class ClockTime

# File lib/clock_time.rb, line 19
def initialize(hour, min)
  @hour = hour
  @minute = min
  if !valid_hour? || !valid_minute?
    raise ArgumentError, 'invalid clock time'
  end
end

# File lib/clock_time.rb, line 10
def parse(string)
  if string =~ /\A(\d{2})[^\d]?(\d{2})\z/
    new($1.to_i, $2.to_i)
  else
    raise ArgumentError, 'invalid clock time'
  end
end

# File lib/clock_time.rb, line 56
def +(augend)
  if augend.is_a?(self.class)
    augend = augend.to_duration
  end
  to_duration + augend
end

# File lib/clock_time.rb, line 63
def -(minuend)
  if minuend.is_a?(self.class)
    minuend = minuend.to_duration
  end
  to_duration - minuend
end

# File lib/clock_time.rb, line 52
def <=>(clock_time)
  to_duration <=> clock_time.to_duration
end

# File lib/clock_time.rb, line 36
def next_time(base_time)
  t = replace_time(base_time)
  return t + 1.day if t < base_time
  t
end

# File lib/clock_time.rb, line 42
def prev_time(base_time)
  t = replace_time(base_time)
  return t - 1.day if t > base_time
  t
end

# File lib/clock_time.rb, line 48
def replace_time(time)
  time.change(hour: @hour, min: @minute)
end

# File lib/clock_time.rb, line 27
def to_duration
  @hour.hours + @minute.minutes
end

# File lib/clock_time.rb, line 31
def to_time(date)
  midnight = date.to_time
  replace_time(midnight)
end

# File lib/clock_time.rb, line 70
def valid_hour?
  return false unless @hour.is_a?(Integer)
  return true if @hour >= 0 && @hour <= 24
  false
end

# File lib/clock_time.rb, line 76
def valid_minute?
  return false unless @minute.is_a?(Integer)
  return true if @minute >= 0 && @minute <= 60
  false
end