I am trying to use add_filter to modify the price, regular price and sale price of a product prior to saving to the database.

I am using dokan plugin and each category is assigned a commission meta value. I have retrieved this commission and created a new price using the retrieved commission.

Now the problem is to modify the prices when adding or updating to use this new price set from the formula.

function get_category_commission(){

    $commission_set=0;

    $worked=0;

    global $woo_options;

    global $post;

    $term_vals = NULL;

    $primary_cat_id=get_post_meta($post->ID,'_yoast_wpseo_primary_product_cat',true);

    if($primary_cat_id){

      $primary_category = $primary_cat_id;

     }

    if($primary_category!=""){

      $term_vals1 = get_term_meta($primary_category);

      foreach($term_vals1 as $key1=>$val1){

      if($key1=="per_category_admin_commission_type"&&$val1[0]!=""){

       $commission_set = 1;

      }
     if($key1=="per_category_admin_commission"){

        $amount = $val1[0];
     }

}

if($commission_set=="1"&&$amount!=""){

    return $amount;
    //continue;

    $worked=1;

}

}

 $terms = get_the_terms( $post->ID, 'product_cat' );

        foreach ($terms as $term) {

            $term_id = $term->term_id;

            $term_vals = get_term_meta($term_id);

foreach($term_vals as $key=>$val){

    if($key=="per_category_admin_commission_type"&&$val[0]!=""){

    $commission_set = 1;

    }
      if($key=="per_category_admin_commission"){

        $amount = $val[0];
    }

}

}

if($worked!="1"){

return $amount;

}

}

function custom_price( $price) {

    $commission = $price/100 * get_category_commission();

    return $price + $commission;

}

add_filter( 'wp_insert_post_data' , 'filter_post_data' , '99', 2 );

function filter_post_data( $data , $postarr ) {

    $data['meta_input']['_regular_price'] = custom_price($data['meta_input']['_price']);

    $data['meta_input']['_regular_price'] = custom_price($data['meta_input']['_regular_price']);

    $data['meta_input']['_sale_price'] = custom_price($data['meta_input']['_sale_price']);

    return $data;
}

Can someone point me in the right direction.