Provide a view of logins to clients.

27 files changed, 417 insertions, 151 deletions

diff --git a/src/app.rs b/src/app.rs
index 6d007a9..177c134 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -3,9 +3,9 @@ use sqlx::sqlite::SqlitePool;
 use crate::{
     boot::app::Boot,
     channel::app::Channels,
-    event::{app::Events, broadcaster::Broadcaster as EventBroadcaster},
+    event::{self, app::Events},
     message::app::Messages,
-    token::{app::Tokens, broadcaster::Broadcaster as TokenBroadcaster},
+    token::{self, app::Tokens},
 };
 
 #[cfg(test)]
@@ -14,15 +14,19 @@ use crate::login::app::Logins;
 #[derive(Clone)]
 pub struct App {
     db: SqlitePool,
-    events: EventBroadcaster,
-    tokens: TokenBroadcaster,
+    events: event::Broadcaster,
+    token_events: token::Broadcaster,
 }
 
 impl App {
     pub fn from(db: SqlitePool) -> Self {
-        let events = EventBroadcaster::default();
-        let tokens = TokenBroadcaster::default();
-        Self { db, events, tokens }
+        let events = event::Broadcaster::default();
+        let token_events = token::Broadcaster::default();
+        Self {
+            db,
+            events,
+            token_events,
+        }
     }
 }
 
@@ -41,7 +45,7 @@ impl App {
 
     #[cfg(test)]
     pub const fn logins(&self) -> Logins {
-        Logins::new(&self.db)
+        Logins::new(&self.db, &self.events)
     }
 
     pub const fn messages(&self) -> Messages {
@@ -49,6 +53,6 @@ impl App {
     }
 
     pub const fn tokens(&self) -> Tokens {
-        Tokens::new(&self.db, &self.tokens)
+        Tokens::new(&self.db, &self.events, &self.token_events)
     }
 }
diff --git a/src/boot/app.rs b/src/boot/app.rs
index fc84b3a..03e7230 100644
--- a/src/boot/app.rs
+++ b/src/boot/app.rs
@@ -2,7 +2,8 @@ use sqlx::sqlite::SqlitePool;
 
 use super::{Channel, Snapshot};
 use crate::{
-    channel::repo::Provider as _, event::repo::Provider as _, message::repo::Provider as _,
+    channel::repo::Provider as _, event::repo::Provider as _, login::repo::Provider as _,
+    message::repo::Provider as _,
 };
 
 pub struct Boot<'a> {
@@ -17,8 +18,14 @@ impl<'a> Boot<'a> {
     pub async fn snapshot(&self) -> Result<Snapshot, sqlx::Error> {
         let mut tx = self.db.begin().await?;
         let resume_point = tx.sequence().current().await?;
-        let channels = tx.channels().all(resume_point.into()).await?;
 
+        let logins = tx.logins().all(resume_point.into()).await?;
+        let logins = logins
+            .into_iter()
+            .filter_map(|login| login.as_of(resume_point))
+            .collect();
+
+        let channels = tx.channels().all(resume_point.into()).await?;
         let channels = {
             let mut snapshots = Vec::with_capacity(channels.len());
 
@@ -48,6 +55,7 @@ impl<'a> Boot<'a> {
 
         Ok(Snapshot {
             resume_point,
+            logins,
             channels,
         })
     }
diff --git a/src/boot/mod.rs b/src/boot/mod.rs
index a68acac..1f94106 100644
--- a/src/boot/mod.rs
+++ b/src/boot/mod.rs
@@ -4,7 +4,7 @@ mod routes;
 use crate::{
     channel,
     event::{Instant, Sequence},
-    login::Login,
+    login::{self, Login},
     message,
 };
 
@@ -13,6 +13,7 @@ pub use self::routes::router;
 #[derive(serde::Serialize)]
 pub struct Snapshot {
     pub resume_point: Sequence,
+    pub logins: Vec<Login>,
     pub channels: Vec<Channel>,
 }
 
@@ -43,7 +44,7 @@ impl Channel {
 pub struct Message {
     #[serde(flatten)]
     pub sent: Instant,
-    pub sender: Login,
+    pub sender: login::Id,
     pub id: message::Id,
     pub body: String,
 }
diff --git a/src/channel/app.rs b/src/channel/app.rs
index a9a9e84..cb7ad32 100644
--- a/src/channel/app.rs
+++ b/src/channel/app.rs
@@ -6,7 +6,7 @@ use super::{repo::Provider as _, Channel, Id};
 use crate::{
     clock::DateTime,
     db::NotFound,
-    event::{broadcaster::Broadcaster, repo::Provider as _, Event, Sequence},
+    event::{repo::Provider as _, Broadcaster, Event, Sequence},
     message::repo::Provider as _,
 };
 
diff --git a/src/channel/routes/test/on_create.rs b/src/channel/routes/test/on_create.rs
index 8c3c62b..eeecc7f 100644
--- a/src/channel/routes/test/on_create.rs
+++ b/src/channel/routes/test/on_create.rs
@@ -12,7 +12,7 @@ async fn new_channel() {
     // Set up the environment
 
     let app = fixtures::scratch_app().await;
-    let creator = fixtures::login::create(&app).await;
+    let creator = fixtures::login::create(&app, &fixtures::now()).await;
 
     // Call the endpoint
 
@@ -64,7 +64,7 @@ async fn duplicate_name() {
     // Set up the environment
 
     let app = fixtures::scratch_app().await;
-    let creator = fixtures::login::create(&app).await;
+    let creator = fixtures::login::create(&app, &fixtures::now()).await;
     let channel = fixtures::channel::create(&app, &fixtures::now()).await;
 
