var SCHEDULE_UPDATE_INTERVAL = 60 * 60;	// 1 hour
var SCHEDULE_DATA_ID = "schedule_data";
var SCHEDULE_DATA_URL = "/stybin/schedule";
var SCHEDULE_DATA_PARAMS = "now_playing=1";
var schedule_url;
var current_schedule_data;

function schedule_init (params)
{
    var d = new Date();
    var interval = (60 - d.getMinutes() + 2) * 60;  // 2 minutes after the hour
    if ( ! params ) params = SCHEDULE_DATA_PARAMS;
    schedule_url = SCHEDULE_DATA_URL + "?" + params;
    setTimeout ("schedule_update()", interval * 1000);
}

function schedule_callback()
{
    var new_schedule_data = document.getElementById(SCHEDULE_DATA_ID).innerHTML;
    if ( current_schedule_data != new_schedule_data )
    {
	// do anything worthwhile on a new song being displayed
	// var o = document.getElementById(SCHEDULE_DATA_ID);
	// if ( o ) o.style.backgroundColor = "#ff0000";
    }
    setTimeout (schedule_update, SCHEDULE_UPDATE_INTERVAL * 1000);
}

function schedule_update ()
{
    var url = schedule_url;
    url += "&t=" + (new Date()).getTime();	// make it bypass cache

    // save off a copy of the current recent schedule so we can compare after update to see if it changed
    current_schedule_data = document.getElementById(SCHEDULE_DATA_ID).innerHTML;
    sndReq (SCHEDULE_DATA_ID, url, schedule_callback);
}