require "date"
require "rd/rdfmt"
require "rd/rd2html-lib"

class RD2DiaryVisitor < RD::RD2HTMLVisitor
  BASE_LEVEL = 2

  WDAYS = ["日", "月", "火", "水", "木", "金", "土"]

  def apply_to_DocumentElement(element, content)
    result = format("<H2><A NAME=\"d%02d\">%d月%d日(%s)</A></H2>\n",
		    @date.day, @date.month, @date.day, WDAYS[@date.wday])
    result.concat(content.join(""))
    return result
  end

  def apply_to_Headline(element, title)
    anchor = refer(element)
    %Q[<H#{BASE_LEVEL+element.level}><A NAME="#{anchor}">#{title}</A>] +
      %Q[</H#{BASE_LEVEL+element.level}><!-- RDLabel: "#{element.label}" -->\n]
  end

  private
  
  def initialize(year, month, day)
    super()
    @date = Date.new(year, month, day)
  end

  def prepare_labels(tree, prefix = "label:")
    super(tree, format("d%d:%s", @date.day, prefix))
  end
end

class RD2DiaryFormatter
  def get_diary(file)
    cache = file + ".dat"
    if File.exist?(cache) &&
	File.mtime(cache) > File.mtime(file)
      open(cache) do |f|
	f.flock(File::LOCK_SH)
	return f.read
      end
    else
      result = format(file)
      open(cache, "w") do |f|
	f.flock(File::LOCK_EX)
	f.write(result)
      end
      return result
    end
  end

  private

  def format(file)
    year, month, day =
      file.scan(/(\d\d\d\d)(\d\d)\/(\d\d)/)[0].collect {|i| i.to_i} #/
    visitor = RD2DiaryVisitor.new(year, month, day)
    lines = []
    lines.push("=begin\n")
    open(file) do |f|
      f.flock(File::LOCK_SH)
      lines += f.readlines
    end
    lines.push("=end\n")
    tree = RD::RDTree.new(lines)
    return visitor.visit(tree)
  end
end