// This can be defined in other modules
if (typeof Zapatec == 'undefined') {
  /// define the global Zapatec namespace
  Zapatec = {};
}

/// define the Utils namespace
Zapatec.Utils = {};



/// Remove a certain [CSS] class from the given element.
/// @param el [HTMLElement] reference to the element.
/// @param className [string] the class to remove.
Zapatec.Utils.removeClass = function(el, className) {
	if (!(el && el.className)) {
		return;
	}
	var cls = el.className.split(" ");
	var ar = [];
	for (var i = cls.length; i > 0;) {
		if (cls[--i] != className) {
			ar[ar.length] = cls[i];
		}
	}
	el.className = ar.join(" ");
};

/// Appends a certain [CSS] class to the given element.
/// @param el [HTMLElement] reference to the element.
/// @param className [string] the class to append.
Zapatec.Utils.addClass = function(el, className) {
	Zapatec.Utils.removeClass(el, className);
	el.className += " " + className;
};










/// Create an element of a certain type using document.createElement().  A
/// function was needed in order to add some common attributes to all created
/// elements, but also in order to be able to use it in XHTML too (Gecko and
/// other W3C-compliant browsers).
///
/// This function will create an element of the given type and set certain
/// properties to it: unselectable for IE, and the CSS "-moz-user-select" for
/// Gecko, in order to make the element unselectable in these browsers.
/// Optionally, if the second argument is passed, it will appendChild() the
/// newly created element to its parent.
///
/// @param type [string] the tag name of the new element.
/// @param parent [HTMLElement, optional] a parent for the new element.
/// @param selectable [boolean] the flag to indicate wether element is selectable(rather usefull).
/// @return [HTMLElement] reference to the new element.
Zapatec.Utils.createElement = function(type, parent, selectable) {
	var el = null;
	if (window.self.document.createElementNS)
		// use the XHTML namespace; IE won't normally get here unless
		// _they_ "fix" the DOM2 implementation.
		el = window.self.document.createElementNS("http://www.w3.org/1999/xhtml", type);
	else
		el = window.self.document.createElement(type);
	if (typeof parent != "undefined" &&parent != null)
		parent.appendChild(el);
	if (!selectable) {
		if (Zapatec.is_ie)
			el.setAttribute("unselectable", true);
		if (Zapatec.is_gecko)
			el.style.setProperty("-moz-user-select", "none", "");
	}
	return el;
};





/**
 * A more flexible way to get the "nextSibling" of a given element.  If the
 * "tag" argument is passed, then this function will return the next sibling
 * that has a certain tag.  Otherwise it will simply return el.nextSibling.
 *
 * @param el [HTMLElement] reference to the anchor element.
 * @param tag [string] the tag name of the returned node.
 * @param alternateTag [string] the alternate tag name of the returned node.
 *
 * @return [HTMLElement or null] el.nextSibling if tag is not passed, or the
 * first element after el having the specified tag.  Null is returned if no
 * element could be found.
 */
Zapatec.Utils.getNextSibling = function(el, tag, alternateTag) {
	el = el.nextSibling;
	if (!tag) {
		return el;
	}
	tag = tag.toLowerCase();
	if (alternateTag) alternateTag = alternateTag.toLowerCase();
	while (el) {
		if (el.nodeType == 1 && (el.tagName.toLowerCase() == tag ||
		 (alternateTag && el.tagName.toLowerCase() == alternateTag))) {
			return el;
		}
		el = el.nextSibling;
	}
	return el;
};




Zapatec.Utils._ids = {};	/**< [number, static] maintains a list of generated IDs */

/**
 * Generates an unique ID, for a certain code (let's say "class").  If the
 * optional "id" argument is passed, then it just returns the id for that code
 * (no generation).  This function is sometimes useful when we need to create
 * elements and be able to access them later by ID.
 *
 * @param code [string] the class of ids.  User defined, can be anything.
 * @param id [string, optional] specify if the ID is already known.
 *
 * @return [string] the unique ID
 */
Zapatec.Utils.generateID = function(code, id) {
	if (typeof id == "undefined") {
		if (typeof this._ids[code] == "undefined")
			this._ids[code] = 0;
		id = ++this._ids[code];
	}
	return "zapatec-" + code + "-" + id;
};