var people;
var events;
var selectedEvent;

// Work-around for missing JQuery.postJSON
jQuery["postJSON"] = function(url,data,callback) {
	$.ajax({
	  url:url,
	  type:'POST',
	  data:JSON.stringify(data),
	  contentType:'application/json',
	  dataType:'json',
	  success: callback
	});
};

// Helper function to map event ids to event objects
function mapIDtoEvent(id) {
    var n;
    for(n = 0;n < events.length;n++) {
        if(events[n].id == id)
            return events[n];
    }
    return null;
}

// Callback function for the GET that fetches a list of people for an event
function receiveAttendees(people) {
    var n;
    for(n = 0;n < people.length;n++) {
        // For each person in the list of people
        // create an option in the select for people
        var newItem = $('<li>');
        newItem.text(people[n].firstname + " " + people[n].lastname);
        $('#attendees').append(newItem);
    }
}

// Callback function for the POST that posted a new registration
function confirm() {
    $("#main").hide();
    $('#confirm').show();

    // Go back to the server and fetch the list 
    // of people for the event
    $.getJSON("https://cmsc106.net/Registration/events/" +$('#events').val()+ "/people",receiveAttendees);
}

// This function is linked to the register button
function registerForEvent() {
    var registration = {person: $("#people").val(), event: $('#events').val()};
    $.postJSON("http://cmsc106.net/Registration/registrations",registration,confirm);
}   

// This function is linked to the 'View Event' button
function showDetails() {
    $('#start').hide();
    $('#main').show();
    var eventId = $('#events').val();   
    selectedEvent = mapIDtoEvent(eventId);
    $('#eventName').text(selectedEvent.title);
    $('#date').text(selectedEvent.day);
    $('#description').text(selectedEvent.description);
}

// Callback function for the GET that fetches a list of people
function receivePeople(data) {
    people = data;
    var n;
    for(n = 0;n < people.length;n++) {
        // For each person in the list of people
        // create an option in the select for people
        var newOption = $('<option>');
        newOption.text(people[n].firstname + " " + people[n].lastname);
        newOption.val(people[n].id);
        $('#people').append(newOption);
    }
}

// Callback function for the GET that fetches a list of events
function receiveEvents(data) {
    events = data;
    var n;
    for(n = 0;n < events.length;n++) {
        // For each person in the list of people
        // create an option in the select for people
        var newOption = $('<option>');
        newOption.text(events[n].title);
        newOption.val(events[n].id);
        $('#events').append(newOption);
    }

}

function setup() {
    $('#main').hide();
    $('#confirm').hide();
    $('#view').click(showDetails);
    $('#register').click(registerForEvent);
    $.getJSON("http://cmsc106.net/Registration/people",receivePeople);
    $.getJSON("http://cmsc106.net/Registration/events",receiveEvents);
}

$(document).ready(setup);