Adjacent post in same category same post format

Hello,

I am trying to modify the function “get_adjacent_post” to add another boolean variable to enable same post format filtering (I’ll create a new function in function.php)

I went into the /wp-includes/link-template.php file to find the function but it looks more complicated than I thought.
Post format entry is not in the post table and I can’t comprehend the sql request in this function very well.

I searched online, but it seems no one ever tried this.

this is the original function:

function get_adjacent_post( $in_same_cat = false, $excluded_categories = '', $previous = true ) {
	global $wpdb;

	if ( ! $post = get_post() )
		return null;

	$current_post_date = $post->post_date;

	$join = '';
	$posts_in_ex_cats_sql = '';
	if ( $in_same_cat || ! empty( $excluded_categories ) ) {
		$join = " INNER JOIN $wpdb->term_relationships AS tr ON p.ID = tr.object_id INNER JOIN $wpdb->term_taxonomy tt ON tr.term_taxonomy_id = tt.term_taxonomy_id";

		if ( $in_same_cat ) {
			if ( ! is_object_in_taxonomy( $post->post_type, 'category' ) )
				return '';
			$cat_array = wp_get_object_terms($post->ID, 'category', array('fields' => 'ids'));
			if ( ! $cat_array || is_wp_error( $cat_array ) )
				return '';
			$join .= " AND tt.taxonomy = 'category' AND tt.term_id IN (" . implode(',', $cat_array) . ")";
		}

		$posts_in_ex_cats_sql = "AND tt.taxonomy = 'category'";
		if ( ! empty( $excluded_categories ) ) {
			if ( ! is_array( $excluded_categories ) ) {
				// back-compat, $excluded_categories used to be IDs separated by " and "
				if ( strpos( $excluded_categories, ' and ' ) !== false ) {
					_deprecated_argument( __FUNCTION__, '3.3', sprintf( __( 'Use commas instead of %s to separate excluded categories.' ), "'and'" ) );
					$excluded_categories = explode( ' and ', $excluded_categories );
				} else {
					$excluded_categories = explode( ',', $excluded_categories );
				}
			}

			$excluded_categories = array_map( 'intval', $excluded_categories );

			if ( ! empty( $cat_array ) ) {
				$excluded_categories = array_diff($excluded_categories, $cat_array);
				$posts_in_ex_cats_sql = '';
			}

			if ( !empty($excluded_categories) ) {
				$posts_in_ex_cats_sql = " AND tt.taxonomy = 'category' AND tt.term_id NOT IN (" . implode($excluded_categories, ',') . ')';
			}
		}
	}

	$adjacent = $previous ? 'previous' : 'next';
	$op = $previous ? '<' : '>';
	$order = $previous ? 'DESC' : 'ASC';

	$join  = apply_filters( "get_{$adjacent}_post_join", $join, $in_same_cat, $excluded_categories );
	$where = apply_filters( "get_{$adjacent}_post_where", $wpdb->prepare("WHERE p.post_date $op %s AND p.post_type = %s AND p.post_status = 'publish' $posts_in_ex_cats_sql", $current_post_date, $post->post_type), $in_same_cat, $excluded_categories );
	$sort  = apply_filters( "get_{$adjacent}_post_sort", "ORDER BY p.post_date $order LIMIT 1" );

	$query = "SELECT p.id FROM $wpdb->posts AS p $join $where $sort";
	$query_key = 'adjacent_post_' . md5($query);
	$result = wp_cache_get($query_key, 'counts');
	if ( false !== $result ) {
		if ( $result )
			$result = get_post( $result );
		return $result;
	}

	$result = $wpdb->get_var( $query );
	if ( null === $result )
		$result = '';

	wp_cache_set($query_key, $result, 'counts');

	if ( $result )
		$result = get_post( $result );

	return $result;
}

I guess I will have to do something like this:

function get_adjacent_post( $in_same_cat = false, $excluded_categories = '', $previous = true, $same_format = false ) {
.
.
.
if ($same_format) {
	$join.='....';
.
.
.
}

If someone could help me find the correct junction, it would be great. It looks too messy for me.