Callback function doesnt works

Hey guys,

I’m developing my first wordpress plugin and i need to use Ajax, but i’ve already know how to do it.

But i’m getting an error, i create a callback function to test with is it working, but i always get a “0” as response text.

The code is this

add_action( 'wp', 'wcwp_register_scripts');
function wcwp_register_scripts( ) {

        wp_register_script( 'wcwp-js', plugins_url('js/wcwp_buscar_cidade.js', __FILE__), array('jquery') );

        wp_enqueue_script( 'jquery' );

	wp_enqueue_script( 'wcwp-js' );	

}

function wcwp_state_proccess( ) {

	echo "You selected state ". $_POST['stateId'];

	exit();

}

I have a selectbox, that works well, when i change my select box, my javascript needs to get the value ‘stateId’ and returns it to me on wcwp_state_proccess(); It’s just to test if its works, but it never shows me the right value, just show me 0

My js script is:

jQuery(document).ready(function($) {

    $('#select_state_withdrawal_point').change(function(e) {
    	var state = document.getElementById("select_state_withdrawal_point");
		var iten = state.options[state.selectedIndex].value;
    	$.post(document.location.protocol+'//'+document.location.host+'/projetos/dgiprint/wp-admin/admin-ajax.php', {action: 'wcwp_state', stateId: iten}, function(response){

    		alert(response);

    	})

    });

});

And to test you need to access https://marcelloruoppolo.in/projetos/dgiprint and add a product to cart, go to checkout and select “Ship to a different address?” at the end of the page will appear a ‘Withdrawal Point’ option.

My plugin works with WooCommerce, it gives you to have a option to select a Withdrawal point, i need it for a client and don’t find anything so i decided to create it, i will share it for free on wordpress plugins when its ready ??

If anybody can help me, i would apprecciate that ??