module Rouge
  module Lexers
    class CSS < RegexLexer
      desc "Cascading Style Sheets, used to style web pages"

      tag 'css'
      filenames '*.css'
      mimetypes 'text/css'

      identifier = /[a-zA-Z0-9_-]+/
      number = /-?(?:[0-9]+(\.[0-9]+)?|\.[0-9]+)/

      def self.attributes
        @attributes ||= Set.new %w(
          azimuth background background-attachment background-color
          background-image background-position background-repeat
          border border-bottom border-bottom-color border-bottom-style
          border-bottom-width border-collapse border-color border-left
          border-left-color border-left-style border-left-width
          border-right border-right-color border-right-style
          border-right-width border-spacing border-style border-top
          border-top-color border-top-style border-top-width
          border-width bottom caption-side clear clip color content
          counter-increment counter-reset cue cue-after cue-before cursor
          direction display elevation empty-cells float font font-family
          font-size font-size-adjust font-stretch font-style font-variant
          font-weight height left letter-spacing line-height list-style
          list-style-image list-style-position list-style-type margin
          margin-bottom margin-left margin-right margin-top marker-offset
          marks max-height max-width min-height min-width opacity orphans
          outline outline-color outline-style outline-width overflow-x
          overflow-y padding padding-bottom padding-left padding-right
          padding-top page page-break-after page-break-before
          page-break-inside pause pause-after pause-before pitch
          pitch-range play-during position quotes richness right size
          speak speak-header speak-numeral speak-punctuation speech-rate
          src stress table-layout text-align text-decoration text-indent
          text-shadow text-transform top unicode-bidi vertical-align
          visibility voice-family volume white-space widows width
          word-spacing z-index
        )
      end

      def self.builtins
        @builtins ||= Set.new %w(
          above absolute always armenian aural auto avoid left bottom
          baseline behind below bidi-override blink block bold bolder
          both bottom capitalize center center-left center-right circle
          cjk-ideographic close-quote collapse condensed continuous crop
          cross crosshair cursive dashed decimal decimal-leading-zero
          default digits disc dotted double e-resize embed expanded
          extra-condensed extra-expanded fantasy far-left far-right fast
          faster fixed georgian groove hebrew help hidden hide high higher
          hiragana hiragana-iroha icon inherit inline inline-table inset
          inside invert italic justify katakana katakana-iroha landscape
          large larger left left-side leftwards level lighter line-through
          list-item loud low lower lower-alpha lower-greek lower-roman
          lowercase ltr medium message-box middle mix monospace n-resize
          narrower ne-resize no-close-quote no-open-quote no-repeat none
          normal nowrap nw-resize oblique once open-quote outset outside
          overline pointer portrait px relative repeat repeat-x repeat-y
          rgb ridge right right-side rightwards s-resize sans-serif scroll
          se-resize semi-condensed semi-expanded separate serif show
          silent slow slower small-caps small-caption smaller soft solid
          spell-out square static status-bar super sw-resize table-caption
          table-cell table-column table-column-group table-footer-group
          table-header-group table-row table-row-group text text-bottom
          text-top thick thin top transparent ultra-condensed
          ultra-expanded underline upper-alpha upper-latin upper-roman
          uppercase url visible w-resize wait wider x-fast x-high x-large
          x-loud x-low x-small x-soft xx-large xx-small yes
        )
      end

