(|f| &f.follower_id == follower_id && &f.following_id == following_id)
+            .cloned())
+    }
+    async fn update_state(
+        &self,
+        follower_id: &UserId,
+        following_id: &UserId,
+        state: &FollowState,
+    ) -> Result<(), DomainError> {
+        if let Some(f) = self
+            .follows
+            .lock()
+            .unwrap()
+            .iter_mut()
+            .find(|f| &f.follower_id == follower_id && &f.following_id == following_id)
+        {
+            f.state = state.clone();
+        }
+        Ok(())
+    }
+    async fn list_followers(
+        &self,
+        _user_id: &UserId,
+        _p: &PageParams,
+    ) -> Result<Paginated<User>, DomainError> {
+        Ok(Paginated {
+            items: vec![],
+            total: 0,
+            page: 1,
+            per_page: 20,
+        })
+    }
+    async fn list_following(
+        &self,
+        _user_id: &UserId,
+        _p: &PageParams,
+    ) -> Result<Paginated<User>, DomainError> {
+        Ok(Paginated {
+            items: vec![],
+            total: 0,
+            page: 1,
+            per_page: 20,
+        })
+    }
+    async fn get_accepted_following_ids(
+        &self,
+        user_id: &UserId,
+    ) -> Result<Vec<UserId>, DomainError> {
+        Ok(self
+            .follows
+            .lock()
+            .unwrap()
+            .iter()
+            .filter(|f| &f.follower_id == user_id && f.state == FollowState::Accepted)
+            .map(|f| f.following_id.clone())
+            .collect())
+    }
+}
+
+#[async_trait]
+impl BlockRepository for TestStore {
+    async fn save(&self, block: &Block) -> Result<(), DomainError> {
+        self.blocks.lock().unwrap().push(block.clone());
+        Ok(())
+    }
+    async fn delete(&self, blocker_id: &UserId, blocked_id: &UserId) -> Result<(), DomainError> {
+        self.blocks
+            .lock()
+            .unwrap()
+            .retain(|b| !(&b.blocker_id == blocker_id && &b.blocked_id == blocked_id));
+        Ok(())
+    }
+    async fn exists(&self, blocker_id: &UserId, blocked_id: &UserId) -> Result<bool, DomainError> {
+        Ok(self
+            .blocks
+            .lock()
+            .unwrap()
+            .iter()
+            .any(|b| &b.blocker_id == blocker_id && &b.blocked_id == blocked_id))
+    }
+}
+
+#[async_trait]
+impl TagRepository for TestStore {
+    async fn find_or_create(&self, name: &str) -> Result<Tag, DomainError> {
+        let mut g = self.tags.lock().unwrap();
+        if let Some(t) = g.iter().find(|t| t.name == name) {
+            return Ok(t.clone());
+        }
+        let tag = Tag {
+            id: g.len() as i32 + 1,
+            name: name.to_string(),
+        };
+        g.push(tag.clone());
+        Ok(tag)
+    }
+    async fn attach_to_thought(&self, _tid: &ThoughtId, _tag_id: i32) -> Result<(), DomainError> {
+        Ok(())
+    }
+    async fn detach_from_thought(&self, _tid: &ThoughtId) -> Result<(), DomainError> {
+        Ok(())
+    }
+    async fn list_for_thought(&self, _tid: &ThoughtId) -> Result<Vec<Tag>, DomainError> {
+        Ok(vec![])
+    }
+    async fn list_thoughts_by_tag(
+        &self,
+        _name: &str,
+        _p: &PageParams,
+    ) -> Result<Paginated<Thought>, DomainError> {
+        Ok(Paginated {
+            items: vec![],
+            total: 0,
+            page: 1,
+            per_page: 20,
+        })
+    }
+    async fn popular_tags(&self, _limit: usize) -> Result<Vec<(String, i64)>, DomainError> {
+        Ok(vec![])
+    }
+}
+
+#[async_trait]
+impl ApiKeyRepository for TestStore {
+    async fn save(&self, key: &ApiKey) -> Result<(), DomainError> {
+        self.api_keys.lock().unwrap().push(key.clone());
+        Ok(())
+    }
+    async fn find_by_hash(&self, hash: &str) -> Result<Option<ApiKey>, DomainError> {
+        Ok(self
+            .api_keys
+            .lock()
+            .unwrap()
+            .iter()
+            .find(|k| k.key_hash == hash)
+            .cloned())
+    }
+    async fn list_for_user(&self, uid: &UserId) -> Result<Vec<ApiKey>, DomainError> {
