module Colorizer
  extend self
  
    def colorize(object)
      # Inspired by Jeremy Ruten (http://stackoverflow.com/questions/1698318/ruby-generate-a-random-hex-color)
      hash = object.hash # hash an object, returns a Fixnum
      trimmed_hash = hash & 0xffffff # trim the hash to the size of 6 hex digits (& is bit-wise AND)
      hex_code = "%06x" % trimmed_hash # format as at least 6 hex digits, pad with zeros
      "##{hex_code}"
    end
  
    def colorize_similarly(object, saturation, lightness)
      rnd = ((send(options[:field]).hash * 7) % 100) * 0.01
      hsl_to_rgb(rnd, saturation, lightness)
    end
  
    private

    def hsl_to_rgb(h, sl, l)
      r = l
      g = l
      b = l
      v = (l <= 0.5) ? (l * (1.0 + sl)) : (l + sl - l * sl);
      if v > 0
        m = l + l - v
        sv = (v - m) / v
        h *= 6.0
        sextant = h.floor
        fract = h - sextant
        vsf = v * sv * fract
        mid1 = m + vsf
        mid2 = v - vsf
        case sextant
        when 0
          r = v
          g = mid1
          b = m
        when 1
          r = mid2
          g = v
          b = m
        when 2
          r = m
          g = v
          b = mid1
        when 3
          r = m
          g = mid2
          b = v
        when 4
          r = mid1
          g = m
          b = v
        when 5
          r = v
          g = m
          b = mid2
        end
      end
      "##{hex_color_component(r)}#{hex_color_component(g)}#{hex_color_component(b)}"
    end

   def hex_color_component(i)
     (i * 255).floor.to_s(16).rjust(2, '0')
   end

end