chamilo-lms/main/auth/courses.php

<?php
/* For licensing terms, see /dokeos_license.txt */
/**
==============================================================================
*	@package dokeos.auth
*	@todo check if unsubscribing from a course WITH group memberships works as it should
*	@todo constants are in uppercase, variables aren't
==============================================================================
*/

/*
==============================================================================
		INIT SECTION
==============================================================================
*/

// Names of the language file that needs to be included.
$language_file = array ('courses', 'registration');

// Delete the globals['_cid'], we don't need it here.
$cidReset = true; // Flag forcing the 'current course' reset

// Including the global file.
require_once '../inc/global.inc.php';

if (api_get_setting('show_courses_descriptions_in_catalog') == 'true') {
	// additional html (javascript and style css)
	$htmlHeadXtra[] = '<script type="text/javascript">' .
				  	  'var GB_ROOT_DIR = "'.api_get_path(WEB_LIBRARY_PATH).'javascript/greybox/"' .
				  	  '</script>';

	$htmlHeadXtra[] = '<script src="'.api_get_path(WEB_LIBRARY_PATH).'javascript/jquery.js" type="text/javascript" language="javascript"></script>';

	$htmlHeadXtra[] = '<script src="'.api_get_path(WEB_LIBRARY_PATH).'javascript/greybox/AJS.js" type="text/javascript" language="javascript"></script>';
	$htmlHeadXtra[] = '<script src="'.api_get_path(WEB_LIBRARY_PATH).'javascript/greybox/AJS_fx.js" type="text/javascript" language="javascript"></script>';
	$htmlHeadXtra[] = '<script src="'.api_get_path(WEB_LIBRARY_PATH).'javascript/greybox/gb_scripts.js" type="text/javascript" language="javascript"></script>';

	$htmlHeadXtra[] = '<link href="'.api_get_path(WEB_LIBRARY_PATH).'javascript/greybox/gb_styles.css" rel="stylesheet" type="text/css" />';
}

// Section for the tabs.
$this_section = SECTION_COURSES;

// Acces rights: anonymous users can't do anything usefull here.
api_block_anonymous_users();

if (!(api_is_platform_admin() || api_is_course_admin() || api_is_allowed_to_create_course())) {
	if (api_get_setting('allow_students_to_browse_courses') == 'false') {
		api_not_allowed();
	}
}

// Include additional libraries.
include_once api_get_path(LIBRARY_PATH).'debug.lib.inc.php';
require_once api_get_path(LIBRARY_PATH).'course.lib.php';
require_once api_get_path(LIBRARY_PATH).'mail.lib.inc.php';

$ctok = $_SESSION['sec_token'];
$stok = Security::get_token();

// Database table definitions.
$tbl_course             = Database::get_main_table(TABLE_MAIN_COURSE);
$tbl_courses_nodes      = Database::get_main_table(TABLE_MAIN_CATEGORY);
$tbl_courseUser         = Database::get_main_table(TABLE_MAIN_COURSE_USER);
$tbl_user               = Database::get_main_table(TABLE_MAIN_USER);


// Filter.
$safe = array();
$safe['action'] = '';
$actions = array('sortmycourses', 'createcoursecategory', 'subscribe', 'deletecoursecategory', 'unsubscribe');

if (in_array(htmlentities($_GET['action']), $actions)) {
	$safe['action'] = htmlentities($_GET['action']);
}

// Title of the page.
if ($safe['action'] == 'sortmycourses' || !isset($safe['action'])) {
	$nameTools = get_lang('SortMyCourses');
}
if ($safe['action'] == 'createcoursecategory') {
	$nameTools = get_lang('CreateCourseCategory');
}
if ($safe['action'] == 'subscribe') {
	$nameTools = get_lang('SubscribeToCourse');
}

// Breadcrumbs.
$interbreadcrumb[] = array('url' => api_get_path(WEB_PATH).'user_portal.php', 'name' => get_lang('MyCourses'));
if (empty($nameTools)) {
	$nameTools = get_lang('CourseManagement');
} else {
	$interbreadcrumb[] = array('url' => api_get_path(WEB_CODE_PATH).'auth/courses.php', 'name' => get_lang('CourseManagement'));
}

// Displaying the header.
Display::display_header($nameTools);

/*
==============================================================================
		COMMANDS SECTION
==============================================================================
*/

unset($message);

// We are moving a course or category of the user up/down the list (=Sort My Courses).
if (isset($_GET['move'])) {
	if (isset($_GET['course'])) {
		if ($ctok == $_GET['sec_token']) {
			$message = move_course($_GET['move'], $_GET['course'], $_GET['category']);
		}
	}
	if (isset($_GET['category']) and !$_GET['course']) {
		if ($ctok == $_GET['sec_token']) {
			$message = move_category($_GET['move'], $_GET['category']);
		}
	}
}

// We are moving the course of the user to a different user defined course category (=Sort My Courses).
if (isset($_POST['submit_change_course_category'])) {
	if ($ctok == $_POST['sec_token']) {
		$message = store_changecoursecategory($_POST['course_2_edit_category'], $_POST['course_categories']);
	}
}

// We are creating a new user defined course category (= Create Course Category).
if (isset($_POST['create_course_category']) && isset($_POST['title_course_category']) && strlen(trim($_POST['title_course_category'])) > 0) {
	if ($ctok == $_POST['sec_token']) {
		$message = store_course_category();
	}
}

if (isset($_POST['submit_edit_course_category']) && isset($_POST['title_course_category']) && strlen(trim($_POST['title_course_category'])) > 0) {
	if ($ctok == $_POST['sec_token']) {
		$message = store_edit_course_category();
	}
}

// We are subcribing to a course (=Subscribe to course).
if (isset($_POST['subscribe'])) {
	if ($ctok == $_POST['sec_token']) {
		$message = subscribe_user($_POST['subscribe']);
	}
}

// We are unsubscribing from a course (=Unsubscribe from course).
if (isset($_POST['unsubscribe'])) {
	if ($ctok == $_POST['sec_token']) {
		$message = remove_user_from_course($_user['user_id'], $_POST['unsubscribe']);
	}
}

// we are deleting a course category
if ($safe['action'] == 'deletecoursecategory' && isset($_GET['id'])) {
	if ($ctok == $_GET['sec_token']) {
		$get_id_cat = Security::remove_XSS($_GET['id']);
		$message = delete_course_category($get_id_cat);
	}
}

/*
==============================================================================
					DISPLAY SECTION
==============================================================================
*/
// Diplaying the tool title
// api_display_tool_title($nameTools);

// we are displaying any result messages;
if (isset($message)) {
	Display::display_confirmation_message($message, false);
}

