<?php
  
  namespace Sabre\VObject;
  
  /**
   * This class helps with generating FREEBUSY reports based on existing sets of
   * objects.
   *
   * It only looks at VEVENT and VFREEBUSY objects from the sourcedata, and
   * generates a single VFREEBUSY object.
   *
   * VFREEBUSY components are described in RFC5545, The rules for what should
   * go in a single freebusy report is taken from RFC4791, section 7.10.
   *

   * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
   * @author Evert Pot (http://evertpot.com/)

   * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
   */
  class FreeBusyGenerator {
  
      /**
       * Input objects
       *
       * @var array
       */
      protected $objects;
  
      /**
       * Start of range
       *
       * @var DateTime|null
       */
      protected $start;
  
      /**
       * End of range
       *
       * @var DateTime|null
       */
      protected $end;
  
      /**
       * VCALENDAR object
       *
       * @var Component
       */
      protected $baseObject;
  
      /**
       * Creates the generator.
       *
       * Check the setTimeRange and setObjects methods for details about the
       * arguments.
       *
       * @param DateTime $start
       * @param DateTime $end
       * @param mixed $objects
       * @return void
       */
      public function __construct(\DateTime $start = null, \DateTime $end = null, $objects = null) {
  
          if ($start && $end) {
              $this->setTimeRange($start, $end);
          }
  
          if ($objects) {
              $this->setObjects($objects);
          }
  
      }
  
      /**
       * Sets the VCALENDAR object.
       *
       * If this is set, it will not be generated for you. You are responsible
       * for setting things like the METHOD, CALSCALE, VERSION, etc..
       *
       * The VFREEBUSY object will be automatically added though.
       *
       * @param Component $vcalendar
       * @return void
       */
      public function setBaseObject(Component $vcalendar) {
  
          $this->baseObject = $vcalendar;
  
      }
  
      /**
       * Sets the input objects
       *
       * You must either specify a valendar object as a strong, or as the parse
       * Component.
       * It's also possible to specify multiple objects as an array.
       *
       * @param mixed $objects
       * @return void
       */
      public function setObjects($objects) {
  
          if (!is_array($objects)) {
              $objects = array($objects);
          }
  
          $this->objects = array();
          foreach($objects as $object) {
  
              if (is_string($object)) {
                  $this->objects[] = Reader::read($object);
              } elseif ($object instanceof Component) {
                  $this->objects[] = $object;
              } else {
                  throw new \InvalidArgumentException('You can only pass strings or \\Sabre\\VObject\\Component arguments to setObjects');
              }
  
          }
  
      }
  
      /**
       * Sets the time range
       *
       * Any freebusy object falling outside of this time range will be ignored.
       *
       * @param DateTime $start
       * @param DateTime $end
       * @return void
       */
      public function setTimeRange(\DateTime $start = null, \DateTime $end = null) {
  
          $this->start = $start;
          $this->end = $end;
  
      }
  
      /**
       * Parses the input data and returns a correct VFREEBUSY object, wrapped in
       * a VCALENDAR.
       *
       * @return Component
       */
      public function getResult() {
  
          $busyTimes = array();
  
          foreach($this->objects as $object) {
  
              foreach($object->getBaseComponents() as $component) {
  
                  switch($component->name) {
  
                      case 'VEVENT' :
  
                          $FBTYPE = 'BUSY';
                          if (isset($component->TRANSP) && (strtoupper($component->TRANSP) === 'TRANSPARENT')) {
                              break;
                          }
                          if (isset($component->STATUS)) {
                              $status = strtoupper($component->STATUS);
                              if ($status==='CANCELLED') {
                                  break;
                              }
                              if ($status==='TENTATIVE') {
                                  $FBTYPE = 'BUSY-TENTATIVE';
                              }
                          }
  
                          $times = array();
  
                          if ($component->RRULE) {
  
                              $iterator = new RecurrenceIterator($object, (string)$component->uid);
                              if ($this->start) {
                                  $iterator->fastForward($this->start);
                              }
  
                              $maxRecurrences = 200;
  
