php - Woocommerce Add To Cart adding whole stock into cart -

i in condition add product product cart. whenever purchasing product complementary product should added cart automatically. here have been trying :

function save_gift_wrap_fee( $cart_item_key ) {      if( $_post['offered-product-id'] )     {         global $woocommerce;          if($_post['offered-product-variation-id']){            $woocommerce->cart->add_to_cart($_post['offered-product-id'],'1',$_post['offered-product-variation-id'],array('flavour'=>$_post['offered-product-variation-name']),null);              }         else{             $woocommerce->cart->add_to_cart($_post['offered-product-id'],'1');                 }          wc()->session->set( $cart_item_key.'_offered_product_id', $_post['offered-product-id'] );         wc()->session->set( $cart_item_key.'_offered_product_price', $_post['offered-product-price'] );         wc()->session->set( $cart_item_key.'_offered_variation_id', $_post['offered-product-variation-id'] );     }     else     {         wc()->session->__unset( $cart_item_key.'_offered_product_id' );     }     } add_action( 'woocommerce_add_to_cart', 'save_gift_wrap_fee', 1, 5 );  

i adding product session can reset price discounted price. problem whenever try add product, main product got added cart complementary 1 adding available stock cart , showing message "you cannot add amount cart — have 3 in stock , have 3 in cart.".

i guessing problem add_to_cart() parameters, have tried followings :

$woocommerce->cart->add_to_cart($_post['offered-product-id'],'1',$_post['offered-product-variation-id'],array('flavour'=>$_post['offered-product-variation-name']),null); 

and

$woocommerce->cart->add_to_cart($_post['offered-product-id'],1,$_post['offered-product-variation-id'],array('flavour'=>$_post['offered-product-variation-name']),null); 

getting same message both lines.

any suggestions ?

im not sure solve problem in code, plugin trying http://woogang.com/product/woocommerce-chained-products-extension/