EI.namespace('Cookie');

// EI.Cookie()
// 
// Requires: EI namespace
// 
// This constructor looks for a cookie with the specified name for the
// current document. If one exists, it parses its value into a set of
// name/value pairs and stores those values as properties of the newly created
// object.
// 
// To store new data in the cookie, simply set properties of the EI.Cookie
// object. Avoid properties named "store" and "remove", since these are
// reserved as method names.
// 
// To save cookie data in the web browser's local store, call store()
// To remove cookie data from the browser's store, call remove()
// 
// The static method EI.Cookie.enabled() returns true if cookies are
// enabled and returns false otherwise.
// 

EI.Cookie = function(name) {
	this.$name = name;	// Remember the name of this cookie
 
	// First, get a list of all cookies that pertain to this document.
	// We do this by reading the magic Document.cookie property.
	// If there are no cookies, we don't have anything to do.
	var allcookies = document.cookie;
	if (allcookies == "") return;
 
	// Break the string of all cookies into individual cookie strings
	// Then loop through the cookie strings, looking for our name
	var cookies = allcookies.split(/\s*;\s*/);
	var cookie = null;

	for(var i = 0; i < cookies.length; i++) {
		// Does this cookie string begin with the name we want?
		if (cookies[i].substring(0, name.length+1) == (name + "=")) {
			cookie = cookies[i];
			break;
		}
	}

	// If we didn't find a matching cookie, quit now
	if (cookie == null) return;
 
	// The cookie value is the part after the equals sign
	var cookieval = cookie.substring(name.length+1);
 
	// 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('&'); // Break it into an array of name/value pairs
	for(var i=0; i < a.length; i++)	 // Break each pair into an array
		a[i] = a[i].split(':');
 
	// Now that we've parsed the cookie value, set all the names and values
	// as properties of this Cookie object. Note that we decode
	// the property value because the store() method encodes it.
	for(var i = 0; i < a.length; i++) {
		this[a[i][0]] = decodeURIComponent(a[i][1]);
	}
}
 

// This function is the store() method of the Cookie object.
// 
// Arguments:
// 
//   daysToLive: the lifetime of the cookie, in days. If you set this
//   to zero, the cookie will be deleted. If you set it to null, or
//   omit this argument, the cookie will be a session cookie and will
//   not be retained when the browser exits. This argument is used to
//   set the max-age attribute of the cookie.
//   path: the value of the path attribute of the cookie
//   domain: the value of the domain attribute of the cookie
//   secure: if true, the secure attribute of the cookie will be set
// 

EI.Cookie.prototype.store = function(daysToLive, path, domain, secure) {
	// 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 encode the value
	// of each property in case it contains punctuation or other
	// illegal characters.
	var cookieval = "";
	for(var prop in this) {
		// Ignore properties with names that begin with '$' and also methods
		if ((prop.charAt(0) == '$') || ((typeof this[prop]) == 'function'))
			continue;
		if (cookieval != "") cookieval += '&';
		cookieval += prop + ':' + encodeURIComponent(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 (daysToLive || daysToLive == 0) {
		var date = new Date();
		date.setTime(date.getTime() + (daysToLive*24*60*60*1000));
		cookie += "; expires="+date.toGMTString();
	}
 
	if (path) cookie += "; path=" + path;
	if (domain) cookie += "; domain=" + domain;
	if (secure) cookie += "; secure";
 
	// Now store the cookie by setting the magic Document.cookie property
	document.cookie = cookie;
}
 

// This function is the remove() method of the Cookie object; it deletes the
// properties of the object and removes the cookie from the browser's
// local store.
// 
// The arguments to this function are all optional, but to remove a cookie
// you must pass the same values you passed to store().
// 

EI.Cookie.prototype.remove = function(path, domain, secure) {
	// Delete the properties of the cookie
	for(var prop in this) {
		if (prop.charAt(0) != '$' && typeof this[prop] != 'function')
			delete this[prop];
	}
 
	// Then, store the cookie with a lifetime of 0
	this.store(0, path, domain, secure);
}
 

// This static method attempts to determine whether cookies are enabled.
// It returns true if they appear to be enabled and false otherwise.
// A return value of true does not guarantee that cookies actually persist.
// Nonpersistent session cookies may still work even if this method
// returns false.
// 

EI.Cookie.enabled = function() {
	// Use navigator.cookieEnabled if this browser defines it
	if (navigator.cookieEnabled != undefined) return navigator.cookieEnabled;
 
	// If we've already cached a value, use that value
	if (EI.Cookie.enabled.cache != undefined) return EI.Cookie.enabled.cache;
 
	// Otherwise, create a test cookie with a lifetime
	document.cookie = "testcookie=test; max-age=10000";	 // Set cookie
 
	// Now see if that cookie was saved
	var cookies = document.cookie;
	if (cookies.indexOf("testcookie=test") == -1) {
		// The cookie was not saved
		return EI.Cookie.enabled.cache = false;
	}
	else {
		// Cookie was saved, so we've got to delete it before returning
		document.cookie = "testcookie=test; max-age=0";	 // Delete cookie
		return EI.Cookie.enabled.cache = true;
	}
}