class Sass::Script::Color

def alpha
  @attrs[:alpha]
end

def alpha?
  alpha < 1
end

def blue
  hsl_to_rgb!
  @attrs[:blue]
end

def div(other)
  if other.is_a?(Sass::Script::Number) || other.is_a?(Sass::Script::Color)
    piecewise(other, :/)
  else
    super
  end
end

def eq(other)
  Sass::Script::Bool.new(
    other.is_a?(Color) && rgb == other.rgb && alpha == other.alpha)
end

def green
  hsl_to_rgb!
  @attrs[:green]
end

def hex_str
  red, green, blue = rgb.map { |num| num.to_s(16).rjust(2, '0') }
  "##{red}#{green}#{blue}"
end

def hsl
  [hue, saturation, lightness].freeze
end

def hsl_to_rgb!
  return if @attrs[:red] && @attrs[:blue] && @attrs[:green]
  h = @attrs[:hue] / 360.0
  s = @attrs[:saturation] / 100.0
  l = @attrs[:lightness] / 100.0
  # Algorithm from the CSS3 spec: http://www.w3.org/TR/css3-color/#hsl-color.
  m2 = l <= 0.5 ? l * (s + 1) : l + s - l * s
  m1 = l * 2 - m2
  @attrs[:red], @attrs[:green], @attrs[:blue] = [
    hue_to_rgb(m1, m2, h + 1.0/3),
    hue_to_rgb(m1, m2, h),
    hue_to_rgb(m1, m2, h - 1.0/3)
  ].map {|c| (c * 0xff).round}
end

def hue
  rgb_to_hsl!
  @attrs[:hue]
end

def hue_to_rgb(m1, m2, h)
  h += 1 if h < 0
  h -= 1 if h > 1
  return m1 + (m2 - m1) * h * 6 if h * 6 < 1
  return m2 if h * 2 < 1
  return m1 + (m2 - m1) * (2.0/3 - h) * 6 if h * 3 < 2
  return m1
end

def initialize(attrs, allow_both_rgb_and_hsl = false)
  super(nil)
  if attrs.is_a?(Array)
    unless (3..4).include?(attrs.size)
      raise ArgumentError.new("Color.new(array) expects a three- or four-element array")
    end
    red, green, blue = attrs[0...3].map {|c| c.to_i}
    @attrs = {:red => red, :green => green, :blue => blue}
    @attrs[:alpha] = attrs[3] ? attrs[3].to_f : 1
  else
    attrs = attrs.reject {|k, v| v.nil?}
    hsl = [:hue, :saturation, :lightness] & attrs.keys
    rgb = [:red, :green, :blue] & attrs.keys
    if !allow_both_rgb_and_hsl && !hsl.empty? && !rgb.empty?
      raise ArgumentError.new("Color.new(hash) may not have both HSL and RGB keys specified")
    elsif hsl.empty? && rgb.empty?
      raise ArgumentError.new("Color.new(hash) must have either HSL or RGB keys specified")
    elsif !hsl.empty? && hsl.size != 3
      raise ArgumentError.new("Color.new(hash) must have all three HSL values specified")
    elsif !rgb.empty? && rgb.size != 3
      raise ArgumentError.new("Color.new(hash) must have all three RGB values specified")
    end
    @attrs = attrs
    @attrs[:hue] %= 360 if @attrs[:hue]
    @attrs[:alpha] ||= 1
  end
  [:red, :green, :blue].each do |k|
    next if @attrs[k].nil?
    @attrs[k] = @attrs[k].to_i
    next if (0..255).include?(@attrs[k])
    raise Sass::SyntaxError.new("#{k.to_s.capitalize} value must be between 0 and 255")
  end
  [:saturation, :lightness].each do |k|
    next if @attrs[k].nil?
    @attrs[k] = 0 if @attrs[k] < 0.00001 && @attrs[k] > -0.00001
    @attrs[k] = 100 if @attrs[k] - 100 < 0.00001 && @attrs[k] - 100 > -0.00001
    next if (0..100).include?(@attrs[k])
    raise Sass::SyntaxError.new("#{k.to_s.capitalize} must be between 0 and 100")
  end
  unless (0..1).include?(@attrs[:alpha])
    raise Sass::SyntaxError.new("Alpha channel must between 0 and 1")
  end
end

