/* Standard AJAX stuff */

var xmlHttp;
var response_text;

function GetXmlHttpObject(handler) {
  var objXmlHttp=null;
  if (navigator.userAgent.indexOf("MSIE")>=0) {
    var strName="Msxml2.XMLHTTP";
    if (navigator.appVersion.indexOf("MSIE 5.5")>=0) {
      strName="Microsoft.XMLHTTP";
    }
    try {
      objXmlHttp=new ActiveXObject(strName);
      objXmlHttp.onreadystatechange=handler;
      return objXmlHttp;
    }
    catch(e) {
      alert("Error. Scripting for ActiveX might be disabled");
      return;
    }
  }
  if (navigator.userAgent.indexOf("Mozilla") >= 0 || navigator.userAgent.indexOf("Opera") >= 0) {
    objXmlHttp=new XMLHttpRequest();
    objXmlHttp.onload=handler;
    objXmlHttp.onerror=handler;
    return objXmlHttp;
  }
}


function response() {
  if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete") {
    response_text = xmlHttp.responseText;
    //response = xmlHttp.responseXML.documentElement;
  }
}


/* Custom functions */

function changeQty() {

  var qtys = document.getElementsByName("qty[]");
  var prices = document.getElementsByName("price[]");
  var product_ids = document.getElementsByName("product_id[]");
  var shipping_unit_ids = document.getElementsByName("shipping_unit_id[]");
  var zone = document.getElementsByName('shipping_zone')[0][document.getElementsByName('shipping_zone')[0].selectedIndex].value;
  var gst_rate = document.getElementsByName('szgst_' + zone)[0].value;
  var currency = document.getElementsByName('currency')[0].value;
  var currency_rate = document.getElementsByName('curr_' + currency)[0].value;
  var currency_symbol = document.getElementsByName('cs_' + currency)[0].value;
  
  var product_total = 0;
  var product_total_nzd = 0;
  var shipping_cost = 0;
  var shipping_cost_nzd = 0;
  var total_units = 0;
  
  /* url for save cart */
  var url = "/lib/order-form/cart-save.php?zone=" + zone + "&currency=" + currency;

  for(i = 0; i < product_ids.length; i++) {
    var qty = qtys[i].value;
    var price = prices[i].value*currency_rate;
    var price_nzd = prices[i].value;
    var subtotal = qty * price;
    var subtotal_nzd = qty * price_nzd;
    var product_shipping = document.getElementsByName('sc_' + zone + '_' + shipping_unit_ids[i].value)[0].value * qty * currency_rate;
    var product_shipping_nzd = document.getElementsByName('sc_' + zone + '_' + shipping_unit_ids[i].value)[0].value * qty;

    total_units += parseInt(qty);
    product_total += subtotal;
    product_total_nzd += subtotal_nzd;
    shipping_cost += product_shipping;
    shipping_cost_nzd += product_shipping_nzd;

    /* url for save cart */
    url += "&qtys[]=" + qty;
    url += "&product_ids[]=" + product_ids[i].value;

    document.getElementById('price_disp_' + product_ids[i].value).innerHTML = currency_symbol + formatAsMoney(price);
    if(gst_rate != 0) {
      //document.getElementById('price_disp_' + product_ids[i].value).innerHTML += ' (plus GST)';
    }

    subtotal_ref = document.getElementById('subtotal_disp_' + product_ids[i].value);
    if(subtotal == 0) {
      subtotal_ref.innerHTML = '';
    }
    else {
      //subtotal_ref.innerHTML = currency_symbol + formatAsMoney(subtotal) + ' + ';
    }

    if(product_shipping == 0) {
      subtotal_ref.innerHTML += '';
    }
    else {
      //subtotal_ref.innerHTML += currency_symbol + formatAsMoney(product_shipping) + ' shipping' + ' (' + currency + ')';
    }

  }
  
  // shipping cost adjustment
  // this only works if all products are the same cost (which they currently are at 11sept2007
  /*
  var shipping_per_unit = shipping_cost / total_units;
  var shipping_per_unit_nzd = shipping_cost_nzd / total_units;
  if(total_units % 2 == 0) {
    shipping_cost = shipping_cost / 2;
    shipping_cost_nzd = shipping_cost_nzd / 2;
  }
  else {
    shipping_cost = shipping_per_unit * (total_units + 1) / 2;
    shipping_cost_nzd = shipping_per_unit_nzd * (total_units + 1) / 2;
  }
  */
    

  var product_and_shipping = product_total + shipping_cost;
  var product_and_shipping_nzd = product_total_nzd + shipping_cost_nzd;
  var gst = product_and_shipping*gst_rate;
  var gst_nzd = product_and_shipping_nzd*gst_rate;
  var grand_total = product_and_shipping + gst;
  var grand_total_nzd = product_and_shipping_nzd + gst_nzd;
  
  document.getElementById("product_total").innerHTML = currency_symbol + formatAsMoney(product_total);
  document.getElementById('shipping_cost').innerHTML = currency_symbol + formatAsMoney(shipping_cost);
  document.getElementById('gst').innerHTML = currency_symbol + formatAsMoney(gst);
  document.getElementById('grand_total').innerHTML = currency_symbol + formatAsMoney(grand_total) + ' (' + currency + ')';
  if(currency != 'NZD') {
    document.getElementById('currency_note').innerHTML = '* Your credit card will be charged in New Zealand Dollars ($' + formatAsMoney(grand_total_nzd) + ' NZD)';
  }
  else {
    document.getElementById('currency_note').innerHTML = '';
  }
  
  /* save qtys to session vars */
  url += '&product_total=' + product_total_nzd;
  url += '&shipping_cost=' + shipping_cost_nzd;
  url += '&gst=' + gst_nzd;
  url += '&grand_total=' + grand_total_nzd;
  
  //alert(url);
  xmlHttp=GetXmlHttpObject(response);
  xmlHttp.open("GET", url , false);
  xmlHttp.send(null);

}


function formatAsMoney(mnt) {
    mnt -= 0;
    mnt = (Math.round(mnt*100))/100;
    return (mnt == Math.floor(mnt)) ? mnt + '.00' 
              : ( (mnt*10 == Math.floor(mnt*10)) ? 
                       mnt + '0' : mnt);
}