/*\
title: $:/core/utils.js
type: application/javascript
module-type: utils

Various static utility functions.

This file is a bit of a dumping ground; the expectation is that most of these functions will be refactored.

\*/
(function(){

/*jslint node: true */
"use strict";

exports.formatDateString = function (date,template) {
	var t = template.replace(/0hh12/g,$tw.utils.pad($tw.utils.getHours12(date)));
	t = t.replace(/hh12/g,$tw.utils.getHours12(date));
	t = t.replace(/0hh/g,$tw.utils.pad(date.getHours()));
	t = t.replace(/hh/g,date.getHours());
	t = t.replace(/mmm/g,$tw.config.dateFormats.shortMonths[date.getMonth()]);
	t = t.replace(/0mm/g,$tw.utils.pad(date.getMinutes()));
	t = t.replace(/mm/g,date.getMinutes());
	t = t.replace(/0ss/g,$tw.utils.pad(date.getSeconds()));
	t = t.replace(/ss/g,date.getSeconds());
	t = t.replace(/[ap]m/g,$tw.utils.getAmPm(date).toLowerCase());
	t = t.replace(/[AP]M/g,$tw.utils.getAmPm(date).toUpperCase());
	t = t.replace(/wYYYY/g,$tw.utils.getYearForWeekNo(date));
	t = t.replace(/wYY/g,$tw.utils.pad($tw.utils.getYearForWeekNo(date)-2000));
	t = t.replace(/YYYY/g,date.getFullYear());
	t = t.replace(/YY/g,$tw.utils.pad(date.getFullYear()-2000));
	t = t.replace(/MMM/g,$tw.config.dateFormats.months[date.getMonth()]);
	t = t.replace(/0MM/g,$tw.utils.pad(date.getMonth()+1));
	t = t.replace(/MM/g,date.getMonth()+1);
	t = t.replace(/0WW/g,$tw.utils.pad($tw.utils.getWeek(date)));
	t = t.replace(/WW/g,$tw.utils.getWeek(date));
	t = t.replace(/DDD/g,$tw.config.dateFormats.days[date.getDay()]);
	t = t.replace(/ddd/g,$tw.config.dateFormats.shortDays[date.getDay()]);
	t = t.replace(/0DD/g,$tw.utils.pad(date.getDate()));
	t = t.replace(/DDth/g,date.getDate()+$tw.utils.getDaySuffix(date));
	t = t.replace(/DD/g,date.getDate());
	var tz = date.getTimezoneOffset();
	var atz = Math.abs(tz);
	t = t.replace(/TZD/g,(tz < 0 ? '+' : '-') + $tw.utils.pad(Math.floor(atz / 60)) + ':' + $tw.utils.pad(atz % 60));
	t = t.replace(/\\/g,"");
	return t;
};

exports.getAmPm = function(date) {
	return date.getHours() >= 12 ? $tw.config.dateFormats.pm : $tw.config.dateFormats.am;
};

exports.getDaySuffix = function(date) {
	return $tw.config.dateFormats.daySuffixes[date.getDate()-1];
};

exports.getWeek = function(date) {
	var dt = new Date(date.getTime());
	var d = dt.getDay();
	if(d === 0) d=7;// JavaScript Sun=0, ISO Sun=7
	dt.setTime(dt.getTime()+(4-d)*86400000);// shift day to Thurs of same week to calculate weekNo
	var n = Math.floor((dt.getTime()-new Date(dt.getFullYear(),0,1)+3600000)/86400000);
	return Math.floor(n/7)+1;
};

exports.getYearForWeekNo = function(date) {
	var dt = new Date(date.getTime());
	var d = dt.getDay();
	if(d === 0) d=7;// JavaScript Sun=0, ISO Sun=7
	dt.setTime(dt.getTime()+(4-d)*86400000);// shift day to Thurs of same week
	return dt.getFullYear();
};

exports.getHours12 = function(date) {
	var h = date.getHours();
	return h > 12 ? h-12 : ( h > 0 ? h : 12 );
};

// Convert & to "&amp;", < to "&lt;", > to "&gt;" and " to "&quot;"
exports.htmlEncode = function(s)
{
	if(s) {
		return s.toString().replace(/&/mg,"&amp;").replace(/</mg,"&lt;").replace(/>/mg,"&gt;").replace(/\"/mg,"&quot;");
	} else {
		return "";
	}
};

