1 files changed, 115 insertions, 0 deletions
diff --git a/src/message/app.rs b/src/message/app.rs
new file mode 100644
index 0000000..33ea8ad
--- /dev/null
+++ b/src/message/app.rs
@@ -0,0 +1,115 @@
+use chrono::TimeDelta;
+use itertools::Itertools;
+use sqlx::sqlite::SqlitePool;
+
+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 _, Event, Sequence},
+    login::Login,
+};
+
+pub struct Messages<'a> {
+    db: &'a SqlitePool,
+    events: &'a Broadcaster,
+}
+
+impl<'a> Messages<'a> {
+    pub const fn new(db: &'a SqlitePool, events: &'a Broadcaster) -> Self {
+        Self { db, events }
+    }
+
+    pub async fn send(
+        &self,
+        channel: &channel::Id,
+        sender: &Login,
+        sent_at: &DateTime,
+        body: &str,
+    ) -> Result<Message, SendError> {
+        let mut tx = self.db.begin().await?;
+        let channel = tx
+            .channels()
+            .by_id(channel)
+            .await
+            .not_found(|| SendError::ChannelNotFound(channel.clone()))?;
+        let sent = tx.sequence().next(sent_at).await?;
+        let message = tx
+            .messages()
+            .create(&channel.snapshot(), sender, &sent, body)
+            .await?;
+        tx.commit().await?;
+
+        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 mut events = Vec::with_capacity(expired.len());
+        for message in expired {
+            let deleted = tx.sequence().next(relative_to).await?;
+            let message = tx.messages().delete(&message, &deleted).await?;
+            events.push(
+                message
+                    .events()
+                    .filter(Sequence::start_from(deleted.sequence)),
+            );
+        }
+
+        tx.commit().await?;
+
+        self.events.broadcast(
+            events
+                .into_iter()
+                .kmerge_by(Sequence::merge)
+                .map(Event::from)
+                .collect::<Vec<_>>(),
+        );
+
+        Ok(())
+    }
+}
+
+#[derive(Debug, thiserror::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),
+}