chamilo-lms2/main/inc/lib/system_announcements.lib.php

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

/**
 * Class SystemAnnouncementManager
 */
class SystemAnnouncementManager
{
    const VISIBLE_GUEST = 'visible_guest';
    const VISIBLE_STUDENT = 'visible_student';
    const VISIBLE_TEACHER = 'visible_teacher';
    // Requires DB change
    const VISIBLE_DRH = 'visible_drh';
    const VISIBLE_SESSION_ADMIN = 'visible_session_admin';
    const VISIBLE_STUDENT_BOSS = 'visible_boss';

    /**
     * @return array
     */
    public static function getVisibilityList()
    {
        $extraRoles = self::newRolesActivated();

        $visibleToUsers = [
            self::VISIBLE_TEACHER => get_lang('Teacher'),
            self::VISIBLE_STUDENT => get_lang('Student'),
            self::VISIBLE_GUEST => get_lang('Guest')
        ];

        if ($extraRoles) {
            $visibleToUsers[self::VISIBLE_DRH] = get_lang('DRH');
            $visibleToUsers[self::VISIBLE_SESSION_ADMIN] = get_lang('SessionAdministrator');
            $visibleToUsers[self::VISIBLE_STUDENT_BOSS] = get_lang('StudentBoss');
        }

        return $visibleToUsers;
    }

    /**
     * @param string $visibility
     * @return string
     */
    public static function getVisibilityCondition($visibility)
    {
        $list = self::getVisibilityList();
        $visibilityCondition = " AND ".self::VISIBLE_GUEST." = 1 ";
        if (in_array($visibility, array_keys($list))) {
            $visibilityCondition = " AND $visibility = 1 ";
        }

        return $visibilityCondition;
    }

    /**
     * Displays all announcements
     * @param string $visibility VISIBLE_GUEST, VISIBLE_STUDENT or VISIBLE_TEACHER
     * @param int $id The identifier of the announcement to display
     */
    public static function display_announcements($visibility, $id = -1)
    {
        $user_selected_language = api_get_interface_language();
        $db_table = Database::get_main_table(TABLE_MAIN_SYSTEM_ANNOUNCEMENTS);
        $tbl_announcement_group = Database::get_main_table(TABLE_MAIN_SYSTEM_ANNOUNCEMENTS_GROUPS);
        $userGroup = new UserGroup();

        $temp_user_groups = $userGroup->get_groups_by_user(api_get_user_id(), 0);
        $groups = array();
        foreach ($temp_user_groups as $user_group) {
            $groups = array_merge($groups, array($user_group['id']));
            $groups = array_merge($groups, $userGroup->get_parent_groups($user_group['id']));
        }

        $groups_string = '('.implode($groups, ',').')';
        $now = api_get_utc_datetime();
        $sql = "SELECT *, DATE_FORMAT(date_start,'%d-%m-%Y %h:%i:%s') AS display_date
                FROM  $db_table
                WHERE
                    (lang='$user_selected_language' OR lang IS NULL) AND
                    (('$now' BETWEEN date_start AND date_end) OR date_end='0000-00-00') ";


        $sql .= self::getVisibilityCondition($visibility);

        if (count($groups) > 0) {
            $sql .= " OR id IN (
                        SELECT announcement_id FROM $tbl_announcement_group
                        WHERE group_id in $groups_string
                    ) ";
        }
        $current_access_url_id = 1;
        if (api_is_multiple_url_enabled()) {
            $current_access_url_id = api_get_current_access_url_id();
        }
        $sql .= " AND access_url_id = '$current_access_url_id' ";
        $sql .= " ORDER BY date_start DESC LIMIT 0,7";

