require "html_filter"

class TextileFilter < HTMLFilter
  # Replace h[1-6]. Tjo with <h[1-6]>Tjo</h[1-6]>
  (1..6).each do |i|
    tag = "h#{i}"

    define_rule(on_one_line(chars("#{tag}. ") + capture)) do |match|
      content_tag tag, match.captures.first
    end
  end

  star = char("*")

  # Replace *tjo* with <strong>tjo</strong>
  define_rule(star + capture + star) do |match|
    content_tag :strong, match.captures.first
  end

  define_rule(/!(.*?)!/) do |match|
    tag :img, :src => match.captures.first
  end

  at = char("@")

  # Replace @tjo@ with <code>tjo</code>
  define_rule(at + capture + at) do |match|
    content_tag :code, match.captures.first
  end

  define_rule(quoted(capture) + char(":") + capture + white_space) do |match|
    content_tag :a, match.captures.first, :href => match.captures.second
  end

  # define_rule(/\n\n+/) { "\n\n" }

  define_rule(on_one_line(capture + newline)) do |match|
    if enclosing_tag(match.captures.first)
      match
    else
      match.to_s + tag(:br) + "\n"
    end
  end

  define_rule(/(\n\n|\A)(.*?)(\n\n|\Z)/) do |match|
    if is_block_level_tag? enclosing_tag(match)
      # Don't put block level tags in <p>s
      match
    else
      "\n\n" + content_tag(:p, match.captures.second) + "\n\n"
    end
  end
end