     // Call the endpoint
diff --git a/src/channel/routes/test/on_send.rs b/src/channel/routes/test/on_send.rs
index d2acc48..3fe3d1e 100644
--- a/src/channel/routes/test/on_send.rs
+++ b/src/channel/routes/test/on_send.rs
@@ -14,7 +14,7 @@ async fn messages_in_order() {
     // Set up the environment
 
     let app = fixtures::scratch_app().await;
-    let sender = fixtures::login::create(&app).await;
+    let sender = fixtures::login::create(&app, &fixtures::now()).await;
     let channel = fixtures::channel::create(&app, &fixtures::now()).await;
 
     // Call the endpoint (twice)
@@ -57,7 +57,7 @@ async fn messages_in_order() {
         assert!(matches!(
             event,
             event::Event::Message(message::Event::Sent(event))
-                if event.message.sender == sender
+                if event.message.sender == sender.id
                     && event.message.body == message
         ));
     }
@@ -68,7 +68,7 @@ async fn nonexistent_channel() {
     // Set up the environment
 
     let app = fixtures::scratch_app().await;
-    let login = fixtures::login::create(&app).await;
+    let login = fixtures::login::create(&app, &fixtures::now()).await;
 
     // Call the endpoint
 
diff --git a/src/event/app.rs b/src/event/app.rs
index 141037d..951ce25 100644
--- a/src/event/app.rs
+++ b/src/event/app.rs
@@ -9,6 +9,7 @@ use sqlx::sqlite::SqlitePool;
 use super::{broadcaster::Broadcaster, Event, ResumePoint, Sequence, Sequenced};
 use crate::{
     channel::{self, repo::Provider as _},
+    login::{self, repo::Provider as _},
     message::{self, repo::Provider as _},
 };
 
@@ -33,6 +34,14 @@ impl<'a> Events<'a> {
 
         let mut tx = self.db.begin().await?;
 
+        let logins = tx.logins().replay(resume_at).await?;
+        let login_events = logins
+            .iter()
+            .map(login::History::events)
+            .kmerge_by(Sequence::merge)
+            .filter(Sequence::after(resume_at))
+            .map(Event::from);
+
         let channels = tx.channels().replay(resume_at).await?;
         let channel_events = channels
             .iter()
@@ -49,7 +58,8 @@ impl<'a> Events<'a> {
             .filter(Sequence::after(resume_at))
             .map(Event::from);
 
-        let replay_events = channel_events
+        let replay_events = login_events
+            .merge_by(channel_events, Sequence::merge)
             .merge_by(message_events, Sequence::merge)
             .collect::<Vec<_>>();
         let resume_live_at = replay_events.last().map(Sequenced::sequence);
diff --git a/src/event/mod.rs b/src/event/mod.rs
index 698e55a..69c7a10 100644
--- a/src/event/mod.rs
+++ b/src/event/mod.rs
@@ -1,13 +1,14 @@
-use crate::{channel, message};
+use crate::{channel, login, message};
 
 pub mod app;
-pub mod broadcaster;
+mod broadcaster;
 mod extract;
 pub mod repo;
 mod routes;
 mod sequence;
 
 pub use self::{
+    broadcaster::Broadcaster,
     routes::router,
     sequence::{Instant, Sequence, Sequenced},
 };
@@ -17,6 +18,7 @@ pub type ResumePoint = Option<Sequence>;
 #[derive(Clone, Debug, Eq, PartialEq, serde::Serialize)]
 #[serde(tag = "type", rename_all = "snake_case")]
 pub enum Event {
+    Login(login::Event),
     Channel(channel::Event),
     Message(message::Event),
 }
@@ -24,12 +26,19 @@ pub enum Event {
 impl Sequenced for Event {
     fn instant(&self) -> Instant {
         match self {
+            Self::Login(event) => event.instant(),
             Self::Channel(event) => event.instant(),
             Self::Message(event) => event.instant(),
         }
     }
 }
 
+impl From<login::Event> for Event {
+    fn from(event: login::Event) -> Self {
+        Self::Login(event)
+    }
+}
+
 impl From<channel::Event> for Event {
     fn from(event: channel::Event) -> Self {
         Self::Channel(event)
diff --git a/src/event/routes/test.rs b/src/event/routes/test.rs
index ba9953e..209a016 100644
--- a/src/event/routes/test.rs
+++ b/src/event/routes/test.rs
@@ -15,13 +15,13 @@ async fn includes_historical_message() {
     // Set up the environment
 
     let app = fixtures::scratch_app().await;
-    let sender = fixtures::login::create(&app).await;
+    let sender = fixtures::login::create(&app, &fixtures::now()).await;
     let channel = fixtures::channel::create(&app, &fixtures::now()).await;
     let message = fixtures::message::send(&app, &channel, &sender, &fixtures::now()).await;
 
     // Call the endpoint
 
-    let subscriber_creds = fixtures::login::create_with_password(&app).await;
+    let subscriber_creds = fixtures::login::create_with_password(&app, &fixtures::now()).await;
     let subscriber = fixtures::identity::identity(&app, &subscriber_creds, &fixtures::now()).await;
     let routes::Events(events) = routes::events(State(app), subscriber, None, Query::default())
         .await
@@ -48,7 +48,7 @@ async fn includes_live_message() {
 
