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

/**
 * Search course widget.
 * Display a search form and a list of courses that matches the search.
 *
 * @copyright (c) 2011 University of Geneva
 * @license GNU General Public License - http://www.gnu.org/copyleft/gpl.html
 * @author Laurent Opprecht
 */
class SearchCourseWidget
{
    const PARAM_ACTION = 'action';
    const ACTION_SUBSCRIBE = 'subscribe';

    /**
     * Returns $_POST data for $key is it exists or $default otherwise.
     *
     * @param string $key
     * @param object $default
     *
     * @return string
     */
    public static function post($key, $default = '')
    {
        return isset($_POST[$key]) ? $_POST[$key] : $default;
    }

    /**
     * Returns $_GET data for $key is it exists or $default otherwise.
     *
     * @param string $key
     * @param object $default
     *
     * @return string
     */
    public static function get($key, $default = '')
    {
        return isset($_GET[$key]) ? $_GET[$key] : $default;
    }

    public static function server($key, $default = '')
    {
        return isset($_SERVER[$key]) ? $_SERVER[$key] : $default;
    }

    public static function get_lang($name)
    {
        return SearchCoursePlugin::create()->get_lang($name);
    }

    /**
     * @return bool
     */
    public function is_homepage()
    {
        $url = self::server('REQUEST_URI');
        $url = explode('?', $url);
        $url = reset($url);
        $url = self::server('SERVER_NAME').$url;

        $root = api_get_path('WEB_PATH');
        $root = str_replace('https://', '', $root);
        $root = str_replace('http://', '', $root);
        $index_url = $root.'index.php';

        return $url == $index_url || $url == $root;
    }

    /**
     * @return bool
     */
    public function is_user_portal()
    {
        $url = self::server('REQUEST_URI');
        $url = explode('?', $url);
        $url = reset($url);
        $url = self::server('SERVER_NAME').$url;

        $root = api_get_path('WEB_PATH');
        $root = str_replace('https://', '', $root);
        $root = str_replace('http://', '', $root);
        $index_url = $root.'user_portal.php';

        return $url == $index_url || $url == $root;
    }

    public function accept()
    {
        return $this->is_homepage() || $this->is_user_portal();
    }

    /**
     * Display the search course widget:.
     *
     * Title
     * Search form
     *
     * Search results
     */
    public function run()
    {
        if (!$this->accept()) {
            return;
        }
        $this->display_header();

        $this->display_form();

        $search_term = self::post('search_term');
        $action = self::get('action');

        $has_content = !empty($search_term) || !empty($action);
        if ($has_content) {
            echo '<div class="list">';
        } else {
            echo '<div>';
        }

        if (RegisterCourseWidget::factory()->run()) {
            $result = true;
        } else {
            $result = $this->action_display();
        }

        echo '</div>';

        $this->display_footer();

        return $result;
    }

    public function get_url($action = '')
    {
        $self = $_SERVER['PHP_SELF'];
        $parameters = [];
        if ($action) {
            $parameters[self::PARAM_ACTION] = $action;
        }
        $parameters = implode('&', $parameters);
        $parameters = $parameters ? '?'.$parameters : '';

        return $self.$parameters;
    }

    /**
     * Handle the display action.
     */
    public function action_display()
    {
        global $charset;

        $search_term = self::post('search_term');
        if ($search_term) {
            $search_result_for_label = self::get_lang('Search results for:');
            $search_term_html = htmlentities($search_term, ENT_QUOTES, $charset);
            echo "<h5>$search_result_for_label $search_term_html</h5>";

            $courses = $this->retrieve_courses($search_term);
            $this->display_list($courses);
        }

        return true;
    }

    public function display_header()
    {
        $search_course_label = self::get_lang('Search courses');
        echo <<<EOT
        <div class="well course_search">
        <div class="menusection">
            <h4>$search_course_label</h4>
EOT;
    }

    public function display_footer()
    {
        echo '</div></div>';
    }

    /**
     * Display the search course form.
     */
    public function display_form()
    {
        global $stok;
        $search_label = self::get_lang('_search');
        $self = api_get_self();
        $search_term = self::post('search_term');
        $form = <<<EOT
        <form class="course_list" method="post" action="$self">
            <input type="hidden" name="sec_token" value="$stok" />
            <input type="hidden" name="search_course" value="1" />
            <input type="text" name="search_term" class="span2" value="$search_term" />
            &nbsp;<input class="btn btn-default" type="submit" value="$search_label" />
        </form>
EOT;
        echo $form;
    }

    /**
     * @param array $courses
     *
     * @return bool
     */
    public function display_list($courses)
    {
        if (empty($courses)) {
            return false;
        }

        $user_courses = $this->retrieve_user_courses();
        $display_coursecode = api_get_setting('display_coursecode_in_courselist') == 'true';
        $display_teacher = api_get_setting('display_teacher_in_courselist') == 'true';

        echo '<table cellpadding="4">';
        foreach ($courses as $key => $course) {
            $details = [];
            if ($display_coursecode) {
                $details[] = $course['visual_code'];
            }
            if ($display_teacher) {
                $details[] = $course['tutor'];
            }
            $details = implode(' - ', $details);
            $title = $course['title'];

