<?php
/**
 * Free/Busy functionality.
 *
 * $Horde: kronolith/lib/FreeBusy.php,v 1.11.2.5 2008/05/22 23:52:42 jan Exp $
 *
 * @author  Chuck Hagenbuch <chuck@horde.org>
 * @since   Kronolith 2.2
 * @package Kronolith
 */
class Kronolith_FreeBusy {

    /**
     * Generates the free/busy text for $calendar. Cache it for at least an
     * hour, as well.
     *
     * @param string|array $calendar  The calendar to view free/busy slots for.
     * @param integer $startstamp     The start of the time period to retrieve.
     * @param integer $endstamp       The end of the time period to retrieve.
     * @param boolean $returnObj      Default false. Return a vFreebusy object
     *                                instead of text.
     * @param string $user            Set organizer to this user.
     *
     * @return string  The free/busy text.
     */
    function generate($calendar, $startstamp = null, $endstamp = null,
                      $returnObj = false, $user = null)
    {
        global $kronolith_shares;

        require_once 'Horde/Identity.php';
        require_once 'Horde/iCalendar.php';
        require_once KRONOLITH_BASE . '/lib/version.php';

        if (!is_array($calendar)) {
            $calendar = array($calendar);
        }

        /* Fetch the appropriate share and check permissions. */
        $share = &$kronolith_shares->getShare($calendar[0]);
        if (is_a($share, 'PEAR_Error')) {
            return $returnObj ? $share : '';
        }

        /* Default the start date to today. */
        if (is_null($startstamp)) {
            $startstamp = mktime(0, 0, 0);
        }

        /* Default the end date to the start date + freebusy_days. */
        if (is_null($endstamp) || $endstamp < $startstamp) {
            $endstamp = mktime(0, 0, 0,
                               date('n', $startstamp),
                               date('j', $startstamp)
                               + $GLOBALS['prefs']->getValue('freebusy_days'),
                               date('Y', $startstamp));
        }

        /* Get the Identity for the owner of the share. */
        $identity = &Identity::singleton('none',
                                         $user ? $user : $share->get('owner'));
        $email = $identity->getValue('from_addr');
        $cn = $identity->getValue('fullname');

        /* Fetch events. */
        $startDate = new Horde_Date($startstamp);
        $endDate = new Horde_Date($endstamp);
        $busy = Kronolith::listEvents($startDate, $endDate, $calendar);
        if (is_a($busy, 'PEAR_Error')) {
            return $busy;
        }

        /* Create the new iCalendar. */
        $vCal = new Horde_iCalendar();
        $vCal->setAttribute('PRODID', '-//The Horde Project//Kronolith '
                            . KRONOLITH_VERSION . '//EN');
        $vCal->setAttribute('METHOD', 'PUBLISH');

        /* Create new vFreebusy. */
        $vFb = &Horde_iCalendar::newComponent('vfreebusy', $vCal);
        $params = array();
        if (!empty($cn)) {
            $params['CN'] = $cn;
        }
        if (!empty($email)) {
            $vFb->setAttribute('ORGANIZER', 'mailto:' . $email, $params);
        } else {
            $vFb->setAttribute('ORGANIZER', '', $params);
        }

        $vFb->setAttribute('DTSTAMP', $_SERVER['REQUEST_TIME']);
        $vFb->setAttribute('DTSTART', $startstamp);
        $vFb->setAttribute('DTEND', $endstamp);
        $vFb->setAttribute(
            'URL',
            Horde::applicationUrl('fb.php?u=' . $share->get('owner'),
                                  true, -1));

        /* Add all the busy periods. */
        foreach ($busy as $day => $events) {
            foreach ($events as $event) {
                if ($event->hasStatus(KRONOLITH_STATUS_FREE)) {
                    continue;
                }
                if ($event->hasStatus(KRONOLITH_STATUS_CANCELLED)) {
                    continue;
                }

                $duration = $event->end->timestamp()
                    - $event->start->timestamp();

                /* Make sure that we're using the current date for recurring
                 * events. */
                if ($event->recurs()) {
                    $startThisDay = mktime($event->start->hour,
                                           $event->start->min,
                                           $event->start->sec,
                                           date('n', $day),
                                           date('j', $day),
                                           date('Y', $day));
                } else {
                    $startThisDay = $event->start->timestamp();
                }
                $vFb->addBusyPeriod('BUSY', $startThisDay, null, $duration);
            }
        }

        /* Remove the overlaps. */
        $vFb->simplify();
        $vCal->addComponent($vFb);

        /* Return the vFreebusy object if requested. */
        if ($returnObj) {
            return $vFb;
        }