     // Call the endpoint
 
-    let subscriber_creds = fixtures::login::create_with_password(&app).await;
+    let subscriber_creds = fixtures::login::create_with_password(&app, &fixtures::now()).await;
     let subscriber = fixtures::identity::identity(&app, &subscriber_creds, &fixtures::now()).await;
     let routes::Events(events) =
         routes::events(State(app.clone()), subscriber, None, Query::default())
@@ -57,7 +57,7 @@ async fn includes_live_message() {
 
     // Verify the semantics
 
-    let sender = fixtures::login::create(&app).await;
+    let sender = fixtures::login::create(&app, &fixtures::now()).await;
     let message = fixtures::message::send(&app, &channel, &sender, &fixtures::now()).await;
 
     let event = events
@@ -75,7 +75,7 @@ async fn includes_multiple_channels() {
     // Set up the environment
 
     let app = fixtures::scratch_app().await;
-    let sender = fixtures::login::create(&app).await;
+    let sender = fixtures::login::create(&app, &fixtures::now()).await;
 
     let channels = [
         fixtures::channel::create(&app, &fixtures::now()).await,
@@ -94,7 +94,7 @@ async fn includes_multiple_channels() {
 
     // Call the endpoint
 
-    let subscriber_creds = fixtures::login::create_with_password(&app).await;
+    let subscriber_creds = fixtures::login::create_with_password(&app, &fixtures::now()).await;
     let subscriber = fixtures::identity::identity(&app, &subscriber_creds, &fixtures::now()).await;
     let routes::Events(events) = routes::events(State(app), subscriber, None, Query::default())
         .await
@@ -122,7 +122,7 @@ async fn sequential_messages() {
 
     let app = fixtures::scratch_app().await;
     let channel = fixtures::channel::create(&app, &fixtures::now()).await;
-    let sender = fixtures::login::create(&app).await;
+    let sender = fixtures::login::create(&app, &fixtures::now()).await;
 
     let messages = vec![
         fixtures::message::send(&app, &channel, &sender, &fixtures::now()).await,
@@ -132,7 +132,7 @@ async fn sequential_messages() {
 
     // Call the endpoint
 
-    let subscriber_creds = fixtures::login::create_with_password(&app).await;
+    let subscriber_creds = fixtures::login::create_with_password(&app, &fixtures::now()).await;
     let subscriber = fixtures::identity::identity(&app, &subscriber_creds, &fixtures::now()).await;
     let routes::Events(events) = routes::events(State(app), subscriber, None, Query::default())
         .await
@@ -166,7 +166,7 @@ async fn resumes_from() {
 
     let app = fixtures::scratch_app().await;
     let channel = fixtures::channel::create(&app, &fixtures::now()).await;
-    let sender = fixtures::login::create(&app).await;
+    let sender = fixtures::login::create(&app, &fixtures::now()).await;
 
     let initial_message = fixtures::message::send(&app, &channel, &sender, &fixtures::now()).await;
 
@@ -177,7 +177,7 @@ async fn resumes_from() {
 
     // Call the endpoint
 
-    let subscriber_creds = fixtures::login::create_with_password(&app).await;
+    let subscriber_creds = fixtures::login::create_with_password(&app, &fixtures::now()).await;
     let subscriber = fixtures::identity::identity(&app, &subscriber_creds, &fixtures::now()).await;
 
     let resume_at = {
@@ -248,13 +248,13 @@ async fn serial_resume() {
     // Set up the environment
 
     let app = fixtures::scratch_app().await;
-    let sender = fixtures::login::create(&app).await;
+    let sender = fixtures::login::create(&app, &fixtures::now()).await;
     let channel_a = fixtures::channel::create(&app, &fixtures::now()).await;
     let channel_b = fixtures::channel::create(&app, &fixtures::now()).await;
 
     // Call the endpoint
 
-    let subscriber_creds = fixtures::login::create_with_password(&app).await;
+    let subscriber_creds = fixtures::login::create_with_password(&app, &fixtures::now()).await;
     let subscriber = fixtures::identity::identity(&app, &subscriber_creds, &fixtures::now()).await;
 
     let resume_at = {
@@ -372,11 +372,11 @@ async fn terminates_on_token_expiry() {
 
     let app = fixtures::scratch_app().await;
     let channel = fixtures::channel::create(&app, &fixtures::now()).await;
-    let sender = fixtures::login::create(&app).await;
+    let sender = fixtures::login::create(&app, &fixtures::now()).await;
 
     // Subscribe via the endpoint
 
-    let subscriber_creds = fixtures::login::create_with_password(&app).await;
+    let subscriber_creds = fixtures::login::create_with_password(&app, &fixtures::now()).await;
     let subscriber =
         fixtures::identity::identity(&app, &subscriber_creds, &fixtures::ancient()).await;
 
@@ -417,11 +417,11 @@ async fn terminates_on_logout() {
 
     let app = fixtures::scratch_app().await;
     let channel = fixtures::channel::create(&app, &fixtures::now()).await;
-    let sender = fixtures::login::create(&app).await;
+    let sender = fixtures::login::create(&app, &fixtures::now()).await;
 