                              while($iterator->valid() && --$maxRecurrences) {
  
                                  $startTime = $iterator->getDTStart();
                                  if ($this->end && $startTime > $this->end) {
                                      break;
                                  }
                                  $times[] = array(
                                      $iterator->getDTStart(),
                                      $iterator->getDTEnd(),
                                  );
  
                                  $iterator->next();
  
                              }
  
                          } else {
  
                              $startTime = $component->DTSTART->getDateTime();
                              if ($this->end && $startTime > $this->end) {
                                  break;
                              }
                              $endTime = null;
                              if (isset($component->DTEND)) {
                                  $endTime = $component->DTEND->getDateTime();
                              } elseif (isset($component->DURATION)) {
                                  $duration = DateTimeParser::parseDuration((string)$component->DURATION);
                                  $endTime = clone $startTime;
                                  $endTime->add($duration);
                              } elseif ($component->DTSTART->getDateType() === Property\DateTime::DATE) {
                                  $endTime = clone $startTime;
                                  $endTime->modify('+1 day');
                              } else {
                                  // The event had no duration (0 seconds)
                                  break;
                              }
  
                              $times[] = array($startTime, $endTime);
  
                          }
  
                          foreach($times as $time) {
  
                              if ($this->end && $time[0] > $this->end) break;
                              if ($this->start && $time[1] < $this->start) break;
  
                              $busyTimes[] = array(
                                  $time[0],
                                  $time[1],
                                  $FBTYPE,
                              );
                          }
                          break;
  
                      case 'VFREEBUSY' :
                          foreach($component->FREEBUSY as $freebusy) {
  
                              $fbType = isset($freebusy['FBTYPE'])?strtoupper($freebusy['FBTYPE']):'BUSY';
  
                              // Skipping intervals marked as 'free'
                              if ($fbType==='FREE')
                                  continue;
  
                              $values = explode(',', $freebusy);
                              foreach($values as $value) {
                                  list($startTime, $endTime) = explode('/', $value);
                                  $startTime = DateTimeParser::parseDateTime($startTime);
  
                                  if (substr($endTime,0,1)==='P' || substr($endTime,0,2)==='-P') {
                                      $duration = DateTimeParser::parseDuration($endTime);
                                      $endTime = clone $startTime;
                                      $endTime->add($duration);
                                  } else {
                                      $endTime = DateTimeParser::parseDateTime($endTime);
                                  }
  
                                  if($this->start && $this->start > $endTime) continue;
                                  if($this->end && $this->end < $startTime) continue;
                                  $busyTimes[] = array(
                                      $startTime,
                                      $endTime,
                                      $fbType
                                  );
  
                              }
  
  
                          }
                          break;
  
  
  
                  }
  
  
              }
  
          }
  
          if ($this->baseObject) {
              $calendar = $this->baseObject;
          } else {

              $calendar = Component::create('VCALENDAR');

              $calendar->version = '2.0';
              $calendar->prodid = '-//Sabre//Sabre VObject ' . Version::VERSION . '//EN';
              $calendar->calscale = 'GREGORIAN';
          }

          $vfreebusy = Component::create('VFREEBUSY');

          $calendar->add($vfreebusy);
  
          if ($this->start) {

              $dtstart = Property::create('DTSTART');

              $dtstart->setDateTime($this->start,Property\DateTime::UTC);
              $vfreebusy->add($dtstart);
          }
          if ($this->end) {

              $dtend = Property::create('DTEND');

              $dtend->setDateTime($this->end,Property\DateTime::UTC);
              $vfreebusy->add($dtend);
          }

          $dtstamp = Property::create('DTSTAMP');

          $dtstamp->setDateTime(new \DateTime('now'), Property\DateTime::UTC);
          $vfreebusy->add($dtstamp);
  
          foreach($busyTimes as $busyTime) {
  
              $busyTime[0]->setTimeZone(new \DateTimeZone('UTC'));
              $busyTime[1]->setTimeZone(new \DateTimeZone('UTC'));

              $prop = Property::create(

                  'FREEBUSY',
                  $busyTime[0]->format('Ymd\\THis\\Z') . '/' . $busyTime[1]->format('Ymd\\THis\\Z')
              );
              $prop['FBTYPE'] = $busyTime[2];
              $vfreebusy->add($prop);
  
          }
  
          return $calendar;
  
      }
  
  }