        $announcements = Database::query($sql);
        if (Database::num_rows($announcements) > 0) {
            $query_string = ereg_replace('announcement=[1-9]+', '', $_SERVER['QUERY_STRING']);
            $query_string = ereg_replace('&$', '', $query_string);
            $url = api_get_self();
            echo '<div class="system_announcements">';
            echo '<h3>'.get_lang('SystemAnnouncements').'</h3>';
            echo '<div style="margin:10px;text-align:right;"><a href="news_list.php">'.get_lang('More').'</a></div>';

            while ($announcement = Database::fetch_object($announcements)) {
                if ($id != $announcement->id) {
                    if (strlen($query_string) > 0) {
                        $show_url = 'news_list.php#'.$announcement->id;
                    } else {
                        $show_url = 'news_list.php#'.$announcement->id;
                    }
                    $display_date = api_convert_and_format_date($announcement->display_date, DATE_FORMAT_LONG);
                    echo '<a name="'.$announcement->id.'"></a>
                        <div class="system_announcement">
                            <div class="system_announcement_title"><a name="ann'.$announcement->id.'" href="'.$show_url.'">'.$announcement->title.'</a></div><div class="system_announcement_date">'.$display_date.'</div>
                        </div>';
                } else {
                    echo '<div class="system_announcement">
                            <div class="system_announcement_title">'
                                .$announcement->display_date.'
                                <a name="ann'.$announcement->id.'" href="'.$url.'?'.$query_string.'#ann'.$announcement->id.'">'.$announcement->title.'</a>
                            </div>';
                }
                echo '<br />';
            }
            echo '</div>';
        }
        return;
    }

    /**
     * @param string $visibility
     * @param int $id
     * @param int $start
     * @param string $user_id
     * @return string
     */
    public static function displayAllAnnouncements($visibility, $id = -1, $start = 0, $user_id = '')
    {
        $user_selected_language = api_get_interface_language();
        $start = intval($start);
        $userGroup = new UserGroup();
        $tbl_announcement_group = Database::get_main_table(TABLE_MAIN_SYSTEM_ANNOUNCEMENTS_GROUPS);
        $temp_user_groups = $userGroup->get_groups_by_user(api_get_user_id(), 0);
        $groups = array();
        foreach ($temp_user_groups as $user_group) {
            $groups = array_merge($groups, array($user_group['id']));
            $groups = array_merge($groups, $userGroup->get_parent_groups($user_group['id']));
        }

        // Checks if tables exists to not break platform not updated
        $groups_string = '('.implode($groups, ',').')';

        $table = Database::get_main_table(TABLE_MAIN_SYSTEM_ANNOUNCEMENTS);
        $now = api_get_utc_datetime();

        $sql = "SELECT * FROM $table
                WHERE
                    (lang = '$user_selected_language' OR lang IS NULL) AND
                    ( '$now' >= date_start AND '$now' <= date_end) ";

        $sql .= self::getVisibilityCondition($visibility);

        if (count($groups) > 0) {
            $sql .= " OR id IN (
                    SELECT announcement_id FROM $tbl_announcement_group
                    WHERE group_id in $groups_string
                    ) ";
        }

        if (api_is_multiple_url_enabled()) {
            $current_access_url_id = api_get_current_access_url_id();
            $sql .= " AND access_url_id IN ('1', '$current_access_url_id')";
        }

        if (!isset($_GET['start']) || $_GET['start'] == 0) {
            $sql .= " ORDER BY date_start DESC LIMIT ".$start.",20";
        } else {
            $sql .= " ORDER BY date_start DESC LIMIT ".($start + 1).",20";
        }
        $announcements = Database::query($sql);
        $content = '';
        if (Database::num_rows($announcements) > 0) {
            $content .= '<div class="system_announcements">';
            $content .= '<h3>'.get_lang('SystemAnnouncements').'</h3>';
            $content .= '<table align="center">';
                $content .= '<tr>';
                    $content .= '<td>';
                        $content .= self::display_arrow($user_id);
                    $content .= '</td>';
                $content .= '</tr>';
            $content .= '</table>';
            $content .= '<table align="center" border="0" width="900px">';
            while ($announcement = Database::fetch_object($announcements)) {
                $display_date = api_convert_and_format_date($announcement->display_date, DATE_FORMAT_LONG);
                $content .= '<tr><td>';
                $content .= '<a name="'.$announcement->id.'"></a>
                        <div class="system_announcement">
                        <h2>'.$announcement->title.'</h2><div class="system_announcement_date">'.$display_date.'</div>
                        <br />
                        <div class="system_announcement_content">'
                                .$announcement->content.'
                        </div>
                      </div><br />';
                $content .= '</tr></td>';
            }
            $content .= '</table>';

