chatservice

server/src/services/chatService/state.js

@@ -0,0 +1,53 @@
+// Chat Service State
+// Purpose: Stores mutable chat runtime state for rate limits, history, and typing bookkeeping.
+// Scope: Encapsulates in-memory collections shared by chat service modules.
+const { RATE_LIMIT_WINDOW_MS, RATE_LIMIT_MAX, MAX_HISTORY } = require('./constants');
+
+const rateBuckets = new Map();
+const history = [];
+const lastMessageBySocket = new Map();
+const typingBySocket = new Map();
+let lastAccessNoticeAt = 0;
+
+function withinRateLimit(socketId) {
+  const now = Date.now();
+  const entries = rateBuckets.get(socketId) || [];
+  const next = entries.filter((ts) => now - ts <= RATE_LIMIT_WINDOW_MS);
+  next.push(now);
+  rateBuckets.set(socketId, next);
+  return next.length <= RATE_LIMIT_MAX;
+}
+
+function pushHistory(message) {
+  history.push(message);
+  if (history.length > MAX_HISTORY) {
+    history.shift();
+  }
+}
+
+function getRecentMessages(limit = 20, options = {}) {
+  const safeLimit = Number.isFinite(limit) ? Math.max(0, Math.floor(limit)) : 20;
+  const includeSystem = options?.includeSystem !== false;
+  const source = includeSystem ? history : history.filter((entry) => !entry?.system);
+  return source.slice(-safeLimit);
+}
+
+function getLastAccessNoticeAt() {
+  return lastAccessNoticeAt;
+}
+
+function setLastAccessNoticeAt(ts) {
+  lastAccessNoticeAt = ts;
+}
+
+module.exports = {
+  rateBuckets,
+  history,
+  lastMessageBySocket,
+  typingBySocket,
+  withinRateLimit,
+  pushHistory,
+  getRecentMessages,
+  getLastAccessNoticeAt,
+  setLastAccessNoticeAt,
+};