Subtitle (srt files) translation with PHP

translate_srt.php

<?php

function translate($text, $source_lang = 'en', $target_lang = 'fa') {
  $url = 'https://translate.googleapis.com/translate_a/single?';
  $url .= http_build_query([
    'client' => 'gtx',
    'sl' => $source_lang,
    'tl' => $target_lang,
    'dt' => 't',
    'q' => $text,
  ]);

  $response = file_get_contents($url);
  $result = json_decode($response, true);

  return $result[0][0][0] ?? false;
}

$srt_filename = "Share.2023.1080p.AMZN.WEB-DL.DDP5.1.H.264.srt";

echo "[*] Loading srt file..." . PHP_EOL;
$srt_file = file_get_contents($srt_filename);
file_put_contents("translated.$srt_filename", '');

$parts = explode("\n\n", $srt_file);
$length = count($parts);

foreach ($parts as $index => $part) {
  $lines = explode("\n", $part);
  $details = implode("\n", array_slice($lines, 0, 2));
  $paragraph = implode("\n", array_slice($lines, 2));
  
  $translated_paragraph = translate($paragraph);
  file_put_contents(
    "translated.$srt_filename",
    ($index == 0 ? '' : "\n") . "$details\n$translated_paragraph" . ((($length - $index) == 1) ? '' : "\n"),
    FILE_APPEND
  );
  
  $precent = (int)(($index * 100) / $length);
  echo "\r[$precent% $index/$length] Translating sentences...";
}

echo "\r[#] Translation completed." . str_repeat(' ', ((strlen("$length") * 2) + 10)) . PHP_EOL;
echo " └─╼ ‘translated." . $srt_filename . "’ saved." . PHP_EOL;