Add endpoints for deleting channels and messages.

It is deliberate that the expire() functions do not use them. To avoid races, the transactions must be committed before events get sent, in both cases, which makes them structurally pretty different.

1 files changed, 44 insertions, 17 deletions

diff --git a/src/message/app.rs b/src/message/app.rs
index 51f772e..1d34c14 100644
--- a/src/message/app.rs
+++ b/src/message/app.rs
@@ -2,12 +2,12 @@ use chrono::TimeDelta;
 use itertools::Itertools;
 use sqlx::sqlite::SqlitePool;
 
-use super::{repo::Provider as _, Message};
+use super::{repo::Provider as _, Id, Message};
 use crate::{
     channel::{self, repo::Provider as _},
     clock::DateTime,
     db::NotFound as _,
-    event::{broadcaster::Broadcaster, repo::Provider as _, Sequence},
+    event::{broadcaster::Broadcaster, repo::Provider as _, Event, Sequence},
     login::Login,
 };
 
@@ -27,13 +27,13 @@ impl<'a> Messages<'a> {
         sender: &Login,
         sent_at: &DateTime,
         body: &str,
-    ) -> Result<Message, Error> {
+    ) -> Result<Message, SendError> {
         let mut tx = self.db.begin().await?;
         let channel = tx
             .channels()
             .by_id(channel)
             .await
-            .not_found(|| Error::ChannelNotFound(channel.clone()))?;
+            .not_found(|| SendError::ChannelNotFound(channel.clone()))?;
         let sent = tx.sequence().next(sent_at).await?;
         let message = tx
             .messages()
@@ -41,24 +41,40 @@ impl<'a> Messages<'a> {
             .await?;
         tx.commit().await?;
 
-        for event in message.events() {
-            self.events.broadcast(event);
-        }
+        self.events
+            .broadcast(message.events().map(Event::from).collect::<Vec<_>>());
 
         Ok(message.snapshot())
     }
 
+    pub async fn delete(&self, message: &Id, deleted_at: &DateTime) -> Result<(), DeleteError> {
+        let mut tx = self.db.begin().await?;
+        let deleted = tx.sequence().next(deleted_at).await?;
+        let message = tx.messages().delete(message, &deleted).await?;
+        tx.commit().await?;
+
+        self.events.broadcast(
+            message
+                .events()
+                .filter(Sequence::start_from(deleted.sequence))
+                .map(Event::from)
+                .collect::<Vec<_>>(),
+        );
+
+        Ok(())
+    }
+
     pub async fn expire(&self, relative_to: &DateTime) -> Result<(), sqlx::Error> {
         // Somewhat arbitrarily, expire after 90 days.
         let expire_at = relative_to.to_owned() - TimeDelta::days(90);
 
         let mut tx = self.db.begin().await?;
-        let expired = tx.messages().expired(&expire_at).await?;
 
+        let expired = tx.messages().expired(&expire_at).await?;
         let mut events = Vec::with_capacity(expired.len());
-        for (channel, message) in expired {
+        for message in expired {
             let deleted = tx.sequence().next(relative_to).await?;
-            let message = tx.messages().delete(&channel, &message, &deleted).await?;
+            let message = tx.messages().delete(&message, &deleted).await?;
             events.push(
                 message
                     .events()
@@ -68,21 +84,32 @@ impl<'a> Messages<'a> {
 
         tx.commit().await?;
 
-        for event in events
-            .into_iter()
-            .kmerge_by(|a, b| a.instant.sequence < b.instant.sequence)
-        {
-            self.events.broadcast(event);
-        }
+        self.events.broadcast(
+            events
+                .into_iter()
+                .kmerge_by(|a, b| a.instant.sequence < b.instant.sequence)
+                .map(Event::from)
+                .collect::<Vec<_>>(),
+        );
 
         Ok(())
     }
 }
 
 #[derive(Debug, thiserror::Error)]
-pub enum Error {
+pub enum SendError {
+    #[error("channel {0} not found")]
+    ChannelNotFound(channel::Id),
+    #[error(transparent)]
+    DatabaseError(#[from] sqlx::Error),
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum DeleteError {
     #[error("channel {0} not found")]
     ChannelNotFound(channel::Id),
+    #[error("message {0} not found")]
+    NotFound(Id),
     #[error(transparent)]
     DatabaseError(#[from] sqlx::Error),
 }