function Hash()
{
	this.length = 0;
	this.items = new Array();
	for (var i = 0; i < arguments.length; i += 2) {
		if (typeof(arguments[i + 1]) != 'undefined') {
			this.items[arguments[i]] = arguments[i + 1];
			this.length++;
		}
	}
   
	this.removeItem = function(in_key)
	{
		var tmp_value;
		if (typeof(this.items[in_key]) != 'undefined') {
			this.length--;
			var tmp_value = this.items[in_key];
			delete this.items[in_key];
		}
	   
		return tmp_value;
	}

	this.getItem = function(in_key) {
		return this.items[in_key];
	}

	this.setItem = function(in_key, in_value)
	{
		if (typeof(in_value) != 'undefined') {
			if (typeof(this.items[in_key]) == 'undefined') {
				this.length++;
			}

			this.items[in_key] = in_value;
		}
	   
		return in_value;
	}

	this.hasItem = function(in_key)
	{
		return typeof(this.items[in_key]) != 'undefined';
	}
}

var pricingScheme = new Hash('',         new Hash("select a time slot", new Array('0',  '0' )),
                              'adult',   new Hash("select a time slot", new Array('0',  '0' ),
															                    "Saturday day",       new Array('1', '10'),
                                                  "Saturday night",     new Array('2', '20'),
																								  "Sunday day",         new Array('3', '10'),
																									"all weekend",        new Array('4', '30')),
													    'VIP',     new Hash("select a time slot", new Array('0',  '0' ),
															                    "Saturday night",     new Array('2', '50')),
															'student', new Hash("select a time slot", new Array('0',  '0' ),
															                    "Saturday night",     new Array('2', '10')));
function populate_session()
{
	var ticket_type = document.forms['ticket_form'].elements['ticket_type'];
	var session = document.forms['ticket_form'].elements['session'];
	session.options.length = 0;
	
	session_hash = pricingScheme.getItem(ticket_type.value);
	
	for (var session_name in session_hash.items) {
		session.options[session.options.length] = new Option(session_name, (session_hash.items[session_name])[0]);
	}
	
	populate_total(false);
}

function populate_total(warnings)
{
	var quantity = document.forms['ticket_form'].elements['quantity'];
	var ticket_type = document.forms['ticket_form'].elements['ticket_type'];
	var session = document.forms['ticket_form'].elements['session'];
	var total = document.forms['ticket_form'].elements['total'];

	var error = "";
	
	if (ticket_type.value == "") {
		error += "Please select a ticket type.\n";
	}
	
	if (session.value == "0") {
		error += "Please select a session.\n";
	}
	
	if (!quantity.value.match(/^[0-9]+$/)) {
		error += "The quantity is not a valid number.\n";
	}

	if (error != "") {
		if (warnings) { alert(error); }
		return false;
	} else {
		var session_hash = pricingScheme.getItem(ticket_type.value);
		total.value = session_hash.items[session.options[session.selectedIndex].text][1] * quantity.value;
		return true;
	}
}