// The menu with the different options in the course management
echo "<div id=\"actions\" class='actions'>";
if ($safe['action'] != 'sortmycourses' && isset($safe['action'])) {
	echo "&nbsp;&nbsp;<a href=\"".api_get_self()."?action=sortmycourses\">".Display::return_icon('deplacer_fichier.gif', get_lang('SortMyCourses')).' '.get_lang('SortMyCourses')."</a>&nbsp;";
} else {
	echo '&nbsp;&nbsp;<strong>'.Display::return_icon('deplacer_fichier.gif', get_lang('SortMyCourses')).' '.get_lang('SortMyCourses').'</strong>&nbsp;';
}
echo '&nbsp;';
if ($safe['action'] != 'createcoursecategory') {
	echo "&nbsp;&nbsp;<a href=\"".api_get_self()."?action=createcoursecategory\">".Display::return_icon('folder_new.gif', get_lang('CreateCourseCategory')).' '.get_lang('CreateCourseCategory')."</a>&nbsp;";
} else {
	echo '&nbsp;&nbsp;<strong>'.Display::return_icon('folder_new.gif', get_lang('CreateCourseCategory')).' '.get_lang('CreateCourseCategory').'</strong>&nbsp;';
}
echo '&nbsp;';
if ($safe['action'] != 'subscribe') {
	echo "&nbsp;&nbsp;<a href=\"".api_get_self()."?action=subscribe\">".Display::return_icon('view_more_stats.gif', get_lang('SubscribeToCourse')).' '.get_lang('SubscribeToCourse')."</a>&nbsp;";
} else {
	echo '&nbsp;&nbsp;<strong>'.Display::return_icon('view_more_stats.gif', get_lang('SubscribeToCourse')).' '.get_lang('SubscribeToCourse').'</strong>&nbsp;';
}
echo "</div>";

echo "<div>";
switch ($safe['action']) {
	case 'subscribe':
		//api_display_tool_title(get_lang('SubscribeToCourse'));
		courses_subscribing();
		break;
	case 'unsubscribe':
		//api_display_tool_title(get_lang('UnsubscribeFromCourse'));
		$user_courses = get_courses_of_user($_user['user_id']);
		display_courses($_user['user_id'], true, $user_courses);
		break;
	case 'createcoursecategory':
		//api_display_tool_title(get_lang('CreateCourseCategory'));
		display_create_course_category_form();
		break;
	case 'deletecoursecategory':
	case 'sortmycourses':
	default:
		//api_display_tool_title(get_lang('SortMyCourses'));
		display_search_courses();
		$user_courses = get_courses_of_user($_user['user_id']);
		display_courses($_user['user_id'], true, $user_courses);
		break;
}
echo '</div>';
Display :: display_footer();

/*
==============================================================================
		FUNCTIONS
==============================================================================
*/
 /**
  * Subscribe the user to a given course
  * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
  * @param string $course_code the code of the course the user wants to subscribe to
  * @return string we return the message that is displayed when the action is succesfull
 */
function subscribe_user($course_code) {
	global $_user, $stok;

	$all_course_information = CourseManager::get_course_information($course_code);

	if ($all_course_information['registration_code'] == '' || $_POST['course_registration_code'] == $all_course_information['registration_code']) {
		if (api_is_platform_admin()) {
			$status_user_in_new_course = COURSEMANAGER;
		} else {
			$status_user_in_new_course=null;
		}
		if (CourseManager::add_user_to_course($_user['user_id'], $course_code, $status_user_in_new_course)) {
			$send = api_get_course_setting('email_alert_to_teacher_on_new_user_in_course', $course_code);
			if ($send == 1) {
				CourseManager::email_to_tutor($_user['user_id'], $course_code, $send_to_tutor_also = false);
			} else if ($send == 2){
				CourseManager::email_to_tutor($_user['user_id'], $course_code, $send_to_tutor_also = true);
			}
			return get_lang('EnrollToCourseSuccessful');
		} else {
			return get_lang('ErrorContactPlatformAdmin');
		}
	} else {
		$return = '';
		if (isset($_POST['course_registration_code']) && $_POST['course_registration_code'] != $all_course_information['registration_code']) {
			Display::display_error_message(get_lang('CourseRegistrationCodeIncorrect'));
		}
		$return .= get_lang('CourseRequiresPassword').'<br />';
		$return .= $all_course_information['visual_code'].' - '.$all_course_information['title'];

		$return .= "<form action=\"".$_SERVER["REQUEST_URI"]."\" method=\"post\">";
		$return .= '<input type="hidden" name="sec_token" value="'.$stok.'" />';
		$return .= "<input type=\"hidden\" name=\"subscribe\" value=\"".$all_course_information['code']."\" />";
		$return .= "<input type=\"text\" name=\"course_registration_code\" value=\"".$_POST['course_registration_code']."\" />";
		$return .= "<input type=\"submit\" name=\"submit_course_registration_code\" value=\"OK\" alt=\"".get_lang('SubmitRegistrationCode')."\" /></form>";
		return $return;
	}
}

/**
 * unsubscribe the user from a given course
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @param int $user_id The user id of the user that is performing the unsubscribe action
 * @param string $course_code the course code of the course the user wants to unsubscribe from
 * @return string we return the message that is displayed when the action is succesfull
*/
function remove_user_from_course($user_id, $course_code) {
	$tbl_course_user = Database::get_main_table(TABLE_MAIN_COURSE_USER);

	// we check (once again) if the user is not course administrator
	// because the course administrator cannot unsubscribe himself
	// (s)he can only delete the course
	$sql_check = "SELECT * FROM $tbl_course_user WHERE user_id='".$user_id."' AND course_code='".$course_code."' AND status='1' ";
	$result_check = Database::query($sql_check);
	$number_of_rows = Database::num_rows($result_check);
	if ($number_of_rows > 0) {
		return false;
	}

	CourseManager::unsubscribe_user($user_id, $course_code);
	return get_lang('YouAreNowUnsubscribed');
}

/**
 * handles the display of the courses to which the user can subscribe
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
*/
function courses_subscribing() {
	browse_courses();
	display_search_courses();
}

/**
 * Allows you to browse through the course categories (faculties) and subscribe to the courses of
 * this category (faculty)
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
*/
function browse_courses() {
	browse_course_categories();
	if (!isset($_POST['search_course'])) {
		browse_courses_in_category();
	}
}

/**
 * Counts the number of courses in a given course category
*/
function count_courses_in_category($category) {
	$tbl_course = Database::get_main_table(TABLE_MAIN_COURSE);
	$TABLE_COURSE_FIELD 			= Database :: get_main_table(TABLE_MAIN_COURSE_FIELD);
	$TABLE_COURSE_FIELD_VALUE		= Database :: get_main_table(TABLE_MAIN_COURSE_FIELD_VALUES);

	// get course list auto-register
	$sql = "SELECT course_code FROM $TABLE_COURSE_FIELD_VALUE tcfv INNER JOIN $TABLE_COURSE_FIELD tcf ON " .
			" tcfv.field_id =  tcf.id WHERE tcf.field_variable = 'special_course' AND tcfv.field_value = 1 ";

	$special_course_result = Database::query($sql);
	if(Database::num_rows($special_course_result)>0) {
		$special_course_list = array();
		while ($result_row = Database::fetch_array($special_course_result)) {
			$special_course_list[] = '"'.$result_row['course_code'].'"';
		}
	}
	$without_special_courses = '';
	if (!empty($special_course_list)) {
		$without_special_courses = ' AND course.code NOT IN ('.implode(',',$special_course_list).')';
	}

