/* Loads the Google data JavaScript client library */
google.load("gdata", "1");

function init() {
// init the Google data JS client library with an error handler and fire custom events
google.gdata.client.init(handleGDError);
loadNCMCCalendar();
}

/**
* Adds a leading zero to a single-digit number.  Used for displaying dates.
*/
function padNumber(num) {
if (num <= 9) {
return "0" + num;
}
return num;
}

function loadNCMCCalendar()
{
loadCalendarByAddress('north.camp.methodist.church@googlemail.com');
}

/**
* Determines the full calendarUrl based upon the calendarAddress
* argument and calls loadCalendar with the calendarUrl value.
*
* @param {string} calendarAddress is the email-style address for the calendar
*/ 
function loadCalendarByAddress(calendarAddress) {
var calendarUrl = 'http://www.google.com/calendar/feeds/' +
                calendarAddress + 
                '/public/full';
loadCalendar(calendarUrl);
}

/**
* Uses Google data JS client library to retrieve a calendar feed from the specified
* URL.  The feed is controlled by several query parameters and a callback 
* function is called to process the feed results.
*
* @param {string} calendarUrl is the URL for a public calendar feed
*/  
function loadCalendar(calendarUrl) {
var service = new 
  google.gdata.calendar.CalendarService('gdata-js-client-samples-simple');
  
var query = new google.gdata.calendar.CalendarEventQuery(calendarUrl);
query.setOrderBy('starttime');
query.setSortOrder('ascending');
query.setFutureEvents(true);
query.setSingleEvents(true);
query.setMaxResults(15);

service.getEventsFeed(query, listEvents, handleGDError);
}

/**
* Callback function for the Google data JS client library to call when an error
* occurs during the retrieval of the feed.  Details available depend partly
* on the web browser, but this shows a few basic examples. In the case of
* a privileged environment using ClientLogin authentication, there may also
* be an e.type attribute in some cases.
*
* @param {Error} e is an instance of an Error 
*/
function handleGDError(e) {
if (e instanceof Error) {
/* alert with the error line number, file and message */
/**
*  alert('Error at line ' + e.lineNumber +
*      ' in ' + e.fileName + '\n' +
*      'Message: ' + e.message);
*/
/* if available, output HTTP error code and status text */
if (e.cause) {
  var status = e.cause.status;
  var statusText = e.cause.statusText;
  alert('Root cause: HTTP error ' + status + ' with status text of: ' + 
        statusText);
}
} else {
alert(e.toString());
}
}

/**
* Callback function for the Google data JS client library to call with a feed 
* of events retrieved.
*
* Creates an unordered list of events in a human-readable form.  This list of
* events is added into a div called 'events'.
*
* @param {json} feedRoot is the root of the feed, containing all entries 
*/
function listEvents(feedRoot) {
var entries = feedRoot.feed.getEntries();
var eventDiv = document.getElementById('events');
if (eventDiv.childNodes.length > 0) {
eventDiv.removeChild(eventDiv.childNodes[0]);
}	  
/* create a new unordered list */
var ul = document.createElement('ul');
/* loop through each event in the feed */
var len = entries.length;
for (var i = 0; i < len; i++) {
var entry = entries[i];
var title = entry.getTitle().getText();
var startDateTime = null;
var startJSDate = null;
var times = entry.getTimes();
if (times.length > 0) {
  startDateTime = times[0].getStartTime();
  startJSDate = startDateTime.getDate();
}
var entryLinkHref = null;
if (entry.getHtmlLink() != null) {
  entryLinkHref = entry.getHtmlLink().getHref();
}
var dateString = startJSDate.getDate() + "/" + (startJSDate.getMonth() + 1);
if (!startDateTime.isDateOnly()) {
  dateString += " " + startJSDate.getHours() + ":" + 
      padNumber(startJSDate.getMinutes());
}
var li = document.createElement('li');

/* if we have a link to the event, create an 'a' element */
if (entryLinkHref != null) {
  entryLink = document.createElement('a');
  entryLink.setAttribute('href', entryLinkHref);
  entryLink.appendChild(document.createTextNode(title));
  li.appendChild(entryLink);
  li.appendChild(document.createTextNode(' - ' + dateString));
} else {
  li.appendChild(document.createTextNode(title + ' - ' + dateString));
}	    

/* append the list item onto the unordered list */
ul.appendChild(li);
}
eventDiv.appendChild(ul);
}

google.setOnLoadCallback(init);