            $content .= '<table align="center">';
                $content .= '<tr>';
                    $content .= '<td>';
                        $content .= self::display_arrow($user_id);
                    $content .= '</td>';
                $content .= '</tr>';
            $content .= '</table>';
            $content .= '</div>';
        }

        return $content;
    }

    /**
     * @param int $user_id
     * @return string
     */
    public static function display_arrow($user_id)
    {
        $start = (int) $_GET['start'];
        $nb_announcement = self::count_nb_announcement($start, $user_id);
        $next = ((int) $_GET['start'] + 19);
        $prev = ((int) $_GET['start'] - 19);
        $content = '';
        if (!isset($_GET['start']) || $_GET['start'] == 0) {
            if ($nb_announcement > 20) {
                $content .= '<a href="news_list.php?start='.$next.'">'.get_lang('NextBis').' >> </a>';
            }
        } else {
            echo '<a href="news_list.php?start='.$prev.'"> << '.get_lang('Prev').'</a>';
            if ($nb_announcement > 20) {
                $content .= '<a href="news_list.php?start='.$next.'">'.get_lang('NextBis').' >> </a>';
            }
        }
        return $content;
    }

    /**
     * @param int $start
     * @param string $user_id
     * @return int
     */
    public static function count_nb_announcement($start = 0, $user_id = '')
    {
        $start = intval($start);
        $user_selected_language = api_get_interface_language();
        $db_table = Database::get_main_table(TABLE_MAIN_SYSTEM_ANNOUNCEMENTS);
        $sql = 'SELECT id FROM '.$db_table.'
                WHERE (lang="'.$user_selected_language.'" OR lang IS NULL) ';

        $visibility = self::getCurrentUserVisibility();
        $sql .= self::getVisibilityCondition($visibility);

        $current_access_url_id = 1;
        if (api_is_multiple_url_enabled()) {
            $current_access_url_id = api_get_current_access_url_id();
        }
        $sql .= " AND access_url_id = '$current_access_url_id' ";
        $sql .= 'LIMIT '.$start.', 21';
        $announcements = Database::query($sql);
        $i = 0;
        while ($rows = Database::fetch_array($announcements)) {
            $i++;
        }

        return $i;
    }

    /**
     * Get all announcements
     * @return array An array with all available system announcements (as php
     * objects)
     */
    public static function get_all_announcements()
    {
        $table = Database::get_main_table(TABLE_MAIN_SYSTEM_ANNOUNCEMENTS);
        $now = api_get_utc_datetime();
        $sql = "SELECT *, IF ( '$now'  >= date_start AND '$now' <= date_end, '1', '0') AS visible
                FROM $table";

        $current_access_url_id = 1;
        if (api_is_multiple_url_enabled()) {
            $current_access_url_id = api_get_current_access_url_id();
        }
        $sql .= " WHERE access_url_id = '$current_access_url_id' ";
        $sql .= " ORDER BY date_start ASC";

        $result = Database::query($sql);
        $announcements = array();
        while ($announcement = Database::fetch_object($result)) {
            $announcements[] = $announcement;
        }
        return $announcements;
    }

