From d11ff421de581a835f1645b22d1f7f4304640b0c Mon Sep 17 00:00:00 2001
From: Owen Jacobson <owen@grimoire.ca>
Date: Mon, 5 May 2025 19:51:58 -0400
Subject: Use the outbox for more than just message sends.

A handful of operations are "synchronized" - that is, the server sends back information about them when the client asks to perform them, but notifies _all_ clients of completion through the event stream. As of this writing, these operations include sending and deleting messages, creating and deleting channels, and anything that creates new users.

We can use the outbox for most of these. I've opted _not_ to use the outbox for creating users, as that often takes place when the client is not connected to the event stream (and can't be) and so cannot discover that the operation has been completed after it is sent.

Outboxed tasks are objects, not closures, even though they behave in closure-like ways (`send()` carries out what amounts to "attempt this operation until it succeeds"). This is deliberate; I want the properties of incomplete tasks to be inspectable down the line, so that we can put them in the UI. If they're mere closures, we can't do that.

It is deliberate that `outbox.postToChannel` et al do not return promises. I contemplated it, but it will interact weirdly with outbox serialization, when we get to that. Rather than relying on a promise to determine when an operation has completed, clients of `Outbox` should monitor its properties. (We can add additional view properties to make that easier.)
---
 ui/lib/outbox.svelte.js                   | 46 +++++++++++++++++++++++++++----
 ui/routes/(app)/+layout.svelte            |  2 +-
 ui/routes/(app)/ch/[channel]/+page.svelte |  5 ++--
 3 files changed, 44 insertions(+), 9 deletions(-)

diff --git a/ui/lib/outbox.svelte.js b/ui/lib/outbox.svelte.js
index 0681f29..de7f80e 100644
--- a/ui/lib/outbox.svelte.js
+++ b/ui/lib/outbox.svelte.js
@@ -1,12 +1,36 @@
 import * as api from './apiServer.js';
 import * as md from './markdown.js';
 
-class Message {
+class PostToChannel {
   constructor(channel, body) {
     this.channel = channel;
     this.body = body;
     this.renderedBody = md.render(body);
   }
+
+  async send() {
+    return await api.retry(() => api.postToChannel(this.channel, this.body));
+  }
+}
+
+class DeleteMessage {
+  constructor(messageId) {
+    this.messageId = messageId;
+  }
+
+  async send() {
+    return await api.retry(() => api.deleteMessage(this.messageId));
+  }
+}
+
+class CreateChannel {
+  constructor(name) {
+    this.name = name;
+  }
+
+  async send() {
+    return await api.retry(() => api.createChannel(this.name));
+  }
 }
 
 export class Outbox {
@@ -20,11 +44,23 @@ export class Outbox {
     this.pending = pending;
   }
 
-  send(channel, body) {
-    this.pending.push(new Message(channel, body));
+  enqueue(operation) {
+    this.pending.push(operation);
     this.start();
   }
 
+  createChannel(name) {
+    this.enqueue(new CreateChannel(name));
+  }
+
+  postToChannel(channel, body) {
+    this.enqueue(new PostToChannel(channel, body));
+  }
+
+  deleteMessage(messageId) {
+    this.enqueue(new DeleteMessage(messageId));
+  }
+
   start() {
     if (this.sending) {
       return;
@@ -38,9 +74,9 @@ export class Outbox {
 
   async drain() {
     while (this.pending.length > 0) {
-      const { channel, body } = this.pending[0];
+      const operation = this.pending[0];
 
-      await api.retry(() => api.postToChannel(channel, body));
+      await operation.send();
       this.pending.shift();
     }
   }
diff --git a/ui/routes/(app)/+layout.svelte b/ui/routes/(app)/+layout.svelte
index 116767d..a4ae442 100644
--- a/ui/routes/(app)/+layout.svelte
+++ b/ui/routes/(app)/+layout.svelte
@@ -87,7 +87,7 @@
   });
 
   async function createChannel(name) {
-    await api.createChannel(name);
+    outbox.createChannel(name);
   }
 
   function onbeforeunload(event) {
diff --git a/ui/routes/(app)/ch/[channel]/+page.svelte b/ui/routes/(app)/ch/[channel]/+page.svelte
index 9506b67..abec00d 100644
--- a/ui/routes/(app)/ch/[channel]/+page.svelte
+++ b/ui/routes/(app)/ch/[channel]/+page.svelte
@@ -4,7 +4,6 @@
   import ActiveChannel from '$lib/components/ActiveChannel.svelte';
   import MessageInput from '$lib/components/MessageInput.svelte';
   import { runs } from '$lib/runs.js';
-  import * as api from '$lib/apiServer';
 
   const { data } = $props();
   const { session, outbox } = data;
@@ -65,11 +64,11 @@
   }
 
   async function sendMessage(message) {
-    outbox.send(channel, message);
+    outbox.postToChannel(channel, message);
   }
 
   async function deleteMessage(id) {
-    await api.deleteMessage(id);
+    outbox.deleteMessage(id);
   }
 </script>
 
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