require 'sass/constant/literal'

module Sass::Constant
  class Color < Literal
  
    REGEXP = /\##{"([0-9a-f]{1,2})" * 3}/
  
    def parse(value)
      @value = value.scan(REGEXP)[0].map { |num| num.ljust(2, 'f').to_i(16) }
    end
    
    def plus(other)
      if other.is_a? Sass::Constant::String
        Sass::Constant::String.from_value(self.to_s + other.to_s)
      else
        piecewise(other, :+)
      end
    end
    
    def minus(other)
      if other.is_a? Sass::Constant::String
        raise NoMethodError.new(nil, :minus)
      else
        piecewise(other, :-)
      end
    end
    
    def times(other)
      if other.is_a? Sass::Constant::String
        raise NoMethodError.new(nil, :times)
      else
        piecewise(other, :*)
      end
    end
    
    def div(other)
      if other.is_a? Sass::Constant::String
        raise NoMethodError.new(nil, :div)
      else
        piecewise(other, :/)
      end
    end
    
    def mod(other)
      if other.is_a? Sass::Constant::String
        raise NoMethodError.new(nil, :mod)
      else
        piecewise(other, :%)
      end
    end
    
    def to_s
      red, green, blue = @value.map { |num| num.to_s(16).rjust(2, '0') }
      "##{red}#{green}#{blue}"
    end
    
    protected
    
    def self.filter_value(value)
      value.map { |num| num.to_i }
    end
    
    private
    
    def piecewise(other, operation)
      other_num = other.is_a? Number
      other_val = other.value
    
      rgb = []
      for i in (0...3)
        res = @value[i].send(operation, other_num ? other_val : other_val[i])
        rgb[i] = [ [res, 255].min, 0 ].max
      end
      Color.from_value(rgb)
    end
  end
end