class User
  include Dynamoid::Document

  attr_reader :password
  attr_accessor :password_confirmation

  field :username
  field :email_address
  field :password_hash

  field :first_name
  field :last_name

  field :time_zone_utc_offset_minutes, :integer, :default => 0

  field :active, :integer, :default => 0
  field :is_superuser, :integer, :default => 0

  field :can_manage_members, :integer, :default => 0
  field :can_manage_users, :integer, :default => 0

  before_validation :normalize_case
  before_save :validate_email_address

  # validates_uniqueness_of :username, :email_address
  validates_presence_of :first_name, :last_name, :username, :email_address
  validates_presence_of :password, :on => :create
  validates_confirmation_of :password, :on => :save

  def self.list
    where(:active => 1).order([ :last_name, :first_name ])
  end

  def password=(val)
    @password = val
    self.password_hash = self.class.hash_password(val) unless val.blank?
  end

  def validate_email_address
    self.class.valid_email_address?(self.email_address)
  end

  def normalize_case
    self.email_address = self.email_address.downcase rescue nil
  end


  def self.salt_length ; 16 ; end
  def self.salt_chars ; (('a'..'f').to_a).concat(('0'..'9').to_a) ; end

  def self.hash_password(val, salt = '')
    require 'digest/sha1'

    # create the salt if we need to
    if salt.length != salt_length
      salt = ''
      salt_length.times do
        salt << salt_chars[rand(salt_chars.length)]
      end
    end

    # now, let the hashing begin
    digest = Digest::SHA1.new
    digest << salt << val.strip
    salt << digest.hexdigest
  end

  # returns a User or an error code string
  def self.authenticate(username, password)
    test = where(:username => username).first || where(:email_address => username).first
    return 'not found' unless test
    test.reload
    return 'not active' unless test.active == 1 && test.password_hash

    if test.password_hash == hash_password(password, test.password_hash[0,salt_length])
      test
    else
      'invalid password'
    end
  end

  # Determines whether the input string is a valid email address per RFC specification
  def self.valid_email_address?(addr, perform_mx_lookup = false)
    valid = !(addr.to_s =~ /\A([\w\d]+(?:[\w\d\!\#\$\%\&\*\+\-\/\=\?\^\`\{\|\}\~\.]*[\w\d]+)*)@((?:[\w\d]+\.)+[\w]{2,})\z/).nil?
    user, host = $1, $2

    if perform_mx_lookup
      begin
        require 'net/dns/resolver'
        res = Net::DNS::Resolver.new
        valid = valid && res.mx(host).size > 0
      rescue Exception => e
        puts e.to_s
      end
    end

    valid
  end

end