     // Subscribe via the endpoint
 
-    let subscriber_creds = fixtures::login::create_with_password(&app).await;
+    let subscriber_creds = fixtures::login::create_with_password(&app, &fixtures::now()).await;
     let subscriber_token =
         fixtures::identity::logged_in(&app, &subscriber_creds, &fixtures::now()).await;
     let subscriber =
diff --git a/src/login/app.rs b/src/login/app.rs
index 4f60b89..bb1419b 100644
--- a/src/login/app.rs
+++ b/src/login/app.rs
@@ -1,24 +1,38 @@
 use sqlx::sqlite::SqlitePool;
 
 use super::{repo::Provider as _, Login, Password};
+use crate::{
+    clock::DateTime,
+    event::{repo::Provider as _, Broadcaster, Event},
+};
 
 pub struct Logins<'a> {
     db: &'a SqlitePool,
+    events: &'a Broadcaster,
 }
 
 impl<'a> Logins<'a> {
-    pub const fn new(db: &'a SqlitePool) -> Self {
-        Self { db }
+    pub const fn new(db: &'a SqlitePool, events: &'a Broadcaster) -> Self {
+        Self { db, events }
     }
 
-    pub async fn create(&self, name: &str, password: &Password) -> Result<Login, CreateError> {
+    pub async fn create(
+        &self,
+        name: &str,
+        password: &Password,
+        created_at: &DateTime,
+    ) -> Result<Login, CreateError> {
         let password_hash = password.hash()?;
 
         let mut tx = self.db.begin().await?;
-        let login = tx.logins().create(name, &password_hash).await?;
+        let created = tx.sequence().next(created_at).await?;
+        let login = tx.logins().create(name, &password_hash, &created).await?;
         tx.commit().await?;
 
-        Ok(login)
+        self.events
+            .broadcast(login.events().map(Event::from).collect::<Vec<_>>());
+
+        Ok(login.as_created())
     }
 }
 
diff --git a/src/login/event.rs b/src/login/event.rs
new file mode 100644
index 0000000..b03451a
--- /dev/null
+++ b/src/login/event.rs
@@ -0,0 +1,36 @@
+use super::snapshot::Login;
+use crate::event::{Instant, Sequenced};
+
+#[derive(Clone, Debug, Eq, PartialEq, serde::Serialize)]
+#[serde(tag = "event", rename_all = "snake_case")]
+pub enum Event {
+    Created(Created),
+}
+
+impl Sequenced for Event {
+    fn instant(&self) -> Instant {
+        match self {
+            Self::Created(created) => created.instant(),
+        }
+    }
+}
+
+#[derive(Clone, Debug, Eq, PartialEq, serde::Serialize)]
+pub struct Created {
+    #[serde(flatten)]
+    pub instant: Instant,
+    #[serde(flatten)]
+    pub login: Login,
+}
+
+impl Sequenced for Created {
+    fn instant(&self) -> Instant {
+        self.instant
+    }
+}
+
+impl From<Created> for Event {
+    fn from(event: Created) -> Self {
+        Self::Created(event)
+    }
+}
diff --git a/src/login/history.rs b/src/login/history.rs
new file mode 100644
index 0000000..add7d1e
--- /dev/null
+++ b/src/login/history.rs
@@ -0,0 +1,47 @@
+use super::{
+    event::{Created, Event},
+    Id, Login,
+};
+use crate::event::{Instant, ResumePoint, Sequence};
+
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct History {
+    pub login: Login,
+    pub created: Instant,
+}
+
+// State interface
+impl History {
+    pub fn id(&self) -> &Id {
+        &self.login.id
+    }
+
+    // Snapshot of this login as it was when created. (Note to the future: it's okay
+    // if this returns a redacted or modified version of the login. If we  implement
+    // renames by redacting the original name, then this should return the edited login, not the original, even if that's not how it was "as created.")
+    #[cfg(test)]
+    pub fn as_created(&self) -> Login {
+        self.login.clone()
+    }
+
+    pub fn as_of(&self, resume_point: impl Into<ResumePoint>) -> Option<Login> {
+        self.events()
+            .filter(Sequence::up_to(resume_point.into()))
+            .collect()
+    }
+}
+
+// Events interface
+impl History {
+    fn created(&self) -> Event {
+        Created {
+            instant: self.created,
+            login: self.login.clone(),
+        }
+        .into()
+    }
+
+    pub fn events(&self) -> impl Iterator<Item = Event> {
+        [self.created()].into_iter()
+    }
+}
diff --git a/src/login/mod.rs b/src/login/mod.rs
index f272f80..98cc3d7 100644
--- a/src/login/mod.rs
+++ b/src/login/mod.rs
@@ -1,22 +1,14 @@
 #[cfg(test)]
 pub mod app;
+pub mod event;
 pub mod extract;
+mod history;
 mod id;
 pub mod password;
 pub mod repo;
 mod routes;
+mod snapshot;
 
-pub use self::{id::Id, password::Password, routes::router};
-
-// This also implements FromRequestParts (see `./extract.rs`). As a result, it
-// can be used as an extractor for endpoints that want to require login, or for
-// endpoints that need to behave differently depending on whether the client is
-// or is not logged in.
-#[derive(Clone, Debug, Eq, PartialEq, serde::Serialize)]
-pub struct Login {
-    pub id: Id,
-    pub name: String,
-    // The omission of the hashed password is deliberate, to minimize the
-    // chance that it ends up tangled up in debug output or in some other chunk
-    // of logic elsewhere.
-}
+pub use self::{
+    event::Event, history::History, id::Id, password::Password, routes::router, snapshot::Login,
+};
diff --git a/src/login/repo.rs b/src/login/repo.rs
index d1a02c4..6d6510c 100644
--- a/src/login/repo.rs
+++ b/src/login/repo.rs
@@ -1,6 +1,10 @@
 use sqlx::{sqlite::Sqlite, SqliteConnection, Transaction};
 
