Wordpress: The Events Calendar, ACF: TEC Filter Bar Filter Based on ACF Relationship Field - wordpress

Question

I've been struggling a bit with this. I have one custom post type that I created called "pt_initiatives" and one that The Event Calendar created called "tribe_events". With Advanced Custom Fields, I added a relationship field to both post types which is also bi-directional. The relationship field is called "bi_initiatives-events".
I have The Events Calendar Pro with the Filter Bar add on. I am trying to create a filter that shows the pt_initiatives posts as options in a multi-checkbox filter. (There are only 9 of these posts). I have that part working so far. I am a bit lost on how to update the list of events when one of these pt_initiatives are chosen.
I've been playing with the wpdb queries with no success. I'm not sure how to tell it to look at tribe_events posts to find which has posts in common. I've been scouring the internet and haven't come across anything too helpful and The Event Calendar folks don't seem too keen on helping since this is considered "Customization". However, they offer the ability to add filters as a feature... They have a very vague page on how to do this but I personally did not find it too helpful.
I am not too familiar with writing wpdb queries, hence you can see me adding a post loop to achieve the same thing. At least, I think it's the same output as some examples I came across.
Thanks in advance!
class Tribe__Events__Filterbar__Filters__Initiative extends Tribe__Events__Filterbar__Filter {
public $type = 'checkbox';
public function get_admin_form() {
$title = $this->get_title_field();
$type = $this->get_multichoice_type_field();
return $title.$type;
}
protected function get_values() {
/** #var wpdb $wpdb */
global $wpdb;
// get initiative IDs associated with published posts
// $initiative_ids = $wpdb->get_col(
// $wpdb->prepare(
// "SELECT DISTINCT m.meta_value
// FROM {$wpdb->postmeta} m
// INNER JOIN {$wpdb->posts} p
// ON p.ID=m.post_id
// WHERE p.post_type=%s,
// AND p.post_status='publish'
// AND m.meta_key='bi_initiatives-events'
// AND m.meta_value > 0", $post_type
// )
// );
$initiative_ids = array();
// WP_Query arguments
$args = array(
'post_type' => array( 'pt_initiatives' ),
'posts_per_page' => -1,
'meta_query' => array(
array(
'key' => 'bi_initiatives-events',
// 'value' => '',
'compare' => 'EXISTS'
)
)
);
$query = new WP_Query( $args );
if ( $query->have_posts() ) {
while ( $query->have_posts() ) {
$query->the_post();
$initiative_ids[] = get_the_ID();
}
}
wp_reset_postdata();
array_filter( $initiative_ids );
if ( empty( $initiative_ids ) ) {
return array();
}
/**
* Filter Total Initiatives in Filter Bar
* Use this with caution, this will load initiatives on the front-end, may be slow
* The base limit is 200 for safety reasons
*
*
* #parm int 200 posts per page limit
* #parm array $initiative_ids ids of initiatives attached to events
*/
$limit = apply_filters( 'tribe_events_filter_bar_pt_initiatives_limit', 200, $initiative_ids );
$initiatives = get_posts( array(
'post_type' => 'pt_initiatives',
'posts_per_page' => $limit,
'suppress_filters' => false,
'post__in' => $initiative_ids,
'post_status' => 'publish',
'orderby' => 'title',
'order' => 'ASC',
) );
$initiatives_array = array();
foreach ( $initiatives as $initiative => $value ) {
$initiatives_array[] = array(
'name' => $value->post_title,
'value' => $value->ID,
);
}
return $initiatives_array;
}
protected function setup_join_clause() {
add_filter( 'posts_join', array( 'Tribe__Events__Query', 'posts_join' ), 10, 2 );
global $wpdb;
$this->joinClause .= " LEFT JOIN {$wpdb->postmeta} AS initiatives_filter ON ({$wpdb->posts}.ID = initiatives_filter.post_id AND initiatives_filter.meta_key = 'bi_initiatives-events')";
}
protected function setup_where_clause() {
if ( is_array( $this->currentValue ) ) {
$initiative_ids = implode( ',', array_map( 'intval', $this->currentValue ) );
} else {
$initiative_ids = esc_attr( $this->currentValue );
}
$this->whereClause = " AND initiatives_filter.meta_value IN ($initiative_ids) ";
}
}
new Tribe__Events__Filterbar__Filters__Initiative( __( 'Initiatives', 'tribe-events-filter-view' ), 'initiatives_filter' );