module Zodiac
  module Finder
    YEAR = 2011
    
    class << self
      def date_for(month, day)
        DateTime.new(YEAR, month, day)
      end
      
      def range_for(month_start, day_start, month_end, day_end)
        start, ending = date_for(month_start, day_start), date_for(month_end, day_end)
        SimpleRange.new(start, ending)
      end
    end
    
    RANGES = {
      range_for(1,  1,  1,  20) => :capricorn,
      range_for(1,  21, 2,  19) => :aquarius,
      range_for(2,  20, 3,  20) => :pisces,
      range_for(3,  21, 4,  20) => :aries,
      range_for(4,  21, 5,  21) => :taurus,
      range_for(5,  22, 6,  21) => :gemini,
      range_for(6,  22, 7,  22) => :cancer,
      range_for(7,  23, 8,  21) => :leo,
      range_for(8,  22, 9,  23) => :virgo,
      range_for(9,  24, 10, 23) => :libra,
      range_for(10, 24, 11, 22) => :scorpio,
      range_for(11, 23, 12, 22) => :sagittarius,
      range_for(12, 23, 12, 31) => :capricorn
    }
    
    SIGN_IDS = {
      :aries        => 1,
      :taurus       => 2,
      :gemini       => 3,
      :cancer       => 4,
      :leo          => 5,
      :virgo        => 6,
      :libra        => 7,
      :scorpio      => 8,
      :sagittarius  => 9,
      :capricorn    => 10,
      :aquarius     => 11,
      :pisces       => 12
    }
    
    def self.sign_for(date)
      I18n.t!("zodiac.#{self.sign_symbol_for date}")
    end
    
    def self.sign_id_for(date)
      SIGN_IDS[self.sign_symbol_for date]
    end
  private
    def self.sign_symbol_for(date)
      RANGES.each do |range, sign|
        if range.days.include? date_for(date[:month], date[:day])
          return sign
        end
      end
      
      raise ArgumentError
    end
  end
end