# encoding: utf-8
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# to you under the Apache License, Version 2.0 (the
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#   http://www.apache.org/licenses/LICENSE-2.0
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module Selenium
  module WebDriver
    module Support
      class Color
        RGB_PATTERN = %r{^\s*rgb\(\s*(\d{1,3})\s*,
                          \s*(\d{1,3})\s*,
                          \s*(\d{1,3})\s*\)\s*$}x
        RGB_PCT_PATTERN = %r{^\s*rgb\(\s*(\d{1,3}|\d{1,2}\.\d+)%\s*,
                              \s*(\d{1,3}|\d{1,2}\.\d+)%\s*,
                              \s*(\d{1,3}|\d{1,2}\.\d+)%\s*\)\s*$}x
        RGBA_PATTERN = %r{^\s*rgba\(\s*(\d{1,3})\s*,
                          \s*(\d{1,3})\s*,
                          \s*(\d{1,3})\s*,
                          \s*(0|1|0\.\d+)\s*\)\s*$}x
        RGBA_PCT_PATTERN = %r{^\s*rgba\(\s*(\d{1,3}|\d{1,2}\.\d+)
                              %\s*,\s*(\d{1,3}|\d{1,2}\.\d+)
                              %\s*,\s*(\d{1,3}|\d{1,2}\.\d+)
                              %\s*,\s*(0|1|0\.\d+)\s*\)\s*$}x
        HEX_PATTERN = /#(\h{2})(\h{2})(\h{2})/
        HEX3_PATTERN = /#(\h)(\h)(\h)/
        HSL_PATTERN = %r{^\s*hsl\(\s*(\d{1,3})\s*,
                         \s*(\d{1,3})%\s*,
                         \s*(\d{1,3})%\s*\)\s*$}x
        HSLA_PATTERN = %r{^\s*hsla\(\s*(\d{1,3})\s*,
                          \s*(\d{1,3})%\s*,
                          \s*(\d{1,3})%\s*,
                          \s*(0|1|0\.\d+)\s*\)\s*$}x

        attr_reader :red, :green, :blue, :alpha

        def self.from_string(str)
          case str
          when RGB_PATTERN
            new Regexp.last_match(1), Regexp.last_match(2), Regexp.last_match(3)
          when RGB_PCT_PATTERN
            array = [Regexp.last_match(1), Regexp.last_match(2), Regexp.last_match(3)]
            new(*array.map { |e| Float(e) / 100 * 255 })
          when RGBA_PATTERN
            new Regexp.last_match(1), Regexp.last_match(2), Regexp.last_match(3), Regexp.last_match(4)
          when RGBA_PCT_PATTERN
            array = [Regexp.last_match(1), Regexp.last_match(2), Regexp.last_match(3)]
            new(*array.map { |e| Float(e) / 100 * 255 } << Regexp.last_match(4))
          when HEX_PATTERN
            array = [Regexp.last_match(1), Regexp.last_match(2), Regexp.last_match(3)]
            new(*array.map { |e| e.to_i(16) })
          when HEX3_PATTERN
            array = [Regexp.last_match(1), Regexp.last_match(2), Regexp.last_match(3)]
            new(*array.map { |e| (e * 2).to_i(16) })
          when HSL_PATTERN, HSLA_PATTERN
            from_hsl(Regexp.last_match(1), Regexp.last_match(2), Regexp.last_match(3), Regexp.last_match(4))
          else
            raise ArgumentError, "could not convert #{str.inspect} into color"
          end
        end

        def self.from_hsl(h, s, l, a)
          h = Float(h) / 360
          s = Float(s) / 100
          l = Float(l) / 100
          a = Float(a || 1)

          if s == 0
            r = l
            g = r
            b = r
          else
            luminocity2 = (l < 0.5) ? l * (1 + s) : l + s - l * s
            luminocity1 = 2 * l - luminocity2

            r = hue_to_rgb(luminocity1, luminocity2, h + 1.0 / 3.0)
            g = hue_to_rgb(luminocity1, luminocity2, h)
            b = hue_to_rgb(luminocity1, luminocity2, h - 1.0 / 3.0)
          end

          new (r * 255).round, (g * 255).round, (b * 255).round, a
        end

        def self.hue_to_rgb(lum1, lum2, hue)
          hue += 1 if hue < 0.0
          hue -= 1 if hue > 1.0

          if hue < 1.0 / 6.0
            (lum1 + (lum2 - lum1) * 6.0 * hue)
          elsif hue < 1.0 / 2.0
            lum2
          elsif hue < 2.0 / 3.0
            lum1 + (lum2 - lum1) * ((2.0 / 3.0) - hue) * 6.0
          else
            lum1
          end
        end

        def initialize(red, green, blue, alpha = 1)
          @red = Integer(red)
          @green = Integer(green)
          @blue = Integer(blue)
          @alpha = Float(alpha)
        end

        def ==(other)
          return true if equal?(other)
          return false unless other.is_a?(self.class)

          [red, green, blue, alpha] == [other.red, other.green, other.blue, other.alpha]
        end
        alias_method :eql?, :==

        def hash
          [red, green, blue, alpha].hash ^ self.class.hash
        end

        def rgb
          "rgb(#{red}, #{green}, #{blue})"
        end

        def rgba
          a = alpha == 1 ? '1' : alpha
          "rgba(#{red}, #{green}, #{blue}, #{a})"
        end

        def hex
          format '#%02x%02x%02x', red, green, blue
        end
      end # Color
    end # Support
  end # WebDriver
end # Selenium
