<?php
/* For licensing terms, see /license.txt */

/**
 * Gradebook link to a survey item
 * @author Ivan Tcholakov <ivantcholakov@gmail.com>, 2010
 * @package chamilo.gradebook
 */
class SurveyLink extends AbstractLink
{
	private $survey_table = null;

	/**
	 * Constructor
	 */
	public function __construct()
	{
		parent::__construct();
		$this->set_type(LINK_SURVEY);
	}

	public function get_name()
	{
		$this->get_survey_data();
		return $this->survey_data['code'].': '.self::html_to_text($this->survey_data['title']);
	}

	public function get_description()
	{
		$this->get_survey_data();
		return $this->survey_data['subtitle'];
	}

	public function get_type_name()
	{
		return get_lang('Survey');
	}

	public function is_allowed_to_change_name()
	{
		return false;
	}

	public function needs_name_and_description()
	{
		return false;
	}

	public function needs_max()
	{
		return false;
	}

	public function needs_results()
	{
		return false;
	}

	/**
	 * Generates an array of all surveys available.
	 * @return array 2-dimensional array - every element contains 2 subelements (id, name)
	 */
	public function get_all_links()
	{
		if (empty($this->course_code)) {
			die('Error in get_all_links() : course code not set');
		}
		$tbl_survey = $this->get_survey_table();
		$session_id = api_get_session_id();
		$course_id = api_get_course_int_id();
		$sql = 'SELECT survey_id, title, code FROM '.$tbl_survey.'
				WHERE c_id = '.$course_id.' AND session_id = '.intval($session_id).'';
		$result = Database::query($sql);
		while ($data = Database::fetch_array($result)) {
			$links[] = array(
				$data['survey_id'],
				api_trunc_str(
					$data['code'] . ': ' . self::html_to_text($data['title']),
					80
				)
			);
		}

		return isset($links) ? $links : null;
	}

	/**
	 * Generates an array of surveys that a teacher hasn't created a link for.
	 * @return array 2-dimensional array - every element contains 2 subelements (id, name)
	 */
	public function get_not_created_links()
	{
		if (empty($this->course_code)) {
			die('Error in get_not_created_links() : course code not set');
		}
		$tbl_grade_links = Database :: get_main_table(TABLE_MAIN_GRADEBOOK_LINK);

		$sql = 'SELECT survey_id, title, code
    			FROM '.$this->get_survey_table().' AS srv
				WHERE survey_id NOT IN
					(
					SELECT ref_id FROM '.$tbl_grade_links.'
					WHERE
						type = '.LINK_SURVEY.' AND
						course_code = "'.$this->get_course_code().'"
					)
					AND srv.session_id = '.api_get_session_id();

		$result = Database::query($sql);

		$links = array();
		while ($data = Database::fetch_array($result)) {
			$links[] = array(
				$data['survey_id'],
				api_trunc_str($data['code'].': '.self::html_to_text($data['title']), 80)
			);
		}
		return $links;
	}

	/**
	 * Has anyone done this survey yet?
	 */
	public function has_results($stud_id=null)
	{
		$ref_id = intval($this->get_ref_id());
		$session_id = api_get_session_id();
		$tbl_survey = Database::get_course_table(TABLE_SURVEY);
		$tbl_survey_invitation = Database::get_course_table(TABLE_SURVEY_INVITATION);
		$sql = "SELECT
				COUNT(i.answered)
				FROM $tbl_survey AS s
				JOIN $tbl_survey_invitation AS i ON s.code = i.survey_code
				WHERE
					s.c_id = {$this->course_id} AND
					i.c_id = {$this->course_id} AND
					s.survey_id = $ref_id AND
					i.session_id = $session_id";

		$sql_result = Database::query($sql);
		$data = Database::fetch_array($sql_result);

		return ($data[0] != 0);
	}

	/**
	 * @param int $stud_id
	 * @return array|null
	 */
	public function calc_score($stud_id = null, $type = null)
	{
		// Note: Max score is assumed to be always 1 for surveys,
		// only student's participation is to be taken into account.
		$max_score = 1;

		$ref_id = intval($this->get_ref_id());
		$session_id = api_get_session_id();
		$tbl_survey = Database::get_course_table(TABLE_SURVEY);
		$tbl_survey_invitation = Database::get_course_table(TABLE_SURVEY_INVITATION);