// Converts all HTML entities to their character equivalents
exports.entityDecode = function(s) {
	var e = s.substr(1,s.length-2); // Strip the & and the ;
	if(e.charAt(0) === "#") {
		if(e.charAt(1) === "x" || e.charAt(1) === "X") {
			return String.fromCharCode(parseInt(e.substr(2),16));	
		} else {
			return String.fromCharCode(parseInt(e.substr(1),10));
		}
	} else {
		var c = $tw.config.htmlEntities[e];
		if(c) {
			return String.fromCharCode(c);
		} else {
			return s; // Couldn't convert it as an entity, just return it raw
		}
	}
};

exports.unescapeLineBreaks = function(s) {
	return s.replace(/\\n/mg,"\n").replace(/\\b/mg," ").replace(/\\s/mg,"\\").replace(/\r/mg,"");
};

/*
 * Returns an escape sequence for given character. Uses \x for characters <=
 * 0xFF to save space, \u for the rest.
 *
 * The code needs to be in sync with th code template in the compilation
 * function for "action" nodes.
 */
// Copied from peg.js, thanks to David Majda
exports.escape = function(ch) {
	var charCode = ch.charCodeAt(0);
	if (charCode <= 0xFF) {
		return '\\x' + $tw.utils.pad(charCode.toString(16).toUpperCase());
	} else {
		return '\\u' + $tw.utils.pad(charCode.toString(16).toUpperCase(),4);
	}
};

// Turns a string into a legal JavaScript string
// Copied from peg.js, thanks to David Majda
exports.stringify = function(s) {
	/*
	* ECMA-262, 5th ed., 7.8.4: All characters may appear literally in a string
	* literal except for the closing quote character, backslash, carriage return,
	* line separator, paragraph separator, and line feed. Any character may
	* appear in the form of an escape sequence.
	*
	* For portability, we also escape escape all non-ASCII characters.
	*/
	return s
		.replace(/\\/g, '\\\\')            // backslash
		.replace(/"/g, '\\"')              // double quote character
		.replace(/'/g, "\\'")              // single quote character
		.replace(/\r/g, '\\r')             // carriage return
		.replace(/\n/g, '\\n')             // line feed
		.replace(/[\x80-\uFFFF]/g, exports.escape); // non-ASCII characters
};

exports.nextTick = function(fn) {
/*global window: false */
	if(typeof window !== "undefined") {
		// Apparently it would be faster to use postMessage - http://dbaron.org/log/20100309-faster-timeouts
		window.setTimeout(fn,4);
	} else {
		process.nextTick(fn);
	}
};

/*
Determines whether element 'a' contains element 'b'
Code thanks to John Resig, http://ejohn.org/blog/comparing-document-position/
*/
exports.domContains = function(a,b) {
	return a.contains ?
		a != b && a.contains(b) :
		!!(a.compareDocumentPosition(b) & 16);
};

exports.hasClass = function(el,className) {
	return el.className.split(" ").indexOf(className) !== -1;
};

exports.addClass = function(el,className) {
	var c = el.className.split(" ");
	if(c.indexOf(className) === -1) {
		c.push(className);
	}
	el.className = c.join(" ");
};

exports.removeClass = function(el,className) {
	var c = el.className.split(" "),
		p = c.indexOf(className);
	if(p !== -1) {
		c.splice(p,1);
		el.className = c.join(" ");
	}
};

exports.toggleClass = function(el,className,status) {
	if(status === undefined) {
		status = !exports.hasClass(el,className);
	}
	if(status) {
		exports.addClass(el,className);
	} else {
		exports.removeClass(el,className);
	}
};

exports.applyStyleSheet = function(id,css) {
	var el = document.getElementById(id);
	if(document.createStyleSheet) { // Older versions of IE
		if(el) {
			el.parentNode.removeChild(el);
		}
		document.getElementsByTagName("head")[0].insertAdjacentHTML("beforeEnd",
			'&nbsp;<style id="' + id + '" type="text/css">' + css + '</style>'); // fails without &nbsp;
	} else { // Modern browsers
		if(el) {
			el.replaceChild(document.createTextNode(css), el.firstChild);
		} else {
			el = document.createElement("style");
			el.type = "text/css";
			el.id = id;
			el.appendChild(document.createTextNode(css));
			document.getElementsByTagName("head")[0].appendChild(el);
		}
	}
};

})();