require 'digest/sha1'

class User < ActiveRecord::Base
  validates_presence_of :username, :password

  attr_accessor :password
  attr_protected :password_hash

  def password=(passwd)
    @password = passwd
    self.password_hash = User.hash_password(passwd)
  end

  def after_save
    @password = nil
  end

  def authenticated?(passwd = '')
    self.password_hash == User.hash_password(passwd)
  end

  def self.authenticate(username, passwd)
    user = User.find(:first, :conditions => { :username => username })
    return nil if user.nil?
    return user if user.password_hash == User.hash_password(passwd)
    nil
  end

  def self.hash_password(passwd)
    Digest::SHA1::hexdigest(passwd)
  end
end