	$sql = "SELECT * FROM $tbl_course WHERE category_code".(empty($category) ? " IS NULL" : "='".$category."'").$without_special_courses;
	// Showing only the courses of the current Dokeos access_url_id.
	global $_configuration;
	if ($_configuration['multiple_access_urls']) {
		$url_access_id = api_get_current_access_url_id();
		if ($url_access_id != -1) {
			$tbl_url_rel_course = Database::get_main_table(TABLE_MAIN_ACCESS_URL_REL_COURSE);
			$sql = "SELECT * FROM $tbl_course as course INNER JOIN $tbl_url_rel_course as url_rel_course
					ON (url_rel_course.course_code=course.code)
					WHERE access_url_id = $url_access_id AND category_code".(empty($category) ? " IS NULL" : "='".$category."'").$without_special_courses;
		}
	}
	return Database::num_rows(Database::query($sql));
}

/**
 * displays the browsing of the course categories (faculties)
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @return HTML code containing a list with all the categories and subcategories and the navigation to go one category up(if needed)
*/
function browse_course_categories() {
	global $stok;
	$tbl_courses_nodes = Database::get_main_table(TABLE_MAIN_CATEGORY);
	$category = Database::escape_string($_GET['category']);
	$safe_url_categ = Security::remove_XSS($_GET['category']);

	echo "<p><strong>".get_lang('CourseCategories')."</strong>";

	$sql = "SELECT * FROM $tbl_courses_nodes WHERE parent_id ".(empty($category) ? "IS NULL" : "='".$category."'")." GROUP BY code, parent_id  ORDER BY tree_pos ASC";

	$result = Database::query($sql);
	echo "<ul>";
	while ($row = Database::fetch_array($result)) {
		$count_courses_in_categ = count_courses_in_category($row['code']);
		if ($row['children_count'] > 0 || $count_courses_in_categ > 0) {
			echo	"<li><a href=\"".api_get_self()."?action=subscribe&amp;category=".$row['code']."&amp;up=".$safe_url_categ."&amp;sec_token=".$stok."\">".$row['name']."</a>".
				" (".$count_courses_in_categ.")</li>";
		} elseif ($row['nbChilds'] > 0) {
			echo	"<li><a href=\"".api_get_self()."?action=subscribe&amp;category=".$row['code']."&amp;up=".$safe_url_categ."&amp;sec_token=".$stok."\">".$row['name']."</a></li>";
		} else {
			echo "<li>".$row['name']."</li>";
		}
	}
	echo "</ul>";
	if ($_GET['category']) {
		echo "<a href=\"".api_get_self()."?action=subscribe&amp;category=".Security::remove_XSS($_GET['up'])."&amp;sec_token=".$stok."\">".Display::return_icon('back.png',get_lang('UpOneCategory'),array('align'=>'absmiddle')).get_lang('UpOneCategory')."</a>";
	}
}

/**
 * Display all the courses in the given course category. I could have used a parameter here
 * but instead I use the already available $_GET['category']
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @return HTML code: a table with all the courses in a given category (title, code, tutor) and a subscription icon if applicable)
*/
function browse_courses_in_category() {
	$tbl_course = Database::get_main_table(TABLE_MAIN_COURSE);
	$TABLE_COURSE_FIELD 			= Database :: get_main_table(TABLE_MAIN_COURSE_FIELD);
	$TABLE_COURSE_FIELD_VALUE		= Database :: get_main_table(TABLE_MAIN_COURSE_FIELD_VALUES);

	// get course list auto-register
	$sql = "SELECT course_code FROM $TABLE_COURSE_FIELD_VALUE tcfv INNER JOIN $TABLE_COURSE_FIELD tcf ON " .
			" tcfv.field_id =  tcf.id WHERE tcf.field_variable = 'special_course' AND tcfv.field_value = 1 ";

	$special_course_result = Database::query($sql);
	if(Database::num_rows($special_course_result)>0) {
		$special_course_list = array();
		while ($result_row = Database::fetch_array($special_course_result)) {
			$special_course_list[] = '"'.$result_row['course_code'].'"';
		}
	}
	$without_special_courses = '';
	if (!empty($special_course_list)) {
		$without_special_courses = ' AND course.code NOT IN ('.implode(',',$special_course_list).')';
	}

	$category = Database::escape_string($_GET['category']);

	echo "<p><strong>".get_lang('CoursesInCategory')."</strong>";
	$my_category = (empty($category) ? " IS NULL" : "='".$category."'");

	$sql = "SELECT * FROM $tbl_course WHERE category_code".$my_category.$without_special_courses.' ORDER BY title, visual_code';

	//showing only the courses of the current Dokeos access_url_id
	global $_configuration;
	if ($_configuration['multiple_access_urls']) {
		$url_access_id = api_get_current_access_url_id();
		if ($url_access_id != -1) {
			$tbl_url_rel_course = Database::get_main_table(TABLE_MAIN_ACCESS_URL_REL_COURSE);
			$sql = "SELECT * FROM $tbl_course as course INNER JOIN $tbl_url_rel_course as url_rel_course
					ON (url_rel_course.course_code=course.code)
					WHERE access_url_id = $url_access_id AND category_code".$my_category.$without_special_courses.' ORDER BY title, visual_code';
		}
	}

	$result = Database::query($sql);
	while ($row = Database::fetch_array($result)) {
		$row['registration_code'] = !empty($row['registration_code']);
		$courses[] = array('code' => $row['code'], 'directory' => $row['directory'], 'db' => $row['db_name'], 'visual_code' => $row['visual_code'], 'title' => $row['title'], 'tutor' => $row['tutor_name'], 'subscribe' => $row['subscribe'], 'unsubscribe' => $row['unsubscribe'], 'registration_code' => $registration_code);
	}
	display_subscribe_to_courses($courses);
}

/**
 * displays the form for searching for a course and the results if a query has been submitted.
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @return HTML code: the form for searching for a course
*/
function display_search_courses() {
	global $_user, $stok;
	echo "<p><strong>".get_lang('SearchCourse')."</strong><br />";
	echo "<form class=\"course_list\" method=\"post\" action=\"".api_get_self()."?action=subscribe\">",
		'<input type="hidden" name="sec_token" value="'.$stok.'">',
		"<input type=\"hidden\" name=\"search_course\" value=\"1\" />",
		"<input type=\"text\" name=\"search_term\" value=\"".(empty($_POST['search_term']) ? '' : Security::remove_XSS($_POST['search_term']))."\" />",
		"&nbsp;<button class=\"search\" type=\"submit\">",get_lang('_search'),"</button>",
		"</form>";
	if (isset($_POST['search_course'])) {
		echo "<p><strong>".get_lang('SearchResultsFor')." ".api_htmlentities($_POST['search_term'], ENT_QUOTES, api_get_system_encoding())."</strong><br />";
		$result_search_courses_array = search_courses($_POST['search_term']);
		display_subscribe_to_courses($result_search_courses_array);
	}
}