-use crate::login::{password::StoredHash, Id, Login};
+use crate::{
+    clock::DateTime,
+    event::{Instant, ResumePoint, Sequence},
+    login::{password::StoredHash, History, Id, Login},
+};
 
 pub trait Provider {
     fn logins(&mut self) -> Logins;
@@ -19,28 +23,100 @@ impl<'c> Logins<'c> {
         &mut self,
         name: &str,
         password_hash: &StoredHash,
-    ) -> Result<Login, sqlx::Error> {
+        created: &Instant,
+    ) -> Result<History, sqlx::Error> {
         let id = Id::generate();
 
-        let login = sqlx::query_as!(
-            Login,
+        let login = sqlx::query!(
             r#"
-                insert or fail
-                into login (id, name, password_hash)
-                values ($1, $2, $3)
+                insert
+                into login (id, name, password_hash, created_sequence, created_at)
+                values ($1, $2, $3, $4, $5)
                 returning
                     id as "id: Id",
-                    name
+                    name,
+                    created_sequence as "created_sequence: Sequence",
+                    created_at as "created_at: DateTime"
             "#,
             id,
             name,
             password_hash,
+            created.sequence,
+            created.at,
         )
+        .map(|row| History {
+            login: Login {
+                id: row.id,
+                name: row.name,
+            },
+            created: Instant {
+                at: row.created_at,
+                sequence: row.created_sequence,
+            },
+        })
         .fetch_one(&mut *self.0)
         .await?;
 
         Ok(login)
     }
+
+    pub async fn all(&mut self, resume_at: ResumePoint) -> Result<Vec<History>, sqlx::Error> {
+        let channels = sqlx::query!(
+            r#"
+                select
+                    id as "id: Id",
+                    name,
+                    created_sequence as "created_sequence: Sequence",
+                    created_at as "created_at: DateTime"
+                from login
+                    where coalesce(created_sequence <= $1, true)
+                    order by created_sequence
+            "#,
+            resume_at,
+        )
+        .map(|row| History {
+            login: Login {
+                id: row.id,
+                name: row.name,
+            },
+            created: Instant {
+                at: row.created_at,
+                sequence: row.created_sequence,
+            },
+        })
+        .fetch_all(&mut *self.0)
+        .await?;
+
+        Ok(channels)
+    }
+    pub async fn replay(&mut self, resume_at: ResumePoint) -> Result<Vec<History>, sqlx::Error> {
+        let messages = sqlx::query!(
+            r#"
+                select
+                    id as "id: Id",
+                    name,
+                    created_sequence as "created_sequence: Sequence",
+                    created_at as "created_at: DateTime"
+                from login
+                where coalesce(login.created_sequence > $1, true)
+            "#,
+            resume_at,
+        )
+        .map(|row| History {
+            login: Login {
+                id: row.id,
+                name: row.name,
+            },
+            created: Instant {
+                at: row.created_at,
+                sequence: row.created_sequence,
+            },
+        })
+        .fetch_all(&mut *self.0)
+        .await?;
+
+        Ok(messages)
+    }
 }
 
 impl<'t> From<&'t mut SqliteConnection> for Logins<'t> {
diff --git a/src/login/routes/test/login.rs b/src/login/routes/test/login.rs
index 3c82738..6a3b79c 100644
--- a/src/login/routes/test/login.rs
+++ b/src/login/routes/test/login.rs
@@ -47,7 +47,7 @@ async fn existing_identity() {
     // Set up the environment
 
     let app = fixtures::scratch_app().await;
-    let (name, password) = fixtures::login::create_with_password(&app).await;
+    let (name, password) = fixtures::login::create_with_password(&app, &fixtures::now()).await;
 
     // Call the endpoint
 
@@ -84,7 +84,7 @@ async fn authentication_failed() {
     // Set up the environment
 
     let app = fixtures::scratch_app().await;
-    let login = fixtures::login::create(&app).await;
+    let login = fixtures::login::create(&app, &fixtures::now()).await;
 
     // Call the endpoint
 
@@ -109,7 +109,7 @@ async fn token_expires() {
     // Set up the environment
 
     let app = fixtures::scratch_app().await;
-    let (name, password) = fixtures::login::create_with_password(&app).await;
+    let (name, password) = fixtures::login::create_with_password(&app, &fixtures::now()).await;
 
     // Call the endpoint
 
diff --git a/src/login/routes/test/logout.rs b/src/login/routes/test/logout.rs
index 42b2534..611829e 100644
--- a/src/login/routes/test/logout.rs
+++ b/src/login/routes/test/logout.rs
@@ -11,7 +11,7 @@ async fn successful() {
 
     let app = fixtures::scratch_app().await;
     let now = fixtures::now();
-    let login = fixtures::login::create_with_password(&app).await;
+    let login = fixtures::login::create_with_password(&app, &fixtures::now()).await;
     let identity = fixtures::identity::logged_in(&app, &login, &now).await;
     let secret = fixtures::identity::secret(&identity);
 