+        Ok(self
+            .api_keys
+            .lock()
+            .unwrap()
+            .iter()
+            .filter(|k| &k.user_id == uid)
+            .cloned()
+            .collect())
+    }
+    async fn delete(&self, id: &ApiKeyId, uid: &UserId) -> Result<(), DomainError> {
+        self.api_keys
+            .lock()
+            .unwrap()
+            .retain(|k| !(&k.id == id && &k.user_id == uid));
+        Ok(())
+    }
+}
+
+#[async_trait]
+impl ApiKeyService for TestStore {
+    async fn validate_key(&self, raw_key: &str) -> Result<Option<UserId>, DomainError> {
+        use sha2::{Digest, Sha256};
+        let hash = hex::encode(Sha256::digest(raw_key.as_bytes()));
+        Ok(self
+            .api_keys
+            .lock()
+            .unwrap()
+            .iter()
+            .find(|k| k.key_hash == hash)
+            .map(|k| k.user_id.clone()))
+    }
+}
+
+#[async_trait]
+impl TopFriendRepository for TestStore {
+    async fn set_top_friends(
+        &self,
+        user_id: &UserId,
+        friends: Vec<(UserId, i16)>,
+    ) -> Result<(), DomainError> {
+        let mut g = self.top_friends.lock().unwrap();
+        g.retain(|tf| &tf.user_id != user_id);
+        for (fid, pos) in friends {
+            g.push(TopFriend {
+                user_id: user_id.clone(),
+                friend_id: fid,
+                position: pos,
+            });
+        }
+        Ok(())
+    }
+    async fn list_for_user(&self, _uid: &UserId) -> Result<Vec<(TopFriend, User)>, DomainError> {
+        Ok(vec![])
+    }
+}
+
+#[async_trait]
+impl NotificationRepository for TestStore {
+    async fn save(&self, n: &Notification) -> Result<(), DomainError> {
+        self.notifications.lock().unwrap().push(n.clone());
+        Ok(())
+    }
+    async fn list_for_user(
+        &self,
+        uid: &UserId,
+        _p: &PageParams,
+    ) -> Result<Paginated<Notification>, DomainError> {
+        let items: Vec<_> = self
+            .notifications
+            .lock()
+            .unwrap()
+            .iter()
+            .filter(|n| &n.user_id == uid)
+            .cloned()
+            .collect();
+        let total = items.len() as i64;
+        Ok(Paginated {
+            items,
+            total,
+            page: 1,
+            per_page: 20,
+        })
+    }
+    async fn count_unread(&self, uid: &UserId) -> Result<u64, DomainError> {
+        Ok(self
+            .notifications
+            .lock()
+            .unwrap()
+            .iter()
+            .filter(|n| &n.user_id == uid && !n.read)
+            .count() as u64)
+    }
+    async fn mark_read(&self, id: &NotificationId, _uid: &UserId) -> Result<(), DomainError> {
+        if let Some(n) = self
+            .notifications
+            .lock()
+            .unwrap()
+            .iter_mut()
+            .find(|n| &n.id == id)
+        {
+            n.read = true;
+        }
+        Ok(())
+    }
+    async fn mark_all_read(&self, uid: &UserId) -> Result<(), DomainError> {
+        for n in self
+            .notifications
+            .lock()
+            .unwrap()
+            .iter_mut()
+            .filter(|n| &n.user_id == uid)
+        {
+            n.read = true;
+        }
+        Ok(())
+    }
+}
+
+#[async_trait]
+impl RemoteActorRepository for TestStore {
+    async fn upsert(&self, _a: &RemoteActor) -> Result<(), DomainError> {
+        Ok(())
+    }
+    async fn find_by_url(&self, _url: &str) -> Result<Option<RemoteActor>, DomainError> {
+        Ok(None)
+    }
+}
+
+#[async_trait]
+impl FederationLookupPort for TestStore {
+    async fn lookup_actor(&self, _handle: &str) -> Result<RemoteActor, DomainError> {
+        Err(DomainError::NotFound)
+    }
+
+    async fn actor_json(&self, _user_id: &UserId) -> Result<String, DomainError> {
+        Err(DomainError::NotFound)
+    }
+
+    async fn followers_collection_json(
+        &self,
+        _user_id: &UserId,
+        _page: Option<u32>,
+    ) -> Result<String, DomainError> {
+        Err(DomainError::NotFound)
+    }
+
+    async fn following_collection_json(