      def self.constants
        @constants ||= Set.new %w(
          indigo gold firebrick indianred yellow darkolivegreen
          darkseagreen mediumvioletred mediumorchid chartreuse
          mediumslateblue black springgreen crimson lightsalmon brown
          turquoise olivedrab cyan silver skyblue gray darkturquoise
          goldenrod darkgreen darkviolet darkgray lightpink teal
          darkmagenta lightgoldenrodyellow lavender yellowgreen thistle
          violet navy orchid blue ghostwhite honeydew cornflowerblue
          darkblue darkkhaki mediumpurple cornsilk red bisque slategray
          darkcyan khaki wheat deepskyblue darkred steelblue aliceblue
          gainsboro mediumturquoise floralwhite coral purple lightgrey
          lightcyan darksalmon beige azure lightsteelblue oldlace
          greenyellow royalblue lightseagreen mistyrose sienna lightcoral
          orangered navajowhite lime palegreen burlywood seashell
          mediumspringgreen fuchsia papayawhip blanchedalmond peru
          aquamarine white darkslategray ivory dodgerblue lemonchiffon
          chocolate orange forestgreen slateblue olive mintcream
          antiquewhite darkorange cadetblue moccasin limegreen saddlebrown
          darkslateblue lightskyblue deeppink plum aqua darkgoldenrod
          maroon sandybrown magenta tan rosybrown pink lightblue
          palevioletred mediumseagreen dimgray powderblue seagreen snow
          mediumblue midnightblue paleturquoise palegoldenrod whitesmoke
          darkorchid salmon lightslategray lawngreen lightgreen tomato
          hotpink lightyellow lavenderblush linen mediumaquamarine green
          blueviolet peachpuff
        )
      end

      # source: http://www.w3.org/TR/CSS21/syndata.html#vendor-keyword-history
      def self.vendor_prefixes
        @vendor_prefixes ||= Set.new %w(
          -ah- -atsc- -hp- -khtml- -moz- -ms- -o- -rim- -ro- -tc- -wap-
          -webkit- -xv- mso- prince-
        )
      end

      state :root do
        mixin :basics
        rule /{/, 'Punctuation', :stanza
        rule /:#{identifier}/, 'Name.Decorator'
        rule /\.#{identifier}/, 'Name.Class'
        rule /##{identifier}/, 'Name.Function'
        rule /@#{identifier}/, 'Keyword', :at_rule
        rule identifier, 'Name.Tag'
        rule %r([~^*!%&\[\]()<>|+=@:;,./?-]), 'Operator'
      end

      state :value do
        mixin :basics
        rule /url\(.*?\)/, 'Literal.String.Other'
        rule /#[0-9a-f]{1,6}/i, 'Literal.Number' # colors
        rule /#{number}(?:em|px|%|pt|pc|in|mm|m|ex|s)?\b/, 'Literal.Number'
        rule /[\[\]():\/.]/, 'Punctuation'
        rule /"(\\\\|\\"|[^"])*"/, 'Literal.String.Single'
        rule /'(\\\\|\\'|[^'])*'/, 'Literal.String.Double'
        rule(identifier) do |m|
          if self.class.constants.include? m[0]
            token 'Name.Constant'
          elsif self.class.builtins.include? m[0]
            token 'Name.Builtin'
          else
            token 'Name'
          end
        end
      end

      state :at_rule do
        rule /{(?=\s*#{identifier}\s*:)/m, 'Punctuation', :at_stanza
        rule /{/, 'Punctuation', :at_body
        rule /;/, 'Punctuation', :pop!
        mixin :value
      end

      state :at_body do
        mixin :at_content
        mixin :root
      end

      state :at_stanza do
        mixin :at_content
        mixin :stanza
      end

      state :at_content do
        rule /}/ do
          token 'Punctuation'
          pop!; pop!
        end
      end

      state :basics do
        rule /\s+/m, 'Text'
        rule %r(/\*(?:.*?)\*/)m, 'Comment'
      end

      state :stanza do
        mixin :basics
        rule /}/, 'Punctuation', :pop!
        rule /(#{identifier})(\s*)(:)/m do |m|
          if self.class.attributes.include? m[1]
            group 'Name.Label'
          elsif self.class.vendor_prefixes.any? { |p| m[1].start_with?(p) }
            group 'Name.Label'
          else
            group 'Name.Property'
          end

          group 'Text'
          group 'Punctuation'

          push :stanza_value
        end
      end

      state :stanza_value do
        rule /;/, 'Punctuation', :pop!
        rule(/(?=})/) { pop! }
        rule /!important\b/, 'Comment.Preproc'
        rule /^@.*?$/, 'Comment.Preproc'
        mixin :value
      end
    end
  end
end