/**
 * This function displays the list of course that can be subscribed to.
 * This list can come from the search results or from the browsing of the platform course categories
*/
function display_subscribe_to_courses($courses) {

	global $_user;
	// getting all the courses to which the user is subscribed to
	$user_courses = get_courses_of_user($_user['user_id']);
	$user_coursecodes = array();

	// we need only the course codes as these will be used to match against the courses of the category
	if ($user_courses != '') {
		foreach ($user_courses as $key => $value) {
			$user_coursecodes[] = $value['code'];
		}
	}

	if ($courses == 0) {
		return false;
	}

	echo "<table cellpadding=\"4\">\n";
	foreach ($courses as $key=>$course) {
		// displaying the course title, visual code and teacher/teaching staff
		echo "\t<tr>\n";

		if (api_get_setting('show_courses_descriptions_in_catalog') == 'true') {
			// block course description
			echo "\t\t<td>";
			$icon_title = get_lang('CourseDetails') . ' - ' . $course['title'];
			echo "<a href='course_description.php?code=".$course['code']."' title='$icon_title' rel='gb_page_center[778]'>".Display::return_icon('synthese_view.gif', $icon_title)."</a>";
			echo "\t\t</td>";
		}

		echo "\t\t<td>\n";
		echo "<strong>".$course['title']."</strong><br />";
		if (api_get_setting('display_coursecode_in_courselist') == 'true') {
			echo $course['visual_code'];
		}
		if (api_get_setting('display_coursecode_in_courselist') == 'true' && api_get_setting('display_teacher_in_courselist') == 'true') {
			echo " - ";
		}
		if (api_get_setting('display_teacher_in_courselist') == 'true') {
			echo $course['tutor'];
		}
		echo "\t\t</td>\n";

		echo "\t\t<td>\n";
		if ($course['registration_code']) {
			Display::display_icon('passwordprotected.png', '', array('style' => 'float:left;'));
		}
		display_subscribe_icon($course, $user_coursecodes);
		echo "\t\t</td>\n";

		echo "</tr>";
	}
	echo "</table>";
}

/**
 * Search the courses database for a course that matches the search term.
 * The search is done on the code, title and tutor field of the course table.
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @param string $search_term: the string that the user submitted, what we are looking for
 * @return array an array containing a list of all the courses (the code, directory, dabase, visual_code, title, ... )
 * 			matching the the search term.
*/
function search_courses($search_term) {
	$TABLECOURS = Database::get_main_table(TABLE_MAIN_COURSE);
	$TABLE_COURSE_FIELD 			= Database :: get_main_table(TABLE_MAIN_COURSE_FIELD);
	$TABLE_COURSE_FIELD_VALUE		= Database :: get_main_table(TABLE_MAIN_COURSE_FIELD_VALUES);

	// get course list auto-register
	$sql = "SELECT course_code FROM $TABLE_COURSE_FIELD_VALUE tcfv INNER JOIN $TABLE_COURSE_FIELD tcf ON " .
			" tcfv.field_id =  tcf.id WHERE tcf.field_variable = 'special_course' AND tcfv.field_value = 1 ";

	$special_course_result = Database::query($sql);
	if(Database::num_rows($special_course_result)>0) {
		$special_course_list = array();
		while ($result_row = Database::fetch_array($special_course_result)) {
			$special_course_list[] = '"'.$result_row['course_code'].'"';
		}
	}
	$without_special_courses = '';
	if (!empty($special_course_list)) {
		$without_special_courses = ' AND course.code NOT IN ('.implode(',',$special_course_list).')';
	}

	$search_term_safe = Database::escape_string($search_term);
	$sql_find = "SELECT * FROM $TABLECOURS WHERE (code LIKE '%".$search_term_safe."%' OR title LIKE '%".$search_term_safe."%' OR tutor_name LIKE '%".$search_term_safe."%') $without_special_courses ORDER BY title, visual_code ASC";

	global $_configuration;
	if ($_configuration['multiple_access_urls']) {
		$url_access_id = api_get_current_access_url_id();
		if ($url_access_id != -1) {
			$tbl_url_rel_course = Database::get_main_table(TABLE_MAIN_ACCESS_URL_REL_COURSE);
			$sql_find = "SELECT * FROM $TABLECOURS as course INNER JOIN $tbl_url_rel_course as url_rel_course
					ON (url_rel_course.course_code=course.code)
					WHERE access_url_id = $url_access_id AND  (code LIKE '%".$search_term_safe."%' OR title LIKE '%".$search_term_safe."%' OR tutor_name LIKE '%".$search_term_safe."%' ) $without_special_courses ORDER BY title, visual_code ASC ";
		}
	}
	$result_find = Database::query($sql_find);
	while ($row = Database::fetch_array($result_find)) {
		$courses[] = array('code' => $row['code'], 'directory' => $row['directory'], 'db' => $row['db_name'], 'visual_code' => $row['visual_code'], 'title' => $row['title'], 'tutor' => $row['tutor_name'], 'subscribe' => $row['subscribe'], 'unsubscribe' => $row['unsubscribe']);
	}
	return $courses;
}

/**
 * deletes a course category and moves all the courses that were in this category to main category
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @param int $id: the id of the user_course_category
 * @return string a language variable saying that the deletion went OK.
*/
function delete_course_category($id) {
	global $_user, $_configuration;

	$tucc = Database::get_user_personal_table(TABLE_USER_COURSE_CATEGORY);
	$TABLECOURSUSER = Database::get_main_table(TABLE_MAIN_COURSE_USER);
	$id = intval($id);
	$sql_delete = "DELETE FROM $tucc WHERE id='".$id."' and user_id='".$_user['user_id']."'";
	$sql_update = "UPDATE $TABLECOURSUSER SET user_course_cat='0' WHERE user_course_cat='".$id."' AND user_id='".$_user['user_id']."' AND relation_type<>".COURSE_RELATION_TYPE_RRHH." ";
	Database::query($sql_delete);
	Database::query($sql_update);
	return get_lang('CourseCategoryDeleted');
}

/**
 * stores the user course category in the chamilo_user database
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @return string a language variable saying that the user course category was stored
*/
function store_course_category() {
	global $_user, $_configuration;

	$tucc = Database::get_user_personal_table(TABLE_USER_COURSE_CATEGORY);

	// step 1: we determine the max value of the user defined course categories
	$sql = "SELECT sort FROM $tucc WHERE user_id='".$_user['user_id']."' ORDER BY sort DESC";
	$result = Database::query($sql);
	$maxsort = Database::fetch_array($result);
	$nextsort = $maxsort['sort'] + 1;

	// step 2: we check if there is already a category with this name, if not we store it, else we give an error.
	$sql = "SELECT * FROM $tucc WHERE user_id='".$_user['user_id']."' AND title='".Database::escape_string($_POST['title_course_category'])."'ORDER BY sort DESC";
	$result = Database::query($sql);
	if (Database::num_rows($result) == 0) {
		$sql_insert = "INSERT INTO $tucc (user_id, title,sort) VALUES ('".$_user['user_id']."', '".api_htmlentities($_POST['title_course_category'], ENT_QUOTES, api_get_system_encoding())."', '".$nextsort."')";
		Database::query($sql_insert);
		Display::display_confirmation_message(get_lang("CourseCategoryStored"));
	} else {
		Display::display_error_message(get_lang('ACourseCategoryWithThisNameAlreadyExists'));
	}
}

