1 files changed, 44 insertions, 0 deletions
diff --git a/lib/banzai/color_parser.rb b/lib/banzai/color_parser.rb
new file mode 100644
index 00000000000..355c364b07b
--- /dev/null
+++ b/lib/banzai/color_parser.rb
@@ -0,0 +1,44 @@
+module Banzai
+  module ColorParser
+    ALPHA = /0(?:\.\d+)?|\.\d+|1(?:\.0+)?/ # 0.0..1.0
+    PERCENTS = /(?:\d{1,2}|100)%/ # 00%..100%
+    ALPHA_CHANNEL = /(?:,\s*(?:#{ALPHA}|#{PERCENTS}))?/
+    BITS = /\d{1,2}|1\d\d|2(?:[0-4]\d|5[0-5])/ # 00..255
+    DEGS = /-?\d+(?:deg)?/i # [-]digits[deg]
+    RADS = /-?(?:\d+(?:\.\d+)?|\.\d+)rad/i # [-](digits[.digits] OR .digits)rad
+    HEX_FORMAT = /\#(?:\h{3}|\h{4}|\h{6}|\h{8})/
+    RGB_FORMAT = %r{
+      (?:rgba?
+        \(
+          (?:
+            (?:(?:#{BITS},\s*){2}#{BITS})
+            |
+            (?:(?:#{PERCENTS},\s*){2}#{PERCENTS})
+          )
+          #{ALPHA_CHANNEL}
+        \)
+      )
+    }xi
+    HSL_FORMAT = %r{
+      (?:hsla?
+        \(
+          (?:#{DEGS}|#{RADS}),\s*#{PERCENTS},\s*#{PERCENTS}
+          #{ALPHA_CHANNEL}
+        \)
+      )
+    }xi
+
+    FORMATS = [HEX_FORMAT, RGB_FORMAT, HSL_FORMAT].freeze
+
+    COLOR_FORMAT = /\A(#{Regexp.union(FORMATS)})\z/ix
+
+    # Public: Analyzes whether the String is a color code.
+    #
+    # text - The String to be parsed.
+    #
+    # Returns the recognized color String or nil if none was found.
+    def self.parse(text)
+      text if COLOR_FORMAT =~ text
+    end
+  end
+end