class TZInfo::TZDataTransition

def <=>(transition)
  if @at_utc == transition.at_utc
    0
  elsif @at_utc.nil?
    -1
  elsif transition.nil?
    1
  else       
    @at_utc - transition.at_utc
  end
end

def clone_with_at(at_utc)
  TZDataTransition.new(at_utc, @utc_offset, @std_offset, @zone_id)
end

def datetime_constructor(datetime)      
  if (1970..2037).include?(datetime.year)
    "#{Time.utc(datetime.year, datetime.mon, datetime.mday, datetime.hour, datetime.min, datetime.sec).to_i}"
  else
    "#{datetime.ajd.numerator}, #{datetime.ajd.denominator}"                    
  end
end

def initialize(at_utc, utc_offset, std_offset, zone_id)
  @at_utc = at_utc
  @utc_offset = utc_offset
  @std_offset = std_offset
  @zone_id = zone_id
  @offset_name = nil
end

def to_s
  "At #{at_utc} UTC switch to UTC offset #{@utc_offset} with std offset #{@std_offset}, zone id #{@zone_id}"
end

def total_offset
  @utc_offset + @std_offset
end

def write(file)        
  if @at_utc
    file.puts "tz.transition #{@at_utc.year}, #{@at_utc.mon}, :#{@offset_name}, #{datetime_constructor(@at_utc)}" 
  end        
end