/**
 * displays the form that is needed to create a course category.
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @return HTML the form (input field + submit button) to create a user course category
*/
function display_create_course_category_form()
{
	global $_user, $_configuration, $stok;

	echo "<form name=\"create_course_category\" method=\"post\" action=\"".api_get_self()."?action=sortmycourses\">\n";
	echo '<input type="hidden" name="sec_token" value="'.$stok.'">';
	echo "<input type=\"text\" name=\"title_course_category\" />\n";
	echo "<button type=\"submit\" class=\"save\" name=\"create_course_category\">".get_lang('Ok')."</button>\n";
	echo "</form>\n";

	echo get_lang('ExistingCourseCategories');
	$tucc = Database::get_user_personal_table(TABLE_USER_COURSE_CATEGORY);
	$sql = "SELECT * FROM $tucc WHERE user_id='".$_user['user_id']."'";
	$result = Database::query($sql);
	if (Database::num_rows($result) > 0) {
		echo "<ul>\n";
		while ($row = Database::fetch_array($result)) {
			echo "\t<li>".$row['title']."</li>\n";
		}
		echo "</ul>\n";
	}
}

// ***************************************************************************
// this function stores the changes in a course category
//
// ***************************************************************************

/**
 * stores the changes in a course category (moving a course to a different course category)
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @param string $course_code : the course_code of the course we are moving
 *		  int $newcategory : the id of the user course category we are moving the course to.
 * @return string a language variable saying that the course was moved.
*/
function store_changecoursecategory($course_code, $newcategory) {
	global $_user;
	$course_code = Database::escape_string($course_code);
	$newcategory = Database::escape_string($newcategory);

	$TABLECOURSUSER = Database::get_main_table(TABLE_MAIN_COURSE_USER);

	$max_sort_value = api_max_sort_value($newcategory, $_user['user_id']); // max_sort_value($newcategory);
	$sql = "UPDATE $TABLECOURSUSER SET user_course_cat='".$newcategory."', sort='".($max_sort_value + 1)."' WHERE course_code='".$course_code."' AND user_id='".$_user['user_id']."' AND relation_type<>".COURSE_RELATION_TYPE_RRHH." ";
	$result = Database::query($sql);
	return get_lang('EditCourseCategorySucces');
}

/**
 * moves the course one place up or down
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @param string $direction : the direction we are moving the course to (up or down)
 *		  string $course2move : the course we are moving
 * @return string a language variable saying that the course was moved.
*/
function move_course($direction, $course2move, $category) {
	global $_user;
	$TABLECOURSUSER = Database::get_main_table(TABLE_MAIN_COURSE_USER);

	$all_user_courses = get_courses_of_user($_user['user_id']);

	// we need only the courses of the category we are moving in
	$user_courses = array();
	foreach ($all_user_courses as $key => $course) {
		if ($course['user_course_category'] == $category) {
			$user_courses[] = $course;
		}
	}

	foreach ($user_courses as $key => $course) {
		if ($course2move == $course['code']) {
			// source_course is the course where we clicked the up or down icon
			$source_course = $course;
			// target_course is the course before/after the source_course (depending on the up/down icon)
			if ($direction == 'up') {
				$target_course = $user_courses[$key - 1];
			} else {
				$target_course = $user_courses[$key + 1];
			}
		} // if ($course2move == $course['code'])
	}

	if (count($target_course) > 0 && count($source_course) > 0) {
		$sql_update1 = "UPDATE $TABLECOURSUSER SET sort='".$target_course['sort']."' WHERE course_code='".$source_course['code']."' AND user_id='".$_user['user_id']."' AND relation_type<>".COURSE_RELATION_TYPE_RRHH." ";
		$sql_update2 = "UPDATE $TABLECOURSUSER SET sort='".$source_course['sort']."' WHERE course_code='".$target_course['code']."' AND user_id='".$_user['user_id']."' AND relation_type<>".COURSE_RELATION_TYPE_RRHH." ";
		Database::query($sql_update2);
		Database::query($sql_update1);
		return get_lang('CourseSortingDone');
	}
	return '';
}

/**
 * Moves the course one place up or down
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @param string $direction : the direction we are moving the course to (up or down)
 *		  string $course2move : the course we are moving
 * @return string a language variable saying that the course was moved.
 */
function move_category($direction, $category2move) {
	global $_user;
	// the database definition of the table that stores the user defined course categories
	$table_user_defined_category = Database::get_user_personal_table(TABLE_USER_COURSE_CATEGORY);

	$user_coursecategories = get_user_course_categories();
	$user_course_categories_info = get_user_course_categories_info();

	foreach ($user_coursecategories as $key => $category_id) {
		if ($category2move == $category_id) {
			// source_course is the course where we clicked the up or down icon
			//$source_category=get_user_course_category($category2move);
			$source_category = $user_course_categories_info[$category2move];
			// target_course is the course before/after the source_course (depending on the up/down icon)
			if ($direction == 'up') {
				$target_category = $user_course_categories_info[$user_coursecategories[$key - 1]];
			} else {
				$target_category = $user_course_categories_info[$user_coursecategories[$key + 1]];
			}
		} // if ($course2move == $course['code'])
	} // foreach ($user_courses as $key => $course)

	if (count($target_category) > 0 && count($source_category) > 0) {
		$sql_update1="UPDATE $table_user_defined_category SET sort='".$target_category['sort']."' WHERE id='".$source_category['id']."' AND user_id='".$_user['user_id']."'";
		$sql_update2="UPDATE $table_user_defined_category SET sort='".$source_category['sort']."' WHERE id='".$target_category['id']."' AND user_id='".$_user['user_id']."'";
		Database::query($sql_update2);
		Database::query($sql_update1);
		return get_lang('CategorySortingDone');
	}
	return '';
}

/**
 * displays everything that is needed when the user wants to manage his current courses (sorting, subscribing, unsubscribing, ...)
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @param int $user_id: the user_id of the current user
 *		  string $parameter: determines weither we are displaying for the sorting, subscribing or unsubscribin
 		  array $user_courses:  the courses to which the user is subscribed
 * @return html a table containing courses and the appropriate icons (sub/unsub/move)
*/

function display_courses($user_id, $show_course_icons, $user_courses) {
	global $_user, $_configuration;

	echo "<table cellpadding=\"4\">\n";

	// building an array that contains all the id's of the user defined course categories
	// initially this was inside the display_courses_in_category function but when we do it here we have fewer
	// sql executions = performance increase.
	$all_user_categories = get_user_course_categories();

	// step 0: we display the course without a user category
	display_courses_in_category(0, 'true');

