refactor: move iMessage channel to extensions/imessage (#45539)

extensions/imessage/src/monitor/echo-cache.ts

@@ -0,0 +1,87 @@
+export type SentMessageLookup = {
+  text?: string;
+  messageId?: string;
+};
+
+export type SentMessageCache = {
+  remember: (scope: string, lookup: SentMessageLookup) => void;
+  has: (scope: string, lookup: SentMessageLookup) => boolean;
+};
+
+// Keep the text fallback short so repeated user replies like "ok" are not
+// suppressed for long; delayed reflections should match the stronger message-id key.
+const SENT_MESSAGE_TEXT_TTL_MS = 5_000;
+const SENT_MESSAGE_ID_TTL_MS = 60_000;
+
+function normalizeEchoTextKey(text: string | undefined): string | null {
+  if (!text) {
+    return null;
+  }
+  const normalized = text.replace(/\r\n?/g, "\n").trim();
+  return normalized ? normalized : null;
+}
+
+function normalizeEchoMessageIdKey(messageId: string | undefined): string | null {
+  if (!messageId) {
+    return null;
+  }
+  const normalized = messageId.trim();
+  if (!normalized || normalized === "ok" || normalized === "unknown") {
+    return null;
+  }
+  return normalized;
+}
+
+class DefaultSentMessageCache implements SentMessageCache {
+  private textCache = new Map<string, number>();
+  private messageIdCache = new Map<string, number>();
+
+  remember(scope: string, lookup: SentMessageLookup): void {
+    const textKey = normalizeEchoTextKey(lookup.text);
+    if (textKey) {
+      this.textCache.set(`${scope}:${textKey}`, Date.now());
+    }
+    const messageIdKey = normalizeEchoMessageIdKey(lookup.messageId);
+    if (messageIdKey) {
+      this.messageIdCache.set(`${scope}:${messageIdKey}`, Date.now());
+    }
+    this.cleanup();
+  }
+
+  has(scope: string, lookup: SentMessageLookup): boolean {
+    this.cleanup();
+    const messageIdKey = normalizeEchoMessageIdKey(lookup.messageId);
+    if (messageIdKey) {
+      const idTimestamp = this.messageIdCache.get(`${scope}:${messageIdKey}`);
+      if (idTimestamp && Date.now() - idTimestamp <= SENT_MESSAGE_ID_TTL_MS) {
+        return true;
+      }
+    }
+    const textKey = normalizeEchoTextKey(lookup.text);
+    if (textKey) {
+      const textTimestamp = this.textCache.get(`${scope}:${textKey}`);
+      if (textTimestamp && Date.now() - textTimestamp <= SENT_MESSAGE_TEXT_TTL_MS) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  private cleanup(): void {
+    const now = Date.now();
+    for (const [key, timestamp] of this.textCache.entries()) {
+      if (now - timestamp > SENT_MESSAGE_TEXT_TTL_MS) {
+        this.textCache.delete(key);
+      }
+    }
+    for (const [key, timestamp] of this.messageIdCache.entries()) {
+      if (now - timestamp > SENT_MESSAGE_ID_TTL_MS) {
+        this.messageIdCache.delete(key);
+      }
+    }
+  }
+}
+
+export function createSentMessageCache(): SentMessageCache {
+  return new DefaultSentMessageCache();
+}