        /* Generate the vCal file. */
        return $vCal->exportvCalendar();
    }

    /**
     * Retrieves the free/busy information for a given email address, if any
     * information is available.
     *
     * @param string $email  The email address to look for.
     *
     * @return Horde_iCalendar_vfreebusy  Free/busy component on success,
     *                                    PEAR_Error on failure
     */
    function get($email)
    {
        require_once 'Horde/iCalendar.php';
        require_once 'Mail/RFC822.php';
        require_once 'Horde/MIME.php';

        /* Properly handle RFC822-compliant email addresses. */
        static $rfc822;
        if (is_null($rfc822)) {
            $rfc822 = new Mail_RFC822();
        }

        $default_domain = empty($GLOBALS['conf']['storage']['default_domain']) ? null : $GLOBALS['conf']['storage']['default_domain'];
        $res = $rfc822->parseAddressList($email, $default_domain);
        if (is_a($res, 'PEAR_Error')) {
            return $res;
        }
        if (!count($res)) {
            return PEAR::raiseError(_("No valid email address found"));
        }

        $email = MIME::rfc822WriteAddress($res[0]->mailbox, $res[0]->host);

        /* Check if we can retrieve a VFB from the Free/Busy URL, if one is
         * set. */
        $url = Kronolith_FreeBusy::getUrl($email);
        if (is_a($url, 'PEAR_Error')) {
            $url = null;
        } else {
            $url = trim($url);
        }
        if ($url) {
            $options['method'] = 'GET';
            $options['timeout'] = 5;
            $options['allowRedirects'] = true;

            if (!empty($GLOBALS['conf']['http']['proxy']['proxy_host'])) {
                $options = array_merge($options, $GLOBALS['conf']['http']['proxy']);
            }

            require_once 'HTTP/Request.php';
            $http = new HTTP_Request($url, $options);
            if (is_a($response = @$http->sendRequest(), 'PEAR_Error')) {
                return PEAR::raiseError(sprintf(_("The free/busy url for %s cannot be retrieved."), $email));
            }
            if ($http->getResponseCode() == 200 &&
                $data = $http->getResponseBody()) {
                // Detect the charset of the iCalendar data.
                $contentType = $http->getResponseHeader('Content-Type');
                if ($contentType && strpos($contentType, ';') !== false) {
                    list(,$charset,) = explode(';', $contentType);
                    $charset = trim(str_replace('charset=', '', $charset));
                } else {
                    $charset = 'UTF-8';
                }

                $vCal = new Horde_iCalendar();
                $vCal->parsevCalendar($data, 'VCALENDAR', $charset);
                $components = $vCal->getComponents();

                $vCal = new Horde_iCalendar();
                $vFb = Horde_iCalendar::newComponent('vfreebusy', $vCal);
                $vFb->setAttribute('ORGANIZER', $email);
                foreach ($components as $component) {
                    if (is_a($component, 'Horde_iCalendar_vfreebusy')) {
                        $found = true;
                        $vFb->merge($component);
                    }
                }

                if ($found) {
                    return $vFb;
                }
            }
        }

        /* Check storage driver. */
        require_once KRONOLITH_BASE . '/lib/Storage.php';
        $storage = &Kronolith_Storage::singleton();

        $fb = $storage->search($email);
        if (!is_a($fb, 'PEAR_Error')) {
            return $fb;
        } elseif ($fb->getCode() == KRONOLITH_ERROR_FB_NOT_FOUND) {
            return $url ?
                PEAR::raiseError(sprintf(_("No free/busy information found at the free/busy url of %s."), $email)) :
                PEAR::raiseError(sprintf(_("No free/busy url found for %s."), $email));
        }

        /* Or else return an empty VFB object. */
        $vCal = new Horde_iCalendar();
        $vFb = Horde_iCalendar::newComponent('vfreebusy', $vCal);
        $vFb->setAttribute('ORGANIZER', $email);

        return $vFb;
    }

    /**
     * Searches address books for the freebusy URL for a given email address.
     *
     * @param string $email  The email address to look for.
     *
     * @return mixed  The url on success or false on failure.
     */
    function getUrl($email)
    {
        $sources = $GLOBALS['prefs']->getValue('search_sources');
        $sources = empty($sources) ? array() : explode("\t", $sources);

        $result = $GLOBALS['registry']->call('contacts/getField',
                                             array($email, 'freebusyUrl', $sources, true, true));
        if (is_a($result, 'PEAR_Error')) {
            return $result;
        } elseif (is_array($result)) {
            return array_shift($result);
        } else {
            return $result;
        }
    }

}