refactor(telegram): centralize target parsing

src/telegram/send.test.ts

@@ -302,6 +302,31 @@ describe("sendMessageTelegram", () => {
     });
   });
 
+  it("parses message_thread_id from recipient string (telegram:group:...:topic:...)", async () => {
+    const chatId = "-1001234567890";
+    const sendMessage = vi.fn().mockResolvedValue({
+      message_id: 55,
+      chat: { id: chatId },
+    });
+    const api = { sendMessage } as unknown as {
+      sendMessage: typeof sendMessage;
+    };
+
+    await sendMessageTelegram(
+      `telegram:group:${chatId}:topic:271`,
+      "hello forum",
+      {
+        token: "tok",
+        api,
+      },
+    );
+
+    expect(sendMessage).toHaveBeenCalledWith(chatId, "hello forum", {
+      parse_mode: "HTML",
+      message_thread_id: 271,
+    });
+  });
+
   it("includes reply_to_message_id for threaded replies", async () => {
     const chatId = "123";
     const sendMessage = vi.fn().mockResolvedValue({

src/telegram/send.ts

@@ -11,6 +11,10 @@ import { loadWebMedia } from "../web/media.js";
 import { resolveTelegramAccount } from "./accounts.js";
 import { resolveTelegramFetch } from "./fetch.js";
 import { markdownToTelegramHtml } from "./format.js";
+import {
+  parseTelegramTarget,
+  stripTelegramInternalPrefixes,
+} from "./targets.js";
 
 type TelegramSendOpts = {
   token?: string;
@@ -65,7 +69,7 @@ function normalizeChatId(to: string): string {
   // Common internal prefixes that sometimes leak into outbound sends.
   // - ctx.To uses `telegram:<id>`
   // - group sessions often use `telegram:group:<id>`
-  let normalized = trimmed.replace(/^(telegram|tg|group):/i, "").trim();
+  let normalized = stripTelegramInternalPrefixes(trimmed);
 
   // Accept t.me links for public chats/channels.
   // (Invite links like `t.me/+...` are not resolvable via Bot API.)
@@ -110,7 +114,8 @@ export async function sendMessageTelegram(
     accountId: opts.accountId,
   });
   const token = resolveToken(opts.token, account);
-  const chatId = normalizeChatId(to);
+  const target = parseTelegramTarget(to);
+  const chatId = normalizeChatId(target.chatId);
   // Use provided api or create a new Bot instance. The nullish coalescing
   // operator ensures api is always defined (Bot.api is always non-null).
   const fetchImpl = resolveTelegramFetch();
@@ -123,8 +128,12 @@ export async function sendMessageTelegram(
   // Build optional params for forum topics and reply threading.
   // Only include these if actually provided to keep API calls clean.
   const threadParams: Record<string, number> = {};
-  if (opts.messageThreadId != null) {
-    threadParams.message_thread_id = Math.trunc(opts.messageThreadId);
+  const messageThreadId =
+    opts.messageThreadId != null
+      ? opts.messageThreadId
+      : target.messageThreadId;
+  if (messageThreadId != null) {
+    threadParams.message_thread_id = Math.trunc(messageThreadId);
   }
   if (opts.replyToMessageId != null) {
     threadParams.reply_to_message_id = Math.trunc(opts.replyToMessageId);

src/telegram/targets.test.ts

@@ -0,0 +1,72 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  parseTelegramTarget,
+  stripTelegramInternalPrefixes,
+} from "./targets.js";
+
+describe("stripTelegramInternalPrefixes", () => {
+  it("strips telegram prefix", () => {
+    expect(stripTelegramInternalPrefixes("telegram:123")).toBe("123");
+  });
+
+  it("strips telegram+group prefixes", () => {
+    expect(stripTelegramInternalPrefixes("telegram:group:-100123")).toBe(
+      "-100123",
+    );
+  });
+
+  it("is idempotent", () => {
+    expect(stripTelegramInternalPrefixes("@mychannel")).toBe("@mychannel");
+  });
+});
+
+describe("parseTelegramTarget", () => {
+  it("parses plain chatId", () => {
+    expect(parseTelegramTarget("-1001234567890")).toEqual({
+      chatId: "-1001234567890",
+    });
+  });
+
+  it("parses @username", () => {
+    expect(parseTelegramTarget("@mychannel")).toEqual({
+      chatId: "@mychannel",
+    });
+  });
+
+  it("parses chatId:topicId format", () => {
+    expect(parseTelegramTarget("-1001234567890:123")).toEqual({
+      chatId: "-1001234567890",
+      messageThreadId: 123,
+    });
+  });
+
+  it("parses chatId:topic:topicId format", () => {
+    expect(parseTelegramTarget("-1001234567890:topic:456")).toEqual({
+      chatId: "-1001234567890",
+      messageThreadId: 456,
+    });
+  });
+
+  it("trims whitespace", () => {
+    expect(parseTelegramTarget("  -1001234567890:99  ")).toEqual({
+      chatId: "-1001234567890",
+      messageThreadId: 99,
+    });
+  });
+
+  it("does not treat non-numeric suffix as topicId", () => {
+    expect(parseTelegramTarget("-1001234567890:abc")).toEqual({
+      chatId: "-1001234567890:abc",
+    });
+  });
+
+  it("strips internal prefixes before parsing", () => {
+    expect(
+      parseTelegramTarget("telegram:group:-1001234567890:topic:456"),
+    ).toEqual({
+      chatId: "-1001234567890",
+      messageThreadId: 456,
+    });
+  });
+});

src/telegram/targets.ts

@@ -0,0 +1,43 @@
+export type TelegramTarget = {
+  chatId: string;
+  messageThreadId?: number;
+};
+
+export function stripTelegramInternalPrefixes(to: string): string {
+  let trimmed = to.trim();
+  while (true) {
+    const next = trimmed.replace(/^(telegram|tg|group):/i, "").trim();
+    if (next === trimmed) return trimmed;
+    trimmed = next;
+  }
+}
+
+/**
+ * Parse a Telegram delivery target into chatId and optional topic/thread ID.
+ *
+ * Supported formats:
+ * - `chatId` (plain chat ID, t.me link, @username, or internal prefixes like `telegram:...`)
+ * - `chatId:topicId` (numeric topic/thread ID)
+ * - `chatId:topic:topicId` (explicit topic marker; preferred)
+ */
+export function parseTelegramTarget(to: string): TelegramTarget {
+  const normalized = stripTelegramInternalPrefixes(to);
+
+  const topicMatch = /^(.+?):topic:(\d+)$/.exec(normalized);
+  if (topicMatch) {
+    return {
+      chatId: topicMatch[1],
+      messageThreadId: Number.parseInt(topicMatch[2], 10),
+    };
+  }
+
+  const colonMatch = /^(.+):(\d+)$/.exec(normalized);
+  if (colonMatch) {
+    return {
+      chatId: colonMatch[1],
+      messageThreadId: Number.parseInt(colonMatch[2], 10),
+    };
+  }
+
+  return { chatId: normalized };
+}