#!/usr/bin/env ruby
# vim: set ts=2 sw=2 et:

require 'find'
require 'colorize'
require 'fileutils'

class Merger
  def initialize
    @ind = 0
  end

  def merge_pdfs where
    pdf_basename = File.basename(File.expand_path(where))
		pdf_path = File.join(File.dirname(where), pdf_basename + '.pdf')
    outpdf_path = output_of pdf_path
    outpdf_dir = File.dirname(outpdf_path)
    FileUtils.mkdir_p outpdf_dir
    FileUtils.mkdir_p (output_of where)

    sub_pdfs = []
    Dir.chdir(where) do
	    sub_pdfs.concat Dir['*.pdf']
    end
    Dir.chdir(output_of where) do
	    sub_pdfs.concat Dir['*.pdf']
    end
    sub_pdfs.sort!

	  puts "#{indent} #{where.yellow} merge PDF"
	  sub_pdfs.each do |file|
	    puts "#{indent} #{where.yellow}   src = %s" % file
	  end
	  if sub_pdfs.size == 0 then
		  puts "#{indent} #{where.yellow}" + " no PDF found in subtree !".red + " skipping merge."
	  else
	    pdfs = sub_pdfs.map do |file|
	      if File.exist? File.join(where, file) then File.join(where, file)
        else File.join(output_of(where), file)
        end
      end
		  puts "#{indent} #{pdf_path.green} merged"
		  system "pdftk", *pdfs, "cat", "output", outpdf_path
	  end
  end

  def recurse where
	  puts "#{indent} #{where.yellow} begin recursing_dir"
    indent_more
	  Find.find(where) do |path|
      next unless FileTest.directory?(path)
		  next if File.basename(path) == "_build"
		  next if path == where
		  next if path == "."
		  recurse path
		  Find.prune
	  end
    indent_less
	  puts "#{indent} #{where.yellow} end recursing_dir"
	  puts "#{indent} #{where.yellow} begin merging_pdfs"
	  merge_pdfs where
	  puts "#{indent} #{where.yellow} end merging_pdfs"
  end

  def run where
    FileUtils.rm_rf "_build"
    recurse where
  end

  private

  def output_of where
    File.join('_build', where)
  end

  def indent
    ("  " * @ind)
  end
  def indent_more
    @ind += 1
  end

  def indent_less
    @ind -= 1
  end

end

app = Merger.new
if ARGV.size > 0 and File.directory? ARGV[0] then
  app.run ARGV[0]
else
  puts "Usage: #{$0} directory"
end