    /**
     * Adds an announcement to the database
     *
     * @param string $title Title of the announcement
     * @param string $content Content of the announcement
     * @param string $date_start Start date (YYYY-MM-DD HH:II: SS)
     * @param string $date_end End date (YYYY-MM-DD HH:II: SS)
     * @param array $visibility
     * @param string $lang The language for which the announvement should be shown. Leave null for all langages
     * @param int    $send_mail Whether to send an e-mail to all users (1) or not (0)
     * @param bool  $add_to_calendar
     * @param bool  $sendEmailTest
     *
     * @return mixed  insert_id on success, false on failure
     */
    public static function add_announcement(
        $title,
        $content,
        $date_start,
        $date_end,
        $visibility,
        $lang = '',
        $send_mail = 0,
        $add_to_calendar = false,
        $sendEmailTest = false
    ) {
        $original_content = $content;
        $a_dateS = explode(' ', $date_start);
        $a_arraySD = explode('-', $a_dateS[0]);
        $a_arraySH = explode(':', $a_dateS[1]);
        $date_start_to_compare = array_merge($a_arraySD, $a_arraySH);

        $a_dateE = explode(' ', $date_end);
        $a_arrayED = explode('-', $a_dateE[0]);
        $a_arrayEH = explode(':', $a_dateE[1]);
        $date_end_to_compare = array_merge($a_arrayED, $a_arrayEH);

        $db_table = Database::get_main_table(TABLE_MAIN_SYSTEM_ANNOUNCEMENTS);

        if (!checkdate($date_start_to_compare[1], $date_start_to_compare[2], $date_start_to_compare[0])) {
            Display::addFlash(Display::return_message(get_lang('InvalidStartDate'), 'warning'));

            return false;
        }

        if (($date_end_to_compare[1] ||
            $date_end_to_compare[2] ||
            $date_end_to_compare[0]) &&
            !checkdate($date_end_to_compare[1], $date_end_to_compare[2], $date_end_to_compare[0])
        ) {
            Display::addFlash(Display::return_message(get_lang('InvalidEndDate'), 'warning'));

            return false;
        }

        if (strlen(trim($title)) == 0) {
            Display::addFlash(Display::return_message(get_lang('InvalidTitle'), 'warning'));

            return false;
        }

        $start = api_get_utc_datetime($date_start);
        $end = api_get_utc_datetime($date_end);

        //Fixing urls that are sent by email
        //$content = str_replace('src=\"/home/', 'src=\"'.api_get_path(WEB_PATH).'home/', $content);
        //$content = str_replace('file=/home/', 'file='.api_get_path(WEB_PATH).'home/', $content);
        $content = str_replace('src=\"'.api_get_path(REL_HOME_PATH), 'src=\"'.api_get_path(WEB_PATH).api_get_path(REL_HOME_PATH), $content);
        $content = str_replace('file='.api_get_path(REL_HOME_PATH), 'file='.api_get_path(WEB_PATH).api_get_path(REL_HOME_PATH), $content);
        $lang = is_null($lang) ? '' : $lang;

        $current_access_url_id = 1;
        if (api_is_multiple_url_enabled()) {
            $current_access_url_id = api_get_current_access_url_id();
        }

        $params = [
            'title' => $title,
            'content' => $content,
            'date_start' => $start,
            'date_end' => $end,
            'lang' => $lang,
            'access_url_id' => $current_access_url_id
        ];

        foreach ($visibility as $key => $value) {
            $params[$key] = $value;
        }

        $resultId = Database::insert($db_table, $params);

        if ($resultId) {
            if ($sendEmailTest) {
                self::send_system_announcement_by_email(
                    $title,
                    $content,
                    $visibility,
                    $lang,
                    true
                );
            } else {
                if ($send_mail == 1) {
                    self::send_system_announcement_by_email(
                        $title,
                        $content,
                        $visibility,
                        $lang
                    );
                }
            }

            if ($add_to_calendar) {
                $agenda = new Agenda('admin');
                $agenda->addEvent(
                    $date_start,
                    $date_end,
                    false,
                    $title,
                    $original_content
                );
            }

            return $resultId;

