#!/bin/sh

set -u
set -e

# Your Settings
#
SWITCH_ON_CMD="touch /tmp/tv_light"
SWITCH_OFF_CMD="rm -f /tmp/tv_light"
USE_DAYLIGHT="yes"
LATITUDE="52.000000"
LONGITUDE="11.000000"
# http://search.cpan.org/~rkhill/DateTime-Event-Sunrise-0.0501/lib/DateTime/Event/Sunrise.pm#METHODS
ALTITUDE="-0.833"
#
# End of user config
# apt-get install libdatetime-event-sunrise-perl



JOB_ID_DIR="${4}/activity/$(basename ${0}).data"
JOB_ID_FILE="${JOB_ID_DIR}/jobid"



daylight(){
  export LATITUDE
  export LONGITUDE
  export ALTITUDE

sunsetsunrise="$(perl <<'EOF' 2> /dev/null
  use DateTime;
  use DateTime::Event::Sunrise;
  use DateTime::Format::Strptime;

  my $latitude = $ENV{'LATITUDE'};
  my $longitude = $ENV{'LONGITUDE'};
  my $altitude = $ENV{'ALTITUDE'};

  my $sunrise = DateTime::Event::Sunrise ->sunrise (longitude => $longitude, latitude => $latitude, altitude => $altitude, iteration => '1');
  my $sunset = DateTime::Event::Sunrise ->sunset (longitude => $longitude, latitude => $latitude, altitude => $altitude, iteration => '1');

  my $strp = DateTime::Format::Strptime->new(pattern => '%H:%M %Y-%m-%d');
  my $day_set = DateTime::SpanSet->from_sets(start_set => $sunrise, end_set => $sunset);
  if ($day_set->contains(DateTime->now())) {
    print $strp->format_datetime($sunset->next(DateTime->now(time_zone=>'local')));
    exit 1;
  } else {
    print $strp->format_datetime($sunrise->next(DateTime->now(time_zone=>'local')));
    exit 0;
  }
EOF
)"

  err=$?

  [ -z "${sunsetsunrise}" ] && return 2

  if [ ${err} = 0 ]; then
    echo "${sunsetsunrise}"
    return 0
  elif [ ${err} = 1 ]; then
    echo "${sunsetsunrise}"
    return 1
  else
    return 2
  fi
}



delete_job(){
  if [ -f "${JOB_ID_FILE}" ]; then
    JOB_ID="$(cat ${JOB_ID_FILE})"
    atrm ${JOB_ID} 2> /dev/null
    rm -f "${JOB_ID_FILE}"
  fi
}



create_job(){
  JOB_ID_TMP="$(echo "rm -f "${JOB_ID_FILE}"; ${1}" | at ${2} 2>&1)"
  JOB_ID="$(echo "${JOB_ID_TMP}" | tr -d '\n' | sed 's/^.*job \([0-9]*\).*$/\1/')"
  mkdir -p "${JOB_ID_DIR}"
  echo "${JOB_ID}" > ${JOB_ID_FILE}
}



switch_tv_light(){
  if [ "${1}" = "on" ]; then
    if [ "${USE_DAYLIGHT}" = "yes" ]; then
      delete_job
      sunsetsunrise="$(daylight)" && light=0 || light=$?
      if [ "${light}" = "1" ]; then
        # daylight now, shedule "light on" for later
        create_job "${SWITCH_ON_CMD}" "${sunsetsunrise}"
      elif [ "${light}" = "0" ]; then
        eval ${SWITCH_ON_CMD}
        # no daylight now, shedule "light off" for later
        create_job "${SWITCH_OFF_CMD}" "${sunsetsunrise}"
      else
        # Some error
        eval ${SWITCH_OFF_CMD}
      fi
    else
      eval ${SWITCH_ON_CMD}
    fi
  else
    [ "${USE_DAYLIGHT}" = "yes" ] && delete_job
    eval ${SWITCH_OFF_CMD}
  fi
}



case "${1}" in
  startup)
    delete_job
  ;;
  started)
    [ "${2}" = "true" ] && switch_tv_light on
  ;;
  shutdown)
    switch_tv_light off
  ;;
  running)
    if [ "${2}" = "true" ]; then
      switch_tv_light on
    else
      switch_tv_light off
    fi
  ;;
esac

exit 0