+        &self,
+        _user_id: &UserId,
+        _page: Option<u32>,
+    ) -> Result<String, DomainError> {
+        Err(DomainError::NotFound)
+    }
+}
+
+#[async_trait]
+impl FederationFollowPort for TestStore {
+    async fn follow_remote(
+        &self,
+        _local_user_id: &UserId,
+        _handle: &str,
+    ) -> Result<(), DomainError> {
+        Ok(())
+    }
+
+    async fn unfollow_remote(
+        &self,
+        _local_user_id: &UserId,
+        _handle: &str,
+    ) -> Result<(), DomainError> {
+        Ok(())
+    }
+
+    async fn get_remote_following(
+        &self,
+        _user_id: &UserId,
+    ) -> Result<Vec<RemoteActor>, DomainError> {
+        Ok(vec![])
+    }
+}
+
+#[async_trait]
+impl FederationFollowRequestPort for TestStore {
+    async fn get_pending_followers(
+        &self,
+        _user_id: &UserId,
+    ) -> Result<Vec<RemoteActor>, DomainError> {
+        Ok(vec![])
+    }
+
+    async fn accept_follow_request(
+        &self,
+        _user_id: &UserId,
+        _actor_url: &str,
+    ) -> Result<(), DomainError> {
+        Ok(())
+    }
+
+    async fn reject_follow_request(
+        &self,
+        _user_id: &UserId,
+        _actor_url: &str,
+    ) -> Result<(), DomainError> {
+        Ok(())
+    }
+
+    async fn get_remote_followers(
+        &self,
+        _user_id: &UserId,
+    ) -> Result<Vec<RemoteActor>, DomainError> {
+        Ok(vec![])
+    }
+
+    async fn remove_remote_follower(
+        &self,
+        _user_id: &UserId,
+        _actor_url: &str,
+    ) -> Result<(), DomainError> {
+        Ok(())
+    }
+}
+
+#[async_trait]
+impl FederationFetchPort for TestStore {
+    async fn fetch_outbox_page(
+        &self,
+        _outbox_url: &str,
+        _page: u32,
+    ) -> Result<Vec<crate::models::remote_note::RemoteNote>, DomainError> {
+        Ok(vec![])
+    }
+
+    async fn fetch_actor_urls_from_collection(
+        &self,
+        _collection_url: &str,
+    ) -> Result<Vec<String>, DomainError> {
+        Ok(vec![])
+    }
+
+    async fn resolve_actor_profiles(
+        &self,
+        _urls: Vec<String>,
+    ) -> Vec<crate::models::actor_connection_summary::ActorConnectionSummary> {
+        vec![]
+    }
+}
+
+#[async_trait]
+impl RemoteActorConnectionRepository for TestStore {
+    async fn upsert_connections(
+        &self,
+        _actor_url: &str,
+        _connection_type: &str,
+        _page: u32,
+        _actors: &[crate::models::actor_connection_summary::ActorConnectionSummary],
+    ) -> Result<(), DomainError> {
+        Ok(())
+    }
+
+    async fn list_connections(
+        &self,
+        _actor_url: &str,
+        _connection_type: &str,
+        _page: u32,
+    ) -> Result<Vec<crate::models::actor_connection_summary::ActorConnectionSummary>, DomainError>
+    {
+        Ok(vec![])
+    }
+
+    async fn connection_page_age(
+        &self,
+        _actor_url: &str,
+        _connection_type: &str,
+        _page: u32,
+    ) -> Result<Option<chrono::DateTime<chrono::Utc>>, DomainError> {
+        Ok(None)
+    }
+}
+
+#[async_trait]
+impl FeedRepository for TestStore {
+    async fn query(&self, _q: &crate::ports::FeedQuery) -> Result<Paginated<FeedEntry>, DomainError> {
+        Ok(Paginated {
+            items: vec![],
+            total: 0,
+            page: 1,
+            per_page: 20,
+        })
+    }
+}
+
+#[async_trait]
+impl SearchPort for TestStore {
+    async fn search_thoughts(
+        &self,
+        _q: &str,
+        _p: &PageParams,
+        _v: Option<&UserId>,
+    ) -> Result<Paginated<FeedEntry>, DomainError> {
+        Ok(Paginated {
+            items: vec![],
+            total: 0,
+            page: 1,
+            per_page: 20,
+        })
+    }
+    async fn search_users(
+        &self,
+        _q: &str,
+        _p: &PageParams,
+    ) -> Result<Paginated<User>, DomainError> {
+        Ok(Paginated {
+            items: vec![],
+            total: 0,
+            page: 1,
+            per_page: 20,
+        })
+    }
+}
+
+
+#[async_trait]
+impl FederationSchedulerPort for TestStore {