        }

        return false;
    }

    /**
     * Makes the announcement id visible only for groups in groups_array
     * @param int $announcement_id
     * @param array $group_array array of group id
     * @return bool
     **/
    public static function announcement_for_groups($announcement_id, $group_array)
    {
        $tbl_announcement_group = Database::get_main_table(
            TABLE_MAIN_SYSTEM_ANNOUNCEMENTS_GROUPS
        );
        //first delete all group associations for this announcement
        $res = Database::query(
            "DELETE FROM $tbl_announcement_group 
             WHERE announcement_id=".intval($announcement_id)
        );

        if ($res === false) {
            return false;
        }

        foreach ($group_array as $group_id) {
            if (intval($group_id) != 0) {
                $sql = "INSERT INTO $tbl_announcement_group SET
                        announcement_id=".intval($announcement_id).",
                        group_id=".intval($group_id);
                $res = Database::query($sql);
                if ($res === false) {
                    return false;
                }
            }
        }

        return true;
    }

    /**
    * Gets the groups of this announce
    * @param int announcement id
    * @return array array of group id
    **/
    public static function get_announcement_groups($announcement_id)
    {
        $tbl_announcement_group = Database::get_main_table(TABLE_MAIN_SYSTEM_ANNOUNCEMENTS_GROUPS);
        $tbl_group = Database::get_main_table(TABLE_USERGROUP);
        //first delete all group associations for this announcement
        $sql = "SELECT
                    g.id as group_id,
                    g.name as group_name
                FROM $tbl_group g , $tbl_announcement_group ag
                WHERE
                    announcement_id =".intval($announcement_id)." AND
                    ag.group_id = g.id";
        $res = Database::query($sql);
        $groups = Database::fetch_array($res);

        return $groups;
    }

    /**
     * Updates an announcement to the database
     *
     * @param integer $id of the announcement
     * @param string $title title of the announcement
     * @param string $content content of the announcement
     * @param array $date_start start date (0 => day ; 1 => month ; 2 => year ; 3 => hour ; 4 => minute)
     * @param array $date_end end date of (0 => day ; 1 => month ; 2 => year ; 3 => hour ; 4 => minute)
     * @param array $visibility
     * @return bool    True on success, false on failure
     */
    public static function update_announcement(
        $id,
        $title,
        $content,
        $date_start,
        $date_end,
        $visibility,
        $lang = null,
        $send_mail = 0,
        $sendEmailTest = false
    ) {
        $em = Database::getManager();
        $announcement = $em->find('ChamiloCoreBundle:SysAnnouncement', $id);
        if (!$announcement) {
            return false;
        }

        $a_dateS = explode(' ', $date_start);
        $a_arraySD = explode('-', $a_dateS[0]);
        $a_arraySH = explode(':', $a_dateS[1]);
        $date_start_to_compare = array_merge($a_arraySD, $a_arraySH);

        $a_dateE = explode(' ', $date_end);
        $a_arrayED = explode('-', $a_dateE[0]);
        $a_arrayEH = explode(':', $a_dateE[1]);
        $date_end_to_compare = array_merge($a_arrayED, $a_arrayEH);

        $lang = is_null($lang) ? '' : $lang;

        if (!checkdate($date_start_to_compare[1], $date_start_to_compare[2], $date_start_to_compare[0])) {
            echo Display::return_message(get_lang('InvalidStartDate'));

            return false;
        }

        if (($date_end_to_compare[1] ||
            $date_end_to_compare[2] ||
            $date_end_to_compare[0]) &&
            !checkdate($date_end_to_compare[1], $date_end_to_compare[2], $date_end_to_compare[0])
        ) {
            echo Display::return_message(get_lang('InvalidEndDate'));

            return false;
        }

        if (strlen(trim($title)) == 0) {
            echo Display::return_message(get_lang('InvalidTitle'));

            return false;
        }

        $start = api_get_utc_datetime($date_start);
        $end = api_get_utc_datetime($date_end);

