feat(plugin): extract rule engine and harden channel/session handling

plugin/index.ts

@@ -1,60 +1,32 @@
 import type { OpenClawPluginApi } from "openclaw/plugin-sdk";
-
-type Config = {
-  enabled?: boolean;
-  discordOnly?: boolean;
-  bypassUserIds?: string[];
-  endSymbols?: string[];
-  noReplyProvider: string;
-  noReplyModel: string;
-};
-
-type Decision = {
-  shouldUseNoReply: boolean;
-  reason: string;
-};
+import { evaluateDecision, type Decision, type WhisperGateConfig } from "./rules.js";
 
 const sessionDecision = new Map<string, Decision>();
+const MAX_SESSION_DECISIONS = 2000;
 
-function getLastChar(input: string): string {
-  const t = input.trim();
-  return t.length ? t[t.length - 1] : "";
+function normalizeChannel(ctx: Record<string, unknown>): string {
+  const candidates = [ctx.commandSource, ctx.messageProvider, ctx.channelId, ctx.channel];
+  for (const c of candidates) {
+    if (typeof c === "string" && c.trim()) return c.trim().toLowerCase();
+  }
+  return "";
 }
 
-function shouldUseNoReply(params: {
-  config: Config;
-  channel?: string;
-  senderId?: string;
-  content?: string;
-}): Decision {
-  const { config } = params;
-
-  if (config.enabled === false) {
-    return { shouldUseNoReply: false, reason: "disabled" };
+function pruneDecisionMap() {
+  if (sessionDecision.size <= MAX_SESSION_DECISIONS) return;
+  const keys = sessionDecision.keys();
+  while (sessionDecision.size > MAX_SESSION_DECISIONS) {
+    const k = keys.next();
+    if (k.done) break;
+    sessionDecision.delete(k.value);
   }
-
-  const channel = (params.channel || "").toLowerCase();
-  if (config.discordOnly !== false && channel !== "discord") {
-    return { shouldUseNoReply: false, reason: "non_discord" };
-  }
-
-  if (params.senderId && (config.bypassUserIds || []).includes(params.senderId)) {
-    return { shouldUseNoReply: false, reason: "bypass_sender" };
-  }
-
-  const lastChar = getLastChar(params.content || "");
-  if (lastChar && (config.endSymbols || []).includes(lastChar)) {
-    return { shouldUseNoReply: false, reason: `end_symbol:${lastChar}` };
-  }
-
-  return { shouldUseNoReply: true, reason: "rule_match_no_end_symbol" };
 }
 
 export default {
   id: "whispergate",
   name: "WhisperGate",
   register(api: OpenClawPluginApi) {
-    const config = (api.pluginConfig || {}) as Config;
+    const config = (api.pluginConfig || {}) as WhisperGateConfig;
 
     api.registerHook("message:received", async (event, ctx) => {
       try {
@@ -71,15 +43,11 @@ export default {
               : undefined;
 
         const content = typeof e.content === "string" ? e.content : "";
-        const channel =
-          typeof c.commandSource === "string"
-            ? c.commandSource
-            : typeof c.channelId === "string"
-              ? c.channelId
-              : "";
+        const channel = normalizeChannel(c);
 
-        const decision = shouldUseNoReply({ config, channel, senderId, content });
+        const decision = evaluateDecision({ config, channel, senderId, content });
         sessionDecision.set(sessionKey, decision);
+        pruneDecisionMap();
         api.logger.debug?.(`whispergate: session=${sessionKey} decision=${decision.reason}`);
       } catch (err) {
         api.logger.warn(`whispergate: message hook failed: ${String(err)}`);

plugin/rules.ts

@@ -0,0 +1,47 @@
+export type WhisperGateConfig = {
+  enabled?: boolean;
+  discordOnly?: boolean;
+  bypassUserIds?: string[];
+  endSymbols?: string[];
+  noReplyProvider: string;
+  noReplyModel: string;
+};
+
+export type Decision = {
+  shouldUseNoReply: boolean;
+  reason: string;
+};
+
+function getLastChar(input: string): string {
+  const t = input.trim();
+  return t.length ? t[t.length - 1] : "";
+}
+
+export function evaluateDecision(params: {
+  config: WhisperGateConfig;
+  channel?: string;
+  senderId?: string;
+  content?: string;
+}): Decision {
+  const { config } = params;
+
+  if (config.enabled === false) {
+    return { shouldUseNoReply: false, reason: "disabled" };
+  }
+
+  const channel = (params.channel || "").toLowerCase();
+  if (config.discordOnly !== false && channel !== "discord") {
+    return { shouldUseNoReply: false, reason: "non_discord" };
+  }
+
+  if (params.senderId && (config.bypassUserIds || []).includes(params.senderId)) {
+    return { shouldUseNoReply: false, reason: "bypass_sender" };
+  }
+
+  const lastChar = getLastChar(params.content || "");
+  if (lastChar && (config.endSymbols || []).includes(lastChar)) {
+    return { shouldUseNoReply: false, reason: `end_symbol:${lastChar}` };
+  }
+
+  return { shouldUseNoReply: true, reason: "rule_match_no_end_symbol" };
+}