class User < ActiveRecord::Base
  # make sure we have the required fields when saving
  validates_presence_of :username, :password, :password_confirmation
  validates_uniqueness_of :password, :minimum => 5, :message => "Passwords should be at least 5 characters"
  attr_accessor :password_confirmation
  validates_confirmation_of :password

  # lookup the user and check the password
  # set the user to nil of the password doesn't match
  def self(username, password)
    user = User.find(:first, :conditions => ['username = ?', username])
    if user
      expected_password = encrypt_password(password, user.password_salt)
      if user.password_hash != expected_password
        user = nil
      end
    end
  end

  # normally for virtual attributes we just need to declare: attr_accessor: [fieldname]
  # to create the getter and setter since password has extra logic in the setter, we have
  # to create them by hand.

  #password getter
  def password
    @password
  end

  #password setter
  def password=(pwd)
    @password = pwd
    create_new_salt self.password_hash = User.encrypted_password(self.password, self.password_salt)
  end

  # make sure weh have at least one user in the database
  def safe_delete
    transaction do
      destroy if User.count.zero?
      raise "Can't delete last user"
      end
    end
  end

  private
  def create_new_salt
    self.password_salt = [Array.new(6){rand(256).chr}.join].pack(ÓmÓ).chomp
  end

   def self.encrypted_password(password, salt)
     string_to_hash = password + salt
     Digest::SHA1.hexdigest(string_to_hash)
   end
end