+    async fn schedule_actor_posts_fetch(&self, _: &str, _: &str) -> Result<(), DomainError> {
+        Ok(())
+    }
+    async fn schedule_connections_fetch(
+        &self,
+        _: &str,
+        _: &str,
+        _: &str,
+        _: u32,
+    ) -> Result<(), DomainError> {
+        Ok(())
+    }
+}
+
+#[async_trait]
+impl EventPublisher for TestStore {
+    async fn publish(&self, event: &DomainEvent) -> Result<(), DomainError> {
+        self.events.lock().unwrap().push(event.clone());
+        Ok(())
+    }
+}
+
+pub struct NoOpEventPublisher;
+#[async_trait]
+impl EventPublisher for NoOpEventPublisher {
+    async fn publish(&self, _e: &DomainEvent) -> Result<(), DomainError> {
+        Ok(())
+    }
+}
+
+#[derive(Default, Clone)]
+pub struct TestOutbox {
+    pub entries: Arc<Mutex<Vec<DomainEvent>>>,
+}
+
+impl TestOutbox {
+    pub fn staged(&self) -> Vec<DomainEvent> {
+        self.entries.lock().unwrap().clone()
+    }
+}
+
+#[async_trait]
+impl OutboxWriter for TestOutbox {
+    async fn append(&self, event: &DomainEvent) -> Result<(), DomainError> {
+        self.entries.lock().unwrap().push(event.clone());
+        Ok(())
+    }
+}
+
+pub struct NoOpOutboxWriter;
+#[async_trait]
+impl OutboxWriter for NoOpOutboxWriter {
+    async fn append(&self, _e: &DomainEvent) -> Result<(), DomainError> {
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod federation_port_tests {
+    use super::*;
+    use crate::value_objects::UserId;
+
+    fn uid() -> UserId {
+        UserId::new()
+    }
+
+    #[tokio::test]
+    async fn test_store_lookup_returns_not_found() {
+        let store = TestStore::default();
+        let err = store.lookup_actor("@alice@example.com").await.unwrap_err();
+        assert!(matches!(err, DomainError::NotFound));
+    }
+
+    #[tokio::test]
+    async fn test_store_follow_remote_is_noop_ok() {
+        let store = TestStore::default();
+        store
+            .follow_remote(&uid(), "@alice@example.com")
+            .await
+            .unwrap();
+    }
+
+    #[tokio::test]
+    async fn test_store_actor_json_returns_not_found() {
+        let store = TestStore::default();
+        let err = store.actor_json(&UserId::new()).await.unwrap_err();
+        assert!(matches!(err, DomainError::NotFound));
+    }
+
+    #[tokio::test]
+    async fn test_store_fetch_outbox_returns_empty() {
+        let store = TestStore::default();
+        let notes = store
+            .fetch_outbox_page("https://example.com/outbox", 1)
+            .await
+            .unwrap();
+        assert!(notes.is_empty());
+    }
+
+    #[tokio::test]
+    async fn test_store_resolve_actor_profiles_returns_empty() {
+        let store = TestStore::default();
+        let result = store
+            .resolve_actor_profiles(vec!["https://example.com/users/alice".into()])
+            .await;
+        assert!(result.is_empty());
+    }
+
+    #[tokio::test]
+    async fn test_store_fetch_collection_urls_returns_empty() {
+        let store = TestStore::default();
+        let urls = store
+            .fetch_actor_urls_from_collection("https://example.com/users/alice/followers")
+            .await
+            .unwrap();
+        assert!(urls.is_empty());
+    }
+}
+
+#[cfg(test)]
+mod search_tests {
+    use super::*;
+    use crate::models::feed::PageParams;
+
+    #[tokio::test]
+    async fn test_store_search_thoughts_returns_empty() {
+        let store = TestStore::default();
+        let result = store
+            .search_thoughts(
+                "hello",
+                &PageParams {
+                    page: 1,
+                    per_page: 20,
+                },
+                None,
+            )
+            .await
+            .unwrap();
+        assert_eq!(result.total, 0);
+    }
+
+    #[tokio::test]
+    async fn test_store_search_users_returns_empty() {
+        let store = TestStore::default();
+        let result = store
+            .search_users(
+                "alice",
+                &PageParams {
+                    page: 1,
+                    per_page: 20,
