Add support for message history pagination, preserve scroll in rendering, and improve draft/message workflows.

test/attachmentComposer.test.js

@@ -4,6 +4,7 @@
 import test from "node:test";
 import assert from "node:assert/strict";
 import { appendAttachments, createAttachmentComposer } from "../public/js/attachments.js";
+import {createDraftStore} from "../public/js/draftStore.js";
 
 class Element {
     constructor() { this.children = []; this.listeners = {}; this.classList = { add() { }, remove() { } }; }
@@ -13,6 +14,34 @@ class Element {
     addEventListener(name, listener) { this.listeners[name] = listener; }
     click() { this.clicked = true; }
 }
+
+test("uploaded draft references recover after reload and unavailable images cannot be sent", async t => {
+    const elements = Object.fromEntries(["attachImage", "imagePicker", "uploadPreviews", "composer"].map(id => [id, new Element()]));
+    const originalDocument = globalThis.document;
+    t.after(() => { globalThis.document = originalDocument; });
+    globalThis.document = {getElementById: id => elements[id], querySelector: () => elements.composer, createElement: () => new Element()};
+    t.mock.method(globalThis, "fetch", async () => Response.json({maxFiles: 5, maxSizeMb: 10}));
+    const values = new Map();
+    const storage = {getItem: key => values.get(key), setItem: (key, value) => values.set(key, value)};
+    const saved = createDraftStore("alice", {storage});
+    const metadata = {id: "12345678-1234-1234-1234-123456789abc", originalName: "draft.png"};
+    saved.setAttachments(7, [metadata]);
+    const composer = createAttachmentComposer({onChange() {}, onError: message => assert.fail(message)});
+    composer.setDraftStore(createDraftStore("alice", {storage}));
+    composer.restoreDraft(7);
+    assert.equal(elements.uploadPreviews.children[0].children[0].src, `/attachments/${metadata.id}`);
+    assert.equal(composer.pending, true);
+    elements.uploadPreviews.children[0].children[0].onload();
+    assert.equal(composer.pending, false);
+    assert.deepEqual(composer.attachments, [metadata]);
+    elements.uploadPreviews.children[0].children[0].onerror();
+    assert.equal(composer.pending, true);
+    assert.deepEqual(composer.attachments, []);
+    assert.deepEqual(createDraftStore("alice", {storage}).attachments(7), [metadata]);
+    elements.uploadPreviews.children[0].children.at(-1).onclick();
+    assert.equal(composer.pending, false);
+    assert.deepEqual(createDraftStore("alice", {storage}).attachments(7), []);
+});
 test("composer preview, pending state, upload failure/retry, removal, paste, and history rendering", async t => {
     const originalDocument = globalThis.document, originalFetch = globalThis.fetch;
     t.after(() => { globalThis.document = originalDocument; globalThis.fetch = originalFetch; });