        //Fixing urls that are sent by email
        //$content = str_replace('src=\"/home/', 'src=\"'.api_get_path(WEB_PATH).'home/', $content);
        //$content = str_replace('file=/home/', 'file='.api_get_path(WEB_PATH).'home/', $content);
        $content = str_replace('src=\"'.api_get_path(REL_HOME_PATH), 'src=\"'.api_get_path(WEB_PATH).api_get_path(REL_HOME_PATH), $content);
        $content = str_replace('file='.api_get_path(REL_HOME_PATH), 'file='.api_get_path(WEB_PATH).api_get_path(REL_HOME_PATH), $content);

        if ($sendEmailTest) {
            self::send_system_announcement_by_email(
                $title,
                $content,
                null,
                null,
                $lang,
                $sendEmailTest
            );
        } else {
            if ($send_mail == 1) {
                self::send_system_announcement_by_email(
                    $title,
                    $content,
                    $visibility,
                    $lang
                );
            }
        }

        $dateStart = new DateTime($start, new DateTimeZone('UTC'));
        $dateEnd = new DateTime($end, new DateTimeZone('UTC'));

        $announcement
            ->setLang($lang)
            ->setTitle($title)
            ->setContent($content)
            ->setDateStart($dateStart)
            ->setDateEnd($dateEnd)
            //->setVisibleTeacher($visible_teacher)
            //->setVisibleStudent($visible_student)
            //->setVisibleGuest($visible_guest)
            ->setAccessUrlId(api_get_current_access_url_id());

        $em->merge($announcement);
        $em->flush();

        // Update visibility
        $list = self::getVisibilityList();
        $table = Database::get_main_table(TABLE_MAIN_SYSTEM_ANNOUNCEMENTS);
        foreach ($list as $key => $title) {
            $value = isset($visibility[$key]) && $visibility[$key] ? 1 : 0;
            $sql = "UPDATE $table SET $key = '$value' WHERE id = $id";
            Database::query($sql);
        }
        return true;
    }

    /**
     * Deletes an announcement
     * @param int $id The identifier of the announcement that should be
     * @return bool    True on success, false on failure
     */
    public static function delete_announcement($id)
    {
        $table = Database::get_main_table(TABLE_MAIN_SYSTEM_ANNOUNCEMENTS);
        $id = intval($id);
        $sql = "DELETE FROM $table WHERE id =".$id;
        $res = Database::query($sql);
        if ($res === false) {
            return false;
        }
        return true;
    }

    /**
     * Gets an announcement
     * @param int $id The identifier of the announcement that should be
     * @return object    Object of class StdClass or the required class, containing the query result row
     */
    public static function get_announcement($id)
    {
        $db_table = Database::get_main_table(TABLE_MAIN_SYSTEM_ANNOUNCEMENTS);
        $id = intval($id);
        $sql = "SELECT * FROM ".$db_table." WHERE id = ".$id;
        $announcement = Database::fetch_object(Database::query($sql));

        return $announcement;
    }

    /**
     * Change the visibility of an announcement
     * @param int $id
     * @param int $user For who should the visibility be changed
     * @param bool $visible
     * @return bool True on success, false on failure
     */
    public static function set_visibility($id, $user, $visible)
    {
        $table = Database::get_main_table(TABLE_MAIN_SYSTEM_ANNOUNCEMENTS);
        $id = (int) $id;
        $list = array_keys(self::getVisibilityList());
        $user = trim($user);
        $visible = (int) $visible;
        if (!in_array($user, $list)) {
            return false;
        }

