#!rsc
# RouterOS script: global-functions
# Copyright (c) 2013-2018 Christian Hesse <mail@eworm.de>
#
# global functions

# return pseudo-random string for PSK
:global GeneratePSK do={
  :local date $1;

  :global "daily-psk-secrets";

  :local months {
    "jan"; "feb"; "mar"; "apr"; "may"; "jun";
    "jul"; "aug"; "sep"; "oct"; "nov"; "dec"
  }
  :local monthtbl {
    0; 3; 3; 6; 1; 4; 6; 2; 5; 0; 3; 5
  }

  :local monthstr [ :pick $date 0 3 ];
  :local month;
  :local day [ :pick $date 4 6 ];
  :local century [ :pick $date 7 9 ];
  :local year [ :pick $date 9 11 ];

  # get numeric value for month
  :for mindex from=0 to=[ :len $months ] do={
    :if ([ :pick $months $mindex ] = $monthstr) do={
      :set month $mindex;
    }
  }

  # calculate day of week
  :local sum 0;
  :set sum ($sum + (2 * (3 - ($century - (($century / 4) * 4)))));
  :set sum ($sum + ($year / 4));
  :set sum ($sum + $year + $day);
  :set sum ($sum + $month);
  :set sum ($sum - (($sum / 7) * 7));

  :local return ([ :pick [ :pick $"daily-psk-secrets" 0 ] ($day - 1) ] . \
    [ :pick [ :pick $"daily-psk-secrets" 1 ] $month ] . \
    [ :pick [ :pick $"daily-psk-secrets" 2 ] $sum ]);

  :return $return;
}