def inspect
  alpha? ? rgba_str : hex_str
end

def lightness
  rgb_to_hsl!
  @attrs[:lightness]
end

def minus(other)
  if other.is_a?(Sass::Script::Number) || other.is_a?(Sass::Script::Color)
    piecewise(other, :-)
  else
    super
  end
end

def mod(other)
  if other.is_a?(Sass::Script::Number) || other.is_a?(Sass::Script::Color)
    piecewise(other, :%)
  else
    raise NoMethodError.new(nil, :mod)
  end
end

def piecewise(other, operation)
  other_num = other.is_a? Number
  if other_num && !other.unitless?
    raise Sass::SyntaxError.new("Cannot add a number with units (#{other}) to a color (#{self}).") 
  end
  result = []
  for i in (0...3)
    res = rgb[i].send(operation, other_num ? other.value : other.rgb[i])
    result[i] = [ [res, 255].min, 0 ].max
  end
  if !other_num && other.alpha != alpha
    raise Sass::SyntaxError.new("Alpha channels must be equal: #{self} #{operation} #{other}")
  end
  with(:red => result[0], :green => result[1], :blue => result[2])
end

def plus(other)
  if other.is_a?(Sass::Script::Number) || other.is_a?(Sass::Script::Color)
    piecewise(other, :+)
  else
    super
  end
end

def red
  hsl_to_rgb!
  @attrs[:red]
end

def rgb
  [red, green, blue].freeze
end

def rgb_to_hsl!
  return if @attrs[:hue] && @attrs[:saturation] && @attrs[:lightness]
  r, g, b = [:red, :green, :blue].map {|k| @attrs[k] / 255.0}
  # Algorithm from http://en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV
  max = [r, g, b].max
  min = [r, g, b].min
  d = max - min
  h =
    case max
    when min; 0
    when r; 60 * (g-b)/d
    when g; 60 * (b-r)/d + 120
    when b; 60 * (r-g)/d + 240
    end
  l = (max + min)/2.0
  s =
    if max == min
      0
    elsif l < 0.5
      d/(2*l)
    else
      d/(2 - 2*l)
    end
  @attrs[:hue] = h % 360
  @attrs[:saturation] = s * 100
  @attrs[:lightness] = l * 100
end

def rgba_str
  "rgba(#{rgb.join(', ')}, #{alpha % 1 == 0.0 ? alpha.to_i : alpha})"
end

def saturation
  rgb_to_hsl!
  @attrs[:saturation]
end

def smallest
  small_hex_str = hex_str.gsub(/^#(.)\1(.)\2(.)\3$/, '#\1\2\3')
  return small_hex_str unless (color = HTML4_COLORS_REVERSE[rgb]) &&
    color.size <= small_hex_str.size
  return color
end

def times(other)
  if other.is_a?(Sass::Script::Number) || other.is_a?(Sass::Script::Color)
    piecewise(other, :*)
  else
    raise NoMethodError.new(nil, :times)
  end
end

def to_s(opts = {})
  return rgba_str if alpha?
  return smallest if options[:style] == :compressed
  return HTML4_COLORS_REVERSE[rgb] if HTML4_COLORS_REVERSE[rgb]
  hex_str
end

def value
  Haml::Util.haml_warn <<END
ECATION WARNING:
Sass::Script::Color #value attribute is deprecated and will be
ved in version 3.2. Use the #rgb attribute instead.
  rgb
end

def with(attrs)
  attrs = attrs.reject {|k, v| v.nil?}
  hsl = !([:hue, :saturation, :lightness] & attrs.keys).empty?
  rgb = !([:red, :green, :blue] & attrs.keys).empty?
  if hsl && rgb
    raise ArgumentError.new("Color#with may not have both HSL and RGB keys specified")
  end
  if hsl
    [:hue, :saturation, :lightness].each {|k| attrs[k] ||= send(k)}
  elsif rgb
    [:red, :green, :blue].each {|k| attrs[k] ||= send(k)}
  else
    # If we're just changing the alpha channel,
    # keep all the HSL/RGB stuff we've calculated
    attrs = @attrs.merge(attrs)
  end
  attrs[:alpha] ||= alpha
  Color.new(attrs, :allow_both_rgb_and_hsl)
end