diff --git a/src/login/snapshot.rs b/src/login/snapshot.rs
new file mode 100644
index 0000000..1379005
--- /dev/null
+++ b/src/login/snapshot.rs
@@ -0,0 +1,49 @@
+use super::{
+    event::{Created, Event},
+    Id,
+};
+
+// This also implements FromRequestParts (see `./extract.rs`). As a result, it
+// can be used as an extractor for endpoints that want to require login, or for
+// endpoints that need to behave differently depending on whether the client is
+// or is not logged in.
+#[derive(Clone, Debug, Eq, PartialEq, serde::Serialize)]
+pub struct Login {
+    pub id: Id,
+    pub name: String,
+    // The omission of the hashed password is deliberate, to minimize the
+    // chance that it ends up tangled up in debug output or in some other chunk
+    // of logic elsewhere.
+}
+
+impl Login {
+    // Two reasons for this allow:
+    //
+    // 1. This is used to collect streams using a fold, below, which requires a type consistent with the fold, and
+    // 2. It's also consistent with the other history state machine types.
+    #[allow(clippy::unnecessary_wraps)]
+    fn apply(state: Option<Self>, event: Event) -> Option<Self> {
+        match (state, event) {
+            (None, Event::Created(event)) => Some(event.into()),
+            (state, event) => panic!("invalid message event {event:#?} for state {state:#?}"),
+        }
+    }
+}
+
+impl FromIterator<Event> for Option<Login> {
+    fn from_iter<I: IntoIterator<Item = Event>>(events: I) -> Self {
+        events.into_iter().fold(None, Login::apply)
+    }
+}
+
+impl From<&Created> for Login {
+    fn from(event: &Created) -> Self {
+        event.login.clone()
+    }
+}
+
+impl From<Created> for Login {
+    fn from(event: Created) -> Self {
+        event.login
+    }
+}
diff --git a/src/message/app.rs b/src/message/app.rs
index 385c92e..3385af2 100644
--- a/src/message/app.rs
+++ b/src/message/app.rs
@@ -7,7 +7,7 @@ use crate::{
     channel::{self, repo::Provider as _},
     clock::DateTime,
     db::NotFound as _,
-    event::{broadcaster::Broadcaster, repo::Provider as _, Event, Sequence},
+    event::{repo::Provider as _, Broadcaster, Event, Sequence},
     login::Login,
 };
 
diff --git a/src/message/repo.rs b/src/message/repo.rs
index e098fb2..0560f4a 100644
--- a/src/message/repo.rs
+++ b/src/message/repo.rs
@@ -38,6 +38,10 @@ impl<'c> Messages<'c> {
 				values ($1, $2, $3, $4, $5, $6)
 				returning
 					id as "id: Id",
+                    channel as "channel: channel::Id",
+                    sender as "sender: login::Id",
+                    sent_at as "sent_at: DateTime",
+                    sent_sequence as "sent_sequence: Sequence",
 					body
 			"#,
             id,
@@ -49,9 +53,12 @@ impl<'c> Messages<'c> {
         )
         .map(|row| History {
             message: Message {
-                sent: *sent,
-                channel: channel.id().clone(),
-                sender: sender.clone(),
+                sent: Instant {
+                    at: row.sent_at,
+                    sequence: row.sent_sequence,
+                },
+                channel: row.channel,
+                sender: row.sender,
                 id: row.id,
                 body: row.body,
             },
@@ -72,18 +79,16 @@ impl<'c> Messages<'c> {
         let messages = sqlx::query!(
             r#"
                 select
-                    message.channel as "channel: channel::Id",
-                    sender.id as "sender_id: login::Id",
-                    sender.name as "sender_name",
-                    message.id as "id: Id",
-                    message.body,
+                    channel as "channel: channel::Id",
+                    sender as "sender: login::Id",
+                    id as "id: Id",
+                    body,
                     sent_at as "sent_at: DateTime",
                     sent_sequence as "sent_sequence: Sequence"
                 from message
-                    join login as sender on message.sender = sender.id
-                where message.channel = $1
-                    and coalesce(message.sent_sequence <= $2, true)
-                order by message.sent_sequence
+                where channel = $1
+                    and coalesce(sent_sequence <= $2, true)
+                order by sent_sequence
             "#,
             channel_id,
             resume_at,
@@ -95,10 +100,7 @@ impl<'c> Messages<'c> {
                     sequence: row.sent_sequence,
                 },
                 channel: row.channel,
-                sender: Login {
-                    id: row.sender_id,
-                    name: row.sender_name,
-                },
+                sender: row.sender,
                 id: row.id,
                 body: row.body,
             },
@@ -114,16 +116,14 @@ impl<'c> Messages<'c> {
         let message = sqlx::query!(
             r#"
                 select
-                    message.channel as "channel: channel::Id",
-                    sender.id as "sender_id: login::Id",
-                    sender.name as "sender_name",
-                    message.id as "id: Id",
-                    message.body,
+                    channel as "channel: channel::Id",
+                    sender as "sender: login::Id",
+                    id as "id: Id",
+                    body,
                     sent_at as "sent_at: DateTime",
                     sent_sequence as "sent_sequence: Sequence"
                 from message
-                    join login as sender on message.sender = sender.id
-                where message.id = $1
+                where id = $1
             "#,
             message,
         )
@@ -134,10 +134,7 @@ impl<'c> Messages<'c> {
                     sequence: row.sent_sequence,
                 },
                 channel: row.channel,
-                sender: Login {
-                    id: row.sender_id,
-                    name: row.sender_name,
-                },
+                sender: row.sender,
                 id: row.id,
                 body: row.body,
             },
@@ -194,15 +191,13 @@ impl<'c> Messages<'c> {
         let messages = sqlx::query!(
             r#"
                 select
-                    message.channel as "channel: channel::Id",
-                    sender.id as "sender_id: login::Id",
-                    sender.name as "sender_name",
-                    message.id as "id: Id",
-                    message.body,
+                    channel as "channel: channel::Id",
+                    sender as "sender: login::Id",
+                    id as "id: Id",
+                    body,
                     sent_at as "sent_at: DateTime",
                     sent_sequence as "sent_sequence: Sequence"
                 from message
-                    join login as sender on message.sender = sender.id
                 where coalesce(message.sent_sequence > $1, true)
             "#,
             resume_at,
@@ -214,10 +209,7 @@ impl<'c> Messages<'c> {
                     sequence: row.sent_sequence,
                 },
                 channel: row.channel,
-                sender: Login {
-                    id: row.sender_id,
-                    name: row.sender_name,
-                },
+                sender: row.sender,
                 id: row.id,
                 body: row.body,
             },
diff --git a/src/message/snapshot.rs b/src/message/snapshot.rs
index 8c1e62a..0eb37bb 100644
--- a/src/message/snapshot.rs
+++ b/src/message/snapshot.rs
@@ -2,14 +2,14 @@ use super::{
     event::{Event, Sent},
     Id,
 };
-use crate::{channel, event::Instant, login::Login};
+use crate::{channel, event::Instant, login};
 
