fix: correct import paths and add missing protocol files for DDD structure

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/infrastructure/telegram/upload-queue.ts

@@ -0,0 +1,81 @@
+import PQueue from 'p-queue';
+import { config } from '../../env';
+import logger from '../../shared/logger/index';
+
+/**
+ * P-queue instance for serialising Telegram upload tasks.
+ *
+ * Concurrency is governed by {@link config.uploadConcurrency}.
+ * Built-in logging emits warnings when the queue grows beyond 5 pending items.
+ */
+const uploadQueue = new PQueue({
+  concurrency: config.uploadConcurrency,
+});
+
+/* Monitor queue growth and emit warnings for large backlogs */
+uploadQueue.on('add', () => {
+  const stats = getQueueStats();
+  if (stats.size > 5) {
+    logger.warn('Upload queue building up', { pending: stats.pending, size: stats.size });
+  }
+});
+
+uploadQueue.on('next', () => {
+  const stats = getQueueStats();
+  logger.debug('Processing next upload', { pending: stats.pending, size: stats.size });
+});
+
+/**
+ * Enqueue an upload task to be executed by the queue.
+ *
+ * Tasks are executed in FIFO order, subject to the concurrency limit.
+ *
+ * @param task - An async function representing the upload operation.
+ * @returns A promise that resolves with the task's result.
+ */
+export const enqueueUpload = <T>(task: () => Promise<T>): Promise<T> => {
+  return uploadQueue.add(task);
+};
+
+/**
+ * Get current queue statistics.
+ *
+ * @returns An object with `pending` (actively executing) and `size` (waiting) counts.
+ */
+export const getQueueStats = (): { pending: number; size: number } => ({
+  pending: uploadQueue.pending,
+  size: uploadQueue.size,
+});
+
+/**
+ * Get the number of items waiting in the queue (not yet started).
+ *
+ * @returns The number of queued items.
+ */
+export const getQueueSize = (): number => uploadQueue.size;
+
+/**
+ * Get the number of items currently being processed.
+ *
+ * @returns The number of pending (in-flight) items.
+ */
+export const getPendingCount = (): number => uploadQueue.pending;
+
+/**
+ * Clear all pending items and wait for in-flight ones to finish.
+ *
+ * @returns A promise that resolves when the queue is idle after clearing.
+ */
+export const clearQueue = async (): Promise<void> => {
+  uploadQueue.clear();
+  await uploadQueue.onIdle();
+};
+
+/**
+ * Wait for the queue to become idle (all tasks finished).
+ *
+ * @returns A promise that resolves when no tasks are pending or in-flight.
+ */
+export const waitForQueue = async (): Promise<void> => {
+  await uploadQueue.onIdle();
+};