feat: certificates, landing pages, ai tutor, website update, compliance

apps/jobs/src/services/transcription/openai.ts

@@ -0,0 +1,67 @@
+import { createReadStream } from 'node:fs';
+import { stat } from 'node:fs/promises';
+
+import OpenAI from 'openai';
+
+/** OpenAI audio transcription file size limit (bytes). */
+export const WHISPER_MAX_FILE_BYTES = 25 * 1024 * 1024;
+
+export class AudioFileTooLargeError extends Error {
+  readonly code = 'AUDIO_TOO_LARGE';
+
+  constructor(readonly fileSizeBytes: number) {
+    super(`Audio file ${fileSizeBytes} bytes exceeds Whisper limit of ${WHISPER_MAX_FILE_BYTES}`);
+    this.name = 'AudioFileTooLargeError';
+  }
+}
+
+export interface TranscriptionSegment {
+  start: number;
+  end: number;
+  text: string;
+}
+
+export interface TranscribeAudioFileResult {
+  language: string;
+  durationSeconds: number;
+  segments: TranscriptionSegment[];
+  fullText: string;
+}
+
+/**
+ * Calls Whisper with verbose_json + segment timestamps. Omit `language` for
+ * auto-detection; the API returns the detected ISO 639-1 code.
+ */
+export async function transcribeAudioFile(params: {
+  apiKey: string;
+  localPath: string;
+  language?: string;
+}): Promise<TranscribeAudioFileResult> {
+  const fileStat = await stat(params.localPath);
+  if (fileStat.size > WHISPER_MAX_FILE_BYTES) {
+    throw new AudioFileTooLargeError(fileStat.size);
+  }
+
+  const client = new OpenAI({ apiKey: params.apiKey });
+
+  const response = await client.audio.transcriptions.create({
+    file: createReadStream(params.localPath),
+    model: 'whisper-1',
+    response_format: 'verbose_json',
+    timestamp_granularities: ['segment'],
+    ...(params.language ? { language: params.language } : {})
+  });
+
+  const language = response.language ?? 'und';
+  const durationSeconds = response.duration ?? 0;
+  const fullText = response.text?.trim() ?? '';
+
+  const rawSegments = response.segments ?? [];
+  const segments: TranscriptionSegment[] = rawSegments.map((seg) => ({
+    start: seg.start,
+    end: seg.end,
+    text: seg.text.trim()
+  }));
+
+  return { language, durationSeconds, segments, fullText };
+}