	// Step 1: We get all the categories of the user.
	$tucc = Database::get_user_personal_table(TABLE_USER_COURSE_CATEGORY);
	$sql = "SELECT * FROM $tucc WHERE user_id='".$_user['user_id']."' ORDER BY sort ASC";
	$result = Database::query($sql);
	while ($row = Database::fetch_array($result)) {
		if ($show_course_icons) {
			// The edit link is clicked.
			if (isset($_GET['categoryid']) && $_GET['categoryid'] == $row['id']) {
				// We display the edit form for the category.
				echo "<tr><td colspan=\"2\" class=\"user_course_category\">";
				echo '<a name="category'.$row['id'].'"></a>'; // display an internal anchor.
				display_edit_course_category_form($row['id']);
			} else {
				// We simply display the title of the category.
				echo "<tr><td colspan=\"2\" class=\"user_course_category\">";
				echo '<a name="category'.$row['id'].'"></a>'; // display an internal anchor.
				echo $row['title'];
			}
			echo "</td><td class=\"user_course_category\">";
			display_category_icons($row['id'], $all_user_categories);
			echo "</td></tr>";
		}
		// Step 2: Show the courses inside this category.
		display_courses_in_category($row['id'], $show_course_icons);
	}
	echo "</table>\n";
}

/**
 * This function displays all the courses in the particular user category;
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @param int id: the id of the user defined course category
 * @return string: the name of the user defined course category
*/
function display_courses_in_category($user_category_id, $showicons) {
	global $_user;

	// table definitions
	$TABLECOURS=Database::get_main_table(TABLE_MAIN_COURSE);
	$TABLECOURSUSER=Database::get_main_table(TABLE_MAIN_COURSE_USER);
	$TABLE_USER_COURSE_CATEGORY = Database::get_user_personal_table(TABLE_USER_COURSE_CATEGORY);
	$TABLE_COURSE_FIELD 			= Database :: get_main_table(TABLE_MAIN_COURSE_FIELD);
	$TABLE_COURSE_FIELD_VALUE		= Database :: get_main_table(TABLE_MAIN_COURSE_FIELD_VALUES);

	// get course list auto-register
	$sql = "SELECT course_code FROM $TABLE_COURSE_FIELD_VALUE tcfv INNER JOIN $TABLE_COURSE_FIELD tcf ON " .
			" tcfv.field_id =  tcf.id WHERE tcf.field_variable = 'special_course' AND tcfv.field_value = 1 ";

	$special_course_result = Database::query($sql);
	if(Database::num_rows($special_course_result)>0) {
		$special_course_list = array();
		while ($result_row = Database::fetch_array($special_course_result)) {
			$special_course_list[] = '"'.$result_row['course_code'].'"';
		}
	}
	$without_special_courses = '';
	if (!empty($special_course_list)) {
		$without_special_courses = ' AND course.code NOT IN ('.implode(',',$special_course_list).')';
	}

	$sql_select_courses = "SELECT course.code, course.visual_code, course.subscribe subscr, course.unsubscribe unsubscr,
								course.title title, course.tutor_name tutor, course.db_name, course.directory, course_rel_user.status status,
								course_rel_user.sort sort, course_rel_user.user_course_cat user_course_cat
		                        FROM    $TABLECOURS       course,
										$TABLECOURSUSER  course_rel_user
		                        WHERE course.code = course_rel_user.course_code
		                        AND  course_rel_user.user_id = '".$_user['user_id']."'
		                        AND  course_rel_user.relation_type <> ".COURSE_RELATION_TYPE_RRHH."
		                        AND  course_rel_user.user_course_cat='".$user_category_id."' $without_special_courses
		                        ORDER BY course_rel_user.user_course_cat, course_rel_user.sort ASC";
	$result = Database::query($sql_select_courses);
	$number_of_courses = Database::num_rows($result);
	$key = 0;
	while ($course = Database::fetch_array($result)) {
		echo "\t<tr>\n";

		if (api_get_setting('show_courses_descriptions_in_catalog') == 'true') {
			// block course description
			echo "\t\t<td>";
			$icon_title = get_lang('CourseDetails') . ' - ' . $course['title'];
			echo "<a href='course_description.php?code=".$course['code']."' title='$icon_title' rel='gb_page_center[778]'>".Display::return_icon('synthese_view.gif', $icon_title)."</a>";
			echo "\t\t</td>";
		}

		echo "\t\t<td>\n";
		echo '<a name="course'.$course['code'].'"></a>'; // display an internal anchor.
		echo "<strong>".$course['title']."</strong><br />";
		if (api_get_setting('display_coursecode_in_courselist') == 'true') {
			echo $course['visual_code'];
		}
		if (api_get_setting('display_coursecode_in_courselist') == 'true' && api_get_setting('display_teacher_in_courselist') == 'true') {
			echo " - ";
		}
		if (api_get_setting('display_teacher_in_courselist') == 'true') {
			echo $course['tutor'];
		}
		echo "\t\t</td>\n";
		// displaying the up/down/edit icons when we are sorting courses
		echo "\t\t<td valign=\"top\">\n";
		//if ($parameter == 'sorting')
		//{
			display_course_icons($key, $number_of_courses, $course);
		//}
		// displaying the delete icon when we are unsubscribing from courses
		//if($parameter == 'deleting')
		//{
		//	display_unsubscribe_icons($course);
		//}
		// display the subscribing icon when we are to courses.
		//if ($parameter == 'subscribing')
		//{
		//	display_subscribe_icon($course);
		//}
		echo "\t\t</td>\n";
		echo "\t</tr>\n";
		$key++;
	}
}

/**
 * gets the title of the user course category
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @param int id: the id of the user defined course category
 * @return string: the name of the user defined course category
*/
function get_user_course_category($id) {
	global $_user, $_configuration;
	$tucc = Database::get_user_personal_table(TABLE_USER_COURSE_CATEGORY);
	$id = intval($id);
	return Database::fetch_array(Database::query("SELECT * FROM $tucc WHERE user_id='".$_user['user_id']."' AND id='$id'"));
}

/**
 * displays the subscribe icon if the subscribing is allowed and if the user is not yet
 * subscribe to this course
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @param string $current_course: the course code of the course we need to display the subscribe icon for
 * @return string a subscribe icon or the text that subscribing is not allowed or the user is already subscribed
*/
function display_subscribe_icon($current_course, $user_coursecodes) {
	global $stok;
	// we display the icon to subscribe or the text already subscribed
	if (in_array($current_course['code'], $user_coursecodes)) {
		Display::display_icon('enroll_na.gif', get_lang('AlreadySubscribed'));
	} else {
		if ($current_course['subscribe'] == SUBSCRIBE_ALLOWED) {
			echo "<form action=\"".$_SERVER["REQUEST_URI"]."\" method=\"post\">";
			echo '<input type="hidden" name="sec_token" value="'.$stok.'">';
			echo "<input type=\"hidden\" name=\"subscribe\" value=\"".$current_course['code']."\" />";
			if (!empty($_POST['search_term'])) {
				echo '<input type="hidden" name="search_course" value="1" />';
				echo '<input type="hidden" name="search_term" value="'.Security::remove_XSS($_POST['search_term']).'" />';
			}
			echo "<input style=\"border-color:#fff\" type=\"image\" name=\"unsub\" src=\"".api_get_path(WEB_IMG_PATH)."enroll.gif\" title=\"".get_lang('Subscribe')."\" alt=\"".get_lang('Subscribe')."\" /></form>";
		} else {
			//	echo get_lang('SubscribingNotAllowed');
			Display::display_icon('enroll_na.gif', get_lang('SubscribingNotAllowed'));

