#!/usr/bin/env perl6

# FIXME: stdin support with lines()
# FIXME: --help and -h support

sub from-timestamp(Int \timestamp) {
  sub formatter($_) {
    sprintf '%04d-%02d-%02d %02d:%02d:%02d',
    .year, .month, .day,
    .hour, .minute, .second,
  }
  given DateTime.new(+timestamp, :&formatter) {
    when .Date.DateTime == $_ { return .Date }
    default { return $_ }
  }
}

sub from-date-string(Str $date, Str $time?) {
  my $d = Date.new($date);
  if $time {
    my ( $hour, $minute, $second ) = $time.split(':');
    return DateTime.new(date => $d, :$hour, :$minute, :$second);
  } else {
    return $d.DateTime;
  }
}

# FIXME: add test
multi sub convert(Int \timestamp) {
  from-timestamp(+timestamp);
}

# FIXME: add test
multi sub convert(Str $date where { try Date.new($_) }, Str $time?) {
  from-date-string($date, $time).posix;
}

# FIXME: add test
#| Convert timestamp to ISO date
multi sub MAIN(Int \timestamp) {
  say convert(+timestamp);
}

# FIXME: add test
#| Convert ISO date to timestamp
multi sub MAIN(Str $date where { try Date.new($_) }, Str $time?) {
  say convert($date, $time);
}

# multi sub MAIN() {
#   for lines() -> $line {

#   }
# }

#| Run internal tests
multi sub MAIN('test') is hidden-from-USAGE {
  use Test;
  plan 2;
  subtest 'timestamp', {
    plan 2;
    is-deeply from-timestamp(1450915200), Date.new('2015-12-24'),
    'Date';;
    my $dt = from-timestamp(1450915201);
    is $dt, "2015-12-24 00:00:01",
    'DateTime with string formatting';
  };
  subtest 'from-date-string', {
    plan 2;
    is from-date-string('2015-12-24').posix, 1450915200,
    'one argument';
    is from-date-string('2015-12-24', '00:00:01').posix,
    1450915201,
    'two arguments';
  };
}