        $field = $user;
        $sql = "UPDATE $table SET ".$field." = '".$visible."'
                WHERE id='".$id."'";
        $res = Database::query($sql);

        if ($res === false) {
            return false;
        }

        return true;
    }

    /**
     * Send a system announcement by e-mail to all teachers/students depending on parameters
     * @param string $title
     * @param string $content
     * @param array $visibility
     * @param string $language Language (optional, considered for all languages if left empty)
     * @param bool $sendEmailTest
     * @return bool True if the message was sent or there was no destination matching.
     * False on database or e-mail sending error.
     */
    public static function send_system_announcement_by_email(
        $title,
        $content,
        $visibility,
        $language = null,
        $sendEmailTest = false
    ) {
        $content = str_replace(array('\r\n', '\n', '\r'), '', $content);
        $now = api_get_utc_datetime();
        $teacher = $visibility['visible_teacher'];
        $student = $visibility['visible_student'];
        if ($sendEmailTest) {
            MessageManager::send_message_simple(api_get_user_id(), $title, $content);

            return true;
        }

        $user_table = Database::get_main_table(TABLE_MAIN_USER);
        if (api_is_multiple_url_enabled()) {
            $current_access_url_id = api_get_current_access_url_id();
            $url_rel_user = Database::get_main_table(TABLE_MAIN_ACCESS_URL_REL_USER);
            $url_condition = " INNER JOIN $url_rel_user uu ON uu.user_id = u.user_id ";
        }

        if ($teacher <> 0 && $student == 0) {
            $sql = "SELECT DISTINCT u.user_id FROM $user_table u $url_condition 
                    WHERE status = '1' ";
        }

        if ($teacher == 0 && $student <> 0) {
            $sql = "SELECT DISTINCT u.user_id FROM $user_table u $url_condition 
                    WHERE status = '5' ";
        }

        if ($teacher <> 0 && $student <> 0) {
            $sql = "SELECT DISTINCT u.user_id FROM $user_table u $url_condition 
                    WHERE 1 = 1 ";
        }

        if (!empty($language)) {
            //special condition because language was already treated for SQL insert before
            $sql .= " AND language = '".Database::escape_string($language)."' ";
        }

        if (api_is_multiple_url_enabled()) {
            $sql .= " AND access_url_id = '".$current_access_url_id."' ";
        }

        // Sent to active users.
        $sql .= " AND email <>'' AND active = 1 ";

        // Expiration date
        $sql .= " AND (expiration_date = '' OR expiration_date IS NULL OR expiration_date > '$now') ";

        if ((empty($teacher) || $teacher == '0') && (empty($student) || $student == '0')) {
            return true;
        }

        $result = Database::query($sql);
        if ($result === false) {
            return false;
        }

        $message_sent = false;
        while ($row = Database::fetch_array($result, 'ASSOC')) {
            MessageManager::send_message_simple($row['user_id'], $title, $content);
            $message_sent = true;
        }

        // Minor validation to clean up the attachment files in the announcement
        if (!empty($_FILES)) {
            $attachments = $_FILES;
            foreach ($attachments as $attachment) {
                unlink($attachment['tmp_name']);
            }
        }

        return $message_sent; //true if at least one e-mail was sent
    }

    /**
     * Displays announcements as an slideshow
     * @param string $visible see self::VISIBLE_* constants
     * @param int $id The identifier of the announcement to display
     *
     * @return string
     */
    public static function displayAnnouncementsSlider($visible, $id = null)
    {
        $user_selected_language = Database::escape_string(api_get_interface_language());
        $table = Database::get_main_table(TABLE_MAIN_SYSTEM_ANNOUNCEMENTS);

        $cut_size = 500;
        $now = api_get_utc_datetime();
        $sql = "SELECT * FROM $table
                WHERE
                    (lang = '$user_selected_language' OR lang = '') AND
                    ('$now' >= date_start AND '$now' <= date_end) ";

        $sql .= self::getVisibilityCondition($visible);

        if (isset($id) && !empty($id)) {
            $id = intval($id);
            $sql .= " AND id = $id ";
        }

        if (api_is_multiple_url_enabled()) {
            $current_url_id = api_get_current_access_url_id();
            $sql .= " AND access_url_id IN ('1', '$current_url_id') ";
        }

