Flexslider used on river pages

aw_flexslider.php

<?php

function relation_get_related_entities($entity_type, $entity_id, $relation_type = NULL, $r_index = NULL) {
   $query = relation_query($entity_type, $entity_id, $r_index);
   if ($relation_type) {
     $query->propertyCondition('relation_type', $relation_type);
   }
   $results = $query->execute();

   $relations = array();
   foreach($results as $result) {
     if (empty($result)) {
       return FALSE;
     }
     $relation = relation_load($result->rid);
     $request_key = $entity_type . ':' . $entity_id;
     $entities = $relation->endpoints[LANGUAGE_NONE];
     $first_entity_key = $entities[0]['entity_type'] . ':' . $entities[0]['entity_id'];
     if (isset($r_index)) {
       $request_key = $request_key . ':' . $r_index;
       $first_entity_key = $first_entity_key . ':' . $entities[0]['r_index'];
     }
     if ($request_key == $first_entity_key) {
       $other_endpoints = entity_load($entities[1]['entity_type'], array($entities[1]['entity_id']));
       foreach($other_endpoints as $endpoint)
         $relations[] = $endpoint;
     }
     else {
       $other_endpoints = entity_load($entities[0]['entity_type'], array($entities[0]['entity_id']));
       foreach($other_endpoints as $endpoint)
         $relations[] = $endpoint;
     }
   }

   return $relations;
}

function generate_image_style($file_uri) {
    $original_path = file_uri_target($file_uri);
    $style_path = image_style_path('large2', $file_uri);

    if (!file_exists($style_path)) {
      image_style_create_derivative(image_style_load('large2'), $file_uri, $style_path);
    }

    if (file_exists($style_path))
        return image_style_url('large2', $file_uri);
    else
        return file_create_url($file_uri);

}


$nid_filter = isset($_REQUEST['nid']) ? $_REQUEST['nid'] : null;
if($nid_filter) {
    
    $nodes_to_check = array( (array) node_load($nid_filter));
    
    if ($nodes_to_check[0]['type'] == 'river_section') {
        $features = relation_get_related_entities('node', $nid_filter, $relation_type = 'has_feature');
        foreach($features as $feature)
            $nodes_to_check[] = (array) $feature;
    } 
    else if ($nodes_to_check[0]['type'] == 'river') {
        $nodes_to_check[] = (array) relation_get_related_entity('node', $nid_filter, $relation_type = 'has_river_section');

        $sections = relation_get_related_entities('node', $nid_filter, $relation_type = 'has_river_section');
        foreach($sections as $section) {
            $nodes_to_check[] = (array) $section;

            $features = relation_get_related_entities('node', $section->nid, $relation_type = 'has_feature');
            foreach($features as $feature)
                $nodes_to_check[] = (array) $feature;
        }


    }

    // print "<pre>";
    // print_r($result);
    // print "</pre>";

    $photos = array();
    foreach($nodes_to_check as $node) {
        if( isset($node['field_photos']) ) {
            // print_r($node['field_photos'][und]);
            foreach($node['field_photos'][und] as $photo) {
                if(!in_array($photo, $photos))
                    $photos[] = $photo;
            }
        }
    }

    if(count($photos)) { ?>
        <div id="river_photo_gallery_slider" class="slider" style="width: 100%;">
            <div class="flexslider">
                <div class="loading">Loading...</div>
                <ul class="slides hidden">
                <?php foreach($photos as $photo) { ?>
                    <li>
                        <div class="img_container">
                            <a href="/file/<?php print $photo['fid']; ?>">
                                <img alt="<?php print $photo['field_caption'][und][0]['value']; ?>"
                                     src="<?php print generate_image_style($photo['uri']);  ?>" >
                             </a>
                         </div>
                     </li>
                <?php } ?>
                </ul>
            </div>
        </div>
    <?php }
}
?>

<!-- this following is added to template.tpl instead
<script src="https://cdnjs.cloudflare.com/ajax/libs/flexslider/2.2.0/jquery.flexslider-min.js"></script>
drupal_add_js('https://cdnjs.cloudflare.com/ajax/libs/flexslider/2.2.0/jquery.flexslider-min.js', 'external');
-->

<script>
    jQuery(document).ready(function(){
        jQuery('.flexslider').flexslider({
            animation: "slide",
            start: function(slider){
              jQuery('.flexslider .loading').hide();
              jQuery('.slides').removeClass('hidden');
            }
        });
    });
</script>