course.lib.php

完美的在线教育系统

			$virtual_courses_exist = false;
		}

		//now determine course code and name

		if ($user_is_registered_in_real_course && $virtual_courses_exist)
		{
			$course_info["name"] = CourseManager :: create_combined_name($user_is_registered_in_real_course, $real_course_name, $user_subscribed_virtual_course_list);
			$course_info['official_code'] = CourseManager :: create_combined_code($user_is_registered_in_real_course, $real_course_visual_code, $user_subscribed_virtual_course_list);
		}
		else
			if ($user_is_registered_in_real_course)
			{
				//course name remains real course name
				$course_info["name"] = $real_course_name;
				$course_info['official_code'] = $real_course_visual_code;
			}
			else
				if ($virtual_courses_exist)
				{
					$course_info["name"] = CourseManager :: create_combined_name($user_is_registered_in_real_course, $real_course_name, $user_subscribed_virtual_course_list);
					$course_info['official_code'] = CourseManager :: create_combined_code($user_is_registered_in_real_course, $real_course_visual_code, $user_subscribed_virtual_course_list);
				}
				else
				{
					//course name remains real course name
					$course_info["name"] = $real_course_name;
					$course_info['official_code'] = $real_course_visual_code;
				}

		$return_result["title"] = $course_info["name"];
		$return_result["code"] = $course_info['official_code'];
		return $return_result;
	}

	/**
	* Create a course title based on all real and virtual courses the user is registered in.
	* @param boolean $user_is_registered_in_real_course
	* @param string $real_course_name, the title of the real course
	* @param array $virtual_course_list, the list of virtual courses
	*/
	function create_combined_name($user_is_registered_in_real_course, $real_course_name, $virtual_course_list)
	{
		if ($user_is_registered_in_real_course || count($virtual_course_list) > 1)
		{
			$complete_course_name_before = get_lang("CombinedCourse")." "; //from course_home lang file
		}

		if ($user_is_registered_in_real_course)
		{
			//add real name to result
			$complete_course_name[] = $real_course_name;
		}

		//add course titles of all virtual courses to the list
		foreach ($virtual_course_list as $current_course)
		{
			$complete_course_name[] = $current_course["title"];
		}

		$complete_course_name = $complete_course_name_before.implode(' & ', $complete_course_name);

		return $complete_course_name;
	}

	/**
	*	Create a course code based on all real and virtual courses the user is registered in.
	*/
	function create_combined_code($user_is_registered_in_real_course, $real_course_code, $virtual_course_list)
	{
		$complete_course_code .= "";

		if ($user_is_registered_in_real_course)
		{
			//add real name to result
			$complete_course_code[] = $real_course_code;
		}

		//add course titles of all virtual courses to the list
		foreach ($virtual_course_list as $current_course)
		{
			$complete_course_code[] = $current_course["visual_code"];
		}

		$complete_course_code = implode(' & ', $complete_course_code);

		return $complete_course_code;
	}

	/**
	*	Return course info array of virtual course
	*
	*	Note this is different from getting information about a real course!
	*
	*	@param $real_course_code, the id of the real course which the virtual course is linked to
	*/
	function get_virtual_course_info($real_course_code)
	{
		$table = Database :: get_main_table(TABLE_MAIN_COURSE);
		$sql_query = "SELECT * FROM $table WHERE `target_course_code` = '$real_course_code'";
		$sql_result = api_sql_query($sql_query, __FILE__, __LINE__);
		$result = array ();
		while ($virtual_course = Database::fetch_array($sql_result))
		{
			$result[] = $virtual_course;
		}
		return $result;
	}

