module Kramdown::Converter::SyntaxHighlighter::Rouge

def self.call(converter, text, lang, type, call_opts)
  opts = options(converter, type)
  call_opts[:default_lang] = opts[:default_lang]
  lexer = ::Rouge::Lexer.find_fancy(lang || opts[:default_lang], text)
  return nil if opts[:disable] || !lexer || lexer.tag == "plaintext"
  opts[:css_class] ||= 'highlight' # For backward compatibility when using Rouge 2.0
  formatter = formatter_class(opts).new(opts)
  formatter.format(lexer.lex(text))
end

def self.formatter_class(opts = {})
  case formatter = opts[:formatter]
  when Class
    formatter
  when /\A[[:upper:]][[:alnum:]_]*\z/
    ::Rouge::Formatters.const_get(formatter)
  else
    # Available in Rouge 2.0 or later
    ::Rouge::Formatters::HTMLLegacy
  end
rescue NameError
  # Fallback to Rouge 1.x
  ::Rouge::Formatters::HTML
end

def self.options(converter, type)
  prepare_options(converter)
  converter.data[:syntax_highlighter_rouge][type]
end

def self.prepare_options(converter)
  return if converter.data.key?(:syntax_highlighter_rouge)
  cache = converter.data[:syntax_highlighter_rouge] = {}
  opts = converter.options[:syntax_highlighter_opts].dup
  span_opts = (opts.delete(:span) || {}).dup
  block_opts = (opts.delete(:block) || {}).dup
  [span_opts, block_opts].each do |hash|
    hash.keys.each do |k|
      hash[k.kind_of?(String) ? Kramdown::Options.str_to_sym(k) : k] = hash.delete(k)
    end
  end
  cache[:span] = opts.merge(span_opts).update(wrap: false)
  cache[:block] = opts.merge(block_opts)
end