            $href = api_get_path(WEB_COURSE_PATH).$course['code'].'/index.php';
            echo '<tr><td><b><a href="'.$href.'">'."$title</a></b><br/>$details</td><td>";
            if (!api_is_anonymous()) {
                if ($course['registration_code']) {
                    Display::display_icon(
                        'passwordprotected.png',
                        '',
                        ['style' => 'float:left;']
                    );
                }
                $this->display_subscribe_icon($course, $user_courses);
            }
            echo '</td></tr>';
        }
        echo '</table>';

        return true;
    }

    /**
     * Displays the subscribe icon if subscribing is allowed and
     * if the user is not yet subscribed to this course.
     *
     * @global type $stok
     *
     * @param array $current_course
     * @param array $user_courses
     *
     * @return bool
     */
    public function display_subscribe_icon($current_course, $user_courses)
    {
        global $stok;

        //Already subscribed
        $code = $current_course['code'];
        if (isset($user_courses[$code])) {
            echo self::get_lang('Already subscribed');

            return false;
        }

        //Not authorized to subscribe
        if ($current_course['subscribe'] != SUBSCRIBE_ALLOWED) {
            echo self::get_lang('Subscribing not allowed');

            return false;
        }

        //Subscribe form
        $self = $_SERVER['PHP_SELF'];
        echo <<<EOT
                <form action="$self?action=subscribe" method="post">
                    <input type="hidden" name="sec_token" value="$stok" />
                    <input type="hidden" name="subscribe" value="$code" />
EOT;

        $search_term = $this->post('search_term');
        if ($search_term) {
            $search_term = Security::remove_XSS($search_term);
            echo <<<EOT
                    <input type="hidden" name="search_course" value="1" />
                    <input type="hidden" name="search_term" value="$search_term" />
EOT;
        }
        echo '<input type="image" name="unsub" src="'.Display::returnIconPath('enroll.gif').'" alt="'.get_lang('Subscribe').'" />
                '.get_lang('Subscribe').'
                </form>
        ';

        return true;
    }

    /**
     * DB functions - DB functions - DB functions.
     */

    /**
     * Search courses that match the search term.
     * Search is done on the code, title and tutor fields.
     *
     * @param string $search_term
     *
     * @return array
     */
    public function retrieve_courses($search_term)
    {
        if (empty($search_term)) {
            return [];
        }
        $search_term = Database::escape_string($search_term);
        $course_table = Database::get_main_table(TABLE_MAIN_COURSE);

        if (api_is_anonymous()) {
            $course_fiter = 'visibility = '.COURSE_VISIBILITY_OPEN_WORLD;
        } else {
            $course_fiter = 'visibility = '.COURSE_VISIBILITY_OPEN_WORLD.' OR ';
            $course_fiter .= 'visibility = '.COURSE_VISIBILITY_OPEN_PLATFORM.' OR ';
            $course_fiter .= '(visibility = '.COURSE_VISIBILITY_REGISTERED.' AND subscribe = 1)';
        }

        $sql = <<<EOT
                SELECT * FROM $course_table
                WHERE ($course_fiter) AND (code LIKE '%$search_term%' OR visual_code LIKE '%$search_term%' OR title LIKE '%$search_term%' OR tutor_name LIKE '%$search_term%')
                ORDER BY title, visual_code ASC
EOT;

        $result = [];
        $resultset = Database::query($sql);
        while ($row = Database::fetch_array($resultset)) {
            $code = $row['code'];
            $result[$code] = [
                'code' => $code,
                'directory' => $row['directory'],
                'visual_code' => $row['visual_code'],
                'title' => $row['title'],
                'tutor' => $row['tutor_name'],
                'subscribe' => $row['subscribe'],
                'unsubscribe' => $row['unsubscribe'],
            ];
        }

        return $result;
    }

    /**
     * Retrieves courses that the user is subscribed to.
     *
     * @param int $user_id
     *
     * @return array
     */
    public function retrieve_user_courses($user_id = null)
    {
        if (is_null($user_id)) {
            global $_user;
            $user_id = $_user['user_id'];
        }
        $course_table = Database::get_main_table(TABLE_MAIN_COURSE);
        $user_course_table = Database::get_main_table(TABLE_MAIN_COURSE_USER);

        $user_id = intval($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.directory dir, course_rel_user.status status,
                      course_rel_user.sort sort, course_rel_user.user_course_cat user_course_cat
                       FROM $course_table course, $user_course_table course_rel_user
                       WHERE course.id = course_rel_user.c_id
                             AND course_rel_user.user_id = $user_id
                       ORDER BY course_rel_user.sort ASC";
        $result = [];
        $resultset = Database::query($sql_select_courses);
        while ($row = Database::fetch_array($resultset)) {
            $code = $row['k'];
            $result[$code] = [
                'code' => $code,
                '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 $result;
    }

    /*
     * Utility functions - Utility functions - Utility functions
     */

    /**
     * Removes from $courses all courses the user is subscribed to.
     *
     * @global array $_user
     *
     * @param array $courses
     *
     * @return array
     */
    public function filter_out_user_courses($courses)
    {
        if (empty($courses)) {
            return $courses;
        }

        global $_user;
        $user_id = $_user['user_id'];

        $user_courses = $this->retrieve_user_courses($user_id);
        foreach ($user_courses as $key => $value) {
            unset($courses[$key]);
        }

        return $courses;
    }
}
