<?php
// -------------------------------------------
// outdoor lights control -- server
// copyright: Jannik Beyerstedt | https://jannikbeyerstedt.de
// license: http://www.gnu.org/licenses/gpl-3.0.txt GPLv3 License
// -------------------------------------------

$config_filename = 'config_times.json';
$timeRegex = '/^((2[0-3]|1[0-9]|0[0-9]|[^0-9][0-9]):([0-5][0-9]|[0-9]))/';
$sunsetTrue = 90+50/60; /* "true" sunrise/ sunset */
$sunsetCivilian = 96;   /* Civilian Twilight */
$sunsetNautical = 102;  /* Nauticla Twilight */

$sun_zenith = $sunsetCivilian;
$timezone = "Europe/Berlin";

class LightStatus {
  public $state = true;   /* current state: lights on/off */
  public $changeTime = 1; /* minutes until next state change */
  public $waitTime = 0;   /* minutes the client should wait until next request */

  public $times = null;   /* config array */

  public $sunrise, $sunset; /* time string hh:mm */
  public $isNight;          /* bool, true if it's at night */

  function __construct() {
    return $this->readTimes();
  }

  /* return string for the service API */
  function __toString() {
    return 's='.(int)$this->state.' t='.$this->waitTime;
  }

  /* re-calculate values */
  public function update() {
    global $sun_zenith;
    global $timezone;

    // calculate sunset and sunrise times
    date_default_timezone_set($timezone);
    $gmtOffset = date("Z") / (60*60);

    $this->sunrise = date_sunrise(time(), SUNFUNCS_RET_STRING, $this->times['position']['lat'], $this->times['position']['long'], $sun_zenith, $gmtOffset);
    $this->sunset = date_sunset(time(), SUNFUNCS_RET_STRING, $this->times['position']['lat'], $this->times['position']['long'], $sun_zenith, $gmtOffset);

    $sunrise = date_sunrise(time(), SUNFUNCS_RET_TIMESTAMP, $this->times['position']['lat'], $this->times['position']['long'], $sun_zenith, $gmtOffset);
    $sunset = date_sunset(time(), SUNFUNCS_RET_TIMESTAMP, $this->times['position']['lat'], $this->times['position']['long'], $sun_zenith, $gmtOffset);

    // -- first check, if an instant-on time is set --
    if ($this->times['instant-on'] != null) {
      if ($this->times['instant-on'] > time()) {
        $this->state = true;
        $this->changeTime = (int)(($this->times['instant-on']-time())/60);
        $this->waitTime = $this->changeTime;

        return true;

      } else {
        // reset instant-on
        $this->state = false;
        $this->times['instant-on'] = null;
        $this->saveTimes();
      }
    }

    // -- otherwise check, if the ruleset requires the lights on --
    // first check, if it's at daylight
    $currentTime = time();
    if ($currentTime < $sunrise || $currentTime > $sunset) {
      $this->isNight = true;

      // it's night: check, if we are in one of the time intervals
      for ($i = 1; $i <= 3; $i++) {
        $timeKey = 'time'.$i;

        $startTime = strtotime($this->times[$timeKey]['on']);
        $stopTime = strtotime($this->times[$timeKey]['off']);
        if ($stopTime < $startTime) {
          $stopTime += (24*60*60);
          if (($stopTime - $currentTime) > (24*60*60)) {
            $startTime -= (24*60*60);
            $stopTime -= (24*60*60);
          }
        }

        if ($currentTime > $startTime && $currentTime < $stopTime) {
          $this->state = true;
          $this->changeTime = (int)(($stopTime - $currentTime) / 60);
          $this->waitTime = 1;
          return true;
        } elseif ( ($startTime - $currentTime) < (12*60*60) || ($startTime+(24*60*60) - $currentTime) < (12*60*60) ) {
          // right before the next time interval
          $this->state = false;
          if ($currentTime < $startTime) {
            $this->changeTime = (int)( ($startTime - $currentTime) / 60 );
          } else {
            $this->changeTime = (int)( (($startTime+(24*60*60)) - $currentTime) / 60 );
          }
          $this->waitTime = 1;
          return true;
        }
      }

      $this->state = false;
      $this->changeTime = (int)(($stopTime - $currentTime) / 60);
      $this->waitTime = 1;
      return true;

    } else if ($currentTime > $sunrise && $currentTime < $sunset) {
      $this->isNight = false;

      // it's day: nothing else check
      $this->state = false;
      $this->changeTime = (int)(($sunset - $currentTime) / 60);
      $this->waitTime = $this->changeTime;
      return true;

    } else {
      echo "ERROR: invalid time of day.";
      return 'ERROR';
    }
  }

  /* save modified $times array to config file */
  public function saveTimes() {
    global $config_filename;

    if (empty($this->times)) {
      return 'ERROR';
    } else {
      $json_string = json_encode($this->times, JSON_PRETTY_PRINT);
      file_put_contents($config_filename, $json_string);
      return true;
    }
  }


  private function readTimes() {
    global $config_filename;

    $file_content = file_get_contents($config_filename);
    if ($file_content == FALSE) {
      return 'ERROR';
    } else {
      $this->times = json_decode($file_content, true);
      return true;
    }
  }
}


function checkTimesInput($times) {
  global $timeRegex;

  if (!isset($_POST['time1-start']) || !preg_match($timeRegex, $_POST['time1-start'])) {
    return "time1-start not valid";
  }
  if (!isset($_POST['time1-stop']) || !preg_match($timeRegex, $_POST['time1-stop'])) {
    return "time1-stop not valid";
  }
  if (!isset($_POST['time2-start']) || !preg_match($timeRegex, $_POST['time2-start'])) {
    return "time2-start not valid";
  }
  if (!isset($_POST['time2-stop']) || !preg_match($timeRegex, $_POST['time2-stop'])) {
    return "time2-stop not valid";
  }
  if (!isset($_POST['time3-start']) || !preg_match($timeRegex, $_POST['time3-start'])) {
    return "time3-start not valid";
  }
  if (!isset($_POST['time3-stop']) || !preg_match($timeRegex, $_POST['time3-stop'])) {
    return "time3-stop not valid";
  }
  return true;
}
?>