# Redmine - project management software
# Copyright (C) 2006-2008  Jean-Philippe Lang
#
# This program 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 2
# 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, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

require 'redcloth3'
require 'coderay'

module Redmine
  module WikiFormatting
    module Textile
      class Formatter < RedCloth3
        include ActionView::Helpers::TagHelper
        
        # auto_link rule after textile rules so that it doesn't break !image_url! tags
        RULES = [:textile, :block_markdown_rule, :inline_auto_link, :inline_auto_mailto, :inline_toc, :inline_macros]
        
        def initialize(*args)
          super
          self.hard_breaks=true
          self.no_span_caps=true
          self.filter_styles=true
        end
        
        def to_html(*rules, &block)
          @toc = []
          @macros_runner = block
          super(*RULES).to_s
        end
  
      private
  
        # Patch for RedCloth.  Fixed in RedCloth r128 but _why hasn't released it yet.
        # <a href="http://code.whytheluckystiff.net/redcloth/changeset/128">http://code.whytheluckystiff.net/redcloth/changeset/128</a>
        def hard_break( text ) 
          text.gsub!( /(.)\n(?!\n|\Z|>| *([#*=]+(\s|$)|[{|]))/, "\\1<br />" ) if hard_breaks
        end
        
        # Patch to add code highlighting support to RedCloth
        def smooth_offtags( text )
          unless @pre_list.empty?
            ## replace <pre> content
            text.gsub!(/<redpre#(\d+)>/) do
              content = @pre_list[$1.to_i]
              if content.match(/<code\s+class="(\w+)">\s?(.+)/m)
                content = "<code class=\"#{$1} CodeRay\">" + 
                  CodeRay.scan($2, $1.downcase).html(:escape => false, :line_numbers => :inline)
              end
              content
            end
          end
        end
        
        # Patch to add 'table of content' support to RedCloth
        def textile_p_withtoc(tag, atts, cite, content)
          # removes wiki links from the item
          toc_item = content.gsub(/(\[\[([^\]\|]*)(\|([^\]]*))?\]\])/) { $4 || $2 }
          # sanitizes titles from links
          # see redcloth3.rb, same as "#{pre}#{text}#{post}"
          toc_item.gsub!(LINK_RE) { [$2, $4, $9].join }
          # sanitizes image links from titles
          toc_item.gsub!(IMAGE_RE) { [$5].join }
          # removes styles
          # eg. %{color:red}Triggers% => Triggers
          toc_item.gsub! %r[%\{[^\}]*\}([^%]+)%], '\\1'
          
          # replaces non word caracters by dashes
          anchor = toc_item.gsub(%r{[^\w\s\-]}, '').gsub(%r{\s+(\-+\s*)?}, '-')
  
          unless anchor.blank?
            if tag =~ /^h(\d)$/
              @toc << [$1.to_i, anchor, toc_item]
            end
            atts << " id=\"#{anchor}\""
            content = content + "<a href=\"##{anchor}\" class=\"wiki-anchor\">&para;</a>"
          end
          textile_p(tag, atts, cite, content)
        end
  
        alias :textile_h1 :textile_p_withtoc
        alias :textile_h2 :textile_p_withtoc
        alias :textile_h3 :textile_p_withtoc
        
        def inline_toc(text)
          text.gsub!(/<p>\{\{([<>]?)toc\}\}<\/p>/i) do
            div_class = 'toc'
            div_class << ' right' if $1 == '>'
            div_class << ' left' if $1 == '<'
            out = "<ul class=\"#{div_class}\">"
            @toc.each do |heading|
              level, anchor, toc_item = heading
              out << "<li class=\"heading#{level}\"><a href=\"##{anchor}\">#{toc_item}</a></li>\n"
            end
            out << '</ul>'
            out
          end
        end
        
        MACROS_RE = /
                      (!)?                        # escaping
                      (
                      \{\{                        # opening tag
                      ([\w]+)                     # macro name
                      (\(([^\}]*)\))?             # optional arguments
                      \}\}                        # closing tag
                      )
                    /x unless const_defined?(:MACROS_RE)
        
        def inline_macros(text)
          text.gsub!(MACROS_RE) do
            esc, all, macro = $1, $2, $3.downcase
            args = ($5 || '').split(',').each(&:strip)
            if esc.nil?
              begin
                @macros_runner.call(macro, args)
              rescue => e
                "<div class=\"flash error\">Error executing the <strong>#{macro}</strong> macro (#{e})</div>"
              end || all
            else
              all
            end
          end
        end
        
        AUTO_LINK_RE = %r{
                        (                          # leading text
                          <\w+.*?>|                # leading HTML tag, or
                          [^=<>!:'"/]|             # leading punctuation, or 
                          ^                        # beginning of line
                        )
                        (
                          (?:https?://)|           # protocol spec, or
                          (?:s?ftps?://)|
                          (?:www\.)                # www.*
                        )
                        (
                          (\S+?)                   # url
                          (\/)?                    # slash
                        )
                        ([^\w\=\/;\(\)]*?)               # post
                        (?=<|\s|$)
                       }x unless const_defined?(:AUTO_LINK_RE)
  
        # Turns all urls into clickable links (code from Rails).
        def inline_auto_link(text)
          text.gsub!(AUTO_LINK_RE) do
            all, leading, proto, url, post = $&, $1, $2, $3, $6
            if leading =~ /<a\s/i || leading =~ /![<>=]?/
              # don't replace URL's that are already linked
              # and URL's prefixed with ! !> !< != (textile images)
              all
            else
              # Idea below : an URL with unbalanced parethesis and
              # ending by ')' is put into external parenthesis
              if ( url[-1]==?) and ((url.count("(") - url.count(")")) < 0 ) )
                url=url[0..-2] # discard closing parenth from url
                post = ")"+post # add closing parenth to post
              end
              tag = content_tag('a', proto + url, :href => "#{proto=="www."?"http://www.":proto}#{url}", :class => 'external')
              %(#{leading}#{tag}#{post})
            end
          end
        end
  
        # Turns all email addresses into clickable links (code from Rails).
        def inline_auto_mailto(text)
          text.gsub!(/([\w\.!#\$%\-+.]+@[A-Za-z0-9\-]+(\.[A-Za-z0-9\-]+)+)/) do
            mail = $1
            if text.match(/<a\b[^>]*>(.*)(#{Regexp.escape(mail)})(.*)<\/a>/)
              mail
            else
              content_tag('a', mail, :href => "mailto:#{mail}", :class => "email")
            end
          end
        end
      end
    end
  end
end