+                },
+            )
+            .await
+            .unwrap();
+        assert_eq!(result.total, 0);
+    }
+}

crates/domain/src/value_objects.rs

@@ -0,0 +1,150 @@
+use crate::errors::DomainError;
+use uuid::Uuid;
+
+const MAX_USERNAME_LENGTH: usize = 32;
+const MAX_EMAIL_LENGTH: usize = 255;
+const MAX_CONTENT_LENGTH: usize = 128;
+
+macro_rules! uuid_id {
+    ($name:ident) => {
+        #[derive(Debug, Clone, PartialEq, Eq, Hash, serde::Serialize, serde::Deserialize)]
+        pub struct $name(Uuid);
+        impl $name {
+            pub fn new() -> Self {
+                Self(Uuid::new_v4())
+            }
+            pub fn from_uuid(u: Uuid) -> Self {
+                Self(u)
+            }
+            pub fn as_uuid(&self) -> Uuid {
+                self.0
+            }
+        }
+        impl Default for $name {
+            fn default() -> Self {
+                Self::new()
+            }
+        }
+        impl std::fmt::Display for $name {
+            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+                write!(f, "{}", self.0)
+            }
+        }
+    };
+}
+
+uuid_id!(UserId);
+uuid_id!(ThoughtId);
+uuid_id!(LikeId);
+uuid_id!(BoostId);
+uuid_id!(ApiKeyId);
+uuid_id!(NotificationId);
+
+#[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
+pub struct Username(String);
+impl Username {
+    pub fn new(s: impl Into<String>) -> Result<Self, DomainError> {
+        let s = s.into();
+        if s.is_empty() || s.len() > MAX_USERNAME_LENGTH {
+            return Err(DomainError::InvalidInput("username: 1-32 chars".into()));
+        }
+        if !s
+            .chars()
+            .all(|c| c.is_alphanumeric() || c == '_' || c == '.')
+        {
+            return Err(DomainError::InvalidInput(
+                "username: alphanumeric, underscore, or dot only".into(),
+            ));
+        }
+        Ok(Self(s))
+    }
+    pub fn from_trusted(s: String) -> Self {
+        Self(s)
+    }
+    pub fn as_str(&self) -> &str {
+        &self.0
+    }
+}
+impl std::fmt::Display for Username {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
+pub struct Email(String);
+impl Email {
+    pub fn new(s: impl Into<String>) -> Result<Self, DomainError> {
+        let s = s.into().to_lowercase();
+        if !s.contains('@') || s.len() > MAX_EMAIL_LENGTH {
+            return Err(DomainError::InvalidInput("invalid email".into()));
+        }
+        Ok(Self(s))
+    }
+    pub fn from_trusted(s: String) -> Self {
+        Self(s)
+    }
+    pub fn as_str(&self) -> &str {
+        &self.0
+    }
+}
+
+#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
+pub struct PasswordHash(pub String);
+
+#[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
+pub struct Content(String);
+impl Content {
+    pub fn new_local(s: impl Into<String>) -> Result<Self, DomainError> {
+        let s = s.into();
+        if s.is_empty() || s.len() > MAX_CONTENT_LENGTH {
+            return Err(DomainError::InvalidInput("content: 1-128 chars".into()));
+        }
+        Ok(Self(s))
+    }
+    pub fn new_remote(s: impl Into<String>) -> Self {
+        Self(s.into())
+    }
+    pub fn as_str(&self) -> &str {
+        &self.0
+    }
+}
+impl std::fmt::Display for Content {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn username_rejects_empty() {
+        assert!(Username::new("").is_err());
+    }
+    #[test]
+    fn username_rejects_too_long() {
+        assert!(Username::new("a".repeat(33)).is_err());
+    }
+    #[test]
+    fn username_rejects_invalid_chars() {
+        assert!(Username::new("hello world").is_err());
+    }
+    #[test]
+    fn username_accepts_valid() {
+        assert!(Username::new("hello_123").is_ok());
+    }
+    #[test]
+    fn content_local_rejects_over_128() {
+        assert!(Content::new_local("a".repeat(129)).is_err());
+    }
+    #[test]
+    fn content_local_accepts_128() {
+        assert!(Content::new_local("a".repeat(128)).is_ok());
+    }
+    #[test]
+    fn email_rejects_no_at() {
+        assert!(Email::new("notanemail").is_err());
+    }
+}