inserting ads between every 7th post of homepage and category wordpress page

I am trying to insert google ads between every 7th posts in my wordpress site with infinite scroll. i searched and found results but that didn’t worked for me because the WordPress theme i am using is little complex. the result i found was to add this code

<?php $postnum++; if($postnum%5 == 0) { ?>
YOUR AD CODE HERE
<?php } ?>

after <?php endwhile; ?> in index.php, but in my case the loop is different from the general wordpress theme. the loop i have is like this and i want to know how can i implement the above code in my case.

loop code

static function loop( $template ) {
        global $wp_query;
        echo '<input type="hidden" id="query-' . $template . '" value="' . urlencode( json_encode( $wp_query -> query ) ) . '" />';
        if ( count( $wp_query->posts) > 0 ) {
            if( self::is_grid( $template ) ){
?>
                <div class="loop-container-view grid">
                    <?php self::loop_switch( $template , 1 ); ?>
                </div>
<?php
            }else{
?>
                <div class="loop-container-view list" id="contloop">
                    <?php self::loop_switch( $template , 0 ); ?>
                </div>
<?php
            }

            get_template_part('pagination');
        } else {
            get_template_part('loop', '404');
        }
    }

which then call this code, i made it a little shorter

static function get( $post , $template = 'blog_page' ){

        $meta = meta::get_meta( $post -> ID  , 'settings' );
        if( isset( $meta['safe'] ) ){
            if( meta::logic( $post , 'settings' , 'safe' ) ){
                $classes = ' nsfw';
            }else{
                $classes = ' ';
            }
        }else{
            $classes = ' ';
        }
    ?>
        <!-- post -->
        <article id="post-<?php echo $post -> ID; ?>" <?php post_class( 'post ' . $classes , $post -> ID ); ?>>
        </article>
    <?php
    }

loop switch function

static function loop_switch( $template = '' , $grid = 1 ) {
        global $wp_query;
        if ( !empty( $template ) ) {
            $ajax = false;
        } else {
            $query = array();
            $template = isset( $_POST['template'] ) && strlen( $_POST['template'] ) ? $_POST['template'] : exit();
            $query = isset( $_POST['query'] ) && !empty( $_POST['query'] ) ? (array)json_decode( urldecode( $_POST['query'] ) ) : exit();
            $query['post_status'] = 'publish';
            $wp_query = new WP_Query( $query );
            $grid = isset($_POST['grid']) ? (int)$_POST['grid'] : 1;
            $ajax = true;
        }

        $template   = str_replace( array( '_hot' , '_new' , '_like' ) , '' , $template );

        if( $grid == 1 ){
            $k = 1;
            $i = 1;
            $nr = $wp_query->post_count;

            if (layout::get_length(0, $template) == 940 ) {
                $div = 3;
            } else {
                $div = 2;
            }

            foreach ($wp_query->posts as $post) {
                $wp_query->the_post();
                if ($i == 1) {
                    if (( $nr - $k ) < $div) {
                        $classes = 'class="last"';
                    } else {
                        $classes = '';
                    }
                    echo '<div ' . $classes . '>';
                }

                self::grid( $post, $template );

                if ($i % $div == 0) {
                    echo '</div>';
                    $i = 0;
                }
                $i++;
                $k++;
            }

            if ($i > 1) {
                echo '</div>';
            }
        }else{
            foreach( $wp_query->posts as $index => $post ) {
                $wp_query->the_post();
                if ($index > 0) {
                    ?><!--<p class="delimiter">&nbsp;</p>--><?php
                }

                self::get( $post, $template );
            }
        }

        if( $ajax ){
            exit();
        }
    }