// The constructor function: creates a Cookie object for the specified document, with a specified
// name and optional attributes.
// Arguments:
//  document:	The Document object for which the cookie is stored.  Required.
//  name:		A string that specifies a name for the cookie.  Required.
//  hours:		An optional number that specifies the number of hours from now after which
//				the cookie should expire.
//	path:		An optional string that specifies the cookie path attribute.
//	domain:		An optional string that specifies the cookie domain attribute.
//	secure:		An optional boolean value that if true requests a secure cookie.
//

function Cookie(document, name, hours, path, domain, secure)
{
	// All the predefinted properties of this object begin with '$'
	// to distinguish them from other properties, which are the values to
	// be stored in the cookie
	this.$document = document;
	this.$name = name;
	if (hours)
		this.$expiration = new Date((new Date()).getTime() + hours*3600000);
	else this.$expiration = null;
	if (path) this.$path = $path; else this.$path = null;
	if (domain) this.$domain = domain; else this.$domain = null;
	if (secure) this.$secure = true; else this.$secure = false;
}

// This function is the store() method of the Cookie object
Cookie.prototype.store = function () {
	// First, loop through the properties of the Cookie object and
	// put together the value of the cookie. Since cookies use the
	// equals sign and semicolons as separators, we'll use colons
	// and ampersands for the individual state variables we store
	// within a single cookie value.  Note that we escape the value
	// of each state variable, in case it contains punctuation or
	// other illegal characters.
	var cookieval = "";
	for (var prop in this) {
		// Ignore porperties with names that begin with '$' and also methods
		if ((prop.charAt(0) == '$') || ((typeof this[prop]) == 'function'))
			continue;
		if (cookieval != "") cookieval += '&';
		cookieval += prop+ ':' + escape(this[prop]);
	}
	
	// Now that we have the value of the cookie, put together the 
	// complete cookie string, which includes the name and the various
	// attributes specified when the Cookie object was created
	var cookie = this.$name + "=" + cookieval;
	if (this.$expiration)
		cookie += '; expires=' + this.$expiration.toGMTString();
	if (this.$path) cookie += '; path=' + this.$path;
	if (this.$domain) cookie += '; domain=' + this.$domain;
	if (this.$secure) cookie += '; secure';
	// Now store the cookie by setting the magic Document.cookie property
	this.$document.cookie = cookie;
}

//	This.function is the load() method of the Cookie object
Cookie.prototype.load = function() {
	// First, get a list of all cookies that pertain to this document
	// We do this by reading the magic Document.cookie property
	var allcookies = this.$document.cookie;
	if (allcookies == "") return false;
	
	// Now extract just the named cookie from that list
	var start = allcookies.indexOf(this.$name + '=');
	if (start == -1) return false; // Cookie not defined for this page
	start += this.$name.length + 1; // Skip name and equals sign
	var end = allcookies.indexOf(';',start);
	if (end == -1) end = allcookies.length;
	var cookieval = allcookies.substring(start, end);
	
	// Now that we've extracted the value of the named cookie, we
	// must break that value down into individual state variable
	// names and values.  The name/value pairs are separated from each
	// other by ampersands, and the individual names and values are
	// separated from each other by colons.  We use the split() method
	// to parse everything.
	var a = cookieval.split('&');
	for (var i=0; i< a.length; i++) // Break down each pair into an array
		a[i] = a[i].split(':');
	// Now that we've parsed the cookie value, set all the names and values
	// of the state variables in this Cookie object.  Note that we unescape()
	// the property value, because we called escape() when we stored it.
	for (var i=0; i<a.length; i++) {
		this[a[i][0]] = unescape(a[i][1]);
	}
	
	// We're done, so return the success code
	return true;
}

// This function is the remove() method of the Cookie object
Cookie.prototype.remove = function() {
	var cookie;
	cookie = this.$name + '=';
	if (this.$path) cookie += '; path=' + this.$path;
	if (this.$domain) cookie += ';domain=' + this.$domain;
	cookie += '; expires=Fri, 02-Jan-1970 00:00:00 GMT';
	
	this.$document.cookie = cookie;
}