v3: api/ gets one layout rule and keeps to it, and whatever crosses the wire is defined once, in shared/ — api/model/interfaces.ts and src/model.ts declared the same 40 types by hand and had drifted: the error envelope, email required on one side and optional on the other, Invitee/InviteTreeEntry and LinkPreview/UrlPreviewResponse for one shape each. The validation limits, the role permissions, the chat length cap, the @mention pattern and the Bandcamp and YouTube player responses were copied too, behind "keep in sync" comments. shared/ now holds them once, one file per domain (api, category, chat, comment, dump, follow, mention, notification, permissions, player, playlist, search, user, validation, ws), and imports nothing from either half. The server sends Dates; the client reads Wire<T>, the same type with every Date an ISO string, and turns it back with src/utils/shared/deserialize.ts. APIErrorCode becomes a const object, since the frontend's erasableSyntaxOnly rejects an enum. The shared types showed two real gaps: the avatar upload and GET /api/users/me return the full self user and the frontend read them as public users, and a stored session may predate media tokens, so the client keeps it as its own Session type. The backend rule: each folder holds one kind of module, each file is named after its domain. routes/ parse and answer; services/ hold the logic and every SQL query (lib/auth.ts's token check moves to user-service); remote/ is the only place that fetches from other sites — the guarded fetch and the HTML scraping out of rich-content-service, public-address, the Bandcamp and YouTube resolvers, the link providers, the image proxy (fetch, checks and cache, out of routes/preview.ts) and the Twemoji glyphs (out of lib/site-icons.ts). model/ holds per table a row type, its guard and its mappers; validators/ the request guards; db/connection.ts the handle and transaction(), db/startup.ts the purges and default admin that db.ts ran on import, called at the same moment. Tests mirror the source one file per module, test/<layer>/<module>.test.ts, with shared/'s under shared/test/ (deno task test runs both); the test that covered the bandcamp and soundcloud providers together is two now, and the backend can() has its own, so 202 tests. deno lint src/ is clean too: window.* becomes globalThis.*, and test bodies and act() callbacks that never awaited lose their async. The README states the rule. No behaviour changes; the catalogues only move their source references.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

api/test/services/chat-service.test.ts

@@ -0,0 +1,163 @@
+import { createUser, db, test } from "../helpers.ts";
+import { assertEquals, assertThrows } from "@std/assert";
+import {
+  createChatMessage,
+  deleteChatMessage,
+  getChatMessagesAfter,
+  getChatReadState,
+  getRecentChatMessages,
+  markChatRead,
+  updateChatMessage,
+} from "../../services/chat-service.ts";
+import { APIException } from "../../lib/api-exception.ts";
+
+function insertMessage(
+  userId: string,
+  body: string,
+  createdAt: string,
+  id?: string,
+) {
+  const messageId = id ?? crypto.randomUUID();
+  db.prepare(
+    `INSERT INTO chat_messages (id, user_id, body, created_at) VALUES (?, ?, ?, ?);`,
+  ).run(messageId, userId, body, createdAt);
+  return messageId;
+}
+
+const T = (n: number) => new Date(Date.UTC(2024, 0, 1, 0, 0, n)).toISOString();
+
+test("createChatMessage: trims, bounds, and drops a dangling reply target", async () => {
+  const user = await createUser();
+  const m = createChatMessage(user.id, "  hello  ");
+  assertEquals(m.body, "hello");
+  assertEquals(m.authorUsername, user.username);
+  assertThrows(() => createChatMessage(user.id, "   "), APIException, "empty");
+  assertThrows(
+    () => createChatMessage(user.id, "x".repeat(2001)),
+    APIException,
+    "2000",
+  );
+  createChatMessage(user.id, "x".repeat(2000));
+
+  const dangling = createChatMessage(user.id, "re", crypto.randomUUID());
+  assertEquals(dangling.replyToId, undefined);
+});
+
+test("replies carry a snippet of their target, which goes when it's deleted", async () => {
+  const user = await createUser();
+  const long = createChatMessage(user.id, "a".repeat(500));
+  const reply = createChatMessage(user.id, "re", long.id);
+  assertEquals(reply.replyToId, long.id);
+  assertEquals(reply.replyToAuthor, user.username);
+  assertEquals(reply.replyToBody, "a".repeat(300));
+  deleteChatMessage(long.id, user.id, false);
+  const [after] = getRecentChatMessages();
+  assertEquals(after.replyToId, long.id);
+  assertEquals(after.replyToBody, undefined);
+});
+
+test("edit and delete: the author or a moderator", async () => {
+  const author = await createUser();
+  const other = await createUser();
+  const m = createChatMessage(author.id, "orig");
+  assertThrows(
+    () => updateChatMessage(m.id, "x", other.id, false),
+    APIException,
+    "Not authorized",
+  );
+  assertThrows(
+    () => deleteChatMessage(m.id, other.id, false),
+    APIException,
+    "Not authorized",
+  );
+  assertThrows(
+    () => updateChatMessage(m.id, " ", author.id, false),
+    APIException,
+    "empty",
+  );
+  const edited = updateChatMessage(m.id, " edited ", author.id, false);
+  assertEquals(edited.body, "edited");
+  assertEquals(typeof edited.updatedAt?.getTime(), "number");
+  assertEquals(updateChatMessage(m.id, "mod", other.id, true).body, "mod");
+  deleteChatMessage(m.id, other.id, true);
+  assertThrows(
+    () => deleteChatMessage(m.id, author.id, false),
+    APIException,
+    "not found",
+  );
+});
+
+test("history pages: newest page in ascending order, older pages by cursor", async () => {
+  const user = await createUser();
+  // Two messages share a timestamp; the id breaks the tie.