		}
	}
}

/**
 * Displays the subscribe icon if the subscribing is allowed and if the user is not yet
 * subscribed to this course
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @param  $key:
 *		   $number_of_courses
 *		   $course
 *		   $user_courses
 * @return html a small table containing the up/down icons and the edit icon (for moving to a different user course category)
 * @todo complete the comments on this function: the parameter section
*/
function display_course_icons($key, $number_of_courses, $course) {
	global $safe, $stok;
	echo "<table><tr><td>";
	// the up icon
	if ($key > 0) {
		echo "<a href=\"courses.php?action=".$safe['action']."&amp;move=up&amp;course=".$course['code']."&amp;category=".$course['user_course_cat']."&amp;sec_token=".$stok."\">";
		Display::display_icon('up.gif', get_lang('Up'));
		echo '</a>';
	}
	echo "</td>";
	// the edit icon OR the edit dropdown list
	if (isset($_GET['edit']) && $course['code'] == $_GET['edit']) {
		echo "<td rowspan=\"2\" valign=\"top\">".display_change_course_category_form($_GET['edit'])."</td>";
	} else {
		echo "<td rowspan=\"2\" valign=\"middle\"><a href=\"courses.php?action=".$safe['action']."&amp;edit=".$course['code']."&amp;sec_token=".$stok."\">";
		Display::display_icon('edit.gif', get_lang('Edit'));
		echo "</a></td>";
	}
	echo "<td rowspan=\"2\" valign=\"top\" class=\"invisible\">";
	if ($course['status'] != 1) {
		if ($course['unsubscr'] == 1) {
				// changed link to submit to avoid action by the search tool indexer
				echo "<form action=\"".api_get_self()."\" method=\"post\" onsubmit=\"javascript: if (!confirm('".addslashes(api_htmlentities(get_lang("ConfirmUnsubscribeFromCourse"), ENT_QUOTES, api_get_system_encoding()))."')) return false;\">";
				echo '<input type="hidden" name="sec_token" value="'.$stok.'">';
				echo "<input type=\"hidden\" name=\"unsubscribe\" value=\"".$course['code']."\" />";
				echo '<input type="image" name="unsub" style="border-color:#fff" src="'.api_get_path(WEB_IMG_PATH).'delete.gif" title="'.get_lang('_unsubscribe').'"  alt="'.get_lang('_unsubscribe').'" /></form>';
		} else {
			display_info_text(get_lang('UnsubscribeNotAllowed'));
		}
	} else {
		display_info_text(get_lang('CourseAdminUnsubscribeNotAllowed'));
	}
	echo "</td>";
	echo "</tr><tr><td>";
	if ($key < $number_of_courses - 1) {
		echo "<a href=\"courses.php?action=".$safe['action']."&amp;move=down&amp;course=".$course['code']."&amp;category=".$course['user_course_cat']."&amp;sec_token=".$stok."\">";
		Display::display_icon('down.gif', get_lang('Down'));
		echo '</a>';
	}
	echo "</td></tr></table>";
}

/**
 * displays the relevant icons for the category (if applicable):move up, move down, edit, delete
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @param 	$current_category the id of the current category
 * 			$allcategories an associative array containing all the categories.
 * @return html: a small table containing the up/down icons and the edit icon (for moving to a different user course category)
 * @todo complete the comments on this function: the parameter section
*/
function display_category_icons($current_category, $all_user_categories) {
	global $safe, $stok;
	$max_category_key = count($all_user_categories);

	if ($safe['action'] != 'unsubscribe') { // we are in the unsubscribe section then we do not show the icons.
		echo "<table>";
		echo "<tr>";
		echo "<td>";
		if ($current_category != $all_user_categories[0]) {
			echo "<a href=\"courses.php?action=".$safe['action']."&amp;move=up&amp;category=".$current_category."&amp;sec_token=".$stok."\">";
			echo Display::return_icon('up.gif', get_lang('Up')).'</a>';
		}
		echo "</td>";
   		echo " <td rowspan=\"2\">";
 		echo " <a href=\"courses.php?action=sortmycourses&amp;categoryid=".$current_category."&amp;sec_token=".$stok."#category".$current_category."\">";
		Display::display_icon('edit.gif', get_lang('Edit'));
		echo "</a>";
   		echo "</td>";
		echo "<td rowspan=\"2\">";
		echo " <a href=\"courses.php?action=deletecoursecategory&amp;id=".$current_category."&amp;sec_token=".$stok."\">";
		Display::display_icon('delete.gif', get_lang('Delete'), array('onclick' => "javascript: if (!confirm('".addslashes(api_htmlentities(get_lang("CourseCategoryAbout2bedeleted"), ENT_QUOTES, api_get_system_encoding()))."')) return false;"));
		echo "</a>";
		echo "</td>";
 		echo "</tr>";
  		echo "<tr>";
		echo " <td>";
		if ($current_category != $all_user_categories[$max_category_key - 1]) {
			echo "<a href=\"courses.php?action=".$safe['action']."&amp;move=down&amp;category=".$current_category."&amp;sec_token=".$stok."\">";
			echo Display::return_icon('down.gif', get_lang('Down')).'</a>';
		}
		echo "</td>";
 		echo " </tr>";
		echo "</table>";
	}
}

/**
 * This function displays the form (dropdown list) to move a course to a
 * different course_category (after the edit icon has been changed)
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @param string $edit_course:
 * @return html a dropdown list containing all the user defined course categories and a submit button
 * @todo when editing (moving) a course inside a user defined course category to a different user defined category
 *			the dropdown list should have the current course category selected.
*/
function display_change_course_category_form($edit_course) {
	global $_user, $_configuration, $safe, $stok;
	$edit_course = Security::remove_XSS($edit_course);

	$DATABASE_USER_TOOLS = $_configuration['user_personal_database'];
	$tucc = Database::get_user_personal_table(TABLE_USER_COURSE_CATEGORY);
	$sql = "SELECT * FROM $tucc WHERE user_id='".$_user['user_id']."'";
	$result = Database::query($sql);

	$output = "<form name=\"edit_course_category\" method=\"post\" action=\"courses.php?action=".$safe['action']."\">\n";
	$output .= '<input type="hidden" name="sec_token" value="'.$stok.'">';
	$output .= "<input type=\"hidden\" name=\"course_2_edit_category\" value=\"".$edit_course."\" />";
	$output .= "\t<select name=\"course_categories\">\n";
	$output .= "\t\t<option value=\"0\">".get_lang("NoCourseCategory")."</option>";
	while ($row = Database::fetch_array($result)) {
		$output.="\t\t<option value=\"".$row['id']."\">".$row['title']."</option>";
	}
	$output .= "\t</select>\n";
	$output .= "\t<button class=\"save\" type=\"submit\" name=\"submit_change_course_category\">".get_lang('Ok')."</button>\n";
	$output .= "</form>";
	return $output;
}