	/**
	*	@param string $system_code, the system code of the course
	*	@return true if the course is a virtual course, false otherwise
	*/
	function is_virtual_course_from_system_code($system_code)
	{
		$table = Database :: get_main_table(TABLE_MAIN_COURSE);
		$sql_query = "SELECT * FROM $table WHERE `code` = '$system_code'";
		$sql_result = api_sql_query($sql_query, __FILE__, __LINE__);
		$result = Database::fetch_array($sql_result);
		$target_number = $result["target_course_code"];

		if ($target_number == NULL)
		{
			return false; //this is not a virtual course
		}
		else
		{
			return true; //this is a virtual course
		}
	}

	/**
	*	What's annoying is that you can't overload functions in PHP.
	*	@return true if the course is a virtual course, false otherwise
	*/
	function is_virtual_course_from_visual_code($visual_code)
	{
		$table = Database :: get_main_table(TABLE_MAIN_COURSE);
		$sql_query = "SELECT * FROM $table WHERE `visual_code` = '$visual_code'";
		$sql_result = api_sql_query($sql_query, __FILE__, __LINE__);
		$result = Database::fetch_array($sql_result);
		$target_number = $result["target_course_code"];

		if ($target_number == NULL)
		{
			return false; //this is not a virtual course
		}
		else
		{
			return true; //this is a virtual course
		}
	}

	/**
	* @return true if the real course has virtual courses that the user is subscribed to, false otherwise
	*/
	function has_virtual_courses_from_code($real_course_code, $user_id)
	{
		$user_subscribed_virtual_course_list = CourseManager :: get_list_of_virtual_courses_for_specific_user_and_real_course($user_id, $real_course_code);
		$number_of_virtual_courses = count($user_subscribed_virtual_course_list);

		if (count($user_subscribed_virtual_course_list) > 0)
		{
			return true;
		}
		else
		{
			return false;
		}
	}

	/**
	*	Return an array of arrays, listing course info of all virtual course
	*	linked to the real course ID $real_course_code
	*
	*	@param $real_course_code, the id of the real course which the virtual courses are linked to
	*/
	function get_virtual_courses_linked_to_real_course($real_course_code)
	{
		$table = Database :: get_main_table(TABLE_MAIN_COURSE);
		$sql_query = "SELECT * FROM $table WHERE `target_course_code` = '$real_course_code'";
		$sql_result = api_sql_query($sql_query, __FILE__, __LINE__);
		$result_array = array ();
		while ($result = Database::fetch_array($sql_result))
		{
			$result_array[] = $result;
		}

		return $result_array;
	}

	/**
	* This function returns the course code of the real course
	* to which a virtual course is linked.
	*
	* @param the course code of the virtual course
	* @return the course code of the real course
	*/
	function get_target_of_linked_course($virtual_course_code)
	{
		$course_table = Database :: get_main_table(TABLE_MAIN_COURSE);

		//get info about the virtual course
		$sql_query = "SELECT * FROM $course_table WHERE `code` = '$virtual_course_code'";
		$sql_result = api_sql_query($sql_query, __FILE__, __LINE__);
		$result = Database::fetch_array($sql_result);
		$target_course_code = $result["target_course_code"];

		return $target_course_code;
	}

	/*
	==============================================================================
		USER FUNCTIONS
	==============================================================================
	*/

	/**
	* Return course info array of virtual course
	*
	* @param $user_id, the id (int) of the user
	* @param $course_info, array with info about the course (comes from course table)
	*
	* @return true if the user is registered in the course, false otherwise
	*/
	function is_user_subscribed_in_course($user_id, $course_code, $in_a_session=false)
	{
		$user_id = intval($user_id);
		$course_code = addslashes($course_code);
		
		$table = Database :: get_main_table(TABLE_MAIN_COURSE_USER);

		$sql_query = "SELECT * FROM $table WHERE `user_id` = '$user_id' AND `course_code` = '$course_code'";
		$sql_result = api_sql_query($sql_query, __FILE__, __LINE__);
		$result = Database::fetch_array($sql_result);

		if (!isset ($result) || empty ($result))
		{
			if($in_a_session)
			{
				$sql = 'SELECT 1 FROM '.Database :: get_main_table(TABLE_MAIN_SESSION_COURSE_USER).'
						WHERE id_user = '.$user_id.' AND course_code="'.$course_code.'"';
				
