running_pace.rb

# first arg is goal time in either seconds or ##:##
# second arg is distance in meters (optional)
# EXAMPLE ruby running_pace.rb 15:30 5000

class Float
  def seconds_to_minutes
    "#{self.to_i/60}:#{(self.to_f%60.0).rjust}"
  end
  
  def rjust
    self.to_i.to_s.rjust(2,"0")
  end
end

goal_time_in_seconds = ARGV[0]
total_meters = ARGV[1].to_f > 0.0 ? ARGV[1].to_f : 5_000.0
raise "Need to pass goal time in seconds or in ##:##" if goal_time_in_seconds.nil? || goal_time_in_seconds.to_i == 0

if goal_time_in_seconds.to_s =~ /:/
  minutes,seconds = goal_time_in_seconds.split(":")
  goal_time_in_seconds = minutes.to_f*60.0 + seconds.to_f
else
  goal_time_in_seconds = goal_time_in_seconds.to_f
end

meters_per_second = total_meters / goal_time_in_seconds.to_f

split_200 = 200.0 / meters_per_second
split_400 = 400.0 / meters_per_second
split_600 = 600.0 / meters_per_second
split_800 = 800.0 / meters_per_second
split_1609 = 1609.0 / meters_per_second


puts "goal time for #{total_meters} meters is #{goal_time_in_seconds.seconds_to_minutes} or #{goal_time_in_seconds} seconds"
puts "200m splits are #{split_200}"
puts "400m splits are #{split_400} or #{split_400.seconds_to_minutes}"
puts "600m splits are #{split_600} or #{split_600.seconds_to_minutes}"
puts "800m splits are #{split_800.seconds_to_minutes}"
puts "1609m splits are #{split_1609.seconds_to_minutes}"