<?php
/**  @class EpnTapMgr
*    @brief Manager to communicates with EPN-TAP services.
*/

class EpnTapMgr {

	private $logEpnTap;

	function __construct()
    {

    	$this->logEpnTap = fopen(LOG_DIR . "epnTap.log", "a");

		$this->addLog("\n---\n");
    }

	function addLog($msg)
    {

  		fwrite($this->logEpnTap, date("h:i:s A") . ": " . $msg . "\n");

    }

	public function call($function_name, $args) {
		switch($function_name) {
			case 'getServiceNbResults':
				if(count($args) == 6)
					return $this->getServiceNbResults($args[0], $args[1], $args[2], $args[3], $args[4], $args[5]);
				break;
			case 'getGranules':
				if(count($args) == 6)
					return $this->getGranules($args[0], $args[1], $args[2], $args[3], $args[4], $args[5]);
				break;
			default:
				return array('success' => false, 'message' => $function_name.' is an unknown function.');
				break;
		}
	return array('success' => false, 'message' => 'The function do not have the required number of arguments');
	}

	private function date2JD($date) {
		list($month, $day, $year) = split('[/.-]', $date);

		if($month == 1 || $month == 2) {
			$yearp = $year - 1;
			$monthp = $month + 12;
		} else {
			$yearp = $year;
			$monthp = $month;
		}

		# this checks where we are in relation to October 15, 1582, the beginning of the Gregorian calendar.

		if (($year < 1582) ||
				($year == 1582 && $month < 10) ||
				($year == 1582 && $month == 10 && $day < 15))
			$j_day = 0;
		else
			$j_day = 2 - (int)($yearp / 100.0) + (int)((int)($yearp / 100.0) / 4.0);

		$j_day += $yearp < 0 ? (int)((365.25 * $yearp) - 0.75) : (int)(365.25 * $yearp);
		$j_day += (int)(30.6001 * ($monthp + 1)) + $day + 1720994.5;

		return $j_day;
	}

	public function createFilter($target_name, $dataproduct_type, $time_min, $time_max) {

		$filter = array();
		if($target_name)
			array_push($filter, "target_name = '$target_name'");
		if($dataproduct_type)
			array_push($filter, "dataproduct_type = '$dataproduct_type'");
		if($time_min)

			array_push($filter, "time_min <= " . $this->date2JD($time_min));

		if($time_max)
			array_push($filter, "time_max >= " . $this->date2JD($time_max));

		return (count($filter) > 0 ? ' WHERE '.join(' AND ', $filter) : '');
	}

	public function request($access_url, $query) {

		$votMgr = new VOTableMgr;
		$params = 'FORMAT=votable&LANG=ADQL&REQUEST=doQuery';
		$url = $access_url . '/sync?' . $params . '&QUERY=' . urlencode($query);

		$this->addLog("Query URL: " . $url);

		$votMgr->load($url);

		$result = $votMgr->isValidSchema() ? $votMgr->parseStream() : NULL;
		return $result;

	}

	private function getGranules($table_name, $access_url, $target_name, $dataproduct_type, $time_min, $time_max) {

		$filter = $this->createFilter($target_name, $dataproduct_type, $time_min, $time_max);
		$query = "SELECT dataproduct_type, target_name, time_min, time_max FROM $table_name.epn_core" . $filter;
		return $this->request($access_url, $query);

	}
}
?>