/**
 * js_forms.js
 * A function library for Acrobat plug-in checking and cookie manipulation
 */

var osmWinParams = "width=600,height=365,resizable=yes,scrollbars=yes";

/**
 * Determine whether the user has the Acrobat Reader ActiveX control by 
 * attempting to instantiate it
 * 
 * @return true if the ActiveX control was successfully instantiated,
 * false otherwise
 * 
 */
function tryActiveXAcro() {
	try {
		acro = new ActiveXObject("PDF.PdfCtrl.1");
		if(!acro) return;
		acro = null;
		return true;
	} catch (e) { return false; }
}

function checkAcrobat(url, doPopup) {
	if(getCookie('HasAcrobat') != 1) {
		if(tryActiveXAcro()) {
			setThreeYearCookie('HasAcrobat');
			window.location = url;
		} else {
			var acroUrl = "/acrobat_help.jsp?url=" + escape(url);
			if(doPopup) {
				var zwindow = window.open(acroUrl, "usePolicy", osmWinParams);
				zwindow.focus();
			} else
				window.location = acroUrl + "&popup=no";
		}
	} else window.location = url;
}

function checkAcrobatAlt(url, alt, doPopup) {
	if(getCookie('HasAcrobat') == 1) window.location = url;
	else if(getCookie('HasAcrobat') == 0) window.location = alt;
	else {
		if(!document.layers && tryActiveXAcro()) {
			setThreeYearCookie('HasAcrobat');
			window.location = url;
		} else {
			var acroUrl =
				"/acrobat_help.jsp?url=" + escape(url) + "&alt=" + escape(alt);
			if(doPopup) window.open(acroUrl, "usePolicy", osmWinParams).focus();
			else window.location = acroUrl + "&popup=no";
		}
	}
}

function changeCookie (name, isChecked) {
	if (isChecked) setThreeYearCookie(name);
	else deleteCookie(name);
}

function setThreeYearCookieVal(name, value) {
	var expireDate = new Date();
	expireDate.setTime(expireDate.getTime() + 1000*60*60*24*365*3);
	document.cookie = name + "=" + value + ";expires="+expireDate.toGMTString();
}

function setThreeYearCookie(name) {
	setThreeYearCookieVal(name, 1);
}

function deleteCookie (name) {
	var oldDate = new Date();
	oldDate.setFullYear(1970); // the expiredate is set to Jan. 1st 1970
	document.cookie = name + "=0" + "; expires="+oldDate.toGMTString();
}

/**
 * read a cookie value
 */
function getCookie (name) {
	var cookieString = document.cookie;
	var startIndex = cookieString.indexOf(name);
	if(startIndex == -1) return (-1);	// the cookie doesn't exist!
	startIndex += name.length + 1;
	endIndex = cookieString.indexOf(";", startIndex);
	if (endIndex == -1) endIndex = cookieString.length;
	return unescape(cookieString.substring(startIndex, endIndex));
}