        $sql .= " ORDER BY date_start DESC";
        $result = Database::query($sql);
        $announcements = [];

        if (Database::num_rows($result) > 0) {
            while ($announcement = Database::fetch_object($result)) {
                $announcementData = [
                    'id' => $announcement->id,
                    'title' => $announcement->title,
                    'content' => $announcement->content,
                    'readMore' => null
                ];

                if (empty($id)) {
                    if (api_strlen(strip_tags($announcement->content)) > $cut_size) {
                        $announcementData['content'] = cut($announcement->content, $cut_size);
                        $announcementData['readMore'] = true;
                    }
                }

                $announcements[] = $announcementData;
            }
        }

        if (count($announcements) === 0) {
            return null;
        }

        $template = new Template(null, false, false);
        $template->assign('announcements', $announcements);
        $layout = $template->get_template('announcement/slider.tpl');

        return $template->fetch($layout);
    }

    /**
     * Get the HTML code for an announcement
     * @param int $announcementId The announcement ID
     * @param int $visibility The announcement visibility
     * @return string The HTML code
     */
    public static function displayAnnouncement($announcementId, $visibility)
    {
        $selectedUserLanguage = Database::escape_string(api_get_interface_language());
        $announcementTable = Database::get_main_table(TABLE_MAIN_SYSTEM_ANNOUNCEMENTS);
        $now = api_get_utc_datetime();

        $whereConditions = [
            "(lang = ? OR lang IS NULL OR lang = '') " => $selectedUserLanguage,
            "AND (? >= date_start AND ? <= date_end) " => [$now, $now],
            "AND id = ? " => intval($announcementId)
        ];

        $condition = self::getVisibilityCondition($visibility);
        $whereConditions[$condition] = 1;

        if (api_is_multiple_url_enabled()) {
            $whereConditions["AND access_url_id IN (1, ?) "] = api_get_current_access_url_id();
        }

        $announcement = Database::select(
            '*',
            $announcementTable,
            [
                'where' => $whereConditions,
                'order' => 'date_start',
            ],
            'first'
        );

        $template = new Template(null, false, false);
        $template->assign('announcement', $announcement);
        $layout = $template->get_template('announcement/view.tpl');

        return $template->fetch($layout);
    }

    /**
     * @return bool
     */
    public static function newRolesActivated()
    {
        /* In order to use this option you need to run this SQL changes :
         ALTER TABLE sys_announcement ADD COLUMN visible_drh INT DEFAULT 0;
         ALTER TABLE sys_announcement ADD COLUMN visible_session_admin INT DEFAULT 0;
         ALTER TABLE sys_announcement ADD COLUMN visible_boss INT DEFAULT 0;
        */

        return api_get_configuration_value('system_announce_extra_roles');
    }

    /**
     * @return string
     */
    public static function getCurrentUserVisibility()
    {
        if (api_is_anonymous()) {
            return SystemAnnouncementManager::VISIBLE_GUEST;
        }

        if (self::newRolesActivated()) {
            if (api_is_student_boss()) {
                return SystemAnnouncementManager::VISIBLE_STUDENT_BOSS;
            }

            if (api_is_session_admin()) {
                return SystemAnnouncementManager::VISIBLE_SESSION_ADMIN;
            }

            if (api_is_drh()) {
                return SystemAnnouncementManager::VISIBLE_DRH;
            }

            if (api_is_allowed_to_create_course()) {
                return SystemAnnouncementManager::VISIBLE_TEACHER;
            } else {
                return SystemAnnouncementManager::VISIBLE_STUDENT;
            }
        } else {
            // Default behaviour
            return api_is_allowed_to_create_course() ? SystemAnnouncementManager::VISIBLE_TEACHER : SystemAnnouncementManager::VISIBLE_STUDENT;
        }
    }
}