require('Time::Piece');

var seasons = %w(Chaos Discord Confusion Bureaucracy The\ Aftermath);
var week_days = %w(Sweetmorn Boomtime Pungenday Prickle-Prickle Setting\ Orange);

func ordinal (n) {
    "#{n}" + (n % 100 ~~ [11,12,13] ? 'th'
                                    : <th st nd rd th th th th th th>[n % 10])
}

func ddate(ymd) {
    var d = %s'Time::Piece'.strptime(ymd, '%Y-%m-%d');
    var yold = "in the YOLD #{d.year + 1166}";

    var day_of_year0 = d.day_of_year;

    if (d.is_leap_year) {
        return "St. Tib's Day, #{yold}" if ([d.mon, d.mday] == [2, 29]);
        day_of_year0-- if (day_of_year0 >= 60); # Compensate for St. Tib's Day
    }

    var weekday = week_days[day_of_year0 % week_days.len];
    var season = seasons[day_of_year0 / 73];
    var season_day = ordinal(day_of_year0 % 73 + 1);

    return "#{weekday}, the #{season_day} day of #{season} #{yold}";
}

%w(2010-07-22 2012-02-28 2012-02-29 2012-03-01).each { |ymd|
    say "#{ymd} is #{ddate(ymd)}"
}