convert.rb

#!/usr/bin/env ruby

require 'fileutils'
require "time"
require "openssl"

if ARGV.length < 2
  $stderr.puts "Error"
  exit 1
end

in_path = ARGV[0]
out_path = ARGV[1]

FileUtils.mkdir_p out_path

Dir.glob("#{in_path}/**") do |file|
  in_data = false
  out_data = ""
  File.open(file) do |r_io|
    while line = r_io.gets
      case line
      when /^---$/
        in_data = !in_data
        out_data << line
      when /^title:/
        out_data << line
      when /^categories:/
        out_data << line  unless in_data
      when /^layout:/
        out_data << line  unless in_data
      when /^date:/
        if in_data
          tm = Time.parse($_.split(":", 2)[1].strip)
          slug = OpenSSL::Digest::SHA1.hexdigest(tm.to_i.to_s + Time.now.to_s)

          filename_prefix = tm.strftime("%Y-%m-%d-")
          if File.basename(file).match(/#{filename_prefix}/).nil?
            $stderr.puts "Not match date: #{file} : #{tm.iso8601}"
          end

          out_data << "date: #{tm.iso8601}\n"
          out_data << "slug: #{slug}\n"
        else
          out_data << line
        end
      else
        out_data << line
      end
    end
  end

  base_name = File.basename(file, ".*")
  File.open("#{out_path}/#{base_name}.md", "w") do |w_io|
    w_io.puts out_data
  end
end