module CodeRay::ForRedCloth

def self.install
  gem 'RedCloth', '>= 4.0.3' if defined? gem
  require 'redcloth'
  unless RedCloth::VERSION.to_s >= '4.0.3'
    if defined? gem
      raise 'CodeRay.for_redcloth needs RedCloth version 4.0.3 or later. ' +
        "You have #{RedCloth::VERSION}. Please gem install RedCloth."
    else
      $".delete 'redcloth.rb'  # sorry, but it works
      require 'rubygems'
      return install  # retry
    end
  end
  unless RedCloth::VERSION.to_s >= '4.2.2'
    warn 'CodeRay.for_redcloth works best with RedCloth version 4.2.2 or later.'
  end
  RedCloth::TextileDoc.send :include, ForRedCloth::TextileDoc
  RedCloth::Formatters::HTML.module_eval do
    def unescape(html)  # :nodoc:
      replacements = {
        '&' => '&',
        '"' => '"',
        '>' => '>',
        '&lt;' => '<',
      }
      html.gsub(/&(?:amp|quot|[gl]t);/) { |entity| replacements[entity] }
    end
    undef code, bc_open, bc_close, escape_pre
    def code(opts)  # :nodoc:
      opts[:block] = true
      if !opts[:lang] && RedCloth::VERSION.to_s >= '4.2.0'
        # simulating pre-4.2 behavior
        if opts[:text].sub!(/\A\[(\w+)\]/, '')
          if CodeRay::Scanners[$1].lang == :text
            opts[:text] = $& + opts[:text]
          else
            opts[:lang] = $1
          end
        end
      end
      if opts[:lang] && !filter_coderay
        require 'coderay'
        @in_bc ||= nil
        format = @in_bc ? :div : :span
        opts[:text] = unescape(opts[:text]) unless @in_bc
        highlighted_code = CodeRay.encode opts[:text], opts[:lang], format
        highlighted_code.sub!(/\A<(span|div)/) { |m| m + pba(@in_bc || opts) }
        highlighted_code
      else
        "<code#{pba(opts)}>#{opts[:text]}</code>"
      end
    end
    def bc_open(opts)  # :nodoc:
      opts[:block] = true
      @in_bc = opts
      opts[:lang] ? '' : "<pre#{pba(opts)}>"
    end
    def bc_close(opts)  # :nodoc:
      opts = @in_bc
      @in_bc = nil
      opts[:lang] ? '' : "</pre>\n"
    end
    def escape_pre(text)  # :nodoc:
      if @in_bc ||= nil
        text
      else
        html_esc(text, :html_escape_preformatted)
      end
    end
  end
end

def bc_close(opts)  # :nodoc:
  opts = @in_bc
  @in_bc = nil
  opts[:lang] ? '' : "</pre>\n"
end

def bc_open(opts)  # :nodoc:
  opts[:block] = true
  @in_bc = opts
  opts[:lang] ? '' : "<pre#{pba(opts)}>"
end

def code(opts)  # :nodoc:
  opts[:block] = true
  if !opts[:lang] && RedCloth::VERSION.to_s >= '4.2.0'
    # simulating pre-4.2 behavior
    if opts[:text].sub!(/\A\[(\w+)\]/, '')
      if CodeRay::Scanners[$1].lang == :text
        opts[:text] = $& + opts[:text]
      else
        opts[:lang] = $1
      end
    end
  end
  if opts[:lang] && !filter_coderay
    require 'coderay'
    @in_bc ||= nil
    format = @in_bc ? :div : :span
    opts[:text] = unescape(opts[:text]) unless @in_bc
    highlighted_code = CodeRay.encode opts[:text], opts[:lang], format
    highlighted_code.sub!(/\A<(span|div)/) { |m| m + pba(@in_bc || opts) }
    highlighted_code
  else
    "<code#{pba(opts)}>#{opts[:text]}</code>"
  end
end

def escape_pre(text)  # :nodoc:
  if @in_bc ||= nil
    text
  else
    html_esc(text, :html_escape_preformatted)
  end
end

def unescape(html)  # :nodoc:
  replacements = {
    '&' => '&',
    '"' => '"',
    '>' => '>',
    '&lt;' => '<',
  }
  html.gsub(/&(?:amp|quot|[gl]t);/) { |entity| replacements[entity] }
end