first commit

src/state.rs

@@ -0,0 +1,52 @@
+use std::{collections::HashMap, sync::Arc};
+
+use sqlx::SqlitePool;
+use tokio::sync::{broadcast, RwLock};
+
+const CHANNEL_CAPACITY: usize = 256;
+
+#[derive(Debug, Clone)]
+pub struct NoteUpdate {
+    pub content: String,
+    pub revision_id: i64,
+    pub updated_at: String,
+}
+
+#[derive(Debug)]
+pub struct AppState {
+    pub db: SqlitePool,
+    pub asset_version: String,
+    channels: RwLock<HashMap<String, broadcast::Sender<NoteUpdate>>>,
+}
+
+impl AppState {
+    pub fn new(db: SqlitePool, asset_version: String) -> Self {
+        Self {
+            db,
+            asset_version,
+            channels: RwLock::new(HashMap::new()),
+        }
+    }
+
+    async fn channel_for_key(&self, key: String) -> broadcast::Sender<NoteUpdate> {
+        if let Some(sender) = self.channels.read().await.get(&key) {
+            return sender.clone();
+        }
+
+        let mut channels = self.channels.write().await;
+        channels
+            .entry(key)
+            .or_insert_with(|| broadcast::channel(CHANNEL_CAPACITY).0)
+            .clone()
+    }
+
+    pub async fn note_channel(&self, workspace_slug: &str, note_slug: &str) -> broadcast::Sender<NoteUpdate> {
+        self.channel_for_key(format!("workspace:{workspace_slug}/{note_slug}")).await
+    }
+
+    pub async fn pad_channel(&self, slug: &str) -> broadcast::Sender<NoteUpdate> {
+        self.channel_for_key(format!("pad:{slug}")).await
+    }
+}
+
+pub type SharedState = Arc<AppState>;