 #[derive(Clone, Debug, Eq, PartialEq, serde::Serialize)]
 pub struct Message {
     #[serde(flatten)]
     pub sent: Instant,
     pub channel: channel::Id,
-    pub sender: Login,
+    pub sender: login::Id,
     pub id: Id,
     pub body: String,
 }
diff --git a/src/test/fixtures/login.rs b/src/test/fixtures/login.rs
index 00c2789..e5ac716 100644
--- a/src/test/fixtures/login.rs
+++ b/src/test/fixtures/login.rs
@@ -3,23 +3,24 @@ use uuid::Uuid;
 
 use crate::{
     app::App,
+    clock::RequestedAt,
     login::{self, Login, Password},
 };
 
-pub async fn create_with_password(app: &App) -> (String, Password) {
+pub async fn create_with_password(app: &App, created_at: &RequestedAt) -> (String, Password) {
     let (name, password) = propose();
     app.logins()
-        .create(&name, &password)
+        .create(&name, &password, created_at)
         .await
         .expect("should always succeed if the login is actually new");
 
     (name, password)
 }
 
-pub async fn create(app: &App) -> Login {
+pub async fn create(app: &App, created_at: &RequestedAt) -> Login {
     let (name, password) = propose();
     app.logins()
-        .create(&name, &password)
+        .create(&name, &password, created_at)
         .await
         .expect("should always succeed if the login is actually new")
 }
diff --git a/src/token/app.rs b/src/token/app.rs
index 5c4fcd5..b8af637 100644
--- a/src/token/app.rs
+++ b/src/token/app.rs
@@ -7,23 +7,34 @@ use futures::{
 use sqlx::sqlite::SqlitePool;
 
 use super::{
-    broadcaster::Broadcaster, event, repo::auth::Provider as _, repo::Provider as _, Id, Secret,
+    repo::auth::Provider as _, repo::Provider as _, Broadcaster, Event as TokenEvent, Id, Secret,
 };
 use crate::{
     clock::DateTime,
     db::NotFound as _,
+    event::{self, repo::Provider as _, Event as ServiceEvent},
     login::{repo::Provider as _, Login, Password},
 };
 
 pub struct Tokens<'a> {
     db: &'a SqlitePool,
-    tokens: &'a Broadcaster,
+    events: &'a event::Broadcaster,
+    token_events: &'a Broadcaster,
 }
 
 impl<'a> Tokens<'a> {
-    pub const fn new(db: &'a SqlitePool, tokens: &'a Broadcaster) -> Self {
-        Self { db, tokens }
+    pub const fn new(
+        db: &'a SqlitePool,
+        events: &'a event::Broadcaster,
+        token_events: &'a Broadcaster,
+    ) -> Self {
+        Self {
+            db,
+            events,
+            token_events,
+        }
     }
+
     pub async fn login(
         &self,
         name: &str,
@@ -32,22 +43,30 @@ impl<'a> Tokens<'a> {
     ) -> Result<Secret, LoginError> {
         let mut tx = self.db.begin().await?;
 
-        let login = if let Some((login, stored_hash)) = tx.auth().for_name(name).await? {
+        let (login, created) = if let Some((login, stored_hash)) = tx.auth().for_name(name).await? {
             if stored_hash.verify(password)? {
-                // Password verified; use the login.
-                login
+                // Password verified, proceed with login
+                (login, false)
             } else {
                 // Password NOT verified.
                 return Err(LoginError::Rejected);
             }
         } else {
             let password_hash = password.hash()?;
-            tx.logins().create(name, &password_hash).await?
+            let created = tx.sequence().next(login_at).await?;
+            let login = tx.logins().create(name, &password_hash, &created).await?;
+
+            (login, true)
         };
 
         let token = tx.tokens().issue(&login, login_at).await?;
         tx.commit().await?;
 
+        if created {
+            self.events
+                .broadcast(login.events().map(ServiceEvent::from).collect::<Vec<_>>());
+        }
+
         Ok(token)
     }
 
@@ -76,7 +95,7 @@ impl<'a> Tokens<'a> {
         E: std::fmt::Debug,
     {
         // Subscribe, first.
-        let token_events = self.tokens.subscribe();
+        let token_events = self.token_events.subscribe();
 
         // Check that the token is valid at this point in time, second. If it is, then
         // any future revocations will appear in the subscription. If not, bail now.
@@ -102,7 +121,9 @@ impl<'a> Tokens<'a> {
         // Then construct the guarded stream. First, project both streams into
         // `GuardedEvent`.
         let token_events = token_events
-            .filter(move |event| future::ready(event.token == token))
+            .filter(move |event| {
+                future::ready(matches!(event, TokenEvent::Revoked(id) if id == &token))
+            })
             .map(|_| GuardedEvent::TokenRevoked);
         let events = events.map(|event| GuardedEvent::Event(event));
 
