Track event sequences globally, not per channel.

Per-channel event sequences were a cute idea, but it made reasoning about event resumption much, much harder (case in point: recovering the order of events in a partially-ordered collection is quadratic, since it's basically graph sort). The minor overhead of a global sequence number is likely tolerable, and this simplifies both the API and the internals.

1 files changed, 9 insertions, 5 deletions

diff --git a/src/channel/app.rs b/src/channel/app.rs
index 70cda47..88f4170 100644
--- a/src/channel/app.rs
+++ b/src/channel/app.rs
@@ -3,8 +3,11 @@ use sqlx::sqlite::SqlitePool;
 
 use crate::{
     clock::DateTime,
-    events::{broadcaster::Broadcaster, repo::message::Provider as _, types::ChannelEvent},
-    repo::channel::{Channel, Provider as _},
+    events::{broadcaster::Broadcaster, types::ChannelEvent},
+    repo::{
+        channel::{Channel, Provider as _},
+        sequence::Provider as _,
+    },
 };
 
 pub struct Channels<'a> {
@@ -19,9 +22,10 @@ impl<'a> Channels<'a> {
 
     pub async fn create(&self, name: &str, created_at: &DateTime) -> Result<Channel, CreateError> {
         let mut tx = self.db.begin().await?;
+        let created_sequence = tx.sequence().next().await?;
         let channel = tx
             .channels()
-            .create(name, created_at)
+            .create(name, created_at, created_sequence)
             .await
             .map_err(|err| CreateError::from_duplicate_name(err, name))?;
         tx.commit().await?;
@@ -49,10 +53,10 @@ impl<'a> Channels<'a> {
 
         let mut events = Vec::with_capacity(expired.len());
         for channel in expired {
-            let sequence = tx.message_events().assign_sequence(&channel).await?;
+            let deleted_sequence = tx.sequence().next().await?;
             let event = tx
                 .channels()
-                .delete_expired(&channel, sequence, relative_to)
+                .delete(&channel, relative_to, deleted_sequence)
                 .await?;
             events.push(event);
         }