		$get_individual_score = !is_null($stud_id);

		$sql = "SELECT i.answered
				FROM $tbl_survey AS s
				JOIN $tbl_survey_invitation AS i
				ON s.code = i.survey_code
				WHERE
					s.c_id = {$this->course_id} AND
					i.c_id = {$this->course_id} AND
					s.survey_id = $ref_id AND
					i.session_id = $session_id
				";

		if ($get_individual_score) {
			$sql .= ' AND i.user = '.intval($stud_id);
		}

		$sql_result = Database::query($sql);

		if ($get_individual_score) {
			// for 1 student
			if ($data = Database::fetch_array($sql_result)) {
				return array($data['answered'] ? $max_score : 0, $max_score);
			}
			return array(0, $max_score);
		} else {
			// for all the students -> get average
			$rescount = 0;
			$sum = 0;
			$bestResult = 0;
			$weight = 0;
			while ($data = Database::fetch_array($sql_result)) {
				$sum += $data['answered'] ? $max_score : 0;
				$rescount++;
				if ($data['answered'] > $bestResult) {
					$bestResult = $data['answered'];
					$weight = $assignment['qualification'];
				}
			}
			$sum = $sum / $max_score;

			if ($rescount == 0) {
				return null;
			}

			switch ($type) {
				case 'best':
					return array($bestResult, $rescount);
					break;
				case 'average':
					return array($sum, $rescount);
					break;
				case 'ranking':
					return null;
					break;
				default:
					return array($sum, $rescount);
					break;
			}
		}
	}

	/**
	 * Lazy load function to get the database table of the surveys
	 */
	private function get_survey_table()
	{
		$this->survey_table = Database :: get_course_table(TABLE_SURVEY);
		return $this->survey_table;
	}

	/**
	 * Check if this still links to a survey
	 */
	public function is_valid_link()
	{
		$session_id = api_get_session_id();
		$sql = 'SELECT count(survey_id) FROM '.$this->get_survey_table().'
        		 WHERE
        		 	c_id = '.$this->course_id.' AND
        		 	survey_id = '.intval($this->get_ref_id()).' AND
        		 	session_id='.intval($session_id).'';
		$result = Database::query($sql);
		$number = Database::fetch_row($result);
		return ($number[0] != 0);
	}

	public function get_test_id()
	{
		return 'DEBUG:ID';
	}

	public function get_link()
	{
		if (api_is_allowed_to_edit()) { // Let students make access only through "Surveys" tool.
			$tbl_name = $this->get_survey_table();
			$session_id = api_get_session_id();
			if ($tbl_name != '') {
				$sql = 'SELECT survey_id FROM '.$this->get_survey_table().'
    					WHERE
    						c_id = '.$this->course_id.' AND
    						survey_id = '.intval($this->get_ref_id()).' AND
    						session_id = '.intval($session_id).' ';
				$result = Database::query($sql);
				$row = Database::fetch_array($result, 'ASSOC');
				$survey_id = $row['survey_id'];
				return api_get_path(WEB_PATH).'main/survey/reporting.php?cidReq='.$this->get_course_code().'&survey_id='.$survey_id;
			}
		}
		return null;
	}

	private function get_survey_data()
	{
		$tbl_name = $this->get_survey_table();
		$session_id = api_get_session_id();
		if ($tbl_name == '') {
			return false;
		} elseif (!isset($this->survey_data)) {
			$sql = 'SELECT * FROM '.$tbl_name.'
					WHERE
						c_id = '.$this->course_id.' AND
						survey_id = '.intval($this->get_ref_id()).' AND
						session_id='.intval($session_id).'';
			$query = Database::query($sql);
			$this->survey_data = Database::fetch_array($query);
		}
		return $this->survey_data;
	}

	public function get_icon_name()
	{
		return 'survey';
	}

	private static function html_to_text($string)
	{
		return strip_tags($string);
		//return trim(api_html_entity_decode(strip_tags(str_ireplace(array('<p>', '</p>', '<br />', '<br/>', '<br>'), array('', ' ', ' ', ' ', ' '), $string)), ENT_QUOTES));
	}
}