reminder.class.php

<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Abstract class for reminder object.
 *
 * @package    local
 * @subpackage reminders
 * @copyright  2012 Isuru Madushanka Weerarathna
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
abstract class reminder {
   
    /**
     * @var int number of days in advance to actual event.
     */
    protected $aheaddays;
    
    /**
     * @var int indicates immediate sending of message as a notification.
     */
    protected $notification = 1;
    
    /**
     *
     * @var object event object correspond to this reminder.
     */
    protected $event;
    
    protected $tbodycssstyle = 'width:100%;font-family:Tahoma,Arial,Sans-serif;border-width:1px 2px 2px 1px;border:1px Solid #ccc';
    protected $titlestyle = 'padding:0 0 6px 0;margin:0;font-family:Arial,Sans-serif;font-size:16px;font-weight:bold;color:#222';
    protected $footerstyle = 'background-color:#f6f6f6;color:#888;border-top:1px Solid #ccc;font-family:Arial,Sans-serif;font-size:11px';
    
    /**
     *
     * @var object cahced reminder message object. This will be reused for other users too.
     */
    public $eventobject;
    
    public function __construct($event, $aheaddays = 1) {
        $this->event = $event;
        $this->aheaddays = $aheaddays;
    }
    
    /**
     * Gets the header content of the e-mail message.
     */
    protected function get_html_header() {
        return html_writer::tag('head', '');
    }
    
    /**
     * Gets the footer content of the e-mail message.
     */
    protected function get_html_footer() {
        global $CFG;
        
        $footer  = html_writer::start_tag('tr');
        $footer .= html_writer::start_tag('td', array('style' => $this->footerstyle, 'colspan' => 2));
        $footer .= get_string('reminderfrom', 'local_reminders').' ';
        $footer .= html_writer::link($CFG->wwwroot.'/calendar/index.php', 'Moodle Calendar', array('target' => '_blank'));
        $footer .= html_writer::end_tag('td').html_writer::end_tag('tr');

        return $footer;
    }
    
    /**
     * Returns the correct link for the calendar event.
     * 
     * @return string complete url for the event
     */
    protected function generate_event_link() {       
        $params = array('view' => 'day', 'cal_d' => date('j', $this->event->timestart), 
            'cal_m' => date('n', $this->event->timestart), 'cal_y' => date('Y', $this->event->timestart));
        $calurl = new moodle_url('/calendar/view.php', $params);
        $calurl->set_anchor('event_'.$this->event->id);
        
        return $calurl->out(false);
    }
    
    /**
     * This function formats the due time of the event appropiately. If this event
     * has a duration then formatted time will be [starttime]-[endtime].
     * 
     * @param object $user user object
     * @return string formatted time string
     */
    protected function format_event_time_duration($user) {
        $followedtimeformat = get_string('strftimedatetime', 'langconfig');

        $tzone = 99;
        if (isset($user) && !empty($user)) {
            $tzone = $user->timezone;
        }
        
        $formattedtime = userdate($this->event->timestart, '', $tzone);
        $sdate = usergetdate($this->event->timestart, $tzone);
        if ($this->event->timeduration > 0) {
            $ddate = usergetdate($this->event->timestart + $this->event->timeduration, $tzone);
            if ($sdate['year'] == $ddate['year'] && $sdate['mon'] == $ddate['mon'] && $sdate['mday'] == $ddate['mday']) {
                $followedtimeformat = get_string('strftimetime', 'langconfig');
            }
            $formattedtime .= ' - '.userdate($this->event->timestart + $this->event->timeduration, $followedtimeformat, $tzone);
        }
        return $formattedtime;
    }
    
    /**
     * This function setup the corresponding message provider for each
     * reminder type. It would be called everytime at the constructor.
     * 
     * @return string Message provider name
     */
    protected abstract function get_message_provider();
    
    /**
     * Generates a message content as a HTML. Suitable for email messages.
     *
     * @param object $event The event object
     * @return string Message content as HTML text.
     */
    public abstract function get_message_html($user=null);
    
    /**
     * Generates a message content as a plain-text. Suitable for popup messages.
     *
     * @param object $event The event object
     * @return string Message content as plain-text.
     */
    public abstract function get_message_plaintext($user=null);
    
    /**
     * Generates a message title for the reminder. Used for all message types.
     * 
     * @return string Message title as a plain-text. 
     */
    public abstract function get_message_title();
    
    /**
     * Gets an array of custom headers for the reminder message, specially
     * for e-mails. For e-mails they will be easier to track when
     * several e-mail reminders are received for a particular event. <br>
     * If no header is wanted, just simply returns an empty array.
     *  
     * @return array array of strings containing header attributes.
     */
    public function get_custom_headers() {
        global $CFG;
        
        $urlinfo = parse_url($CFG->wwwroot);
        $hostname = $urlinfo['host'];
        
        mtrace(" [Local Reminders] host [ $hostname ]");
        
        return array('Message-ID: <moodlereminder'.$this->event->id.'@'.$hostname.'>');
    }
    
    /**
     * Creates the final reminder message object from given information.
     * 
     * @param object $name impersonated user for sending messages. This 
     *          name will display in 'from' field in every reminder message.
     * 
     * @return object a message object which will be sent to the messaging API
     */
    public function create_reminder_message_object($admin=null) {  
        global $CFG;
        
        if ($admin == null) {
            $admin = get_admin();
            //$admin->maildisplay = false;
        } 
        
        $contenthtml = $this->get_message_html();
        $titlehtml = $this->get_message_title();
        $subjectprefix = get_string('titlesubjectprefix', 'local_reminders');
        if (isset($CFG->local_reminders_messagetitleprefix) && !empty($CFG->local_reminders_messagetitleprefix)) {
            $subjectprefix = $CFG->local_reminders_messagetitleprefix;
        }
        
        $cheaders = $this->get_custom_headers();
        if (!empty($cheaders)) {
            $admin->customheaders = $cheaders;
        }
        
        $eventdata = new stdClass();
        $eventdata->component           = 'local_reminders';   // plugin name
        $eventdata->name                = $this->get_message_provider();     // message interface name
        $eventdata->userfrom            = $admin;
        //$eventdata->userto              = 3;
        $eventdata->subject             = '['.$subjectprefix.'] '.$titlehtml;    // message title
        $eventdata->fullmessage         = $this->get_message_plaintext(); 
        $eventdata->fullmessageformat   = FORMAT_PLAIN;
        $eventdata->fullmessagehtml     = $contenthtml;
        $eventdata->smallmessage        = $titlehtml . ' - ' . $contenthtml;
        $eventdata->notification        = $this->notification;
        
        // save created object with reminder object
        $this->eventobject = $eventdata;
        
        return $eventdata;
    }
    
    /**
     * Assign user which the reminder message is sent to
     * 
     * @param object $user user object (id field must contain)
     * @param boolean $refreshcontent indicates whether content of message should
     * be refresh based on given user
     * 
     * @return event object
     */
    public function set_sendto_user($user, $refreshcontent=true) {
        if (!isset($this->eventobject) || empty($this->eventobject)) {
            $this->create_reminder_message_object();
        }
        
        $this->eventobject->userto = $user;
        
        if ($refreshcontent) {
            $contenthtml = $this->get_message_html($user);
            $titlehtml = $this->get_message_title();
            
            $this->eventobject->fullmessagehtml = $contenthtml;
            $this->eventobject->smallmessage = $titlehtml . ' - ' . $contenthtml;
            $this->eventobject->fullmessage = $this->get_message_plaintext($user);
        }
        
        return $this->eventobject;
    }
    
}