/**
 * util.js Some utilities functions
 * 
 * @company Nectil
 * @team Nectil Team
 * @author Thomas Hermant
 * @version 1.0
 */
 
/**
	 * Return the element specified by a id
	 * @param id element's identifiant
	 * @return a html element
*/
function $id(id){
	return document.getElementById(id);
}

/**
	 * Return a array of element with a specific tag
	 * @param tag elements's tag
	 * @param [from] (optional) specified where we must search elements with specified tag 
	 * @return array of html elements
*/
function $tags(tag,from){
	if(from != undefined){
		el = $id(from);
		if(el != null) return el.getElementsByTagName(tag);
	}	
	return document.getElementsByTagName(tag);
}

/**
	 * Return the style object of a element
	 * @param id element's identifiant
	 * @return a style object
*/
function $style(id){
	var el = $id(id);
	if(el != null) return el.style;
}

/**
	 * Return the value of a input
	 * @param id element's identifiant
	 * @return the input's value
*/
function $value(id){
	var el = $id(id);
	if(el != null) return el.value;
}

/**
	 * Show the element with specified id
	 * @param id element's identifiant to show
*/
function show(id){
	$style(id).display = 'block';
}

/**
	 * Hide the element with specified id
	 * @param id element's identifiant to hide
*/
function hide(id){
	$style(id).display = 'none';
}

/**
	 * Hide all element with specified tag and show one element specified by id
	 * @param tag elements's tag to hide
	 * @param id element's identifiant to show
	 * @param [from] (optional) specified where we must search elements with specified tag
	 * @param [name] (optional) to hide tags with a id who content the specific string(name)
*/
function hideAllTagsShowId(tag,id,from,name){
	var elements;
	if(from != undefined){
		elements = $tags(tag,from);
	}else{
		elements = $tags(tag);
	}	
	var n = elements.length;
	for (var i = 0 ; i < n ; i++){
		var current = elements[i];
		var idCurrent = current.id;
		if(name != undefined){
			if(idCurrent.indexOf(name) != -1)
				current.style.display = 'none';
		}else{
			current.style.display = 'none';
		}	
	}
	$style(id).display = 'block';
}

/**
	 * Affect the textDecoration style
	 * @param id element's identifiant
	 * @param type the tpe of the decoration (underline, none, ...)
*/
function setDecoration(id,type){
	$style(id).textDecoration = type;
}

/**
	 * Delete the px of a value and transform this in a number
	 * @param value a string (i.e: 50px)
	 * @return the number of the specified value
*/
function delPx(value){
	if(value == "") return 0;
	return parseFloat(value.substring(0,value.length - 2 ));
}

/**
	 * Add px of a value and transform this in a string
	 * @param value number  (i.e: 50)
	 * @return the string of the specified value with px
*/
function addPx(value){
	if(value == "") return '0px';
	if(typeof(value) == 'string'){
		var pos = value.indexOf('px') 
		if(pos != -1){
			if (pos == value.length - 2){
				return value;
			}else{
				alert('error addPx the value is a string who content px but not at the end')
				return value;
			}
		}	
	}	
	return value + 'px';
}

/**
	 * Change the size of element 
	 * @param value number  (i.e: 50)
	 * @return the string of the specified value with px
*/
function changeHeight(id,size){
	var el = $id(id);
	if(el != null){
		var height = el.offsetHeight;
		var newHeight = height + size;
		el.style.height = addPx(newHeight);
	}	
}

/**
	 * Get the size of the window 
	 * @return the size of th e window
	 * thanks to http://pompage.net
*/
function getWindowHeight() {
	var windowHeight=0;
	if (typeof(window.innerHeight)=='number') {
		windowHeight=window.innerHeight;
	}else{
		if (document.documentElement&&
			document.documentElement.clientHeight) {
			windowHeight = document.documentElement.clientHeight;
		}else{
			if (document.body&&document.body.clientHeight) {
				windowHeight=document.body.clientHeight;
			}
		}
	}
	return windowHeight;
}

/**
	 * Set a footer (relative or absolute) at the right place
	 * thanks to http://pompage.net
*/
function setFooter(content,footer) {
	if (document.getElementById) {
		var windowHeight = getWindowHeight();
		if (windowHeight > 0) {
			var contentHeight = $id(content).offsetHeight;
			var footerElement = $id(footer);
			var footerHeight = footerElement.offsetHeight;
			if (windowHeight-(contentHeight+footerHeight)>=0) {
				$style(footer).position='relative';
				$style(footer).top = addPx(windowHeight - (contentHeight + footerHeight));
			}else {
				$style(footer).position='static';
			}
		}
	}
}