/**
 * This function displays the unsubscribe part which can be
 * 1. the unsubscribe link
 * 2. text: you are course admin of this course (=> unsubscription is not possible
 * 3. text: you are not allowed to unsubscribe from this course
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @param array $course: the array with all the course & course_rel_user information
 * @return html a delete icon or a text that unsubscribing is not possible (course admin) or not allowed.
*/
function display_unsubscribe_icons($course) {
	global $stok;
	if ($course['status'] != 1) {
		if ($course['unsubscribe'] == 1) {
			// Changed link to submit to avoid action by the search tool indexer.
			echo "<form action=\"".api_get_self()."\" method=\"post\" onsubmit=\"javascript: if (!confirm('".addslashes(api_htmlentities(get_lang('ConfirmUnsubscribeFromCourse'), ENT_QUOTES, api_get_system_encoding()))."')) return false;\">";
			echo '<input type="hidden" name="sec_token" value="'.$stok.'">';
			echo "<input type=\"hidden\" name=\"unsubscribe\" value=\"".$course['code']."\" />";
			echo "<input type=\"image\" name=\"unsub\" src=\"".api_get_path(WEB_IMG_PATH)."delete.gif\" alt=\"".get_lang('_unsubscribe')."\" /></form>";
		} else {
			display_info_text(get_lang('UnsubscribeNotAllowed'));
		}
	} else {
		display_info_text(get_lang('CourseAdminUnsubscribeNotAllowed'));
	}
}

/**
 * retrieves all the courses that the user has already subscribed to
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @param int $user_id: the id of the user
 * @return array an array containing all the information of the courses of the given user
*/
function get_courses_of_user($user_id) {
	$TABLECOURS = Database::get_main_table(TABLE_MAIN_COURSE);
	$TABLECOURSUSER = Database::get_main_table(TABLE_MAIN_COURSE_USER);
	$TABLE_COURSE_FIELD 			= Database :: get_main_table(TABLE_MAIN_COURSE_FIELD);
	$TABLE_COURSE_FIELD_VALUE		= Database :: get_main_table(TABLE_MAIN_COURSE_FIELD_VALUES);

	// get course list auto-register
	$sql = "SELECT course_code FROM $TABLE_COURSE_FIELD_VALUE tcfv INNER JOIN $TABLE_COURSE_FIELD tcf ON " .
			" tcfv.field_id =  tcf.id WHERE tcf.field_variable = 'special_course' AND tcfv.field_value = 1 ";

	$special_course_result = Database::query($sql);
	if(Database::num_rows($special_course_result)>0) {
		$special_course_list = array();
		while ($result_row = Database::fetch_array($special_course_result)) {
			$special_course_list[] = '"'.$result_row['course_code'].'"';
		}
	}
	$without_special_courses = '';
	if (!empty($special_course_list)) {
		$without_special_courses = ' AND course.code NOT IN ('.implode(',',$special_course_list).')';
	}

	// Secondly we select the courses that are in a category (user_course_cat<>0) and sort these according to the sort of the category
	$user_id = intval($user_id);


	$sql_select_courses = "SELECT course.code k, course.visual_code  vc, course.subscribe subscr, course.unsubscribe unsubscr,
								course.title i, course.tutor_name t, course.db_name db, course.directory dir, course_rel_user.status status,
								course_rel_user.sort sort, course_rel_user.user_course_cat user_course_cat
		                        FROM    $TABLECOURS       course,
										$TABLECOURSUSER  course_rel_user
		                        WHERE course.code = course_rel_user.course_code
		                        AND   course_rel_user.relation_type<>".COURSE_RELATION_TYPE_RRHH."
		                        AND   course_rel_user.user_id = '".$user_id."' $without_special_courses
		                        ORDER BY course_rel_user.sort ASC";
	$result = Database::query($sql_select_courses);
	while ($row = Database::fetch_array($result)) {
		// we only need the database name of the course
		$courses[] = array('db' => $row['db'], 'code' => $row['k'], 'visual_code' => $row['vc'], 'title' => $row['i'], 'directory' => $row['dir'], 'status' => $row['status'], 'tutor' => $row['t'], 'subscribe' => $row['subscr'], 'unsubscribe' => $row['unsubscr'], 'sort' => $row['sort'], 'user_course_category' => $row['user_course_cat']);
	}

	return $courses;
}

/**
 * retrieves the user defined course categories
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @return array containing all the IDs of the user defined courses categories, sorted by the "sort" field
*/
function get_user_course_categories() {
	global $_user;
	$table_category = Database::get_user_personal_table(TABLE_USER_COURSE_CATEGORY);
	$sql = "SELECT * FROM ".$table_category." WHERE user_id='".$_user['user_id']."' ORDER BY sort ASC";
	$result = Database::query($sql);
	while ($row = Database::fetch_array($result)) {
		$output[] = $row['id'];
	}
	return $output;
}


/**
 * Retrieves the user defined course categories and all the info that goes with it
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @return array containing all the info of the user defined courses categories with the id as key of the array
*/
function get_user_course_categories_info() {
	global $_user;
	$table_category = Database::get_user_personal_table(TABLE_USER_COURSE_CATEGORY);
	$sql = "SELECT * FROM ".$table_category." WHERE user_id='".$_user['user_id']."' ORDER BY sort ASC";
	$result = Database::query($sql);
	while ($row = Database::fetch_array($result)) {
		$output[$row['id']] = $row;
	}
	return $output;
}

/**
 * @author unknown
 * @param string $text: the text that has to be written in grey
 * @return string: the text with the grey formatting
 * @todo move this to a stylesheet
 * Added id grey to CSS
*/
function display_info_text($text) {
	//echo "<font color=\"#808080\">" . $text . "</font>\n";
	echo $text;
}

/**
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @param string $edit_course:
 * @return html output: the form
*/
function display_edit_course_category_form($edit_course_category) {
	global $safe, $stok;
	echo "<form name=\"edit_course_category\" method=\"post\" action=\"courses.php?action=".$safe['action']."\">\n";
	echo "\t<input type=\"hidden\" name=\"edit_course_category\" value=\"".$edit_course_category."\" />\n";
	echo '<input type="hidden" name="sec_token" value="'.$stok.'">';
	$info_this_user_course_category = get_user_course_category($edit_course_category);
	echo "\t<input type=\"text\" name=\"title_course_category\" value=\"".$info_this_user_course_category['title']."\" />";
	echo "\t<button class=\"save\" type=\"submit\" name=\"submit_edit_course_category\">".get_lang('Ok')."</button>\n";
	echo "</form>";
}

/**
 * Updates the user course category in the chamilo_user database
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @return string a language variable saying that the user course category was stored
*/
function store_edit_course_category() {
	global $_user, $_configuration;
	$tucc = Database::get_user_personal_table(TABLE_USER_COURSE_CATEGORY);
	$sql_update = "UPDATE $tucc SET title='".api_htmlentities($_POST['title_course_category'], ENT_QUOTES, api_get_system_encoding())."' WHERE id='".(int)$_POST['edit_course_category']."'";
	Database::query($sql_update);
	return get_lang('CourseCategoryEditStored');
}