require 'fileutils'

POSIX_NAME_PREFIX = "emacs"

$user_count = 0
$users = []
$id_map = {}

#####################
# User manipulation #
#####################

class User
  attr_accessor :id, :path, :posixname

  def to_s
    "#{@id}, #{@path}"
  end
end

def get_user(id)
  $id_map[id]
end

def add_user(id)
  if not system("useradd -m #{POSIX_NAME_PREFIX}#{id}") then
    raise "User creation failed"
  end
  
  user = User.new
  user.id = id
  user.path = "/home/#{POSIX_NAME_PREFIX}#{id}"
  user.posixname = "#{POSIX_NAME_PREFIX}#{id}"
  $user_count += 1
  $users << user
  $id_map[id] = user

  FileUtils.mkdir "#{user.path}/.ssh"
  FileUtils.touch "#{user.path}/.ssh/authorized_keys"
  FileUtils.chown_R user.id, user.id, "#{user.path}/.ssh"
  
  user
end

def remove_user(id)
  system("userdel -r #{POSIX_NAME_PREFIX}#{id}")
  $user_count -= 1
end

####################
# Key manipulation #
####################

class SSHKey
  attr_accessor :cipher, :pubkey, :comment

  def initialize(cipher,pubkey,comment="")
    @cipher  = cipher
    @pubkey  = pubkey
    @comment = comment
  end

  def ==(o)
    o.class == self.class && o.attrs == attrs
  end
  
  def pretty
    "#{@cipher} #{@comment}"
  end
  
  def to_s
    "ssh-#{@cipher} #{@pubkey} #{@comment}"
  end

  def attrs
    [@cipher, @pubkey, @comment]
  end
end

def get_ssh_keyfile(user,mode,&block)
  file = File.open("#{user.path}/.ssh/authorized_keys",mode)
  return file unless block_given?
  yield(file)
ensure
  file.close
end

def get_ssh_pubkeys(user)
  extract_ssh_pubkeys("#{user.path}/.ssh/authorized_keys")
end

def add_ssh_pubkey(user,key)
  if not valid_pubkey? key then raise "Public key not valid" end
  get_ssh_keyfile(user,"a") do |key_file|
    key_file << "#{key.to_s}\n"
  end
end

def reset_pubkeys(user)
  FileUtils.rm "#{user.path}/.ssh/authorized_keys"
  FileUtils.touch "#{user.path}/.ssh/authorized_keys"
  FileUtils.chown_R user.id, user.id, "#{user.path}/.ssh"
end

def remove_ssh_pubkey(user,key)
  keys = get_ssh_pubkeys(user)
  reset_pubkeys(user)
  keys.each{ |k| unless k == key then add_ssh_pubkey(user,k) end}
end

def remove_ssh_pubkey_by_key
end

def remove_ssh_pubkey_by_comment
end

def valid_pubkey?(key)
  IO.popen("ssh-keygen -qlf -","r+") do |io|
    io.write key.to_s
    io.close_write
    io.read
  end
  if $?.to_i == 0
    true
  else
    false
  end
end

def extract_ssh_pubkeys(file)
  File.open(file,"r") do |f|
    f.read.split("\n").select{ |line| line[0..2] == "ssh" }.map{ |ks| k = ks.split(" "); SSHKey.new(k[0][4..6], k[1], k[2]) }
  end
end

##################


remove_user 5
add_user 5
add_ssh_pubkey(get_user(5), "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC7ZKN2fKcUQUaQqDjNCQQBSdqBVGX7lprNCJmceDBfybhbnuZJ8KvzJJIJIIbzqheW5BVCfkWJY6OgkpAumLWSRCS5n2+AnDHwQgpKDS93OeV+9/kattVtsVUBZaghymyJ2UfA0r918dkxcT9SZbNSl9raiDUUmj3JY8UM219BQP7BRqoZ6e/YZz9lO7ORy6yQT6fIMaVOaZcoDPr6oyNJfadm9POvS/Wl63onoRI9dzpHQG9RuHCcUhHJhkGtzY7GeRWc85WqA9Q4vYo0SK5Je9BG1cvAAVTfV+eYEJEiSDMwWj60roH0C3/ipmzxD/kWqg6YBJWL+XAyQkDnmbuD christoffermadsen@strawberry.thedevcave.net")