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

/**
 * Class ForumThreadLink
 *
 * @author Bert Steppé
 *
 * @package chamilo.gradebook
 */
class ForumThreadLink extends AbstractLink
{
	private $forum_thread_table = null;
	private $itemprop_table = null;

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

	/**
	 * @return string
	 */
	public function get_type_name()
	{
		return get_lang('ForumThreads');
	}

	/**
	 * @return bool
	 */
	public function is_allowed_to_change_name()
	{
		return false;
	}

	/**
	 * Generate an array of exercises 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);

		$sql = 'SELECT thread_id,thread_title,thread_title_qualify FROM '.$this->get_forum_thread_table()
			.' forum_thread WHERE thread_id NOT IN'
			.' (SELECT ref_id FROM '.$tbl_grade_links
			.' WHERE type = '.LINK_FORUM_THREAD
			." AND c_id = ".intval($this->course_id)
			.') AND forum_thread.session_id='.api_get_session_id().'';

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

        $cats = array();
        while ($data = Database::fetch_array($result)) {
            if (isset($data['thread_title_qualify']) && $data['thread_title_qualify'] != "") {
                $cats[] = array(
                    $data['thread_id'],
                    $data['thread_title_qualify'],
                );
            } else {
                $cats[] = array($data['thread_id'], $data['thread_title']);
            }
        }

        return $cats;
	}

	/**
	 * Generate an array of all exercises 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_not_created_links() : course code not set');
		}

		$tbl_grade_links 	= Database :: get_course_table(TABLE_FORUM_THREAD);
		$tbl_item_property	= Database :: get_course_table(TABLE_ITEM_PROPERTY);
		$session_id = api_get_session_id();

		if ($session_id) {
			$session_condition = 'tl.session_id='.api_get_session_id();
		} else {
			$session_condition = '(tl.session_id = 0 OR tl.session_id IS NULL)';
		}

		$sql = 'SELECT tl.thread_id, tl.thread_title, tl.thread_title_qualify
				FROM '.$tbl_grade_links.' tl ,'.$tbl_item_property.' ip
				WHERE
				    tl.c_id = '.$this->course_id.' AND
                    ip.c_id = '.$this->course_id.' AND
                    tl.thread_id = ip.ref AND
                    ip.tool = "forum_thread" AND
                    ip.visibility<>2 AND
                    '.$session_condition.'
                GROUP BY ip.ref ';

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

		while ($data = Database::fetch_array($result)) {
			if ( isset($data['thread_title_qualify']) and $data['thread_title_qualify']!=""){
				$cats[] = array ($data['thread_id'], $data['thread_title_qualify']);
			} else {
				$cats[] = array ($data['thread_id'], $data['thread_title']);
			}
		}
		$my_cats = isset($cats) ? $cats : null;

		return $my_cats;
	}

    /**
    * Has anyone done this exercise yet ?
    * @return int
    */
    public function has_results()
    {
        $table = Database :: get_course_table(TABLE_FORUM_POST);
        $sql = 'SELECT count(*) AS number FROM '.$table."
                WHERE
                    c_id = ".$this->course_id." AND
                    thread_id = '".$this->get_ref_id()."'";
        $result = Database::query($sql);
        $number = Database::fetch_row($result);

        return $number[0] != 0;
	}

	/**
	 * @param int    $stud_id
     * @param string $type
     *
	 * @return array|null
	 */
	public function calc_score($stud_id = null, $type = null)
	{
        require_once api_get_path(SYS_CODE_PATH).'forum/forumfunction.inc.php';
        $threadInfo = get_thread_information($this->get_ref_id());

		$thread_qualify = Database :: get_course_table(TABLE_FORUM_THREAD_QUALIFY);

		$sql = 'SELECT thread_qualify_max
		        FROM '.Database :: get_course_table(TABLE_FORUM_THREAD)."
  				WHERE c_id = ".$this->course_id." AND thread_id = '".$this->get_ref_id()."'";
		$query = Database::query($sql);
		$assignment = Database::fetch_array($query);

		$sql = "SELECT * FROM $thread_qualify
				WHERE c_id = ".$this->course_id." AND thread_id = ".$this->get_ref_id();
		if (isset($stud_id)) {
			$sql .= ' AND user_id = '.intval($stud_id);
		}

		// order by id, that way the student's first attempt is accessed first
		$sql .= ' ORDER BY qualify_time DESC';