+  const ids = [
+    insertMessage(user.id, "m1", T(1)),
+    insertMessage(user.id, "m2a", T(2), "00000000-0000-4000-8000-00000000000a"),
+    insertMessage(user.id, "m2b", T(2), "00000000-0000-4000-8000-00000000000b"),
+    insertMessage(user.id, "m3", T(3)),
+  ];
+  const bodies = (ms: { body: string }[]) => ms.map((m) => m.body);
+  assertEquals(bodies(getRecentChatMessages()), ["m1", "m2a", "m2b", "m3"]);
+  assertEquals(bodies(getRecentChatMessages(2)), ["m2b", "m3"]);
+  // Older than m2b: the page boundary falls between the two tied messages.
+  assertEquals(
+    bodies(getRecentChatMessages(10, { createdAt: T(2), id: ids[2] })),
+    ["m1", "m2a"],
+  );
+  // No id: everything strictly before the timestamp.
+  assertEquals(bodies(getRecentChatMessages(10, { createdAt: T(2) })), ["m1"]);
+
+  assertEquals(
+    bodies(getChatMessagesAfter({ createdAt: T(2), id: ids[1] })),
+    ["m2b", "m3"],
+  );
+  // No id: inclusive of the timestamp.
+  assertEquals(bodies(getChatMessagesAfter({ createdAt: T(2) })), [
+    "m2a",
+    "m2b",
+    "m3",
+  ]);
+  assertEquals(bodies(getChatMessagesAfter({ createdAt: T(0) }, 1)), ["m1"]);
+  // Limits are clamped to 1..100.
+  assertEquals(getRecentChatMessages(0).length, 1);
+  assertEquals(getRecentChatMessages(-5).length, 1);
+});
+
+test("read state: unread counts others' messages since the marker", async () => {
+  const me = await createUser({ createdAt: T(0) });
+  const other = await createUser();
+  insertMessage(other.id, "a", T(1));
+  insertMessage(me.id, "mine", T(2));
+  insertMessage(other.id, "b", T(3));
+  // No marker yet: everything since the account was created.
+  assertEquals(getChatReadState(me.id), { readAt: T(0), unread: 2 });
+  assertEquals(markChatRead(me.id, T(1)), { readAt: T(1), unread: 1 });
+  // Never backward.
+  assertEquals(markChatRead(me.id, T(0)).readAt, T(1));
+  // Never past the newest message.
+  assertEquals(markChatRead(me.id, "2999-01-01T00:00:00Z"), {
+    readAt: T(3),
+    unread: 0,
+  });
+  assertThrows(
+    () => markChatRead(me.id, "not a date"),
+    APIException,
+    "Invalid",
+  );
+  assertThrows(
+    () => getChatReadState(crypto.randomUUID()),
+    APIException,
+    "not found",
+  );
+});
+
+test("read state: with no messages at all the marker can't be moved", async () => {
+  const me = await createUser({ createdAt: T(0) });
+  assertEquals(markChatRead(me.id, "2999-01-01T00:00:00Z"), {
+    readAt: T(0),
+    unread: 0,
+  });
+  const other = await createUser();
+  insertMessage(other.id, "later", T(5));
+  assertEquals(getChatReadState(me.id).unread, 1);
+});