refine telegram adapter

lib/notification/adapter/telegram.js

@@ -8,6 +8,9 @@ import logger from '../../services/logger.js';
 const RATE_LIMIT_INTERVAL = 1000;
 const chatThrottleMap = new Map();
 
+/**
+ * Removes stale throttled call entries to keep memory bounded.
+ */
 function cleanupOldThrottles() {
   const now = Date.now();
   const maxAge = RATE_LIMIT_INTERVAL + 1000;
@@ -18,6 +21,15 @@ function cleanupOldThrottles() {
   for (const chatId of toBeDeleted) chatThrottleMap.delete(chatId);
 }
 
+/**
+ * Return a throttled wrapper for a chatId to limit Telegram API calls.
+ * Uses p-throttle with 1 request per RATE_LIMIT_INTERVAL per chat.
+ *
+ * @template {Function} T
+ * @param {string|number} chatId
+ * @param {T} call - async function (endpoint: string, body: any) => Promise<Response>
+ * @returns {T}
+ */
 function getThrottled(chatId, call) {
   cleanupOldThrottles();
   const now = Date.now();
@@ -31,15 +43,38 @@ function getThrottled(chatId, call) {
   return throttled;
 }
 
+/**
+ * Shorten a string to a maximum length with an ellipsis suffix.
+ * @param {string} str
+ * @param {number} [len=90]
+ * @returns {string}
+ */
 function shorten(str, len = 90) {
   if (!str) return '';
   return str.length > len ? str.substring(0, len).trim() + '...' : str;
 }
 
+/**
+ * Escape basic HTML entities for Telegram HTML parse mode.
+ * @param {string} [s='']
+ * @returns {string}
+ */
 function escapeHtml(s = '') {
   return s.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;');
 }
 
+/**
+ * Build a Telegram photo caption (max 1024 characters) using HTML parse mode.
+ * @param {string} jobName
+ * @param {string} serviceName
+ * @param {Object} o - Listing object
+ * @param {string} [o.title]
+ * @param {string} [o.address]
+ * @param {string|number} [o.price]
+ * @param {string|number} [o.size]
+ * @param {string} [o.link]
+ * @returns {string}
+ */
 function buildCaption(jobName, serviceName, o) {
   const title = shorten((o.title || '').replace(/\*/g, ''), 90);
   const meta = [o.address, o.price, o.size].filter(Boolean).join(' | ');
@@ -48,6 +83,13 @@ function buildCaption(jobName, serviceName, o) {
   )}'><b>${escapeHtml(title)}</b></a>\n${escapeHtml(meta)}`.slice(0, 1024);
 }
 
+/**
+ * Build a Telegram message text using HTML parse mode.
+ * @param {string} jobName
+ * @param {string} serviceName
+ * @param {Object} o - Listing object
+ * @returns {string}
+ */
 function buildText(jobName, serviceName, o) {
   const title = shorten((o.title || '').replace(/\*/g, ''), 90);
   const meta = [o.address, o.price, o.size].filter(Boolean).join(' | ');
@@ -58,8 +100,27 @@ function buildText(jobName, serviceName, o) {
   );
 }
 
-export const send = ({ serviceName, newListings, notificationConfig, jobKey }) => {
-  const { token, chatId } = notificationConfig.find((adapter) => adapter.id === config.id).fields;
+/**
+ * Send new listings to Telegram.
+ * - Respects per-chat Telegram rate limits using a lightweight throttle cache.
+ * - Falls back to sendMessage when sendPhoto fails or image is missing.
+ *
+ * @param {Object} params
+ * @param {string} params.serviceName - Name of the crawler/service producing the listings.
+ * @param {Array<Object>} params.newListings - Array of new listing objects.
+ * @param {Array<Object>} params.notificationConfig - Notification adapters configuration array.
+ * @param {string} params.jobKey - Storage job key to resolve the human readable job name.
+ * @returns {Promise<Array<Response>>} Promise resolving when all send operations complete.
+ */
+export const send = ({ serviceName, newListings = [], notificationConfig, jobKey }) => {
+  const adapterCfg = notificationConfig.find((adapter) => adapter.id === config.id);
+  if (!adapterCfg || !adapterCfg.fields) {
+    throw new Error(`Telegram adapter configuration missing for job '${jobKey || ''}'`);
+  }
+  const { token, chatId } = adapterCfg.fields;
+  if (!token || !chatId) {
+    throw new Error("Telegram 'token' and 'chatId' must be provided in notification config");
+  }
   const job = getJob(jobKey);
   const jobName = job == null ? jobKey : job.name;
 
@@ -77,6 +138,8 @@ export const send = ({ serviceName, newListings, notificationConfig, jobKey }) =
     return res;
   });
 
+  if (!Array.isArray(newListings) || newListings.length === 0) return Promise.resolve([]);
+
   const promises = newListings.map(async (o) => {
     const img = normalizeImageUrl(o.image);
     const textPayload = {
@@ -109,6 +172,10 @@ export const send = ({ serviceName, newListings, notificationConfig, jobKey }) =
   return Promise.all(promises);
 };
 
+/**
+ * Telegram notification adapter configuration schema.
+ * @type {{id:string,name:string,readme:string,description:string,fields:{token:{type:string,label:string,description:string},chatId:{type:string,label:string,description:string}}}}
+ */
 export const config = {
   id: 'telegram',
   name: 'Telegram',