# encoding: utf-8

#--

#   Copyright (C) 2009 Johan Sørensen

#

#   This program is free software: you can redistribute it and/or modify

#   it under the terms of the GNU Affero 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 Affero General Public License for more details.

#

#   You should have received a copy of the GNU Affero General Public License

#   along with this program.  If not, see <http://www.gnu.org/licenses/>.

#++

require "zlib"

class MarkupRenderer

  class NotProcessedYetError < StandardError; end

  WRAPPER_NAME = "markdown-wrapper".freeze

  PRE_TAG_EXTRATION_KEY = "gts-markup-renderer".freeze

  def initialize(content, options = {})

    @content = content.to_s

    @options = options

    @options[:markdown] ||= [:smart]

    @markdown = nil

  end

  def markdown

    raise NotProcessedYetError unless @markdown

    @markdown

  end

  def to_html

    pre_process

    @markdown = RDiscount.new(@content, *@options[:markdown])

    post_process(@markdown.to_html)

  end

  def pre_process

    # Extract <pre> tags

    pre_tag_content = {}

    @content.gsub!(/(<pre>.*?<\/pre>)/im) do |pre|

      crc = Zlib.crc32(pre)

      pre_tag_content[crc] = pre

      "$#{PRE_TAG_EXTRATION_KEY}-#{crc}$"

    end

    # Convert windows lineendings

    @content.gsub!(/\r\n?/, "\n")

    # Convert any single newlines to space-space-newline

    # so markdown will break them

    @content.gsub!(/([^\n]\n)(?=[^\n])/) do |m|

      m.gsub!(/^(.+)$/, '\1  ')

    end

    # re-insert the extracted <pre> tag content

    @content.gsub!(/\$#{PRE_TAG_EXTRATION_KEY}-(\d+)\$/) do

      pre_tag_content[$1.to_i]

    end

    @content

  end

  def post_process(text)

    if @options[:wrapper].blank?

      text

    else

      if @options[:wrapper] == true

        "<div class=\"#{WRAPPER_NAME}\">\n#{text}</div>\n"

      else

        "<div class=\"#{@options[:wrapper]} #{WRAPPER_NAME}\">\n#{text}</div>\n"

      end

    end

  end

end