				$rs = api_sql_query($sql, __FILE__, __LINE__);
				if(Database::num_rows($rs)>0)
				{
					return true;
				}
				else{
					$sql = 'SELECT 1 FROM '.Database :: get_main_table(TABLE_MAIN_SESSION_COURSE).'
						WHERE id_coach = '.$user_id.' AND course_code="'.$course_code.'"';
					$rs = api_sql_query($sql, __FILE__, __LINE__);
					if(Database::num_rows($rs)>0)
					{
						return true;
					}
				}
			}
			else
				return false; //user is not registered in course
		}
		else
		{
			return true; //user is registered in course
		}
	}
	
	/**
	*	Is the user a teacher in the given course?
	*
	*	@param $user_id, the id (int) of the user
	*	@param $course_code, the course code
	*
	*	@return true if the user is a teacher in the course, false otherwise
	*/
	function is_course_teacher($user_id,$course_code)
	{
		$tbl_course_user	= Database::get_main_table(TABLE_MAIN_COURSE_USER);
		$sql_query='SELECT status FROM '.$tbl_course_user.' WHERE course_code="'.$course_code.'" and user_id="'.$user_id.'"';
		$sql_result = api_sql_query($sql_query, __FILE__, __LINE__);
		if(Database::num_rows($sql_result)>0)
		{
			$status=Database::result($sql_result,0,'status');
			if($status==1) return true; else return false;
		}
		return false;
	}

	/**
	*	Is the user subscribed in the real course or linked courses?
	*
	*	@param $user_id, the id (int) of the user
	*	@param $course_info, array with info about the course (comes from course table, see database lib)
	*
	*	@return true if the user is registered in the real course or linked courses, false otherwise
	*/
	function is_user_subscribed_in_real_or_linked_course($user_id, $course_code, $session_id='')
	{
		if($session_id==''){
			$course_table = Database :: get_main_table(TABLE_MAIN_COURSE);
			$course_user_table = Database :: get_main_table(TABLE_MAIN_COURSE_USER);

			$sql_query = "	SELECT *
								FROM $course_table course
								LEFT JOIN $course_user_table course_user
								ON course.`code` = course_user.`course_code`
								WHERE course_user.`user_id` = '$user_id' AND ( course.`code` = '$course_code' OR `target_course_code` = '$course_code') ";

			$sql_result = api_sql_query($sql_query, __FILE__, __LINE__);
			$result = Database::fetch_array($sql_result);

			if (!isset ($result) || empty ($result))
			{
				return false; //user is not registered in course
			}
			else
			{
				return true; //user is registered in course
			}
		}
		else {
			// is he subscribed to the course of the session ?
			// Database Table Definitions
			$tbl_sessions			= Database::get_main_table(TABLE_MAIN_SESSION);
			$tbl_sessions_course	= Database::get_main_table(TABLE_MAIN_SESSION_COURSE);
			$tbl_session_course_user= Database::get_main_table(TABLE_MAIN_SESSION_COURSE_USER);


			//users
			$sql = "SELECT id_user
					FROM $tbl_session_course_user
					WHERE id_session='".$_SESSION['id_session']."'
					AND id_user='$user_id'";

			$result = api_sql_query($sql,__FILE__,__LINE__);
			if(Database::num_rows($result))
				return true;

			// is it a course coach ?
			$sql = "SELECT id_coach
					FROM $tbl_sessions_course AS session_course
					WHERE id_session='".$_SESSION['id_session']."'
					AND id_coach = '$user_id'
					AND course_code='$course_code'";

			$result = api_sql_query($sql,__FILE__,__LINE__);
			if(Database::num_rows($result))
				return true;

			// is it a session coach ?
			$sql = "SELECT id_coach