import { spawn } from 'child_process';

/** Convert browser webm/opus to ogg/opus for WhatsApp PTT delivery. */
export function convertWebmToOggOpus(input: Buffer): Promise<Buffer> {
  return new Promise((resolve, reject) => {
    const ff = spawn(
      'ffmpeg',
      ['-hide_banner', '-loglevel', 'error', '-i', 'pipe:0', '-c:a', 'libopus', '-f', 'ogg', 'pipe:1'],
      { stdio: ['pipe', 'pipe', 'pipe'] },
    );
    const out: Buffer[] = [];
    const err: Buffer[] = [];
    ff.stdout.on('data', (c: Buffer) => out.push(c));
    ff.stderr.on('data', (c: Buffer) => err.push(c));
    ff.on('error', reject);
    ff.on('close', code => {
      if (code === 0 && out.length) resolve(Buffer.concat(out));
      else reject(new Error(`ffmpeg exit ${code}: ${Buffer.concat(err).toString('utf8').slice(0, 200)}`));
    });
    ff.stdin.write(input);
    ff.stdin.end();
  });
}