require 'fileutils'

POSIX_NAME_PREFIX = "emacs"
USER_LOCATION = "./users/"

$projects = []
$users = []
$project_id_map = {}
$user_id_map = {}


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

class User
  attr_accessor :id, :keypath
  attr_reader :keys

  def to_s
    "#{@id}"
  end

  def initialize(id)
    @id = id
    @keypath = "#{USER_LOCATION}#{id}"
    refresh_keys
  end

  def add_key_from_string(keystring)
    unless valid_pubkey? keystring
      raise InvalidSSHPubKey, "Public key not valid"
    end
    ks = keystring.split(" ");
    key = SSHKey.new(ks[0][4..6], ks[1], ks[2])

    unless @keys.include? key
      @keys << key
    else
      raise DuplicateSSHPubKey, "Public key is already added to user"
    end
    
    flush
    refresh_keys
    flush_projects_with_user(self)
  end

  def remove_key(key)
    @keys.delete(key)
    flush
    refresh_keys
    flush_projects_with_user(self)
  end

  def refresh_keys
    File.open(@keypath,"r") do |f|
      @keys = 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

  def flush
    File.open(@keypath,"w+") do |key_file|
      @keys.each do |key|
        key_file << "#{key.to_s}\n"
      end
    end
  end
end

def add_user(id)
  user = User.new(id)
  $users << user
  $user_id_map[id] = user
end

def get_user_by_id(id)
  $user_id_map[id]
end

def validate_password
  
end

########################
# Project manipulation #
########################

class Project
  attr_accessor :id, :path, :posixname, :users
  attr_reader :keys

  def initialize
    @users = []
  end
  
  def to_s
    "#{@id}, #{@path}"
  end
  
  def add_key(key)
    @keys << key
  end

  def add_user(user)
    @users << user
    user.keys.each do |key|
      add_key(key)
    end
    flush
    refresh
  end

  def remove_user(user)
    @user.delete(user)
    flush
    refresh
  end

  def refresh
    @users = File.open("#{@path}/.ssh/users","r") do |f|
      f.read.split("\n").map{|id| get_user_by_id(id)}
    end
    @keys = extract_ssh_pubkeys("#{@path}/.ssh/authorized_keys")
  end

  def flush
    File.open("#{@path}/.ssh/users","w+") do |user_file|
      @users.each do |u|
        user_file << "#{u.id}\n"
      end
    end
    
    get_ssh_keyfile(self,"w+") do |key_file|
      @users.each do |user|
        user.keys.each do |key|
          key_file << "#{key.to_s}\n"
        end
      end
    end
  end
  
end

class DuplicateProjectError < StandardError
end

def get_project(id)
  $project_id_map[id]
end

def add_project(project)
  $projects << project
  $project_id_map[project.id] = project
end

def create_project(id)
  $projects.each do |p|
    if p == id then
      raise DuplicateProjectError, "Project with id #{id} already exists"
    end
  end
  
  if not system("useradd -m #{POSIX_NAME_PREFIX}#{id} -s /usr/bin/eshell") then
    raise "Project creation failed"
  end 
  
  project = Project.new
  project.id = id
  project.path = "/home/#{POSIX_NAME_PREFIX}#{id}"
  project.posixname = "#{POSIX_NAME_PREFIX}#{id}"
  $projects << project
  $project_id_map[id] = project

  FileUtils.mkdir "#{project.path}/.ssh"
  FileUtils.touch "#{project.path}/.ssh/authorized_keys"
  FileUtils.touch "#{project.path}/.ssh/users"
  FileUtils.chown_R project.posixname, project.posixname, "#{project.path}/.ssh"
  
  project
end

def remove_project(project)
  system("userdel -r #{project.posixname}")
  $projects.delete(project)
  $project_id_map[id] = nil
end

def project_by_posix_name(posix_name)
  project = Project.new
  project.id = posix_name[POSIX_NAME_PREFIX.length..-1]
  project.path = "/home/#{posix_name}"
  project.posixname = posix_name
  project
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

class InvalidSSHPubKey < StandardError
end

class DuplicateSSHPubKey < StandardError
end

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

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

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


###########
# Project DB #
###########

def reload_projects_from_passwd
  $projects = []
  `cut -d: -f1 /etc/passwd`.split("\n").
    select{|u| u.start_with? POSIX_NAME_PREFIX}.
    map{|u| project_by_posix_name(u)}.
    each{|u| add_project(u)}
  $projects.each{|p| p.refresh}
end

def reload_users_from_dir
  `ls -1 #{USER_LOCATION}`.split("\n").
    map{|u| User.new(u)}.
    each{|u| add_user(u.id)}
end

def flush_all_to_disk
  $users.each {|u| u.flush}
  $projects.each {|p| p.flush}
end
                               
def flush_projects_with_user(user)
  $projects.select{|p| p.users.include? user}.each do |p|
    p.flush
  end
end

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

reload_users_from_dir
reload_projects_from_passwd

#remove_project 5
#create_project 3
#add_ssh_pubkey(get_project(3), "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC7ZKN2fKcUQUaQqDjNCQQBSdqBVGX7lprNCJmceDBfybhbnuZJ8KvzJJIJIIbzqheW5BVCfkWJY6OgkpAumLWSRCS5n2+AnDHwQgpKDS93OeV+9/kattVtsVUBZaghymyJ2UfA0r918dkxcT9SZbNSl9raiDUUmj3JY8UM219BQP7BRqoZ6e/YZz9lO7ORy6yQT6fIMaVOaZcoDPr6oyNJfadm9POvS/Wl63onoRI9dzpHQG9RuHCcUhHJhkGtzY7GeRWc85WqA9Q4vYo0SK5Je9BG1cvAAVTfV+eYEJEiSDMwWj60roH0C3/ipmzxD/kWqg6YBJWL+XAyQkDnmbuD christoffermadsen@strawberry.thedevcave.net")