Given today's date and a weekday find the date of that weekday in the future (or today)

gistfile1.rb

require 'time'

DAYS = {
  "Sun" => 0,
  "Mon" => 1,
  "Tue" => 2,
  "Wed" => 3,
  "Thu" => 4,
  "Fri" => 5,
  "Sat" => 6
}
DAY_IN_SECONDS = 24 * 60 * 60

def date_for_day(day)
  now = Time.new

  difference = DAYS[day] - now.wday
  difference += 7 if difference < 0

  now + difference * DAY_IN_SECONDS
end

p "Thu: " + date_for_day('Thu').to_s
p "Fri: " + date_for_day('Fri').to_s
p "Sat: " + date_for_day('Sat').to_s
p "Sun: " + date_for_day('Sun').to_s
p "Mon: " + date_for_day('Mon').to_s
p "Tue: " + date_for_day('Tue').to_s
p "Wed: " + date_for_day('Wed').to_s