Format YouTube video link for embed without cross domain origin error.

functions.php

if (get_field('video_link')) :
  // Video_link is the field from WP's ACF (can be any URL string
  // from YouTube), while embed_link will be the string we use.
  $video_link = get_field('video_link');
  $embed_link = "";
  // Proper embed link, move along.
  if ( strpos($video_link, '/embed/') !== false ) {
    $embed_link = $video_link;
  }
  // Share link, will need to grab video ID.
  elseif ( strpos($video_link, 'youtu.be/') !== false ) {
    $video_link_array = explode('youtu.be/', $video_link);
    $video_link_id = $video_link_array[1];
    if ( strpos($video_link_id, '&') !== false ) {
      $video_link_params = explode('&', $video_link_array[1]);
      $video_link_id = $video_link_params[0];
    }
    $embed_link = 'https://www.youtube.com/embed/' . $video_link_id;
  }
  // Page URL, will need to grab video ID.
  elseif ( strpos($video_link, '/watch?v=') !== false ) {
    $video_link_array = explode('/watch?v=', $video_link);
    $video_link_id = $video_link_array[1];
    if ( strpos($video_link_id, '&') !== false ) {
      $video_link_params = explode('&', $video_link_array[1]);
      $video_link_id = $video_link_params[0];
    }
    $embed_link = 'https://www.youtube.com/embed/' . $video_link_id;
  }
endif;