/**
 * opens a popup with default-options
 *
 * @param string filename the name of the file to display in the popup
 * @param string title the title of the popup
 * @param int width the width of the popup
 * @param int height the height of the popup
 */
function openDefaultPopup(filename,title,width,height)
{
	var options = 'toolbar=no,status=no,menubar=no,width=' + width + ',height=' + height;
	options += ',resizable=yes,scrollbars=yes,left=0,top=0,screenX=0,screenY=0';
	window.open(filename,title,options);
}

/**
 * opens a popup with the given parameters
 *
 * @param string filename the name of the file to display in the popup
 * @param string title the title of the popup
 * @param string options the options of die popup
 */
function openPopup(filename,title,options)
{
	window.open(filename,title,options);
}

/**
 * performs a mod-action for some topics
 * collects the ids from the checkboxes and redirects to the given url
 *
 * @param string base_url the base_url ending with &URL_ID=
 */
function performModAction(base_url)
{
	if(base_url == '')
		return;
	
	var ids = "";
	var cb = null;
	for(var i = 0;(cb = document.getElementById('id_' + i)) != null;i++)
	{
		if(cb.checked)
			ids += cb.value + ",";
	}

	if(ids == "")
		return;

	document.location.href = base_url + ids;
}

/**
 * changes the form-target to the given target and submits the form
 * this way we will quote a post
 *
 * @param string formTarget the new target of the form
 */
function quotePost(formTarget)
{
	var button = document.getElementById('quotePostButton');
	if(document.quotePostForm != null && button != null)
	{
		document.quotePostForm.action = formTarget;
		button.click();
	}
}

/**
 * claps the area with given id including image and cookie
 * 
 * @param string id the id of the element
 * @param string img_id the id of the image
 * @param string cookie_name the name of the cookie where to store the current status
 * @param string display_value the value for "display" if the element should be displayed
 * 							   (default = 'block')
 */
function clapArea(id,img_id,cookie_name,display_value)
{
	if(typeof display_value == 'undefined')
		display_value = 'block';
	
	var area = document.getElementById(id);
	var display;
	if(area.style.display == 'none')
	{
		if(display_value != 'block')
			display = document.all && !window.opera ? 'block' : display_value;
		else
			display = display_value;
	}
	else
		display = 'none';
	
	area.style.display = display;
	
	setCookie(cookie_name,display == 'none' ? '0' : '1',86400 * 30);

	var img = document.images[img_id];
	if(img != null)
	{
		if(display == "none")
			img.src = img.src.replace(/crossopen/,'crossclosed');
		else
			img.src = img.src.replace(/crossclosed/,'crossopen');
	}
}

/**
 * claps the forum with given id
 *
 * @param int id the id of the forum
 * @param string cookiePrefix the cookie-prefix
 */
function clapForum(id,cookiePrefix)
{
	var setcookies = '';
	var subForums = document.getElementById('subForums_' + id);
	
	if(subForums.style.display == 'none')
	{
		var cookieParts = global_cookie.split(',');
		for(var i = 0;i < cookieParts.length;i++)
		{
			if(cookieParts[i] != '' && cookieParts[i] != id)
				setcookies += cookieParts[i] + ',';
		}
		
		subForums.style.display = 'block';
	}
	else
	{
		setcookies = global_cookie + id + ',';
		subForums.style.display = 'none';
	}

	setCookie(cookiePrefix + 'hidden_forums',setcookies,86400 * 30);
	global_cookie = setcookies;
	
	var image = document.getElementById('cross_' + id);
	if(subForums.style.display == "none")
		image.src = image.src.replace(/crossopen/,'crossclosed');
	else
		image.src = image.src.replace(/crossclosed/,'crossopen');
}

/**
 * scrolls to the bottom in the given textarea
 *
 * @param object textarea the textarea
 */
function scrollToBottom(textArea)
{
	textArea.scrollTop = textArea.scrollHeight;
}

/**
 * trims the given string
 *
 * @param string input the input-string
 * @return string the trim`ed string
 */
function trim(input)
{
	if(input == "")
		return "";

	// determine the first not-whitespace-character
	var i = 0;
	for(;i < input.length;i++)
	{
		if(input[i] != '\n' && input[i] != '\r' && input[i] != '\t' && input[i] != ' ')
			break;
	}

	// determine the last not-whitespace-character
	var a = input.length - 1;
	for(;a >= 0;a--)
	{
		if(input[a] != '\n' && input[a] != '\r' && input[a] != '\t' && input[a] != ' ')
			break;
	}

	return input.substr(i,a - i + 1);
}

/**
 * inverts all checkboxes with the following id:
 * <code>&lt;prefix&gt;&lt;number&gt; , &lt;number&gt; ? {start, start + 1, ...}</code>
 *
 * @param string prefix the prefix of the checkbox-ids
 * @param int start the start-number
 * @param boolean nullNotRequired if enabled is the id "&lt;prefix&gt;0" not required
 */
function invertSelection(prefix,start,nullNotRequired)
{
	if(!start)
		start = 0;

	var f;
	for(var i = start;;i++)
	{
		f = document.getElementById(prefix + i);
		if(f == null && (!nullNotRequired || i > 0))
			return;

		if(f != null)
			f.checked = !f.checked;
	}
}

/**
 * inverts the enable-status of the agreement button at the registration
 *
 * @param object checkbox the checkbox
 * @param string submit_id the id of the button
 */
function checkAgreement(checkbox,submit_id)
{
	var f = document.getElementById(submit_id);
	if(checkbox.checked)
	{
		f.disabled = false;
		f.style.color = '#000000';
	}
	else
	{
		f.disabled = true;
		f.style.color = '#BBBBBB';
	}
}