@@ -126,8 +147,8 @@ impl<'a> Tokens<'a> {
         let tokens = tx.tokens().expire(&expire_at).await?;
         tx.commit().await?;
 
-        for event in tokens.into_iter().map(event::TokenRevoked::from) {
-            self.tokens.broadcast(event);
+        for event in tokens.into_iter().map(TokenEvent::Revoked) {
+            self.token_events.broadcast(event);
         }
 
         Ok(())
@@ -138,8 +159,8 @@ impl<'a> Tokens<'a> {
         tx.tokens().revoke(token).await?;
         tx.commit().await?;
 
-        self.tokens
-            .broadcast(event::TokenRevoked::from(token.clone()));
+        self.token_events
+            .broadcast(TokenEvent::Revoked(token.clone()));
 
         Ok(())
     }
diff --git a/src/token/broadcaster.rs b/src/token/broadcaster.rs
index 8e2e006..de2513a 100644
--- a/src/token/broadcaster.rs
+++ b/src/token/broadcaster.rs
@@ -1,4 +1,3 @@
-use super::event;
 use crate::broadcast;
 
-pub type Broadcaster = broadcast::Broadcaster<event::TokenRevoked>;
+pub type Broadcaster = broadcast::Broadcaster<super::Event>;
diff --git a/src/token/event.rs b/src/token/event.rs
index d53d436..51b74d7 100644
--- a/src/token/event.rs
+++ b/src/token/event.rs
@@ -1,12 +1,6 @@
 use crate::token;
 
 #[derive(Clone, Debug)]
-pub struct TokenRevoked {
-    pub token: token::Id,
-}
-
-impl From<token::Id> for TokenRevoked {
-    fn from(token: token::Id) -> Self {
-        Self { token }
-    }
+pub enum Event {
+    Revoked(token::Id),
 }
diff --git a/src/token/mod.rs b/src/token/mod.rs
index d122611..eccb3cd 100644
--- a/src/token/mod.rs
+++ b/src/token/mod.rs
@@ -1,9 +1,9 @@
 pub mod app;
-pub mod broadcaster;
+mod broadcaster;
 mod event;
 pub mod extract;
 mod id;
 mod repo;
 mod secret;
 
-pub use self::{id::Id, secret::Secret};
+pub use self::{broadcaster::Broadcaster, event::Event, id::Id, secret::Secret};
diff --git a/src/token/repo/auth.rs b/src/token/repo/auth.rs
index b299697..ddb5136 100644
--- a/src/token/repo/auth.rs
+++ b/src/token/repo/auth.rs
@@ -1,6 +1,10 @@
 use sqlx::{sqlite::Sqlite, SqliteConnection, Transaction};
 
-use crate::login::{self, password::StoredHash, Login};
+use crate::{
+    clock::DateTime,
+    event::{Instant, Sequence},
+    login::{self, password::StoredHash, History, Login},
+};
 
 pub trait Provider {
     fn auth(&mut self) -> Auth;
@@ -21,25 +25,33 @@ impl<'t> Auth<'t> {
     pub async fn for_name(
         &mut self,
         name: &str,
-    ) -> Result<Option<(Login, StoredHash)>, sqlx::Error> {
+    ) -> Result<Option<(History, StoredHash)>, sqlx::Error> {
         let found = sqlx::query!(
             r#"
 				select
 					id as "id: login::Id",
 					name,
-					password_hash as "password_hash: StoredHash"
+					password_hash as "password_hash: StoredHash",
+                    created_sequence as "created_sequence: Sequence",
+                    created_at as "created_at: DateTime"
 				from login
 				where name = $1
 			"#,
             name,
         )
-        .map(|rec| {
+        .map(|row| {
             (
-                Login {
-                    id: rec.id,
-                    name: rec.name,
+                History {
+                    login: Login {
+                        id: row.id,
+                        name: row.name,
+                    },
+                    created: Instant {
+                        at: row.created_at,
+                        sequence: row.created_sequence,
+                    },
                 },
-                rec.password_hash,
+                row.password_hash,
             )
         })
         .fetch_optional(&mut *self.0)
diff --git a/src/token/repo/token.rs b/src/token/repo/token.rs
index 5f64dac..c592dcd 100644
--- a/src/token/repo/token.rs
+++ b/src/token/repo/token.rs
@@ -3,7 +3,7 @@ use uuid::Uuid;
 
 use crate::{
     clock::DateTime,
-    login::{self, Login},
+    login::{self, History, Login},
     token::{Id, Secret},
 };
 
@@ -24,11 +24,12 @@ impl<'c> Tokens<'c> {
     // be used to control expiry, until the token is actually used.
     pub async fn issue(
         &mut self,
-        login: &Login,
+        login: &History,
         issued_at: &DateTime,
     ) -> Result<Secret, sqlx::Error> {
         let id = Id::generate();
         let secret = Uuid::new_v4().to_string();
+        let login = login.id();
 
         let secret = sqlx::query_scalar!(
             r#"
@@ -39,7 +40,7 @@ impl<'c> Tokens<'c> {
             "#,
             id,
             secret,
-            login.id,
+            login,
             issued_at,
         )
         .fetch_one(&mut *self.0)
@@ -127,7 +128,7 @@ impl<'c> Tokens<'c> {
                 select
                     token.id as "token_id: Id",
                     login.id as "login_id: login::Id",
-                    name as "login_name"
+                    login.name as "login_name"
                 from login
                 join token on login.id = token.login
                 where token.secret = $1