class CodeRay::Scanners::CSS

def scan_tokens encoder, options
  states = Array(options[:state] || @state)
  value_expected = @value_expected
  
  until eos?
    
    if match = scan(/\s+/)
      encoder.text_token match, :space
      
    elsif case states.last
      when :initial, :media
        if match = scan(/(?>#{RE::Ident})(?!\()|\*/ox)
          encoder.text_token match, :type
          next
        elsif match = scan(RE::Class)
          encoder.text_token match, :class
          next
        elsif match = scan(RE::Id)
          encoder.text_token match, :constant
          next
        elsif match = scan(RE::PseudoClass)
          encoder.text_token match, :pseudo_class
          next
        elsif match = scan(RE::AttributeSelector)
          # TODO: Improve highlighting inside of attribute selectors.
          encoder.text_token match[0,1], :operator
          encoder.text_token match[1..-2], :attribute_name if match.size > 2
          encoder.text_token match[-1,1], :operator if match[-1] == ?]
          next
        elsif match = scan(/@media/)
          encoder.text_token match, :directive
          states.push :media_before_name
          next
        end
      
      when :block
        if match = scan(/(?>#{RE::Ident})(?!\()/ox)
          if value_expected
            encoder.text_token match, :value
          else
            encoder.text_token match, :key
          end
          next
        end
        
      when :media_before_name
        if match = scan(RE::Ident)
          encoder.text_token match, :type
          states[-1] = :media_after_name
          next
        end
      
      when :media_after_name
        if match = scan(/\{/)
          encoder.text_token match, :operator
          states[-1] = :media
          next
        end
      
      else
        #:nocov:
        raise_inspect 'Unknown state', encoder
        #:nocov:
        
      end
      
    elsif match = scan(/\/\*(?:.*?\*\/|\z)/m)
      encoder.text_token match, :comment
      
    elsif match = scan(/\{/)
      value_expected = false
      encoder.text_token match, :operator
      states.push :block
      
    elsif match = scan(/\}/)
      value_expected = false
      encoder.text_token match, :operator
      if states.last == :block || states.last == :media
        states.pop
      end
      
    elsif match = scan(/#{RE::String}/o)
      encoder.begin_group :string
      encoder.text_token match[0, 1], :delimiter
      encoder.text_token match[1..-2], :content if match.size > 2
      encoder.text_token match[-1, 1], :delimiter if match.size >= 2
      encoder.end_group :string
      
    elsif match = scan(/#{RE::Function}/o)
      encoder.begin_group :function
      start = match[/^\w+\(/]
      encoder.text_token start, :delimiter
      if match[-1] == ?)
        encoder.text_token match[start.size..-2], :content
        encoder.text_token ')', :delimiter
      else
        encoder.text_token match[start.size..-1], :content
      end
      encoder.end_group :function
      
    elsif match = scan(/(?: #{RE::Dimension} | #{RE::Percentage} | #{RE::Num} )/ox)
      encoder.text_token match, :float
      
    elsif match = scan(/#{RE::Color}/o)
      encoder.text_token match, :color
      
    elsif match = scan(/! *important/)
      encoder.text_token match, :important
      
    elsif match = scan(/(?:rgb|hsl)a?\([^()\n]*\)?/)
      encoder.text_token match, :color
      
    elsif match = scan(RE::AtKeyword)
      encoder.text_token match, :directive
      
    elsif match = scan(/ [+>:;,.=()\/] /x)
      if match == ':'
        value_expected = true
      elsif match == ';'
        value_expected = false
      end
      encoder.text_token match, :operator
      
    else
      encoder.text_token getch, :error
      
    end
    
  end
  
  if options[:keep_state]
    @state = states
    @value_expected = value_expected
  end
  
  encoder
end

def setup
  @state = :initial
  @value_expected = nil
end