require 'singleton'
require 'redcloth'
require 'cgi'

require 'glue/sanitize'

module Nitro

# Generalised Markup transformations.
#
# The expand methods evaluate (expand) the markup
# code to produce the final content. The compact
# methods reverse this process to create the original
# markup code. Not all markup transformations are
# reversible.
#
# When this library is included, the default PropertyUtils 
# implementation is overriden to add markup support.
#
# === Examples
#
# Define your custom markup methods like this:
#
# module MarkupMixin
#   def markup_simple
#      ...
#    end
#    def markup_special
#      ...
#    end
#
#   # maps the {{..}} macro
#    alias_method :sanitize, :markup_simple
#    # maps the {|..|} macro
#    alias_method :markup, :markup_special
#  end
#
# here comes the #{obj.body} # => prints the expanded version.
#
#  obj.body = markup(@params['body'])  

module Markup
private

  # The default markup method. You should override this method 
  # in your application to call your custom markup 
  # methods.

  def expand(str)
    if str
      xstr = str.dup
      xstr.gsub!(/</, '&lt;')    
      xstr.gsub!(/>/, '&gt;')
      return String.sanitize(xstr)
    end
    return nil
  end
  alias_method :sanitize, :expand

  # ...
  
  def expand_redcloth(str)
    if str
      return RedCloth.new(expand(str)).to_html
    end
    return nil
  end
  alias_method :markup, :expand_redcloth
      
  # Compact (reverse) the content to the origial markup
  # code. Not all markup transformations are reversible.
  # You should override this method in your application 
  # to call your custom markup methods.
  #
  # NOT IMPLEMENTED.
  
  def compact(str, meth = nil)
  end

  # Remove markup code from the input string.
  #
  # NOT IMPLEMENTED.
  
  def clear(str)
  end  
  
  def escape(str)
    CGI.escape(str.gsub(/ /, '_'))
  end

  def unescape(str)
    CGI.unescape(str.gsub(/_/, ' '))
  end      
  
  class << self
    # Helper method for manipulating the sanitize transformation.
    
    def setup_sanitize_transform(&block)
      self.send :define_method, :sanitize, block
    end
    alias_method :setup_sanitize_transformation, :setup_sanitize_transform

    # Helper method for manipulating the markup transformation.
    
    def setup_markup_transform(&block)
      self.send :define_method, :markup, block
    end
    alias_method :setup_markup_transformation, :setup_markup_transform
  end  
end

# An abstract Markup class.

class MarkupKit
  extend Markup
  include Markup
end

end

# * George Moschovitis <gm@navel.gr>