jdxv.rb

#!/usr/bin/env ruby

EXCLUDE_DIRECTORY_PATTERN = /\A\d{4}-\d{2}-\d{2}\z/

files = Dir["*/*"].reject {|filename|
  File.dirname(filename).match(EXCLUDE_DIRECTORY_PATTERN)
}

directories = Dir["*"].reject {|dirname|
  dirname.match(EXCLUDE_DIRECTORY_PATTERN)
}

abort "ファイル数がおかしい" unless directories.size == files.size
abort "ファイルじゃないやつが混ざってる" unless files.all? {|filename| File.file?(filename) }
abort "ディレクトリじゃないやつが混ざってる" unless directories.all? {|dirname| File.directory?(dirname) }

birthdates = files.map {|filename|
  File.birthtime(filename).strftime("%F")
}
tempdir = birthdates.uniq.sort_by{|birthdate|
  birthdates.count(birthdate)
}.last
Dir.mkdir(tempdir)

files.each do |filename|
  basename = File.basename(filename)
  dirname = File.dirname(filename)
  File.rename(filename, "#{tempdir}/#{basename}")
  Dir.rmdir(dirname)
end