class Chronic::Scalar

def self.make_year(year, bias)
  return year if year.to_s.size > 2
  start_year = Chronic.time_class.now.year - bias
  century = (start_year / 100) * 100
  full_year = century + year
  full_year += 100 if full_year < start_year
  full_year
end

def self.scan(tokens, options)
  tokens.each_index do |i|
    if t = scan_for_scalars(tokens[i], tokens[i + 1]) then tokens[i].tag(t) end
    if t = scan_for_days(tokens[i], tokens[i + 1]) then tokens[i].tag(t) end
    if t = scan_for_months(tokens[i], tokens[i + 1]) then tokens[i].tag(t) end
    if t = scan_for_years(tokens[i], tokens[i + 1], options) then tokens[i].tag(t) end
  end
end

def self.scan_for_days(token, post_token)
  if token.word =~ /^\d\d?$/
    toi = token.word.to_i
    unless toi > 31 || toi < 1 || (post_token && DAY_PORTIONS.include?(post_token.word))
      return ScalarDay.new(toi)
    end
  end
end

def self.scan_for_months(token, post_token)
  if token.word =~ /^\d\d?$/
    toi = token.word.to_i
    unless toi > 12 || toi < 1 || (post_token && DAY_PORTIONS.include?(post_token.word))
      return ScalarMonth.new(toi)
    end
  end
end

def self.scan_for_scalars(token, post_token)
  if token.word =~ /^\d*$/
    unless post_token && DAY_PORTIONS.include?(post_token.word)
      return Scalar.new(token.word.to_i)
    end
  end
end

def self.scan_for_years(token, post_token, options)
  if token.word =~ /^([1-9]\d)?\d\d?$/
    unless post_token && DAY_PORTIONS.include?(post_token.word)
      year = make_year(token.word.to_i, options[:ambiguous_year_future_bias])
      return ScalarYear.new(year.to_i)
    end
  end
end

def to_s
  'scalar'
end