feat: add audio waveform generation for WhatsApp voice messages

- Import audio-decode library for PCM audio analysis
- Add getAudioDuration() helper to extract audio duration in seconds
- Add getAudioWaveform() helper to generate 64-value waveform array
- Modify audioWhatsapp() to include seconds and waveform in message metadata
- Support waveform generation for both encoded and non-encoded audio paths
- Fallback to default values (1 second, flat waveform) if generation fails

This enables proper waveform visualization in WhatsApp voice messages,
addressing issue #1587 in Baileys library.

Author: ffigueroa

src/api/integrations/channel/whatsapp/whatsapp.baileys.service.ts

@@ -90,6 +90,7 @@ import useMultiFileAuthStatePrisma from '@utils/use-multi-file-auth-state-prisma
 import { AuthStateProvider } from '@utils/use-multi-file-auth-state-provider-files';
 import { useMultiFileAuthStateRedisDb } from '@utils/use-multi-file-auth-state-redis-db';
 import axios from 'axios';
+import audioDecode from 'audio-decode';
 import makeWASocket, {
   AnyMessageContent,
   BufferedEventData,
@@ -3038,6 +3039,42 @@ export class BaileysStartupService extends ChannelStartupService {
     }
   }
 
+  private async getAudioDuration(audioBuffer: Buffer): Promise<number> {
+    try {
+      const audioData = await audioDecode(audioBuffer);
+      return Math.ceil(audioData.duration);
+    } catch (error) {
+      this.logger.warn('Failed to get audio duration, using default 1 second');
+      return 1;
+    }
+  }
+
+  private async getAudioWaveform(audioBuffer: Buffer): Promise<number[]> {
+    try {
+      const audioData = await audioDecode(audioBuffer);
+      const samples = audioData.channelData[0]; // Get first channel
+      const waveformLength = 64;
+      const samplesPerWaveform = Math.floor(samples.length / waveformLength);
+
+      const waveform: number[] = [];
+      for (let i = 0; i < waveformLength; i++) {
+        const start = i * samplesPerWaveform;
+        const end = start + samplesPerWaveform;
+        let sum = 0;
+        for (let j = start; j < end && j < samples.length; j++) {
+          sum += Math.abs(samples[j]);
+        }
+        const avg = sum / samplesPerWaveform;
+        waveform.push(Math.floor(avg * 100));
+      }
+
+      return waveform;
+    } catch (error) {
+      this.logger.warn('Failed to generate waveform, using default');
+      return new Array(64).fill(50);
+    }
+  }
+
   public async audioWhatsapp(data: SendAudioDto, file?: any, isIntegration = false) {
     const mediaData: SendAudioDto = { ...data };
 
@@ -3056,9 +3093,12 @@ export class BaileysStartupService extends ChannelStartupService {
       const convert = await this.processAudio(mediaData.audio);
 
       if (Buffer.isBuffer(convert)) {
+        const seconds = await this.getAudioDuration(convert);
+        const waveform = await this.getAudioWaveform(convert);
+
         const result = this.sendMessageWithTyping<AnyMessageContent>(
           data.number,
-          { audio: convert, ptt: true, mimetype: 'audio/ogg; codecs=opus' },
+          { audio: convert, ptt: true, mimetype: 'audio/ogg; codecs=opus', seconds, waveform },
           { presence: 'recording', delay: data?.delay },
           isIntegration,
         );
@@ -3069,12 +3109,24 @@ export class BaileysStartupService extends ChannelStartupService {
       }
     }
 
+    const audioBuffer = isURL(data.audio) ? { url: data.audio } : Buffer.from(data.audio, 'base64');
+    let seconds: number | undefined;
+    let waveform: number[] | undefined;
+
+    // Only generate waveform for buffers, not URLs
+    if (Buffer.isBuffer(audioBuffer)) {
+      seconds = await this.getAudioDuration(audioBuffer);
+      waveform = await this.getAudioWaveform(audioBuffer);
+    }
+
     return await this.sendMessageWithTyping<AnyMessageContent>(
       data.number,
       {
-        audio: isURL(data.audio) ? { url: data.audio } : Buffer.from(data.audio, 'base64'),
+        audio: audioBuffer,
         ptt: true,
         mimetype: 'audio/ogg; codecs=opus',
+        ...(seconds !== undefined && { seconds }),
+        ...(waveform !== undefined && { waveform }),
       },
       { presence: 'recording', delay: data?.delay },
       isIntegration,