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

		// for 1 student
		if (isset($stud_id)) {
            if ($threadInfo['thread_peer_qualify'] == 0) {
                // Classic way of calculate score
                if ($data = Database::fetch_array($scores)) {
                    return array(
                        $data['qualify'],
                        $assignment['thread_qualify_max']
                    );
                } else {
                    // We sent the 0/thread_qualify_max instead of null for correct calculations
                    return array(0, $assignment['thread_qualify_max']);
                }
            } else {
                // Take average
                $score = 0;
                $counter = 0;
                if (Database::num_rows($scores)) {
                    while ($data = Database::fetch_array($scores, 'ASSOC')) {
                        $score += $data['qualify'];
                        $counter++;
                    }
                }
                // If no result
                if (empty($counter) || $counter <= 2) {
                    return array(0, $assignment['thread_qualify_max']);
                }
                return [$score/$counter, $assignment['thread_qualify_max']];
            }
		} else {
			// All students -> get average
			$students = array();  // user list, needed to make sure we only
			// take first attempts into account
			$counter = 0;
			$sum = 0;
			$bestResult = 0;
			$weight = 0;
			$sumResult = 0;

			while ($data = Database::fetch_array($scores)) {
				if (!(array_key_exists($data['user_id'], $students))) {
					if ($assignment['thread_qualify_max'] != 0) {
						$students[$data['user_id']] = $data['qualify'];
						$counter++;
						$sum += $data['qualify'] / $assignment['thread_qualify_max'];
						$sumResult += $data['qualify'];
						if ($data['qualify'] > $bestResult) {
							$bestResult = $data['qualify'];
						}
						$weight = $assignment['thread_qualify_max'];
					}
				}
			}

			if ($counter == 0) {
				return null;
			} else {
				switch ($type) {
					case 'best':
						return array($bestResult, $weight);
						break;
					case 'average':
						return array($sumResult/$counter, $weight);
						break;
					case 'ranking':
						return AbstractLink::getCurrentUserRanking($stud_id, $students);
						break;
					default:
						return array($sum, $counter);
						break;
				}
			}
		}
	}

	/**
	 * Lazy load function to get the database table of the student publications
	 */
	private function get_forum_thread_table()
	{
		return $this->forum_thread_table = Database :: get_course_table(TABLE_FORUM_THREAD);
	}

	public function needs_name_and_description()
	{
		return false;
	}

	public function needs_max()
	{
		return false;
	}

	public function needs_results()
	{
		return false;
	}

    /**
     * @return string
     */
	public function get_name()
	{
		$this->get_exercise_data();
		$thread_title=isset($this->exercise_data['thread_title']) ? $this->exercise_data['thread_title'] : '';
		$thread_title_qualify=isset($this->exercise_data['thread_title_qualify']) ? $this->exercise_data['thread_title_qualify'] : '';
		if ( isset($thread_title_qualify) && $thread_title_qualify!="") {
			return $this->exercise_data['thread_title_qualify'];
		} else {
			return $thread_title;
		}
	}

    /**
     * @return string
     */
	public function get_description()
	{
		return '';//$this->exercise_data['description'];
	}

	/**
	 * Check if this still links to an exercise
	 */
	public function is_valid_link()
	{
		$sql = 'SELECT count(id) from '.$this->get_forum_thread_table().'
        		WHERE c_id = '.$this->course_id.' AND thread_id = '.$this->get_ref_id().' AND session_id='.api_get_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()
	{
		//it was extracts the forum id
		$sql = 'SELECT * FROM '.$this->get_forum_thread_table()."
    			WHERE c_id = '.$this->course_id.' AND thread_id = '".$this->get_ref_id()."' AND session_id = ".api_get_session_id()."";
		$result = Database::query($sql);
		$row    = Database::fetch_array($result,'ASSOC');
		$forum_id=$row['forum_id'];

		$url = api_get_path(WEB_PATH).'main/forum/viewthread.php?cidReq='.$this->get_course_code().'&thread='.$this->get_ref_id().'&gradebook=view&forum='.$forum_id;
		return $url;
	}

	private function get_exercise_data()
	{
		$session_id = api_get_session_id();
		if ($session_id) {
			$session_condition = 'session_id='.api_get_session_id();
		} else {
			$session_condition = '(session_id = 0 OR session_id IS NULL)';
		}

		if (!isset($this->exercise_data)) {
			$sql = 'SELECT * FROM '.$this->get_forum_thread_table().'
                    WHERE c_id = '.$this->course_id.' AND  thread_id = '.$this->get_ref_id().' AND '.$session_condition;
			$query = Database::query($sql);
			$this->exercise_data = Database::fetch_array($query);
		}
		return $this->exercise_data;
	}

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

	function save_linked_data()
	{
		$weight = (float)$this->get_weight();
		$ref_id = $this->get_ref_id();

		if (!empty($ref_id)) {
			$sql = 'UPDATE '.$this->get_forum_thread_table().' SET thread_weight='.$weight.'
                    WHERE c_id = '.$this->course_id.' AND thread_id= '.$ref_id;
			Database::query($sql);
		}
	}

	function delete_linked_data()
	{
		$ref_id = $this->get_ref_id();
		if (!empty($ref_id)) {
			//Cleans forum
			$sql = 'UPDATE '.$this->get_forum_thread_table().' SET thread_qualify_max=0,thread_weight=0,thread_title_qualify=""
                    WHERE c_id = '.$this->course_id.' AND thread_id= '.$ref_id;
			Database::query($sql);
		}
	}
}