# -*- coding: utf-8 -*-
#
#--
# Copyright (C) 2009 Thomas Leitner <t_leitner@gmx.at>
#
# This file is part of kramdown.
#
# kramdown is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#++
#

module Kramdown

  # The base extension class.
  #
  # This class provides implementations for the default extensions defined in the kramdown
  # specification.
  #
  # An extension is a method called <tt>parse_EXTNAME</tt> where +EXTNAME+ is the extension name.
  # These methods are called with three parameters:
  #
  # [+parser+]
  #    The parser instance from which the extension method is called.
  # [+opts+]
  #    A hash containing the options set in the extension.
  # [+body+]
  #    A string containing the body of the extension. If no body is available, this is +nil+.
  class Extension

    # Just ignore everything and do nothing.
    def parse_comment(parser, opts, body)
      nil
    end

    # Add the body (if available) as <tt>:raw</tt> Element to the +parser.tree+.
    def parse_nomarkdown(parser, opts, body)
      parser.tree.children << Element.new(:raw, body) if body.kind_of?(String)
    end

    # Update the document options with the options set in +opts+.
    def parse_options(parser, opts, body)
      if val = opts.delete('auto_ids')
        parser.doc.options[:auto_ids] = boolean_value(val)
      end
      if val = opts.delete('filter_html')
        parser.doc.options[:filter_html] = val.split(/\s+/)
      end
      if val = opts.delete('footnote_nr')
        parser.doc.options[:footnote_nr] = Integer(val) rescue parser.doc.options[:footnote_nr]
      end
      if val = opts.delete('parse_block_html')
        parser.doc.options[:parse_block_html] = boolean_value(val)
      end
      if val = opts.delete('parse_span_html')
        parser.doc.options[:parse_span_html] = boolean_value(val)
      end
      opts.each {|k,v| parser.warning("Unknown kramdown options '#{k}'")}
    end

    def boolean_value(val)
      val.downcase.strip != 'false' && !val.empty?
    end

  end

end