/**
 * toggles the display-status of the div-area with given id
 *
 * @param int id the id of the div-area
 */
function toggleArea(id)
{
	var div = document.getElementById(id);
	div.style.display = div.style.display == 'none' ? 'block' : 'none';
}

/**
 * analyses the given password and tries to rate it
 * 
 * @param string pw the password to check
 * @return string the rating: low,medium,high,veryhigh
 */
function analysePassword(pw)
{
	var uppercase = 0;
	var lowercase = 0;
	var numbers = 0;
	var other = 0;
	
	for(var i = 0;i < pw.length;i++)
	{
		var c = pw.charAt(i);
		
		if(Number(c))
			numbers++;
		else if(c >= 'a' && c <= 'z')
			lowercase++; 
		else if(c >= 'A' && c <= 'Z')
			uppercase++;
		else
			other++;
	}
	
	var mixed_number = 0;
	if(uppercase > 0)
		mixed_number++;
	if(lowercase > 0)
		mixed_number++;
	if(numbers > 0)
		mixed_number++;
	if(other > 0)
		mixed_number++;
	
	var complex = (pw.length / 3) * (mixed_number / 3);
	if(complex < 1)
		complexity = 'low';
	else if(complex < 2)
		complexity = 'medium';
	else if(complex < 3)
		complexity = 'high';
	else
		complexity = 'veryhigh';
	
	return complexity;
}

/**
 * determines the left page-offset of the given element
 *
 * @param object el the element
 * @return int the left page-offset
 */
function getPageOffsetLeft(el)
{
  var x = el.offsetLeft;
  if(el.offsetParent != null)
    x += getPageOffsetLeft(el.offsetParent);

  return x;
}

/**
 * determines the top page-offset of the given element
 *
 * @param object el the element
 * @return int the top page-offset
 */
function getPageOffsetTop(el)
{
  var y = el.offsetTop;
  if(el.offsetParent != null)
    y += getPageOffsetTop(el.offsetParent);

  return y;
}

var xmlHttpIsBusy;
/**
 * sends an HTTP request via AJAX to the given file
 *
 * @param object xmlHttp the XML-HTTP-object
 * @param string file the target (server-side script) including parameters
 * @param function callback the callback-function to retrieve the result
 */
function sendHTTPRequest(xmlHttp,file,callback)
{
	if(!xmlHttp)
		return;

	if(xmlHttpIsBusy)
	{
		xmlHttp.onreadystatechange = function() { };
		xmlHttp.abort();
	}
	
	xmlHttpIsBusy = true;
	// does not work in IE
	// TODO: the special chars will not be transferred correctly in IE. how to fix that?
	if(!document.all || window.opera)
		xmlHttp.overrideMimeType('text/plain; charset=UTF-8');
	xmlHttp.onreadystatechange = callback;
	xmlHttp.open("GET",file,true);
	xmlHttp.send(null);
}

/**
 * builds the XML-HTTP-object
 * 
 * @return object the object
 */
function getXmlHttpObject()
{
	var req = null;
	if(typeof XMLHttpRequest != "undefined")
		req = new XMLHttpRequest();
	
	if(!req && typeof ActiveXObject != "undefined")
	{
		try
		{
			req = new ActiveXObject("Msxml2.XMLHTTP");
		}
		catch(e)
		{
			try
			{
				req = new ActiveXObject("Microsoft.XMLHTTP");
			}
			catch(e2)
			{
				try
				{
					req = new ActiveXObject("Msxml2.XMLHTTP.4.0");
				}
				catch(e3)
				{
					req = null;
				}
			}
		}
	}
	
	if(!req && window.createRequest)
		req = window.createRequest();
		
	return req;
}

/**
 * determines how many occurrences of needle haystack has
 *
 * @param string haystack the string in which you want to search
 * @param string needle the string where to look for
 * @return int the number of occurrences
 */
function substr_count(haystack,needle)
{
	var matches = 0;
	var i = 0;
	while(matches < 5)
	{
		i = -1;
		try
		{
			i = haystack.indexOf(needle);
		}
		catch(Exception)
		{
		
		}
		
		if(i < 0)
			break;
		
		matches++;
		haystack = haystack.substring(i + needle.length);
	}
	
	return matches;
}

/**
 * Reloads the given image
 *
 * @param object object the image-object
 */
function reloadImage(object)
{
	var url;
	var matches = object.src.match(/dummy=(\d+)/);
	if(matches)
		url = object.src.replace(/dummy=(\d+)/,"dummy=" + (parseInt(matches[1]) + 1));
	else
	{
		if(object.src.indexOf("?") >= 0)
			url = object.src + "&dummy=1";
		else
			url = object.src + "?dummy=1";
	}
	
	object.src = url;
}