// upravi selectbox
function updateSelect(id, vals) {
 /* 
 * Kalkulator teras 
 *  
 * Naprogramoval: 
 *    Matous Borak - Platanus, Praha, 2008 
 * Kontakt: 
 *    matous.borak@platanus.cz 
 */ 

  opt = $(id).options;
  selectedItem = opt[$(id).selectedIndex].value;
  for(var i=0;i<opt.length;i++){
    opt[i] = null;
  }
  keys = vals.keys();
  for(var i=0;i<keys.length;i++){
    selected = keys[i] == selectedItem ? true : false;
    opt[i] = new Option(vals.get(keys[i]), keys[i], false, selected);
  }
}

// na zaklade typu prken zmeni barvu etc...
function timberTypeChanged(field, value) {
  // zmenime barvy
  new Ajax.Request('ajax.php?type=timberColors&value='+encodeURIComponent(value), {
    onSuccess: function(transport) {
      if (response = transport.responseJSON) {
        colors = $H(eval(response));
        updateSelect('timberColor', colors);
      }
    }
  });
  // nastavime cik-cak
  new Ajax.Request('ajax.php?type=timberZigZag&value='+encodeURIComponent(value), {
    onSuccess: function(transport) {
      if ((response = transport.responseJSON) != null) {
        zigzag = response ? true : false;
        if (zigzag) {
          $('zigzag').disabled = false;
        } else {
          $('zigzag').checked = false;
          $('zigzag').disabled = true;
        }
      }
    }
  });
}

// pripravne funkce pro formular
function prepareForm() {
  if (!$('timberType')) return;
  new Form.Element.EventObserver('timberType', timberTypeChanged);
  
}