<?PHP
class shiftCycle {
		
	public $timestamp;
	public $daysSince;
	public $cyclesSince;
	public $cyclePart;
	public $currentShift;
	
	function __construct($conf){

		$dtz = new DateTimeZone($conf['timeZone']);
		$dt = new DateTime('now', $dtz); //DateTime object set to defined TZ
		$this->timestamp = $dt->format('U');
		
		$adj = ($this->timestamp - ($this->timeToSeconds($conf['startTime']))); //align shift start change to midnight.
		$this->daysSince = floor($adj / 86400); //Whole days since EPOCH
		$this->cyclesSince = floor(($this->daysSince / 3)*10)/10; //Cycles since EPOCH
		$this->cyclePart = floor(((($this->cyclesSince - floor($this->cyclesSince)) * 10) / count($conf['shifts']))); //Day in cycle
		$this->currentShift = $conf['shifts'][$this->cyclePart]; //Current Shift

	}
	
	private function timeToSeconds($time){ // returns 24-hour time into seconds since midnight 
		
		$hm1 = explode(':', $time); // split hours and minutes
		$hm2 = $hm1[0] + round($hm1[1] / 60, 2); // determine number of hours since midnight
		$hm3 = $hm2 * 3600; // convert hours to seconds
		
		return $hm3;
		
	}
}
?>