/* Directional control for webOS remotes and standard keyboards. */
function setupRemoteNavigation(buttons, doc, win) {
 var lastFocused=buttons[0], enterDown=false;
 buttons.forEach(function(button){
  button.addEventListener('focus',function(){lastFocused=button;});
  button.addEventListener('mouseenter',function(){if(!button.disabled)button.focus();});
 });
 doc.addEventListener('keydown',function(event){
  var code=event.keyCode||event.which;
  var direction=event.key==='ArrowLeft'||event.key==='ArrowUp'||code===37||code===38?-1:
   event.key==='ArrowRight'||event.key==='ArrowDown'||code===39||code===40?1:0;
  var enter=event.key==='Enter'||code===13;
  if(!direction&&!enter)return;
  var editing=doc.activeElement && !doc.activeElement.readOnly && (doc.activeElement.tagName==='INPUT' && doc.activeElement.type!=='checkbox' || doc.activeElement.tagName==='TEXTAREA');
  if(editing)return;
  event.preventDefault();
  var enabled=buttons.filter(function(button){return !button.disabled && (typeof button.getClientRects!=='function' || button.getClientRects().length) && (!win.remoteNavigationScope || win.remoteNavigationScope.indexOf(button.id)>=0);});
  if(!enabled.length)return;
  var focused=doc.activeElement,index=enabled.indexOf(focused);
  if(direction){
   if(index<0){index=enabled.indexOf(lastFocused);if(index<0)index=0;enabled[index].focus();}
   else enabled[(index+direction+enabled.length)%enabled.length].focus();
  }else{
   if(enterDown||event.repeat)return;
   enterDown=true;
   if(index<0){index=enabled.indexOf(lastFocused);enabled[index<0?0:index].focus();}
   else focused.click();
  }
 });
 doc.addEventListener('keyup',function(event){if(event.key==='Enter'||event.keyCode===13||event.which===13)enterDown=false;});
 win.addEventListener('blur',function(){enterDown=false;});
}