the_post_thumbnail unless video id is added

Question

I have 2 choices on the edit post page to insert an video ID from either vimeo or youtube. The user needs to select, with a select field (channel), if he wants to embed video from one or the other.

<?php if (get_field('channel') == 'Youtube') {
        echo get_field('youtube_video_id');
    }
    if (get_field('channel') == 'Vimeo') {
        echo get_field('vimeo_video_id');
    }
?>

Now I'd like this to overrule the_post_thumbnail. So when a video is posted is shows the video instead of the thumb. Is that possible?

<?php if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>
<?php if ( has_post_thumbnail()) : ?>
    <?php the_post_thumbnail(); ?>

    *** MAGIC HERE I GUESS? ***

    <?php endif; ?>
<?php endwhile; else: ?>
    <p>Nothing here</p>    
<?php endif; ?>

Hope somebody can push me in the right direction. Or am I doing this the other way arround? I'm my PHP is still a learning curve.

Thanks, /Paul

Answer 1

I think all you need is this:

<?php if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>
  if (get_field('channel') == 'Youtube') {
    echo get_field('youtube_video_id');
  } elseif (get_field('channel') == 'Vimeo') {
    echo get_field('vimeo_video_id');
  } elseif ( has_post_thumbnail()) {
    the_post_thumbnail();
  }

That should use a Youtube video, then a Vimeo video, then the thumbnail, and do nothing otherwise.