var img = new Image().src = '/img/notok.png';
var max_upload_size;

function validate() {
  var result, elm_jmeno, elm_zprava;
  result = true;
  elm_jmeno = document.getElementById('jmeno');
  elm_zprava = document.getElementById('zprava');

  if(elm_jmeno.value == '' && elm_zprava.value == '') {
    window.alert('- Please insert your name\n- No message to post');
    document.getElementById('jmeno_cap').style.color = '#CC0000';
    document.getElementById('zprava_cap').style.color = '#CC0000';
    elm_jmeno.focus();
    return false;
  }

  if(elm_jmeno.value == '') {
    window.alert('Please insert your name');
    document.getElementById('jmeno_cap').style.color = '#CC0000';
    elm_jmeno.focus();
    result = false;
  }
  else {
    document.getElementById('jmeno_cap').style.color = '';
  }

  if(elm_zprava.value == '') {
    window.alert('No message to post!');
    document.getElementById('zprava_cap').style.color = '#CC0000';
    elm_zprava.focus();
    result = false;
  }
  else {
    document.getElementById('zprava_cap').style.color = '';
  }

  return result;
}


/* *****************************************************************************
pridat policko na upload souboru

@param    obj - objekt tlacitka pro pridani noveho pole
@return   void
***************************************************************************** */
function addAttachment(obj) {
  var col, att, maxSize, uploadFields;
  maxSize = obj.form.MAX_FILE_SIZE.value;
  
  if(obj.uploadFields) obj.uploadFields++;
  else obj.uploadFields = 1;
  uploadFields = obj.uploadFields;
  
  obj = obj.parentNode.parentNode;
  obj = previousSibling(obj)
  obj.style.display = '';

  obj = obj.parentNode.insertBefore(document.createElement('tr'), obj);

  obj.appendChild(document.createElement('th')).innerHTML = "File:";
  col = obj.appendChild(document.createElement('td'));
  obj.appendChild(document.createElement('td'));

  att = document.createElement('input');
  att.type = 'file';
  att.name = 'att' + uploadFields;

  // pouze pro FF
  if(att.files) {
		att.onchange = function() {
			var size, obj, maxSize;
			obj = this.form;
			size = 0;
			maxSize = this.form.MAX_FILE_SIZE.value;
	
			for(var i = 0; i < obj.elements.length; i++) {
				if(obj.elements[i].nodeName == 'input' && obj.elements[i].type == 'file' && obj.elements[i].files.length > 0) {
					size += obj.elements[i].files[0].fileSize;
				}
			}
			
			if(this.parentNode.lastChild.nodeType == 3) {
				this.parentNode.lastChild.nodeValue = formatSize(this.files[0].fileSize);
			}
			else {
				this.parentNode.appendChild(document.createTextNode(" " + formatSize(this.files[0].fileSize)));
			}
			
			if(size > maxSize) {
				alert("Files are too large to be uploaded!\nTotal file size is: " + formatSize(size) + "\nAllowed file size: " + formatSize(maxSize));
			}
		}
	}
  
  col.appendChild(att);
  
  att = document.createElement('img');
  att.alt = att.title = 'Remove';
  att.src = '/img/notok.png';
  att.onclick = function() {
    this.parentNode.parentNode.parentNode.removeChild(this.parentNode.parentNode);
  }
  col.appendChild(att);
}


function formatSize(size) {
  if(size > 1073741824) {
    size = Math.round((size / 1073741824) * 100) / 100 + " GB";
  } else if(size > 1048576) {
    size = Math.round((size / 1048576) * 100) / 100 + " MB";
  } else if(size > 1024) {
    size = Math.round((size / 1024) * 100) / 100 + " kB";
  } else {
    size = size + " B";
  }
  
  return size;
}