<?php
  
  namespace Sabre\VObject\Property;
  
  use Sabre\VObject;
  
  /**
   * DateTime property
   *
   * This element is used for iCalendar properties such as the DTSTART property.
   * It basically provides a few helper functions that make it easier to deal
   * with these. It supports both DATE-TIME and DATE values.
   *
   * In order to use this correctly, you must call setDateTime and getDateTime to
   * retrieve and modify dates respectively.
   *
   * If you use the 'value' or properties directly, this object does not keep
   * reference and results might appear incorrectly.
   *

   * @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 DateTime extends VObject\Property {
  
      /**
       * Local 'floating' time
       */
      const LOCAL = 1;
  
      /**
       * UTC-based time
       */
      const UTC = 2;
  
      /**
       * Local time plus timezone
       */
      const LOCALTZ = 3;
  
      /**
       * Only a date, time is ignored
       */
      const DATE = 4;
  
      /**
       * DateTime representation
       *
       * @var \DateTime
       */
      protected $dateTime;
  
      /**
       * dateType
       *
       * @var int
       */
      protected $dateType;
  
      /**
       * Updates the Date and Time.
       *
       * @param \DateTime $dt
       * @param int $dateType
       * @return void
       */
      public function setDateTime(\DateTime $dt, $dateType = self::LOCALTZ) {
  
          switch($dateType) {
  
              case self::LOCAL :
                  $this->setValue($dt->format('Ymd\\THis'));
                  $this->offsetUnset('VALUE');
                  $this->offsetUnset('TZID');
                  $this->offsetSet('VALUE','DATE-TIME');
                  break;
              case self::UTC :
                  $dt->setTimeZone(new \DateTimeZone('UTC'));
                  $this->setValue($dt->format('Ymd\\THis\\Z'));
                  $this->offsetUnset('VALUE');
                  $this->offsetUnset('TZID');
                  $this->offsetSet('VALUE','DATE-TIME');
                  break;
              case self::LOCALTZ :
                  $this->setValue($dt->format('Ymd\\THis'));
                  $this->offsetUnset('VALUE');
                  $this->offsetUnset('TZID');
                  $this->offsetSet('VALUE','DATE-TIME');
                  $this->offsetSet('TZID', $dt->getTimeZone()->getName());
                  break;
              case self::DATE :
                  $this->setValue($dt->format('Ymd'));
                  $this->offsetUnset('VALUE');
                  $this->offsetUnset('TZID');
                  $this->offsetSet('VALUE','DATE');
                  break;
              default :
                  throw new \InvalidArgumentException('You must pass a valid dateType constant');
  
          }
          $this->dateTime = $dt;
          $this->dateType = $dateType;
  
      }
  
      /**
       * Returns the current DateTime value.
       *
       * If no value was set, this method returns null.
       *
       * @return \DateTime|null
       */
      public function getDateTime() {
  
          if ($this->dateTime)
              return $this->dateTime;
  
          list(
              $this->dateType,
              $this->dateTime
          ) = self::parseData($this->value, $this);
          return $this->dateTime;
  
      }
  
      /**
       * Returns the type of Date format.
       *
       * This method returns one of the format constants. If no date was set,
       * this method will return null.
       *
       * @return int|null
       */
      public function getDateType() {
  
          if ($this->dateType)
              return $this->dateType;
  
          list(
              $this->dateType,
              $this->dateTime,
          ) = self::parseData($this->value, $this);
          return $this->dateType;
  
      }
  
      /**

       * This method will return true, if the property had a date and a time, as
       * opposed to only a date.
       *
       * @return bool
       */
      public function hasTime() {
  
          return $this->getDateType()!==self::DATE;
  
      }
  
      /**

       * Parses the internal data structure to figure out what the current date
       * and time is.
       *
       * The returned array contains two elements:
       *   1. A 'DateType' constant (as defined on this class), or null.
       *   2. A DateTime object (or null)
       *
       * @param string|null $propertyValue The string to parse (yymmdd or
       *                                   ymmddThhmmss, etc..)
       * @param \Sabre\VObject\Property|null $property The instance of the
       *                                              property we're parsing.
       * @return array
       */
      static public function parseData($propertyValue, VObject\Property $property = null) {
  
          if (is_null($propertyValue)) {
              return array(null, null);
          }
  
          $date = '(?P<year>[1-2][0-9]{3})(?P<month>[0-1][0-9])(?P<date>[0-3][0-9])';
          $time = '(?P<hour>[0-2][0-9])(?P<minute>[0-5][0-9])(?P<second>[0-5][0-9])';
          $regex = "/^$date(T$time(?P<isutc>Z)?)?$/";
  
          if (!preg_match($regex, $propertyValue, $matches)) {
              throw new \InvalidArgumentException($propertyValue . ' is not a valid \DateTime or Date string');
          }
  
          if (!isset($matches['hour'])) {
              // Date-only
              return array(
                  self::DATE,
                  new \DateTime($matches['year'] . '-' . $matches['month'] . '-' . $matches['date'] . ' 00:00:00', new \DateTimeZone('UTC')),
              );
          }
  
          $dateStr =
              $matches['year'] .'-' .
              $matches['month'] . '-' .
              $matches['date'] . ' ' .
              $matches['hour'] . ':' .
              $matches['minute'] . ':' .
              $matches['second'];
  
          if (isset($matches['isutc'])) {
              $dt = new \DateTime($dateStr,new \DateTimeZone('UTC'));
              $dt->setTimeZone(new \DateTimeZone('UTC'));
              return array(
                  self::UTC,
                  $dt
              );
          }
  
          // Finding the timezone.
          $tzid = $property['TZID'];
          if (!$tzid) {
              // This was a floating time string. This implies we use the
              // timezone from date_default_timezone_set / date.timezone ini
              // setting.
              return array(
                  self::LOCAL,
                  new \DateTime($dateStr)
              );
          }
  
          // To look up the timezone, we must first find the VCALENDAR component.
          $root = $property;
          while($root->parent) {
              $root = $root->parent;
          }
          if ($root->name === 'VCALENDAR') {
              $tz = VObject\TimeZoneUtil::getTimeZone((string)$tzid, $root);
          } else {
              $tz = VObject\TimeZoneUtil::getTimeZone((string)$tzid);
          }
  
          $dt = new \DateTime($dateStr, $tz);
          $dt->setTimeZone($tz);
  
          return array(
              self::LOCALTZ,
              $dt
          );
  
      }
  
  }