fix: discord mention handling (#33224) (thanks @thewilloftheshadow) (#33224)

src/discord/directory-cache.ts

@@ -0,0 +1,111 @@
+import { DEFAULT_ACCOUNT_ID, normalizeAccountId } from "../routing/account-id.js";
+
+const DISCORD_DIRECTORY_CACHE_MAX_ENTRIES = 4000;
+const DISCORD_DISCRIMINATOR_SUFFIX = /#\d{4}$/;
+
+const DIRECTORY_HANDLE_CACHE = new Map<string, Map<string, string>>();
+
+function normalizeAccountCacheKey(accountId?: string | null): string {
+  const normalized = normalizeAccountId(accountId ?? DEFAULT_ACCOUNT_ID);
+  return normalized || DEFAULT_ACCOUNT_ID;
+}
+
+function normalizeSnowflake(value: string | number | bigint): string | null {
+  const text = String(value ?? "").trim();
+  if (!/^\d+$/.test(text)) {
+    return null;
+  }
+  return text;
+}
+
+function normalizeHandleKey(raw: string): string | null {
+  let handle = raw.trim();
+  if (!handle) {
+    return null;
+  }
+  if (handle.startsWith("@")) {
+    handle = handle.slice(1).trim();
+  }
+  if (!handle || /\s/.test(handle)) {
+    return null;
+  }
+  return handle.toLowerCase();
+}
+
+function ensureAccountCache(accountId?: string | null): Map<string, string> {
+  const cacheKey = normalizeAccountCacheKey(accountId);
+  const existing = DIRECTORY_HANDLE_CACHE.get(cacheKey);
+  if (existing) {
+    return existing;
+  }
+  const created = new Map<string, string>();
+  DIRECTORY_HANDLE_CACHE.set(cacheKey, created);
+  return created;
+}
+
+function setCacheEntry(cache: Map<string, string>, key: string, userId: string): void {
+  if (cache.has(key)) {
+    cache.delete(key);
+  }
+  cache.set(key, userId);
+  if (cache.size <= DISCORD_DIRECTORY_CACHE_MAX_ENTRIES) {
+    return;
+  }
+  const oldest = cache.keys().next();
+  if (!oldest.done) {
+    cache.delete(oldest.value);
+  }
+}
+
+export function rememberDiscordDirectoryUser(params: {
+  accountId?: string | null;
+  userId: string | number | bigint;
+  handles: Array<string | null | undefined>;
+}): void {
+  const userId = normalizeSnowflake(params.userId);
+  if (!userId) {
+    return;
+  }
+  const cache = ensureAccountCache(params.accountId);
+  for (const candidate of params.handles) {
+    if (typeof candidate !== "string") {
+      continue;
+    }
+    const handle = normalizeHandleKey(candidate);
+    if (!handle) {
+      continue;
+    }
+    setCacheEntry(cache, handle, userId);
+    const withoutDiscriminator = handle.replace(DISCORD_DISCRIMINATOR_SUFFIX, "");
+    if (withoutDiscriminator && withoutDiscriminator !== handle) {
+      setCacheEntry(cache, withoutDiscriminator, userId);
+    }
+  }
+}
+
+export function resolveDiscordDirectoryUserId(params: {
+  accountId?: string | null;
+  handle: string;
+}): string | undefined {
+  const cache = DIRECTORY_HANDLE_CACHE.get(normalizeAccountCacheKey(params.accountId));
+  if (!cache) {
+    return undefined;
+  }
+  const handle = normalizeHandleKey(params.handle);
+  if (!handle) {
+    return undefined;
+  }
+  const direct = cache.get(handle);
+  if (direct) {
+    return direct;
+  }
+  const withoutDiscriminator = handle.replace(DISCORD_DISCRIMINATOR_SUFFIX, "");
+  if (!withoutDiscriminator || withoutDiscriminator === handle) {
+    return undefined;
+  }
+  return cache.get(withoutDiscriminator);
+}
+
+export function __resetDiscordDirectoryCacheForTest(): void {
+  DIRECTORY_HANDLE_CACHE.clear();
+}