Make `/api/events` a firehose endpoint.

It now includes events for all channels. Clients are responsible for filtering.

The schema for channel events has changed; it now includes a channel name and ID, in the same format as the sender's name and ID. They also now include a `"type"` field, whose only valid value (as of this writing) is `"message"`.

This is groundwork for delivering message deletion (expiry) events to clients, and notifying clients of channel lifecycle events.

1 files changed, 145 insertions, 0 deletions

diff --git a/src/events/repo/message.rs b/src/events/repo/message.rs
new file mode 100644
index 0000000..b4724ea
--- /dev/null
+++ b/src/events/repo/message.rs
@@ -0,0 +1,145 @@
+use sqlx::{sqlite::Sqlite, SqliteConnection, Transaction};
+
+use crate::{
+    clock::DateTime,
+    events::types::{self, Sequence},
+    repo::{
+        channel::Channel,
+        login::{self, Login},
+        message,
+    },
+};
+
+pub trait Provider {
+    fn message_events(&mut self) -> Events;
+}
+
+impl<'c> Provider for Transaction<'c, Sqlite> {
+    fn message_events(&mut self) -> Events {
+        Events(self)
+    }
+}
+
+pub struct Events<'t>(&'t mut SqliteConnection);
+
+impl<'c> Events<'c> {
+    pub async fn create(
+        &mut self,
+        sender: &Login,
+        channel: &Channel,
+        body: &str,
+        sent_at: &DateTime,
+    ) -> Result<types::ChannelEvent, sqlx::Error> {
+        let sequence = self.next_sequence_for(channel).await?;
+
+        let id = message::Id::generate();
+
+        let message = sqlx::query!(
+            r#"
+				insert into message
+					(id, channel, sequence, sender, body, sent_at)
+				values ($1, $2, $3, $4, $5, $6)
+				returning
+					id as "id: message::Id",
+                    sequence as "sequence: Sequence",
+					sender as "sender: login::Id",
+					body,
+					sent_at as "sent_at: DateTime"
+			"#,
+            id,
+            channel.id,
+            sequence,
+            sender.id,
+            body,
+            sent_at,
+        )
+        .map(|row| types::ChannelEvent {
+            sequence: row.sequence,
+            at: row.sent_at,
+            channel: channel.clone(),
+            data: types::MessageEvent {
+                id: row.id,
+                sender: sender.clone(),
+                body: row.body,
+            }
+            .into(),
+        })
+        .fetch_one(&mut *self.0)
+        .await?;
+
+        Ok(message)
+    }
+
+    async fn next_sequence_for(&mut self, channel: &Channel) -> Result<Sequence, sqlx::Error> {
+        let current = sqlx::query_scalar!(
+            r#"
+                -- `max` never returns null, but sqlx can't detect that
+                select max(sequence) as "sequence!: Sequence"
+                from message
+                where channel = $1
+            "#,
+            channel.id,
+        )
+        .fetch_one(&mut *self.0)
+        .await?;
+
+        Ok(current.next())
+    }
+
+    pub async fn expire(&mut self, expire_at: &DateTime) -> Result<(), sqlx::Error> {
+        sqlx::query!(
+            r#"
+                delete from message
+                where sent_at < $1
+            "#,
+            expire_at,
+        )
+        .execute(&mut *self.0)
+        .await?;
+
+        Ok(())
+    }
+
+    pub async fn replay(
+        &mut self,
+        channel: &Channel,
+        resume_at: Option<Sequence>,
+    ) -> Result<Vec<types::ChannelEvent>, sqlx::Error> {
+        let events = sqlx::query!(
+            r#"
+				select
+					message.id as "id: message::Id",
+                    sequence as "sequence: Sequence",
+					login.id as "sender_id: login::Id",
+					login.name as sender_name,
+					message.body,
+					message.sent_at as "sent_at: DateTime"
+				from message
+					join login on message.sender = login.id
+				where channel = $1
+					and coalesce(sequence > $2, true)
+				order by sequence asc
+			"#,
+            channel.id,
+            resume_at,
+        )
+        .map(|row| types::ChannelEvent {
+            sequence: row.sequence,
+            at: row.sent_at,
+            channel: channel.clone(),
+            data: types::MessageEvent {
+                id: row.id,
+                sender: login::Login {
+                    id: row.sender_id,
+                    name: row.sender_name,
+                },
+                body: row.body,
+            }
+            .into(),
+        })
+        .fetch_all(&mut *self.0)
+        .await?;
+
+        Ok(events)
+    }
+}